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  • richardmitnick 12:04 pm on February 25, 2019 Permalink | Reply
    Tags: "LS2 report: a technological leap for SPS acceleration", , , CERN LHC, CERN LS2, , , , , The SPS radiofrequency acceleration system is being enhanced with a new technology: solid-state amplifiers   

    From CERN: “LS2 report: a technological leap for SPS acceleration” 

    Cern New Bloc

    Cern New Particle Event

    CERN New Masthead

    From CERN

    25 February, 2019
    Corinne Pralavorio

    The SPS radiofrequency acceleration system is being enhanced with a new technology: solid-state amplifiers.

    CERN LS2 SPS The new solid-state amplifier system developed by CERN with the Thales Gérac company comprises 32 towers, in which 2560 RF modules, each containing four transistors, will be installed. (Image: Maximilien Brice/CERN)

    Big changes are under way at the Super Proton Synchrotron (SPS). One of the major operations is the upgrade of the machine’s acceleration system. “The beams in the High-Luminosity LHC will be twice as intense, which requires an increase in radiofrequency power,” explains Erk Jensen, leader of the Radiofrequency (BE-RF) group. One aspect of the LHC Injectors Upgrade (LIU) project is therefore bringing the SPS acceleration system up to standard.

    Erk Jensen shows us around the huge Building 870, just behind the CERN Control Centre on the Prévessin site, which is a hive of activity. Everywhere you look, teams are pulling out cables, unscrewing components and removing electronic modules. Dismantling is one of the main activities of this first phase of the Long Shutdown. No fewer than 400 km of cables are being removed at Points 3 and 5 of the SPS, for example.

    In the large halls, we can see the huge power converter and amplifier installations that supply the radiofrequency (RF) accelerator cavities of the SPS. The amplifiers use an electronic tube technology dating back to the 1970s and 80s, as the SPS was commissioned in 1976 and transformed into a proton-antiproton collider in 1981. Two tube systems exist alongside each other, each producing 2 megawatts of power.

    To supply the power needed for the High-Luminosity LHC, a team from the RF group, headed by Eric Montesinos, working with the firm Thales Gérac, has developed a new system that uses solid-state amplifiers, similar to those that were recently developed for the SOLEIL and ESRF synchrotrons. The transistors for these amplifiers are assembled in sets of four on modules that supply 2 kilowatts, much less power than was delivered by the electronic tubes (between 35 and 135 kilowatts). But a total of 2560 modules, i.e. 10 240 transistors, will be spread across 32 towers. The power from 16 towers will be combined via an RF power combiner. The whole system will be able to provide RF power of two times 1.6 megawatts to the cavities.

    This system is much more flexible, since the power is distributed across thousands of transistors,” observes Eric Montesinos. “If a few transistors stop working, the RF system will not stop completely, whereas if one of the tubes failed, we had to intervene quickly.” In addition, it’s much easier to change a module, especially since electronic tubes in this frequency range are an endangered species, accelerators being among the last applications of the technology.

    CERN LS2 CPS RF cavities 200 MHz accelerating removed from their tunnel to be upgraded. Image: Maximilien Brice/CERN)

    Development of the solid-state amplifier system began in 2016. A team from the RF group worked in collaboration with scientists from Thales Gérac, and many tests and adjustments had to be carried out. Power electronics are subject to significant thermomechanical effects, so the technique for fitting the transistors onto the plate of the module, to take one example, turned out to be a particularly tricky aspect to get right. After several dozen complex prototypes had been produced, the work finally came to a successful conclusion last year: the first tower housing 80 transistor modules operated for 1000 hours, passing the validation tests in August. This was a great success that allowed series production to begin while the tests continued.

    The structures, i.e. the 32 towers, have already been installed in a new room, giving it the air of a science-fiction movie set. Only one of them so far is equipped with its RF power modules, offering a taste of the even more futuristic look that the room will have in a few months’ time. The modules will be delivered as of May, continuing through to the end of the year; all of them will be tested on a specially designed test bench before being installed in the towers. Some painstaking work faces the teams that will install all the modules.

    In parallel, the cavities have been removed from the tunnel. The SPS has four 200 MHz cavities: two formed of four sections, and two of five sections, each section measuring four metres. “To accelerate more intense beams, we need to reduce the length of the cavities in order to maintain a sufficiently strong electromagnetic field along their whole length,” explains Erk Jensen. The teams will therefore reassemble the sections in order to form a total of six cavities: two of four sections and four of three sections.

    At the same time, the beam control system is being replaced. The Faraday cage, which houses the electronic racks for the beam control system, has been completely emptied, ready to be fitted with the latest electronics and new infrastructure (lighting, cooling and ventilation systems, among others). Finally, an improved system for eliminating parasitic resonances will be installed, based on HOM (higher order mode) couplers, which were tested during the last run.

    The teams must stick to a tight schedule, comprising all the dismantling work, the start of installation later in 2019, and numerous tests and commissioning tasks in 2020.

    See the full article here.


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    Please help promote STEM in your local schools.

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    Meet CERN in a variety of places:

    Quantum Diaries
    QuantumDiaries

    Cern Courier

     
  • richardmitnick 4:37 pm on February 19, 2019 Permalink | Reply
    Tags: , , CERN LHC, Looking for Dak Energy at CERN,   

    From Symmetry: “Taking a collider to the dark energy problem” 

    Symmetry Mag
    From Symmetry

    02/14/19
    Sarah Charley

    1
    Ralf Kaehler, based on a simulation by John Wise and Tom Abel

    Every second, the universe grows a little bigger. Scientists are using the LHC to try to find out why.

    With the warmth of holiday cheer in the air, Nottingham University theoretical physicist Clare Burrage and her colleagues decided to hit the pub after a conference in December 2014 and do what many physicists tend to do after work: keep talking about physics.

    That evening’s topic of conversation: dark energy particles. The chat would lead to a new line of investigation at the Large Hadron Collider at CERN.

    LHC

    CERN map


    CERN LHC Tunnel

    CERN LHC particles

    Dark energy is a catch-all term that scientists coined to describe whatever seems to be pushing the bounds of the universe farther and farther apart. If gravity were the only force choreographing the interstellar ballet of stars and galaxies, then—after the initial grand jeté of all of the matter and energy in the universe during the big bang—every celestial body would slowly chassé back to a central point. But that’s not what’s happening. Instead, the universe continues to drift apart—and it’s happening at an accelerating rate.

    “We really don’t know what’s going on,” says Burrage. “At the moment, there are problems with all of our possible solutions to this problem.”

    Dark Energy Survey


    Dark Energy Camera [DECam], built at FNAL


    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam at an altitude of 7200 feet

    Most experiments studying this mysterious cosmic expansion look at intergalactic movements and precision measurements of the effects of gravity. Dark energy could be a property of spacetime itself, or just a huge misunderstanding of how gravity works on a cosmic scale.

    But many theorists suspect that dark energy is a new type of force or field—something that changes how gravity works. And if this is true, then scientists might be able to put just the right amount of energy into that field to pop out a particle, a particle that could potentially show up in a detector at the LHC. This is the way scientists discovered the Higgs field, by interacting with it in just the right way for it to produce a Higgs boson.

    CERN CMS Higgs Event


    CERN ATLAS Higgs Event

    “Cosmologists know that there is new physics we don’t understand, and all the evidence is pointing towards something very fundamental about our universe,” Burrage says. “The experiments on the LHC are also very interested in the fundamentals.”

    The ATLAS and CMS experiments, the big general-purpose experiments at the LHC, search for new fundamental forces and properties of nature by recording what happens when the LHC smashes together protons at just under the speed of light.

    CERN/ATLAS detector


    The giant detectors surround the collision points and map the energy and matter released from the collisions, giving scientists a unique view of the clandestine threads that weave together to build everything in the universe.

    The theory Burrage and her colleagues were poring over at the pub predicted that if dark energy is a new type of field, it might produce light particles with strong and specific interactions with matter. “The main focus of LHC has been heavy particles, so we had to go back and re-interpret the data to look for something light,” she says.

    Burrage worked with Philippe Brax of Université Paris-Saclay and Christophe Englert of the University of Glasgow to check publicly available data from the first run of the world’s most powerful collider for signs of a lightweight dark energy particles. They quickly determined that the signs they were looking for had not appeared.

    With this simple model easily eliminated, they decided to take on another idea with a more cryptic signature. They knew that more complex analyses would require the expertise of an experimentalist. So in April 2016, along with Michael Spannowsky of Durham University in the UK, they published a new hypothesis in the scientific journal Physical Review Letters—and waited.

    They found their experimentalist in Spyros Argyropoulos, a postdoc at the University of Iowa working on the ATLAS experiment, who read their article.

    “The idea of testing dark energy was intriguing,” Argyropoulos says. “It’s not something we typically look for at the LHC, and making progress on this problem is a win-win for both cosmologist and particle physicist.”

    Argyropoulos reached out to Burrage and her colleagues to define the parameters, and then he and a group of ATLAS scientists went to the data.

    According to this new theory, dark energy particles should radiate off of energetic top quarks and show up in the detector as missing energy. Argyropoulos and his colleagues went through ATLAS analyses of top quarks and, in a separate search, looked at certain other collisions to see if any of them showed the signatures they were looking for. They did not.

    While this might seem like a disappointing result, Argyropoulos assures that it’s anything but. “Physics isn’t just about finding the right answer,” he says. “It’s also about narrowing down all the possibilities.”

    Burrage agrees: “Eliminating an idea with experimental data is a positive thing, even if it means our pet theory gets killed in the process. Theorists can always come up with more ideas, and it’s good for the field to have the spectrum of possibilities narrowed down.”

    The landscape of dark energy theories is enormous. Burrage’s specialty is scouring that landscape, searching for theories that can be tested, and then proposing ways to test them.

    “Ten years ago, nobody was thinking that collider physics could put constraints on dark energy searches,” she says. “Theories have to pass all relevant experimental tests, and it’s looking like surviving the Large Hadron Collider is going to be an important one to our field.”

    See the full article here .


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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 7:09 pm on February 13, 2019 Permalink | Reply
    Tags: A key link in CERN’s accelerator complex, A new set of quadrupole magnets will be installed along the Booster-to-PS injection line, , Also delivering particles to several experimental areas such as the Antiproton Decelerator (AD), , CERN LHC, CERN Proton Synchrotron, , It takes ten hours to extract one magnet, , Mainly accelerating protons to 26 GeV before sending them to the Super Proton Synchrotron (SPS), New cooling systems are being installed to increase the cooling capacity of the PS, One major component of the PS that will be consolidated is the magnet system, One of the elements known as the pole-face windings which is located between the beam pipe and the magnet yoke needs replacing, , PS will undergo a major overhaul to prepare it for the higher injection and beam intensities of the LHC’s Run 3 as well as for the High-Luminosity LHC   

    From CERN- “LS2 report: The Proton Synchrotron’s magnets prepare for higher energies” 

    Cern New Bloc

    Cern New Particle Event

    CERN New Masthead

    From CERN

    13 February, 2019
    Achintya Rao

    CERN Proton Synchrotron

    1
    One of the magnets being driven on a locomotive to the workshop (right) after being extracted from the PS itself (left) (Image: Julien Marius Ordan/Maximilien Brice/CERN)

    The Proton Synchrotron (PS), which was CERN’s first synchrotron and which turns 60 this year, once held the record for the particle accelerator with the highest energy. Today, it forms a key link in CERN’s accelerator complex, mainly accelerating protons to 26 GeV before sending them to the Super Proton Synchrotron (SPS), but also delivering particles to several experimental areas such as the Antiproton Decelerator (AD). Over the course of Long Shutdown 2 (LS2), the PS will undergo a major overhaul to prepare it for the higher injection and beam intensities of the LHC’s Run 3 as well as for the High-Luminosity LHC.

    One major component of the PS that will be consolidated is the magnet system [Many magnets will come from Fermilab and Brookhaven Lab, two US D.O.E. labs]. The synchrotron has a total of 100 main magnets within it (plus one reference magnet unit outside the ring), which bend and focus the particle beams as they whizz around it gaining energy. “During the last long shutdown (LS1) and at the beginning of LS2, the TE-MSC team performed various tests to identify weak points in the magnets,” explains Fernando Pedrosa, who is coordinating the LS2 work on the PS. The team identified 50 magnets needing refurbishment, of which seven were repaired during LS1 itself. “The remaining 43 magnets that need attention will be refurbished this year.”

    Specifically, one of the elements, known as the pole-face windings, which is located between the beam pipe and the magnet yoke, needs replacing. In order to reach into the magnet innards to replace these elements, the magnet units have to be transferred to a workshop in building 151. Once disconnected, each magnet is placed onto a small locomotive system that drives them to the workshops. The locomotives themselves are over 50 years old, and their movement must be delicately managed. It takes ten hours to extract one magnet. So far, six magnets have been taken to the workshop and this work will last until 18 October 2019.

    The workshop where the magnets are being treated is divided into two sections. In the first room, the vacuum chamber of the magnets is cut so as to access the pole-face windings. The magnet units are then taken to the second room, where prefabricated replacements are installed.

    As mentioned in the previous LS2 Report, the PS Booster will see an increase in the energy it imparts to accelerating protons, from 1.4 GeV to 2 GeV. A new set of quadrupole magnets will be installed along the Booster-to-PS injection line, to increase the focusing strength required for the higher-energy beams. Higher-energy beams require higher-energy injection elements; therefore some elements will be replaced in the PS injection region as part of the LHC Injectors Upgrade (LIU) project, namely septum 42, kicker 45 and five bumper magnets.

    Other improvements as part of the LIU project include the new cooling systems being installed to increase the cooling capacity of the PS. A new cooling station is being built at building 355, while one cooling tower in building 255 is being upgraded. The TT2 line, which is involved in the transfer from the PS to the SPS, will have its cooling system decoupled from the Booster’s, to allow the PS to operate independent of the Booster schedule. “The internal dumps of the PS, which are used in case the beam needs to be stopped, are also being changed, as are some other intercepting devices,” explains Pedrosa.

    The LS2 operations are on a tight schedule,” notes Pedrosa, pointing out that works being performed on several interconnected systems create constraints for what can be done concurrently. As LS2 proceeds, we will bring you more news about the PS, including the installation of new instrumentation in wire scanners that help with beam-size measurement, an upgraded transverse-feedback system to stabilise the beam and more.

    See the full article here.


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    Please help promote STEM in your local schools.

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    Meet CERN in a variety of places:

    Quantum Diaries
    QuantumDiaries

    Cern Courier

    THE FOUR MAJOR PROJECT COLLABORATIONS

    ATLAS
    CERN ATLAS New
    ALICE

    CERN/ALICE Detector


    CMS
    CERN CMS New

    LHCb
    CERN LHCb New II

    LHC

    CERN map

    CERN LHC Grand Tunnel

    CERN LHC particles

     
  • richardmitnick 3:51 pm on February 5, 2019 Permalink | Reply
    Tags: , , CERN LHC, , , , Particle Physics Is Doing Just Fine, ,   

    From slate.com: “Particle Physics Is Doing Just Fine” 

    SLATE

    From slate.com

    Jan 31, 2019
    Chanda Prescod-Weinstein
    Tim M.P. Tait


    CERN/ALICE Detector

    Research is a search through the unknown. If you knew the answer, there would be no need to do the research, and until you do the research, you don’t know the answer. Science is a complex social phenomenon, but certainly its history includes repeated episodes of people having ideas, trying experiments to test those ideas, and using the results to inform the next round of ideas. When an experimental result indicates that one particular idea is not correct, this is neither a failure of the experiment nor of the original idea itself; it’s an advancement of our understanding of the world around us.

    Recently, particle physics has become the target of a strange line of scientific criticism. Articles like Sabine Hossenfelder’s New York Times op-ed questioning the “uncertain future” of particle physics and Vox’s “The $22 Billion Gamble: Why Some Physicists Aren’t Excited About Building a Bigger Particle Collider” raise the specter of failed scientists. To read these articles, you’d think that unless particle physics comes home with a golden ticket in the form of a new particle, it shouldn’t come home at all. Or at least, it shouldn’t get a new shot at exploring the universe’s subatomic terrain. But the proposal that particle physicists are essentially setting money on fire comes with an insidious underlying message: that science is about the glory of discovery, rather than the joy of learning about the world. Finding out that there are no particles where we had hoped tells us about the distance between human imagination and the real world. It can operate as a motivation to expand our vision of what the real world is like at scales that are totally unintuitive. Not finding something is just as informative as finding something.

    That’s not to say resources should be infinite or to suggest that community consensus isn’t important. To the contrary, the particle physics community, like the astronomy and planetary science communities, takes the conversation about what our priorities should be so seriously that we have it every half decade or so. Right now, the European particle physics community is in the middle of a “strategy update,” and plans are underway for the U.S. particle physics community to hold the next of its “Snowmass community studies,” which take place approximately every five years. These events are opportunities to take stock of recent developments and to devise a strategy to maximize scientific progress in the field. In fact, we’d wager that they’re exactly what Hossenfelder is asking for when she suggests “it’s time for particle physicists to step back and reflect on the state of the field.”

    One of the interesting questions that both of these studies will confront is whether or not the field should prioritize construction of a new high-energy particle accelerator. In past decades, many resources have been directed toward the construction and operation of the Large Hadron Collider, a gigantic device whose tunnel spans two countries and whose budget is in the billions of dollars. Given funding constraints, it is entirely appropriate to ask whether it makes sense to prioritize a future particle accelerator at this moment in history. A new collider is likely to have a price tag measured in tens of billions of dollars and would represent a large investment—though not large compared with the scale of other areas of government spending, and the collider looks even less expensive when spread out over decades and shared by many nations.

    The LHC was designed to reach energies of 14 trillion electron volts, about seven times more than its predecessor, the Tevatron at Fermilab in Chicagoland.

    LHC

    CERN map


    CERN LHC Tunnel

    CERN LHC particles

    FNAL/Tevatron map

    FNAL/Tevatron

    There was very strong motivation to explore collisions at these energies; up until the LHC began operations, our understanding of the Standard Model of particle physics, the leading theory describing subatomic particles and their interactions, contained a gaping hole.

    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    The theory could only consistently describe the massive fundamental particles that are observed in our experiments if one included the Higgs boson—a particle that had yet to be observed.

    Self-consistency demanded that either the Higgs or something else providing masses would appear at the energies studied by the LHC. There were a host of competing theories, and only experimental data could hope to judge which one was realized in nature.

    So we tried it. And because the LHC allowed us to actually observe the Higgs, we now know that the picture in which masses arise from the Higgs is either correct or very close to being correct.

    Peter Higgs

    CERN CMS Higgs Event

    CERN ATLAS Higgs Event

    The LHC discovered a particle whose interactions with the known particles matches the predictions to within about 10 percent or so. This represents a triumph in our understanding of the fundamental building blocks of nature, one that would have been impossible without both 1) the theoretical projections that defined the characteristics that the Higgs must have to play its role and 2) the experimental design of the accelerator and particle detectors and the analysis of the data that they collected. In order to learn nature’s secrets, theory and experiment must come together.

    [I.E., you must do the math.]

    Some people have labeled the LHC a failure because even though it confirmed the Standard Model’s vision for how particles get their masses, it did not offer any concrete hint of any further new particles besides the Higgs. We understand the disappointment. Given the exciting new possibilities opened up by exploring energy levels we’ve never been privy to here on earth, this feeling is easy to relate to. But it is also selling the accomplishments short and fails to appreciate how research works. Theorists come up with fantastical ideas about what could be. Most of them are wrong, because the laws of physics are unchanging and universal. Experimentalists are taking on the task of actually popping open the hood and looking at what’s underneath it all. Sometimes, they may not find anything new.

    A curious species, we are left to ask more questions. Why did we find this and not that? What should we look for next? What a strange and fascinating universe we live in, and how wonderful to have the opportunity to learn about it.

    It cannot be ignored that if the U.S. had built the Superconducting Super Collider a particle accelerator complex under construction in the vicinity of Waxahachie, Texas, Higgs would have been found in the U.S. and High Energy Physics would not have been ceded to Europe.

    3
    Tracing the path of the particle accelerators and tunnels planned for the Superconducting Supercollider Project. You can see the main ring circling Waxahachie.

    The Superconducting Super Collider planned ring circumference was 87.1 kilometers (54.1 mi) with an energy of 20 TeV per proton and was set to be the world’s largest and most energetic. It would have greatly surpassed the current record held by the Large Hadron Collider which has ring circumference 27 km (17 mi) and energy of 13 TeV per proton. The project’s director was Roy Schwitters, a physicist at the University of Texas at Austin. Dr. Louis Ianniello served as its first Project Director for 15 months. The project was cancelled in 1993 due to budget problems [Congress cancelled the Collider for having “no immediate econmic value].

    See the full article here .
    See also the possible future of HEP here .

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    Please help promote STEM in your local schools.

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    Slate is a daily magazine on the Web. Founded in 1996, we are a general-interest publication offering analysis and commentary about politics, news, business, technology, and culture. Slate’s strong editorial voice and witty take on current events have been recognized with numerous awards, including the National Magazine Award for General Excellence Online. The site, which is owned by Graham Holdings Company, does not charge for access and is supported by advertising revenues.

     
  • richardmitnick 1:15 pm on January 25, 2019 Permalink | Reply
    Tags: , CERN LHC, , , , , , , Wish list of particle colliders   

    From The New York Times- “Opinion: The Uncertain Future of Particle Physics” 

    New York Times

    From The New York Times

    Jan. 23, 2019
    Sabine Hossenfelder

    Ten years in, the Large Hadron Collider has failed to deliver the exciting discoveries that scientists promised.

    LHC

    CERN map


    CERN LHC Tunnel

    CERN LHC particles

    THE FOUR MAJOR PROJECT COLLABORATIONS

    ATLAS
    CERN ATLAS New

    ALICE

    CERN/ALICE Detector


    CMS
    CERN CMS New

    LHCb
    CERN LHCb New II

    The Large Hadron Collider is the world’s largest particle accelerator. It’s a 16-mile-long underground ring, located at CERN in Geneva, in which protons collide at almost the speed of light. With a $5 billion price tag and a $1 billion annual operation cost, the L.H.C. is the most expensive instrument ever built — and that’s even though it reuses the tunnel of an earlier collider.

    CERN Large Electron Positron Collider

    The L.H.C. has collected data since September 2008. Last month, the second experimental run completed, and the collider will be shut down for the next two years for scheduled upgrades. With the L.H.C. on hiatus, particle physicists are already making plans to build an even larger collider. Last week, CERN unveiled plans to build an accelerator that is larger and far more powerful than the L.H.C. — and would cost over $10 billion.

    CERN FCC Future Circular Collider map

    I used to be a particle physicist. For my Ph.D. thesis, I did L.H.C. predictions, and while I have stopped working in the field, I still believe that slamming particles into one another is the most promising route to understanding what matter is made of and how it holds together. But $10 billion is a hefty price tag. And I’m not sure it’s worth it.

    In 2012, experiments at the L.H.C. confirmed the discovery of the Higgs boson — a prediction that dates back to the 1960s — and it remains the only discovery made at the L.H.C.

    Peter Higgs

    CERN CMS Higgs Event

    CERN ATLAS Higgs Event

    Particle physicists are quick to emphasize that they have learned other things: For example, they now have better knowledge about the structure of the proton, and they’ve seen new (albeit unstable) composite particles. But let’s be honest: It’s disappointing.

    Before the L.H.C. started operation, particle physicists had more exciting predictions than that. They thought that other new particles would also appear near the energy at which the Higgs boson could be produced. They also thought that the L.H.C. would see evidence for new dimensions of space. They further hoped that this mammoth collider would deliver clues about the nature of dark matter (which astrophysicists think constitutes 85 percent of the matter in the universe) or about a unified force.

    The stories about new particles, dark matter and additional dimensions were repeated in countless media outlets from before the launch of the L.H.C. until a few years ago. What happened to those predictions? The simple answer is this: Those predictions were wrong — that much is now clear.

    The trouble is, a “prediction” in particle physics is today little more than guesswork. (In case you were wondering, yes, that’s exactly why I left the field.) In the past 30 years, particle physicists have produced thousands of theories whose mathematics they can design to “predict” pretty much anything. For example, in 2015 when a statistical fluctuation in the L.H.C. data looked like it might be a new particle, physicists produced more than 500 papers in eight months to explain what later turned out to be merely noise. The same has happened many other times for similar fluctuations, demonstrating how worthless those predictions are.

    To date, particle physicists have no reliable prediction that there should be anything new to find until about 15 orders of magnitude above the currently accessible energies. And the only reliable prediction they had for the L.H.C. was that of the Higgs boson. Unfortunately, particle physicists have not been very forthcoming with this information. Last year, Nigel Lockyer, the director of Fermilab, told the BBC, “From a simple calculation of the Higgs’ mass, there has to be new science.” This “simple calculation” is what predicted that the L.H.C. should already have seen new science.

    I recently came across a promotional video for the Future Circular Collider that physicists have proposed to build at CERN. This video, which is hosted on the CERN website, advertises the planned machine as a test for dark matter and as a probe for the origin of the universe. It is extremely misleading: Yes, it is possible that a new collider finds a particle that makes up dark matter, but there is no particular reason to think it will. And such a machine will not tell us anything about the origin of the universe. Paola Catapano, head of audiovisual productions at CERN, informed me that this video “is obviously addressed to politicians and not fellow physicists and uses the same arguments as those used to promote the L.H.C. in the ’90s.”

    But big science experiments are investments in our future. Decisions about what to fund should be based on facts, not on shiny advertising. For this, we need to know when a prediction is just a guess. And if particle physicists have only guesses, maybe we should wait until they have better reasons for why a larger collider might find something new.

    It is correct that some technological developments, like strong magnets, benefit from these particle colliders and that particle physics positively contributes to scientific education in general. These are worthy investments, but if that’s what you want to spend money on, you don’t also need to dig a tunnel.

    And there are other avenues to pursue. For example, the astrophysical observations pointing toward dark matter should be explored further; better understanding those observations would help us make more reliable predictions about whether a larger collider can produce the dark matter particle — if it even is a particle.

    There are also medium-scale experiments that tend to fall off the table because giant projects eat up money. One important medium-scale project is the interface between the quantum realm and gravity, which is now accessible to experimental testing. Another place where discoveries could be waiting is in the foundations of quantum mechanics. These could have major technological impacts.

    Now that the L.H.C. is being upgraded and particle physics experiments at the detector are taking a break, it’s time for particle physicists to step back and reflect on the state of the field. It’s time for them to ask why none of the exciting predictions they promised have resulted in discoveries. Money will not solve this problem. And neither will a larger particle collider.

    See the full article here .

    See also From Science News: “Physicists aim to outdo the LHC with this wish list of particle colliders

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

     
  • richardmitnick 10:45 am on January 22, 2019 Permalink | Reply
    Tags: , CERN Compact Linear Collider, CERN LHC, China-Circular Electron Positron Collider, Future colliders, , , International Linear Collider in northern Japan, , ,   

    From Science News: “Physicists aim to outdo the LHC with this wish list of particle colliders” 

    From Science News

    THIS HAS BECOME A HOT TOPIC AD THERE WILL BE MANY IMPORTANT ARTICLES BASED UPON NEEDS AND COSTS

    January 22, 2019
    Emily Conover

    CERN Future Circular Collider artist’s rendering

    If built, the accelerators could pump out oodles of Higgs bosons.

    If particle physicists get their way, new accelerators could one day scrutinize the most tantalizing subatomic particle in physics — the Higgs boson.

    CERN CMS Higgs Event

    CERN ATLAS Higgs Event

    Six years after the particle’s discovery at the Large Hadron Collider, scientists are planning enormous new machines that would stretch for tens of kilometers across Europe, Japan or China.

    The 2012 discovery of the subatomic particle, which reveals the origins of mass, put the finishing touch on the standard model, the overarching theory of particle physics (SN: 7/28/12, p. 5).

    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    And it was a landmark achievement for the LHC, currently the world’s biggest accelerator.

    LHC

    CERN map


    CERN LHC Tunnel

    CERN LHC particles

    Now, physicists want to delve further into the mysteries of the Higgs boson in the hope that it could be key to solving lingering puzzles of particle physics. “The Higgs is a very special particle,” says physicist Yifang Wang, director of the Institute of High Energy Physics in Beijing. “We believe the Higgs is the window to the future.”

    But the LHC — which consists of a ring 27 kilometers in circumference, inside which protons are accelerated to nearly the speed of light and smashed together a billion times a second — can take scientists only so far. That accelerator was great for discovering the Higgs, but not ideal for studying it in detail.

    So particle physicists are clamoring for a new particle collider, specifically designed to crank out oodles of Higgs bosons. Several blueprints for powerful new machines have been put forth, and researchers are hopeful these “Higgs factories” could help reveal solutions to glaring weak spots in the standard model.

    “The standard model is not a complete theory of the universe,” says experimental particle physicist Halina Abramowicz of Tel Aviv University. For example, the theory can’t explain dark matter, an unidentified substance whose mass is necessary to account for cosmic observations such as the motions of stars in galaxies. Nor can it explain why the universe is made up of matter, while antimatter is exceedingly rare.

    Carefully scrutinizing the Higgs boson might point scientists in the direction of solutions to those puzzles, proponents of the new colliders claim. But, among scientists, the desire for new, costly accelerators is not universal, especially since it’s unclear what exactly the machines might find.

    Next in line

    Closest to inception is the International Linear Collider in northern Japan. Unlike the LHC, in which particles zip around a ring, the ILC would accelerate two beams of particles along a straight line, directly at one another over its 20-kilometer length. And instead of crashing protons together, it would collide electrons and their antimatter partners, positrons.

    But, in an ominous sign, a multidisciplinary committee of the Science Council of Japan came down against the project in a December 2018 report, urging the government to be cautious with its support and questioning whether the expected scientific achievements justified the accelerator’s cost, currently estimated at around $5 billion.

    Supporters argue that the ILC’s plan to smash together electrons and positrons, rather than protons, has some big advantages. Electrons and positrons are elementary particles, meaning they have no smaller constituents, while protons are made up of smaller particles called quarks. That means that proton collisions are messier, with more useless particle debris to sift through.

    ILC


    THIN LINE An accelerator planned for Japan, the International Linear Collider (design illustrated), would slam together electrons and positrons to better understand the Higgs boson.

    Additionally, in proton smashups, only a fraction of each proton’s energy actually goes into the collision, whereas in electron-positron colliders, particles bring the full brunt of the accelerator’s energy to bear. That means scientists can tune the energy of collisions to maximize the number of Higgs bosons produced. At the same time, the ILC would require only 250 billion electron volts to produce Higgs bosons, compared with the LHC’s 13 trillion electron volts.

    For the ILC, “the quality of the data coming out will be much higher, and there will be much more of it on the Higgs,” says particle physicist Lyn Evans of CERN in Geneva. One in every 100 ILC collisions would pump out a Higgs, whereas that happens only once in 10 billion collisions at the LHC.

    The Japanese government is expected to decide about the collider in March. If the ILC is approved, it should take about 12 years to build, Evans says. The accelerator could also be upgraded later to increase the energy it can reach.

    CERN has plans for a similar machine known as the Compact Linear Collider.

    Cern Compact Linear Collider

    It would also collide electrons and positrons, but at higher energies than the ILC. Its energy would start at 380 billion electron volts and increase to 3 trillion electron volts in a series of upgrades. But to reach those higher energies, new particle acceleration technology needs to be developed, meaning that CLIC is even further in the future than the ILC, says Evans, who leads a collaboration of researchers from both projects.

    Running in circles

    Two other planned colliders, in China and Europe, would be circular like the LHC, but would dwarf that already giant machine; both would be 100 kilometers around. That’s a circle big enough that the country of Liechtenstein could easily fit inside — twice.

    At a location yet to be determined in China, the Circular Electron Positron Collider, or CEPC, would collide electrons and positrons at 240 billion electron volts, according to a conceptual plan officially released in November and championed by Wang and the Institute of High Energy Physics.

    China Circular Electron-Positron collider depiction


    China Circular Electron Positron Collider (CEPC) map

    The accelerator could later be upgraded to collide protons at higher energies. Scientists say they could begin constructing the $5 billion to 6 billion machine by 2022 and have it ready to go by 2030.

    And at CERN, the proposed Future Circular Collider, or FCC, would likewise operate in stages, colliding electrons and positrons before moving on to protons. The ultimate goal would be to reach proton collisions with 100 trillion electron volts, more than seven times the LHC’s energy, according to a Jan. 15 report from an international group of researchers.

    FCC Future Circular Collider at CERN

    Meanwhile, scientists have shut down the LHC for two years, while they upgrade the machine to function at a slightly higher energy (SN Online: 12/3/18). Further down the line, a souped-up version known as the High-Luminosity LHC could come online in 2026 and would increase the proton collision rate by at least a factor of five (SN Online: 6/15/18).

    Portrait of the Higgs

    When the LHC was built, scientists were fairly confident they’d find the Higgs boson with it. But with the new facilities, there’s no promise of new particles. Instead, the machines will aim to catalog how strongly the Higgs interacts with other known particles; in physicist lingo, these are known as its “couplings.”

    Measurements of the Higgs’ couplings may simply confirm expectations of the standard model. But if the observations differ from expectations, the discrepancy could indirectly hint at the presence of something new, such as the particles that make up dark matter.

    Some scientists are hopeful that something unexpected might arise. That’s because the Higgs is an enigma: The particles condense into a kind of molasses-like fluid. “Why does this fluid do that? We have no clue,” says theoretical particle physicist Michael Peskin of Stanford University. That fluid pervades the universe, slowing particles down and giving them heft.

    Another puzzle is that the Higgs’ mass is a million billion times smaller than expected (SN Online: 10/22/13). Certain numbers in the standard model must be fine-tuned to extreme precision make the Higgs less hefty, a situation physicists find unnatural.

    The weirdness of the Higgs suggests other particles might be out there. Scientists previously thought they had an answer to the Higgs quandaries, via a theory called supersymmetry, which posits that each known particle has a heavier partner (SN: 10/1/16, p. 12). “Before the LHC started, there were huge expectations,” says Abramowicz: Some scientists claimed the LHC would quickly find supersymmetric particles. “Well, it didn’t happen,” she says.

    The upcoming colliders may yet find evidence of supersymmetry, or otherwise hint at new particles, but this time around, scientists aren’t making promises.

    4
    BIG SMASH In the new accelerators, collisions would produce showers of exotic particles (illustrated), including the Higgs boson, which explains how particles get mass.

    “In the past, some people have clearly oversold what the LHC was expected to deliver,” says theoretical particle physicist Juan Rojo of Vrije University Amsterdam. When it comes to any new colliders, “we should avoid making the same mistake if we want to keep our field alive for decades to come,” he says.

    Researchers around the world are now hashing out priorities, making arguments for the new colliders and other particle physics experiments. European physicists, for example, will meet in May to discuss options, working toward a document called the European Particle Physics Strategy Update, to guide research there in 2020 and beyond.

    One thing is certain: The proposed accelerators would explore unknown territory, with unpredictable results. The unanswered questions surrounding the Higgs boson make it the most obvious place to look for hints of new physics, Peskin says. “It’s the place that we haven’t looked yet, so it’s really compelling.”

    Citations

    CERN. Future Circular Collider Conceptual Design Report. Published online January 15, 2018.

    European Particle Physics. Strategy Update 2018–2020.

    Linear Collider Collaboration. Executive Summary of the Science Council of Japan’s Report. LC Newsline. Published online December 21, 2018.

    The Institute of High Energy Physics of the Chinese Academy of Sciences. CEPC Conceptual Design Report Volume I – Accelerator. November 14, 2018.

    The Institute of High Energy Physics of the Chinese Academy of Sciences. CEPC Conceptual Design Report Volume II – Physics & Detector. November 14, 2018.

    See the full article here .


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  • richardmitnick 11:06 am on December 25, 2018 Permalink | Reply
    Tags: , , CERN LHC, , , , , ,   

    From The New York Times: “It’s Intermission for the Large Hadron Collider” 

    New York Times

    From The New York Times

    This is a special Augmented reality production of the NYT. Please view the original full article to take advantage of the 360 degree images inside the LHC.

    DEC. 21, 2018
    Dennis Overbye

    The largest machine ever built is shutting down for two years of upgrades. Take an immersive tour of the collider and study the remnants of a Higgs particle in augmented reality.

    4

    CERN Control Center

    MEYRIN, Switzerland — There is silence on the subatomic firing range.

    A quarter-century ago, the physicists of CERN, the European Center for Nuclear Research, bet their careers and their political capital on the biggest and most expensive science experiment ever built, the Large Hadron Collider.

    LHC

    CERN map


    CERN LHC Tunnel

    CERN LHC particles

    THE FOUR MAJOR PROJECT COLLABORATIONS

    ATLAS
    CERN ATLAS New

    ALICE

    CERN/ALICE Detector

    CMS
    CERN CMS New

    LHCb
    CERN LHCb New II

    The collider is a kind of microscope that works by flinging subatomic particles around a 17-mile electromagnetic racetrack beneath the French-Swiss countryside, smashing them together 600 million times a second and sifting through the debris for new particles and forces of nature. The instrument is also a time machine, providing a glimpse of the physics that prevailed in the early moments of the universe and laid the foundation for the cosmos as we see it today.

    The reward came in 2012 with the discovery of the Higgs boson, a long-sought particle that helps explain why there is mass, diversity and life in the cosmos.

    CERN CMS Higgs Event

    CERN ATLAS Higgs Event

    The discovery was celebrated with champagne and a Nobel prize.

    The collider will continue smashing particles and expectations for another 20 years. But first, an intermission. On December 3rd, the particle beams stopped humming. The giant magnets that guide the whizzing protons sighed and released their grip. The underground detectors that ring the tunnel stood down from their watch.

    Over the next two years, during the first of what will be a series of shutdowns, engineers will upgrade the collider to make its beams more intense and its instruments more sensitive and discerning. And theoretical physicists will pause to make sense of the tantalizing, bewildering mysteries that the Large Hadron Collider has generated so far.

    When protons collide

    The collider gets its mojo from Einstein’s dictum that mass and energy are the same. The more energy that the collider can produce, the more massive are the particles created by the collisions. With every increase in the energy of their collider, CERN physicists are able to edge farther and farther back in time, closer to the physics of the Big Bang, when the universe was much hotter than today.

    Inside CERN’s subterranean ring, some 10,000 superconducting electromagnets, powered by a small city’s worth of electricity, guide two beams of protons in opposite directions around the tunnel at 99.99999 percent of the speed of light, or an energy of 7 trillion electron volts. Those protons make the 17-mile circuit 11,000 times a second. (In physics, mass and energy are both expressed in terms of units called electron volts. A single proton, the building block of ordinary atoms, weighs about a billion electron volts.)

    The protons enter the collider as atoms in a puff of hydrogen gas squirted from a bottle. As the atoms travel, electrical fields strip them of electrons, leaving bare, positively charged protons. These are sped up by a series of increasingly larger and more energetic electromagnets, until they are ready to enter the main ring of the collider.

    When protons finally enter the main ring, they have been boosted into flying bombs of primordial energy, primed to smash apart — and recombine — when they strike their opposite numbers head-on, coming from the other direction.

    The protons circulate inside vacuum pipes – one running clockwise, the other counterclockwise – and these are surrounded by superconducting electromagnets strung together around the tunnel like sausages. To generate enough force to bend the speeding protons, the magnets must be uncommonly strong: 8.3 Tesla, or more than a hundred thousand times stronger than Earth’s magnetic field — and more than strong enough to wreck a fancy Swiss watch.

    Such a field in turn requires an electrical current of 12,000 amperes. That’s only feasible if the magnets are superconducting, meaning that electricity flows without expensive resistance. For that to happen, the magnets must be supercold; they are bathed in 150 tons of superfluid helium at a temperature of 1.9 Kelvin, making the Large Hadron Collider literally one of the coldest places in the universe.

    If things go wrong down here, they can go very wrong. In 2008, as the collider was still being tuned up, the link between a pair of magnets exploded, delaying operations for almost two years.

    The energy stored in the magnetic fields is equivalent to a fully loaded jumbo jet going 500 miles per hour; if a magnet loses its cool and heats up, all that energy must go someplace. And the proton beam itself can cut through many feet of steel.

    A tale of four detectors

    The beams cross at four points around the racetrack.

    At each juncture, gigantic detectors — underground mountains of electronics, cables, computers, pipes, magnets and even more magnets — have been erected. The two biggest and most expensive experiments, CMS (the Compact Muon Solenoid) and Atlas (A Toroidal L.H.C. Apparatus) sit, respectively, at the noon and 6 o’clock positions of the circular track.

    Wrapped around them, like the layers of an onion, are instruments designed to measure every last spark of energy or matter that might spew from the collision. Silicon detectors track the paths of lightweight, charged particles such as electrons. Scintillation crystals capture the energies of gamma rays. Chambers of electrified gas track more far-flung particles. And powerful magnets bend the paths of these particles so that their charges and masses can be determined.

    The proton beams cross 40 million times per second in each of the four detectors, resulting in about a billion actual collisions every second.

    What’s the antimatter?

    Why is there something instead of nothing in the universe?

    Answering that question is the mission of the detector known as LHCb, which sits at about 4 o’clock on the collider dial. The “b” stands for beauty — and for the B meson, a subatomic particle that is crucial to the experiment.

    When matter is created — in a collider, in the Big Bang — equal amounts of matter and its opposite, antimatter, should be formed, according to the laws of physics As We Know Them. When matter and antimatter meet, they annihilate each other, producing energy.

    By that logic, when matter and antimatter formed in the Big Bang, they should have cancelled out each other, leaving behind an empty universe. But it’s not empty: We are here, and our antimatter is not.

    Why not? Physicists suspect that some subtle imbalance between matter and antimatter is responsible. The LHCb experiment looks for that imbalance in the behavior of B mesons, which are often sprayed from the proton collisions.

    B mesons have an exotic property: They flicker back and forth between being matter and antimatter. Sensors record their passage through the LHCb room, seeking differences between the particles and their antimatter twins. Any discrepancy between the two could be a clue to why matter flourished billions of years ago and antimatter perished.

    Turning back the cosmic clock

    At about 8 o’clock on the collider dial is Alice, another detector with a special purpose. It, too, is fixed on the distant past: the brief moment a couple of microseconds after the Big Bang, before the first protons and neutrons congealed out of a “primordial soup” of quarks and gluons.

    Alice’s job is to study tiny droplets of that distant past that are created when the collider bangs together lead ions instead of protons. Researchers expected this material, known in the lingo as a quark-gluon plasma, to behave like a gas, but it turns out to behave more like a liquid.

    Sifting the data

    The collider’s enormous detectors are like 100 megapixel cameras that take 40 million pictures a second. Most of the data from that deluge is immediately thrown away. Triggers, programmed to pick out events that physicists thought might be interesting, save only about a thousand collision events per second. Even still, an enormous pool of data winds up in the CERN computer banks.

    CERN DATA Center

    According to the casino rules of modern quantum physics, anything that can happen will happen eventually. Before a single proton is fired through the collider, computers have calculated all the possible outcomes of a collision according to known physics. Any unexpected bump in the real data at some energy could be a signal of unknown physics, a new particle.

    That was how the Higgs was discovered, emerging from the statistical noise in the autumn of 2011. Only one of every 10 billion collisions creates a Higgs boson. The Higgs vanishes instantly and can’t be observed directly, but it decays into fragments that can be measured and identified.

    What eventually stood out from the data was evidence for a particle that weighs all by itself as much as an iodine atom: a flake of an invisible force field that permeates space like molasses, impeding motion and assigning mass to objects that pass through it.

    And so in 2012, after half a century and billions of dollars, thousands of physicists toasted over champagne. Peter Higgs, for whom the elusive boson was named, shared the Nobel prize with François Englert, who had independently predicted the particle’s existence.

    Peter Higgs

    François Englert

    An intermission underground

    The current shutdown is the first of a pair of billion-dollar upgrades intended to boost the productivity of the Large Hadron Collider tenfold by the end of the decade.

    The first shutdown will last for two years, until 2021; during that time, engineers will improve the series of smaller racetracks that speed up protons and inject them into the main collider. The collider then will run for two years and shut down again, in 2024, for two more years, so that engineers can install new magnets to intensify the proton beams and collisions.

    Reincarnated in 2026 as the High Luminosity L.H.C., the collider is scheduled to run for another decade, until 2035 or so, which means its career probing the edge of human knowledge is still beginning.

    Judging by the collider’s productivity, measured in terms of trillions of subatomic smashups, more than 95 percent of its scientific potential lies ahead.

    Both the Atlas and CMS experiments will receive major upgrades during the next two shutdowns, including new silicon trackers, to replace the olds ones burned out by radiation.

    To keep up with the increased collision rate, both Atlas and CMS have had to upgrade the finicky trigger systems that decide which collision events to keep and study. Currently, of a billion events per second, they can keep 1,500; the upgrade will raise that figure to 10,000.

    And what a flow of collisions it will be. Physicists measure the productivity, or luminosity, of their colliders in terms of collisions. It took about 3,000 trillion collisions to confirm the Higgs boson. As of the December shutdown the collider had logged about 20,000 trillion collisions. But those were, and are, early days.

    By 2037, the Large Hadron Collider should have produced roughly 4 million trillion primordial fireballs, bristling with who knows what. The whole universe is still up for grabs.

    After the Higgs

    Discovering the Higgs was an auspicious start. But the champagne came with a mystery.

    Over the last century, physicists have learned to explain some of the grandest and subtlest phenomena in nature — the arc of a rainbow, the scent of a gardenia, the twitch of a cat’s whiskers — as a handful of elementary particles interacting through four basic forces, playing a game of catch with force-carrying particles called bosons according to a set of equations called the Standard Model.

    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    But why these particles and these forces? Why is the universe made of matter but not antimatter? What happens at the center of a black hole, or happened at the first instant of the Big Bang? If the Higgs boson determines the masses of particles, what determines the mass of the Higgs?

    Who, in other words, watches the watchman?

    The Standard Model, for all its brilliance and elegance, does not say. Particles that might answer these questions have not shown up yet in the collider. Fabiola Gianotti, the director-general of CERN, expressed surprise. “I would have expected new physics to manifest itself at the energy scale of the Large Hadron Collider,” she said.

    Some physicists have responded by speculating about multiple universes and other exotic phenomena. Some clues, Dr. Gianotti said, might come from studying the new particle on the block, the Higgs.

    “We physicists are happy when we understand things, but we are even happier when we don’t understand,” she said. “And today we know that we don’t understand everything. We know that we are missing something important and fundamental. And this is very exciting.”

    Colliders of tomorrow

    Humans soon must decide which machines, if any, will be built to augment or replace the Large Hadron Collider. That collider had a “killer app” of sorts: it was designed to achieve an energy at which, according to the prediction of the Standard Model, the Higgs or something like it would become evident and provide an explanation for particle masses.

    But the Standard Model doesn’t predict a new keystone particle in the next higher energy range. Luckily, nobody believes the Standard Model is the last word about the universe, but as the machines increase in energy, particle physicists will be shooting in the dark.

    For a long time, the leading candidate for Next Big Physics Machine has been the International Linear Collider, which would fire electrons and their antimatter opposites, positrons, at each other.

    ILC schematic, being planned for the Kitakami highland, in the Iwate prefecture of northern Japan

    The collisions would produce showers of Higgs bosons. The experiment would be built in Japan, if it is built at all, but Japan has yet to commit to hosting the project, which would require them to pay for about half of the $5.5 billion cost- see https://sciencesprings.wordpress.com/2018/12/21/from-nature-via-ilc-plans-for-worlds-next-major-particle-collider-dealt-big-blow.

    In the meantime, Europe has convened meetings and workshops to decide on a plan for the future of particle physics there. “If there is no word from Japan by the end of the year, then the I.L.C. will not figure in the next five-year plan for Europe,” Lyn Evans, a CERN physicist who was in charge of building the Large Hadron Collider, said in an email.

    CERN has proposed its own version of a linear collider, the Compact Linear Collider, that could be scaled up gradually from Higgs bosons to higher energies. Also being considered is a humongous collider, 100 kilometers around, that would lie under Lake Geneva and would reach energies of 100 trillion electron volts — seven times the power of the Large Hadron Collider.

    Cern Compact Linear Collider

    CLC map

    CLC TWO-BEAM ACCELERATION TEST STAND

    And in November the Chinese Academy of Sciences released the design for a next-generation collider of similar size, called the Circular Electron Positron Collider.

    China Circular Electron Positron Collider (CEPC) map

    China Circular Electron-Positron collider depiction

    The machine could be the precursor for a still more powerful machine that has been dubbed the Great Collider. Politics and economics, as well as physics, will decide which, if any, of these machines will see a shovel.

    “If we want a new machine, nothing is possible before 2035,” Frederick Bordry, CERN’s director of accelerators, said of European plans. Building such a machine is a true human adventure, he said: “Twenty-five years to build and another 25 to operate.”

    Noting that he himself is 64, he added, “I’m working for the young people.”

    See the full article here .

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  • richardmitnick 1:48 pm on September 27, 2018 Permalink | Reply
    Tags: , , CERN LHC, , LHCb experiment discovers two perhaps three new particles, , ,   

    From CERN: “LHCb experiment discovers two, perhaps three, new particles” 

    Cern New Bloc

    Cern New Particle Event

    CERN New Masthead

    From CERN

    27 Sep 2018
    Ana Lopes

    1
    The LHCb experiment at CERN. (Image: CERN)

    It could be three for the price of one. The LHCb collaboration has found two never-before-seen particles, as well as hints of another new particle, in high-energy proton collisions at the Large Hadron Collider (LHC). Future studies of the properties of these new particles will shed light on the strong force that binds subatomic particles called quarks together.

    The new particles are predicted by the well-established quark model, and belong to the same family of particles as the protons that the LHC accelerates and collides: baryons, which are made up of three quarks. But the type of quarks they contain are different: whereas protons contain two up quarks and one down quark, the new particles, dubbed Σb(6097)+ and Σb(6097)-, are bottom baryons composed of one bottom quark and two up quarks (buu) or one bottom quark and two down quarks (bdd) respectively. Four relatives of these particles, known as Σb+, Σb-, Σb*+ and Σb*-, were first observed at a Fermilab experiment, but this is the first time that their two higher-mass counterparts, Σb(6097)+ and Σb(6097)-, have been detected.

    The LHCb collaboration found these particles using the classic particle-hunting technique of looking for an excess of events, or bump, over a smooth background of events in data from particle collisions. In this case, the researchers looked for such bumps in the mass distribution of a two-particle system consisting of a neutral baryon called Λb0 and a charged quark-antiquark particle called the π meson. They found two bumps corresponding to the Σb(6097)+ and Σb(6097)- particles, with the whopping significances of 12.7 and 12.6 standard deviations respectively; five standard deviations is the usual threshold to claim the discovery of a new particle. The 6097 in the names refers to the approximate masses of the new particles in MeV, about six times more massive than the proton.

    The third particle, named Zc-(4100) by the LHCb collaboration, is a possible candidate for a different type of quark beast, one made not of the usual two or three quarks but of four quarks (strictly speaking, two quarks and two antiquarks), two of which are heavy charm quarks. Such exotic mesons, sometimes described as “tetraquarks”, as well as five-quark particles called “pentaquarks”, have long been predicted to exist but have only relatively recently been discovered. Searching for structures in the decays of heavier B mesons, the LHCb researchers detected evidence for Zc-(4100) with a significance of more than three standard deviations, short of the threshold for discovery. Future studies with more data, at LHCb or at other experiments, may be able to boost or disprove this evidence.

    The new findings, described in two papers posted online and submitted for publication to physics journals, represent another step in physicists’ understanding of the strong force, one of the four fundamental forces of nature.

    For more information, see the LHCb website.

    See the full article here.


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    Meet CERN in a variety of places:

    Quantum Diaries
    QuantumDiaries

    Cern Courier

    THE FOUR MAJOR PROJECT COLLABORATIONS

    ATLAS
    CERN ATLAS New

    ALICE
    CERN ALICE New

    CMS
    CERN CMS New

    LHCb
    CERN LHCb New II

    LHC

    CERN map

    CERN LHC Grand Tunnel

    CERN LHC particles

    OTHER PROJECTS AT CERN

    CERN AEGIS

    CERN ALPHA

    CERN ALPHA

    CERN AMS

    CERN ACACUSA

    CERN ASACUSA

    CERN ATRAP

    CERN ATRAP

    CERN AWAKE

    CERN AWAKE

    CERN CAST

    CERN CAST Axion Solar Telescope

    CERN CLOUD

    CERN CLOUD

    CERN COMPASS

    CERN COMPASS

    CERN DIRAC

    CERN DIRAC

    CERN ISOLDE

    CERN ISOLDE

    CERN LHCf

    CERN LHCf

    CERN NA62

    CERN NA62

    CERN NTOF

    CERN TOTEM

    CERN UA9

    CERN Proto Dune

    CERN Proto Dune

     
  • richardmitnick 3:39 pm on September 25, 2018 Permalink | Reply
    Tags: , , , Argonne's Theta supercomputer, Aurora exascale supercomputer, , CERN LHC, , , , ,   

    From Argonne National Laboratory ALCF: “Argonne team brings leadership computing to CERN’s Large Hadron Collider” 

    Argonne Lab
    News from Argonne National Laboratory

    From Argonne National Laboratory ALCF

    ANL ALCF Cetus IBM supercomputer

    ANL ALCF Theta Cray supercomputer

    ANL ALCF Cray Aurora supercomputer

    ANL ALCF MIRA IBM Blue Gene Q supercomputer at the Argonne Leadership Computing Facility

    September 25, 2018
    Madeleine O’Keefe

    CERN’s Large Hadron Collider (LHC), the world’s largest particle accelerator, expects to produce around 50 petabytes of data this year. This is equivalent to nearly 15 million high-definition movies—an amount so enormous that analyzing it all poses a serious challenge to researchers.

    LHC

    CERN map


    CERN LHC Tunnel

    CERN LHC particles

    A team of collaborators from the U.S. Department of Energy’s (DOE) Argonne National Laboratory is working to address this issue with computing resources at the Argonne Leadership Computing Facility (ALCF), a DOE Office of Science User Facility. Since 2015, this team has worked with the ALCF on multiple projects to explore ways supercomputers can help meet the growing needs of the LHC’s ATLAS experiment.

    The efforts are especially important given what is coming up for the accelerator. In 2026, the LHC will undergo an ambitious upgrade to become the High-Luminosity LHC (HL-LHC). The aim of this upgrade is to increase the LHC’s luminosity—the number of events detected per second—by a factor of 10. “This means that the HL-LHC will be producing about 20 times more data per year than what ATLAS will have on disk at the end of 2018,” says Taylor Childers, a member of the ATLAS collaboration and computer scientist at the ALCF who is leading the effort at the facility. “CERN’s computing resources are not going to grow by that factor.”

    Luckily for CERN, the ALCF already operates some of the world’s most powerful supercomputers for science, and the facility is in the midst of planning for an upgrade of its own. In 2021, Aurora—the ALCF’s next-generation system, and the first exascale machine in the country—is scheduled to come online.

    It will provide the ATLAS experiment with an unprecedented resource for analyzing the data coming out of the LHC—and soon, the HL-LHC.

    CERN/ATLAS detector

    Why ALCF?

    CERN may be best known for smashing particles, which physicists do to study the fundamental laws of nature and gather clues about how the particles interact. This involves a lot of computationally intense calculations that benefit from the use of the DOE’s powerful computing systems.

    The ATLAS detector is an 82-foot-tall, 144-foot-long cylinder with magnets, detectors, and other instruments layered around the central beampipe like an enormous 7,000-ton Swiss roll. When protons collide in the detector, they send a spray of subatomic particles flying in all directions, and this particle debris generates signals in the detector’s instruments. Scientists can use these signals to discover important information about the collision and the particles that caused it in a computational process called reconstruction. Childers compares this process to arriving at the scene of a car crash that has nearly completely obliterated the vehicles and trying to figure out the makes and models of the cars and how fast they were going. Reconstruction is also performed on simulated data in the ATLAS analysis framework, called Athena.

    An ATLAS physics analysis consists of three steps. First, in event generation, researchers use the physics that they know to model the kinds of particle collisions that take place in the LHC. In the next step, simulation, they generate the subsequent measurements the ATLAS detector would make. Finally, reconstruction algorithms are run on both simulated and real data, the output of which can be compared to see differences between theoretical prediction and measurement.

    “If we understand what’s going on, we should be able to simulate events that look very much like the real ones,” says Tom LeCompte, a physicist in Argonne’s High Energy Physics division and former physics coordinator for ATLAS.

    “And if we see the data deviate from what we know, then we know we’re either wrong, we have a bug, or we’ve found new physics,” says Childers.

    Some of these simulations, however, are too complicated for the Worldwide LHC Computing Grid, which LHC scientists have used to handle data processing and analysis since 2002.

    MonALISA LHC Computing GridMap http:// monalisa.caltech.edu/ml/_client.beta

    The Grid is an international distributed computing infrastructure that links 170 computing centers across 42 countries, allowing data to be accessed and analyzed in near real-time by an international community of more than 10,000 physicists working on various LHC experiments.

    The Grid has served the LHC well so far, but as demand for new science increases, so does the required computing power.

    That’s where the ALCF comes in.

    In 2011, when LeCompte returned to Argonne after serving as ATLAS physics coordinator, he started looking for the next big problem he could help solve. “Our computing needs were growing faster than it looked like we would be able to fulfill them, and we were beginning to notice that there were problems we were trying to solve with existing computing that just weren’t able to be solved,” he says. “It wasn’t just an issue of having enough computing; it was an issue of having enough computing in the same place. And that’s where the ALCF really shines.”

    LeCompte worked with Childers and ALCF computer scientist Tom Uram to use Mira, the ALCF’s 10-petaflops IBM Blue Gene/Q supercomputer, to carry out calculations to improve the performance of the ATLAS software.

    MIRA IBM Blue Gene Q supercomputer at the Argonne Leadership Computing Facility

    Together they scaled Alpgen, a Monte Carlo-based event generator, to run efficiently on Mira, enabling the generation of millions of particle collision events in parallel. “From start to finish, we ended up processing events more than 20 times as fast, and used all of Mira’s 49,152 processors to run the largest-ever event generation job,” reports Uram.

    But they weren’t going to stop there. Simulation, which takes up around five times more Grid computing than event generation, was the next challenge to tackle.
    Moving forward with Theta

    In 2017, Childers and his colleagues were awarded a two-year allocation from the ALCF Data Science Program (ADSP), a pioneering initiative designed to explore and improve computational and data science methods that will help researchers gain insights into very large datasets produced by experimental, simulation, or observational methods. The goal is to deploy Athena on Theta, the ALCF’s 11.69-petaflops Intel-Cray supercomputer, and develop an end-to-end workflow to couple all the steps together to improve upon the current execution model for ATLAS jobs which involves a many­step workflow executed on the Grid.

    ANL ALCF Theta Cray XC40 supercomputer

    “Each of those steps—event generation, simulation, and reconstruction—has input data and output data, so if you do them in three different locations on the Grid, you have to move the data with it,” explains Childers. “Ideally, you do all three steps back-to-back on the same machine, which reduces the amount of time you have to spend moving data around.”

    Enabling portions of this workload on Theta promises to expedite the production of simulation results, discovery, and publications, as well as increase the collaboration’s data analysis reach, thus moving scientists closer to new particle physics.

    One challenge the group has encountered so far is that, unlike other computers on the Grid, Theta cannot reach out to the job server at CERN to receive computing tasks. To solve this, the ATLAS software team developed Harvester, a Python edge service that can retrieve jobs from the server and submit them to Theta. In addition, Childers developed Yoda, an MPI-enabled wrapper that launches these jobs on each compute node.

    Harvester and Yoda are now being integrated into the ATLAS production system. The team has just started testing this new workflow on Theta, where it has already simulated over 12 million collision events. Simulation is the only step that is “production-ready,” meaning it can accept jobs from the CERN job server.

    The team also has a running end-to-end workflow—which includes event generation and reconstruction—for ALCF resources. For now, the local ATLAS group is using it to run simulations investigating if machine learning techniques can be used to improve the way they identify particles in the detector. If it works, machine learning could provide a more efficient, less resource-intensive method for handling this vital part of the LHC scientific process.

    “Our traditional methods have taken years to develop and have been highly optimized for ATLAS, so it will be hard to compete with them,” says Childers. “But as new tools and technologies continue to emerge, it’s important that we explore novel approaches to see if they can help us advance science.”
    Upgrade computing, upgrade science

    As CERN’s quest for new science gets more and more intense, as it will with the HL-LHC upgrade in 2026, the computational requirements to handle the influx of data become more and more demanding.

    “With the scientific questions that we have right now, you need that much more data,” says LeCompte. “Take the Higgs boson, for example. To really understand its properties and whether it’s the only one of its kind out there takes not just a little bit more data but takes a lot more data.”

    This makes the ALCF’s resources—especially its next-generation exascale system, Aurora—more important than ever for advancing science.

    Depiction of ANL ALCF Cray Shasta Aurora exascale supercomputer

    Aurora, scheduled to come online in 2021, will be capable of one billion billion calculations per second—that’s 100 times more computing power than Mira. It is just starting to be integrated into the ATLAS efforts through a new project selected for the Aurora Early Science Program (ESP) led by Jimmy Proudfoot, an Argonne Distinguished Fellow in the High Energy Physics division. Proudfoot says that the effective utilization of Aurora will be key to ensuring that ATLAS continues delivering discoveries on a reasonable timescale. Since increasing compute resources increases the analyses that are able to be done, systems like Aurora may even enable new analyses not yet envisioned.

    The ESP project, which builds on the progress made by Childers and his team, has three components that will help prepare Aurora for effective use in the search for new physics: enable ATLAS workflows for efficient end-to-end production on Aurora, optimize ATLAS software for parallel environments, and update algorithms for exascale machines.

    “The algorithms apply complex statistical techniques which are increasingly CPU-intensive and which become more tractable—and perhaps only possible—with the computing resources provided by exascale machines,” explains Proudfoot.

    In the years leading up to Aurora’s run, Proudfoot and his team, which includes collaborators from the ALCF and Lawrence Berkeley National Laboratory, aim to develop the workflow to run event generation, simulation, and reconstruction. Once Aurora becomes available in 2021, the group will bring their end-to-end workflow online.

    The stated goals of the ATLAS experiment—from searching for new particles to studying the Higgs boson—only scratch the surface of what this collaboration can do. Along the way to groundbreaking science advancements, the collaboration has developed technology for use in fields beyond particle physics, like medical imaging and clinical anesthesia.

    These contributions and the LHC’s quickly growing needs reinforce the importance of the work that LeCompte, Childers, Proudfoot, and their colleagues are doing with ALCF computing resources.

    “I believe DOE’s leadership computing facilities are going to play a major role in the processing and simulation of the future rounds of data that will come from the ATLAS experiment,” says LeCompte.

    This research is supported by the DOE Office of Science. ALCF computing time and resources were allocated through the ASCR Leadership Computing Challenge, the ALCF Data Science Program, and the Early Science Program for Aurora.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation’s first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America’s scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science. For more visit http://www.anl.gov.

    About ALCF

    The Argonne Leadership Computing Facility’s (ALCF) mission is to accelerate major scientific discoveries and engineering breakthroughs for humanity by designing and providing world-leading computing facilities in partnership with the computational science community.

    We help researchers solve some of the world’s largest and most complex problems with our unique combination of supercomputing resources and expertise.

    ALCF projects cover many scientific disciplines, ranging from chemistry and biology to physics and materials science. Examples include modeling and simulation efforts to:

    Discover new materials for batteries
    Predict the impacts of global climate change
    Unravel the origins of the universe
    Develop renewable energy technologies

    Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science

    Argonne Lab Campus

     
  • richardmitnick 2:32 pm on September 25, 2018 Permalink | Reply
    Tags: , , , CERN LHC, , , , ,   

    From ALICE at CERN: “What the LHC upgrade brings to CERN” 

    CERN
    CERN New Masthead

    From From ALICE at CERN

    25 September 2018
    Rashmi Raniwala
    Sudhir Raniwala

    Six years after discovery, Higgs boson validates a prediction. Soon, an upgrade to Large Hadron Collider will allow CERN scientists to produce more of these particles for testing Standard Model of physics.

    FNAL magnets such as this one, which is mounted on a test stand at Fermilab, for the High-Luminosity LHC Photo Reidar Hahn

    Six years after the Higgs boson was discovered at the CERN Large Hadron Collider (LHC), particle physicists announced last week that they have observed how the elusive particle decays.

    CERN CMS Higgs Event


    CERN ATLAS Higgs Event

    The finding, presented by ATLAS and CMS collaborations, observed the Higgs boson decaying to fundamental particles known as bottom quarks.

    In 2012, the Nobel-winning discovery of the Higgs boson validated the Standard Model of physics, which also predicts that about 60% of the time a Higgs boson will decay to a pair of bottom quarks.

    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.


    Standard Model of Particle Physics from Symmetry Magazine

    According to CERN, “testing this prediction is crucial because the result will either lend support to the Standard Model — which is built upon the idea that the Higgs field endows quarks and other fundamental particles with mass — or rock its foundations and point to new physics”.

    The Higgs boson was detected by studying collisions of particles at different energies. But they last only for one zeptosecond, which is 0.000000000000000000001 seconds, so detecting and studying their properties requires an incredible amount of energy and advanced detectors. CERN announced earlier this year that it is getting a massive upgrade, which will be completed by 2026.

    Why study particles?

    Particle physics probes nature at extreme scales, to understand the fundamental constituents of matter. Just like grammar and vocabulary guide (and constrain) our communication, particles communicate with each other in accordance with certain rules which are embedded in what are known as the ‘four fundamental interactions’. The particles and three of these interactions are successfully described by a unified approach known as the Standard Model. The SM is a framework that required the existence of a particle called the Higgs boson, and one of the major aims of the LHC was to search for the Higgs boson.

    How are such tiny particles studied?

    Protons are collected in bunches, accelerated to nearly the speed of light and made to collide. Many particles emerge from such a collision, termed as an event. The emergent particles exhibit an apparently random pattern but follow underlying laws that govern part of their behaviour. Studying the patterns in the emission of these particles help us understand the properties and structure of particles.

    Initially, the LHC provided collisions at unprecedented energies allowing us to focus on studying new territories. But, it is now time to increase the discovery potential of the LHC by recording a larger number of events.

    3
    No image credit or caption

    So, what will an upgrade mean?

    After discovering the Higgs boson, it is imperative to study the properties of the newly discovered particle and its effect on all other particles. This requires a large number of Higgs bosons. The SM has its shortcomings, and there are alternative models that fill these gaps. The validity of these and other models that provide an alternative to SM can be tested by experimenting to check their predictions. Some of these predictions, including signals for “dark matter”, “supersymmetric particles” and other deep mysteries of nature are very rare, and hence difficult to observe, further necessitating the need of a High Luminosity LHC (HL-LHC).

    Imagine trying to find a rare variety of diamond amongst a very large number of apparently similar looking pieces. The time taken to find the coveted diamond will depend on the number of pieces provided per unit time for inspection, and the time taken in inspection. To complete this task faster, we need to increase the number of pieces provided and inspect faster. In the process, some new pieces of diamond, hitherto unobserved and unknown, may be discovered, changing our perspective about rare varieties of diamonds.

    Once upgraded, the rate of collisions will increase and so will the probability of most rare events. In addition, discerning the properties of the Higgs boson will require their copious supply. After the upgrade, the total number of Higgs bosons produced in one year may be about 5 times the number produced currently; and in the same duration, the total data recorded may be more than 20 times.

    With the proposed luminosity (a measure of the number of protons crossing per unit area per unit time) of the HL-LHC, the experiments will be able to record about 25 times more data in the same period as for LHC running. The beam in the LHC has about 2,800 bunches, each of which contains about 115 billion protons. The HL- LHC will have about 170 billion protons in each bunch, contributing to an increase in luminosity by a factor of 1.5.

    How will it be upgraded?

    The protons are kept together in the bunch using strong magnetic fields of special kinds, formed using quadrupole magnets. Focusing the bunch into a smaller size requires stronger fields, and therefore greater currents, necessitating the use of superconducting cables. Newer technologies and new material (Niobium-tin) will be used to produce the required strong magnetic fields that are 1.5 times the present fields (8-12 tesla).

    The creation of long coils for such fields is being tested. New equipment will be installed over 1.2 km of the 27-km LHC ring close to the two major experiments (ATLAS and CMS), for focusing and squeezing the bunches just before they cross.

    CERN crab cavities that will be used in the HL-LHC


    FNAL Crab cavities for the HL-LHC

    Hundred-metre cables of superconducting material (superconducting links) with the capacity to carry up to 100,000 amperes will be used to connect the power converters to the accelerator. The LHC gets the protons from an accelerator chain, which will also need to be upgraded to meet the requirements of the high luminosity.

    Since the length of each bunch is a few cm, to increase the number of collisions a slight tilt is being produced in the bunches just before the collisions to increase the effective area of overlap. This is being done using ‘crab cavities’.

    The experimental particle physics community in India has actively participated in the experiments ALICE and CMS. The HL-LHC will require an upgrade of these too. Both the design and the fabrication of the new detectors, and the ensuing data analysis will have a significant contribution from the Indian scientists.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    Meet CERN in a variety of places:


    Cern Courier

    THE FOUR MAJOR PROJECT COLLABORATIONS
    ATLAS
    CERN/ATLAS detector

    ALICE
    CERN ALICE New

    CMS
    CERN/CMS Detector

    LHCb

    CERN/LHCb

    LHC

    CERN map

    CERN LHC Grand Tunnel

    CERN LHC particles


    Quantum Diaries

     
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