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  • richardmitnick 2:33 pm on September 26, 2016 Permalink | Reply
    Tags: Accelerator Science, , , , , , , uperconducting part of the European XFEL accelerator ready,   

    From European XFEL: “Superconducting part of the European XFEL accelerator ready” 

    XFEL bloc

    European XFEL

    26 September 2016
    No writer credit found

    Ninety-six modules fully installed in 1.7-km long tunnel section.

    An important milestone in the construction of the X-ray laser European XFEL has been reached: The 1.7-km long superconducting accelerator is installed in the tunnel. The linear accelerator will accelerate bunches of free electrons flying at near-light speed to the extremely high energy of 17.5 gigaelectronvolts. The bunches are accelerated in devices called resonators, which are cooled to a temperature of -271°C. In the next part of the facility, the electron bunches are used to generate the flashes of X-ray light that will allow scientists new insights into the nanocosmos. The European XFEL accelerator will be put into operation step by step in the next weeks. It will be the largest and most powerful linear accelerator of its type in the world. On 6 October, the German Minister for Education and Research, Prof. Johanna Wanka, and the Polish Vice Minister of Science and Education Dr Piotr Dardziński, will officially initiate the commissioning of the X-ray laser, including the accelerator. User operation at the European XFEL is anticipated to begin in mid-2017.

    Responsible for the construction of the accelerator was an international consortium of 17 research institutes under the leadership of Deutsches Elektronen-Synchrotron (DESY), which is also the largest shareholder of the European XFEL.

    DESY

    The central section consists of 96 accelerator modules, each 12 metres long, which contain almost 800 resonators made from ultrapure niobium surrounded by liquid helium. The electrons are accelerated inside of these resonators. The modules, which were industrially produced in cooperation with several partners, are on average about 16% more powerful than specified, so the original goal of 100 modules in the accelerator could be reduced to 96.

    1
    Using a small box as a clean area, technicians make connections between two accelerator modules in the European XFEL tunnel in April.
    Heiner Müller-Elsner / European XFEL

    “I congratulate the accelerator team for this milestone and thank all partners for their perseverance and their tireless efforts”, said the Chairman of the DESY Board of Directors Helmut Dosch. “The individual teams involved meshed like the gears of a clock to build the world’s most powerful and modern linear accelerator. That all was delivered within a tight budget deserves the utmost respect.”

    “We are excited that the installation of the accelerator modules has been successfully completed”, said European XFEL Managing Director and Chairman of the Management Board Massimo Altarelli. “This is an important step on the way to user operation next year. On this path there were numerous challenges that, in the past months and years, we faced together successfully. I thank DESY and our European partners for their enormous effort, and we look together with excitement towards the next weeks and months, when the accelerator goes into operation.”

    2
    The European XFEL accelerator tunnel. European XFEL

    The French project partner CEA in Saclay assembled the modules. Colleagues from the Polish partner institute IFJ-PAN in Kraków performed comprehensive tests of each individual module at DESY before it was installed in the 2-km long accelerator tunnel. Magnets for focusing and steering the electron beam inside the modules came from the Spanish research centre CIEMAT in Madrid. The niobium resonators were manufactured by companies in Germany and Italy, supervised by research centres DESY and INFN in Rome. Russian project partners such as the Efremov Institute in St. Petersburg and the Budker Institute in Novosibirsk delivered the different parts for vacuum components for the accelerator, within which the electron beam will be directed and focused in the non-superconducting portions of the facility at room temperature. Many other components were manufactured by DESY and their partners, including diagnostics and electron beam stabilization mechanisms, among others.

    In October, the accelerator is expected to move towards operation in several steps. As soon as the system for access control is installed, the interior of the modules can be slowly cooled to the operating temperature of two degrees above absolute zero—colder than outer space. Then DESY scientists can send the first electrons through the accelerator. At first, the electrons will be stopped in an “electron dump” at the end of the accelerator, until all of the beam properties are optimized. Then the electron beam will be sent further towards the X-ray light-generating magnetic structures called undulators. Here, the alternating poles of the undulator’s magnets will force the electron bunches to move in a tight, zigzagging “slalom” course for a 210-m stretch. In a self-amplifying intensification process, extremely short and bright X-ray flashes with laser-like properties will be generated. Reaching the conditions needed for this process is a massive technical challenge. Among other things, the electron bunches from the accelerator must meet precisely defined specifications. But the participating scientists have reason for optimism. All foundational principles and techniques have been proven at the free-electron laser FLASH at DESY, the prototype for the European XFEL. At European XFEL itself, the commissioning of the 30-m long injector has been complete since July. The injector generates the electron bunches for the main accelerator and accelerates them in an initial section to near-light speed.

    The beginning of user operation, the final step in the transition from the construction phase to the operation phase, is foreseen for summer 2017.

    See the full article here .

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    XFEL Campus

    The Hamburg area will soon boast a research facility of superlatives: The European XFEL will generate ultrashort X-ray flashes—27 000 times per second and with a brilliance that is a billion times higher than that of the best conventional X-ray radiation sources.

    The outstanding characteristics of the facility are unique worldwide. Starting in 2017, it will open up completely new research opportunities for scientists and industrial users.

     
  • richardmitnick 10:57 am on September 23, 2016 Permalink | Reply
    Tags: Accelerator Science, , , , , , Vox,   

    From Yale via Vox: “Why physicists really, really want to find a new subatomic particle” 

    Yale University bloc

    Yale University

    1

    Vox

    Sep 21, 2016
    Brian Resnick

    The latest search for a new particle has fizzled. Scientists are excited, and a bit scared.

    2
    Particle physicists are begging nature to reveal the secrets of the universe. The universe isn’t talking back. FABRICE COFFRINI/AFP/Getty Images

    Particle physicists are rather philosophical when describing their work.

    “Whatever we find out, that is what nature chose,” Kyle Cranmer, a physics professor at New York University, tells me. It’s a good attitude to have when your field yields great disappointments.

    For months, evidence was mounting that the Large Hadron Collider, the biggest and most powerful particle accelerator in the world, had found something extraordinary: a new subatomic particle, which would be a discovery surpassing even the LHC’s discovery of the Higgs boson in 2012, and perhaps the most significant advance since Einstein’s theory of relativity.

    CERN/LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    And yet, nature had other plans.

    In August, the European Organization for Nuclear Research (CERN) reported that the evidence for the new particle had run thin. What looked like a promising “bump” in the data, indicating the presence of a particle with a unique mass, was just noise.

    But to Cranmer — who has analyzed LHC data in his work — the news did not equate failure. “You have to keep that in mind,” he says. “Because it can feel that way. It wasn’t there to be discovered. It’s like being mad that someone didn’t find an island when someone is sailing in the middle of the ocean.”

    What’s more, the LHC’s journey is far from over. The machine is expected to run for another 20 or so years. There will be more islands to look for.

    “We’re either going to discover a bunch of new particles or we will not,” Cranmer says. “If we find new particles, we can study them, and then we have a foothold to make progress. And if we don’t, then [we’ll be] staring at a flat wall in front figuring out how to climb it.”

    This is a dramatic moment, one that could provoke “a crisis at the edge of physics,” according to a New York Times op-ed. Because if the superlative LHC can’t find answers, it will cast doubt that answers can be found experimentally.

    From here, there are two broad scenarios that could play out, both of which will vastly increase our understanding of nature. One scenario will open up physics to a new world of understanding about the universe; the other could end particle physics as we know it.

    The physicists themselves can’t control the outcome. They’re waiting for nature to tell them the answers.

    Why do we care about new subatomic particles anyway?

    3
    A graphic showing traces of collision of particles at the Compact Muon Solenoid (CMS) experience is pictured with a slow speed experience at Universe of Particles exhibition of the the European Organization for Nuclear Research (CERN) on December 13, 2011, in Geneva. FABRICE COFFRINI/AFP/GettyImages

    The LHC works by smashing together atoms at incredibly high velocities. These particles fuse and can form any number of particles that were around in the universe from the Big Bang onward.

    When the Higgs boson was confirmed in 2012, it was a cause for celebration and unease.

    CERN CMS Higgs Event
    CERN CMS Higgs Event

    CERN ATLAS Higgs Event
    CERN ATLAS Higgs Event

    The Higgs was the last piece of a puzzle called the standard model, which is a theory that connects all the known components of nature (except gravity) together in a balanced, mathematical equation.

    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 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 Higgs was the final piece that had been theorized to exist but never seen.

    After the Higgs discovery, the scientists at the LHC turned their hopes in a new direction. They hoped the accelerator could begin to find particles that had never been theorized nor ever seen. It was like going from a treasure hunt with a map to chartering a new ocean.

    They want to find these new subatomic particles because even though the standard model is now complete, it still can’t answer a lot of lingering questions about the universe. Let’s go through the two scenarios step by step.

    Scenario 1: There are more subatomic particles! Exciting!

    If the LHC finds new subatomic particles, it lend evidence to a theory known as supersymmetry. Supersymmetry posits that all the particles in the standard model must have a shadow “super partner” that spins in a slightly different direction.

    Standard model of Supersymmetry DESY
    Standard model of Supersymmetry DESY

    Scientists have never seen one of these supersymmetrical particles, but they’re keen to. Supersymmetry could neatly solve some of the biggest problems vexing physicists right now.

    Such as:

    1) No one knows what dark matter is

    One of these particles could be what scientists call “dark matter,” which is theorized to make up 27 percent of the universe. But we’ve never seen dark matter, and that leaves a huge gaping hole in our understanding of the how the universe formed and exists today.

    “It could be that one particle is responsible for dark matter,” Cranmer explains. Simple enough.

    2) The Higgs boson is much too light

    The Higgs discovery was an incredible triumph, but it also contained a mystery to solve. The boson — at 126 GeV (giga electron volts) — was much lighter than the standard model and the math of quantum mechanics suggests it should be.

    Why is that a problem? Because it’s a wrinkle to be ironed out in our understanding of the universe. It suggests the standard model can’t explain everything. And physicists want to know everything.

    “Either nature is sort of ugly, which is entirely conceivable, and we just have to live with the fact that the Higgs boson mass is light and we don’t know why,” Ray Brock, a Michigan State University physicist who has worked on the LHC, says, “or nature is trying to tell us something.”

    It could be that a yet-to-be-discovered subatomic particle interacts with the Higgs, making it lighter than it ought to be.

    3) The standard model doesn’t unify the forces of the universe

    There are four major forces that make the universe tick: the strong nuclear force (which holds atoms together), the weak nuclear force (what makes Geiger counters tick), electromagnetism (you’re using it right now, reading this article on an electronic screen), and gravity (don’t look down.)

    Scientists aren’t content with the four forces. They, for decades, have been trying to prove that the universe works more elegantly, that, deep down, all these forces are just manifestations of one great force that permeates the universe.

    Physicists call this unification, and the standard model doesn’t provide it.

    “If we find supersymmetry at the LHC, it is a huge boost to the dream that three of the fundamental forces we have [all of them except gravity] are all going to unify,” Cranmer says.

    4) Supersymmetry would lead to more particle hunting

    If scientists find one new particle, supersymmetry means they’ll find many more. That’s exciting. “It’s not going to be just one new particle that we discovered, and yay!” Cranmer says. “We’re going to be finding new forces, or learn something really deep about the nature of space and time. Whatever it is, it’s going to be huge.”

    Scenario 2: There are no new subatomic particles. Less exciting! But still interesting. And troubling.

    The LHC is going to run for around another 20 years, at least. There’s a lot of time left to find new particles, even if there is no supersymmetry. “This is what always blows my mind,” Brock says. “We’ve only taken about 5 percent of the total planned data that the LHC is going to deliver until the middle 2020s.”

    But the accelerator also might not find anything. If the new particles aren’t there to find, the LHC won’t find them. (Hence, the notion that physicists are looking for “what nature chose.”)

    But again, this doesn’t represent a failure. It will actually yield new insights about the universe.

    “It would be a profound discovery to find that we’re not going to see anything else,” Cranmer says.

    1) For one, it would suggest that supersymmetry isn’t the answer

    If supersymmetry is dead, then theoretical physicists will have to go back to the drawing board to figure out how to solve the mysteries left open by the standard model.

    “If we’re all coming up empty, we would have to question our fundamental assumptions,” Sarah Demers, a Yale physicist, tells me. “Which is something we’re trying to do all the time, but that would really force us.”

    2) The answers exist, but they exist in a different universe

    If the LHC can’t find answers to questions like “why is the Higgs so light?” scientists might grow to accept a more out-of-the-box idea: the multiverse.

    That’s the idea where there are tons of universes all existing parallel to one another. It could be that “in most of [the universes], the Higgs boson is really heavy, and in only in very unusual universes [like our own] is the Higgs boson so light that life can form,” Cranmer says.

    Basically: On the scale of our single universe, it might not make sense for the Higgs to be light. But if you put it together with all the other possible universes, the math might check out.

    There’s a problem with this theory, however: If heavier Higgs bosons exist in different universes, there’s no possible way to observe them. They’re in different universes!

    “Which is why a lot of people hate it, because they consider it to be anti-science,” Cranmer says. “It might be impossible to test.”

    3) The new subatomic particles do exist, but the LHC isn’t powerful enough to find them

    In 20 years, if the LHC doesn’t find any new particles, there might be a simple reason: These particles are too heavy for the LHC to detect.

    This is basic E=mc2 Einstein: The more energy in the particle accelerator, the heavier the particles it can create. The LHC is the most powerful particle accelerator in the history of man, but even it has its limits.

    So what will physicists do? Build an even bigger, even smashier particle collider? That’s an option. There are currently preliminary plans in China for a collider double the size of the LHC.

    Building a bigger collider might be a harder sell for international funding agencies. The LHC was funded in part because of the quest to confirm the Higgs. Will governments really spend billions on a machine that may not yield epic insights?

    “Maybe we were blessed as a field that we always had a target or two to shoot for. We don’t have that anymore,” says Markus Klute, an MIT physicist stationed at CERN in Europe. “It’s easier to explain to the funding agencies specifically that there’s a specific endpoint.”

    The LHC will keep running for the foreseeable future. But it could prove a harder task to make the case to build a new collider.

    Either way, these are exciting times for physics

    4
    Dean Mouhtaropoulos/Getty Images

    “I think we have had a tendency to be prematurely depressed,” Demers says. “It’s never a step backward to learn something new,” even if the news is negative. “Ruling out ideas teaches us an incredible amount.”

    And she says that even if the LHC can never find another particle, it can still produce meaningful insights. Already, her colleagues are using it to help determine why there’s so much more matter than antimatter in the universe. And she reminds me the LHC can still teach us more about the mysterious Higgs. We will be able to measure it to a more precise degree.

    Brock, the MSU physicist, notes that since the 1960s, physicists have been chasing the standard model. Now they don’t quite know what they’re chasing. But they know it will change the world.

    “I can’t honestly say in all those 40 years, I’ve been exploring,” Brock says. “I’ve been testing the standard model. The Higgs boson was the last missing piece. Now, we have to explore.”

    See the full article here .

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    Yale University Campus

    Yale University comprises three major academic components: Yale College (the undergraduate program), the Graduate School of Arts and Sciences, and the professional schools. In addition, Yale encompasses a wide array of centers and programs, libraries, museums, and administrative support offices. Approximately 11,250 students attend Yale.

     
  • richardmitnick 3:29 pm on September 20, 2016 Permalink | Reply
    Tags: Accelerator Science, , LHC hits 2016 luminosity target   

    From CERN Courier: “LHC hits 2016 luminosity target” 

    CERN Courier

    Sep 16, 2016
    No writer credit found

    1
    Integrated luminosity

    At the end of August, two months ahead of schedule, the integrated luminosity delivered by the LHC reached the 2016 target value of 25 fb–1 in both the ATLAS and CMS experiments. The milestone is the result of a large group of scientists and technical experts who work behind the scenes to keep the 27 km-circumference machine operating at the highest possible performance.

    Following a push to produce as many proton–proton collisions as possible before the summer conferences, several new ideas, such as a novel beam-production technique in the injectors, have been incorporated to boost the LHC performance. Thanks to these improvements, over the summer the LHC was routinely operating with peak luminosities 10%–15% above the design value of 1034 cm–2 s–1.

    This is a notable success, especially considering that a temporary limitation in the Super Proton Synchrotron only allows the injection of 2220 bunches per beam instead of the foreseen 2750, and that the LHC energy is currently limited to 6.5 TeV instead of the nominal 7 TeV. The excellent availability of all the key systems of the LHC is one of the main reasons behind these achievements.

    The accelerator team is now gearing up for the season finale. Following a technical stop, a forward proton–proton physics run took place in mid-September. Proton–proton physics is scheduled to continue until the last week in October, after which proton–lead physics will take over for a period of one month. The LHC and its experiments can look forward to the completion of what is already a very successful year.

    See the full article here .
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    THE FOUR MAJOR PROJECT COLLABORATIONS

    ATLAS
    CERN ATLAS New

    ALICE
    CERN ALICE New

    CMS
    CERN CMS New

    LHCb
    CERN LHCb New II

    LHC

    CERN LHC Map
    CERN LHC Grand Tunnel

    CERN LHC particles

     
  • richardmitnick 2:42 pm on September 20, 2016 Permalink | Reply
    Tags: Accelerator Science, CERN SCOAP3, , ,   

    From CERN: “Global open access initiative, SCOAP3, set to continue” 

    Cern New Bloc

    Cern New Particle Event

    CERN New Masthead

    CERN

    20 Sep 2016
    Harriet Kim Jarlett

    1
    After three years of successful operation and growth, CERN announces continuation of global SCOAP3 Open Access initiative for another three (Image: Maximilian Brice/ CERN)

    After three years of successful operation and growth, CERN announced today the continuation of the global SCOAP3 Open Access initiative for at least three more years. SCOAP3, the Sponsoring Consortium for Open Access Publishing in Particle Physics, is an innovative partnership of over 3 000 libraries, funding agencies and research organisations from 44 countries. It has made tens of thousands of scientific articles freely available to everyone, with neither cost nor barrier for any author worldwide.

    “It is in the spirit of CERN’s Convention, and in the culture of our discipline, to make research results fully and freely available to everyone,” said CERN Director-General Fabiola Gianotti. “SCOAP3 allows everybody in the world to access high-quality scientific knowledge in peer-reviewed particle physics journals. CERN will continue to be fully engaged in such a vital initiative.”

    In cooperation with leading scientific publishers and learned societies, SCOAP3 has supported the transition to Open Access of key journals in the field of High-Energy Physics since 2014. In the first three years of SCOAP3 operation, 20 000 scientists from 100 countries have benefited from the opportunity to publish more than 13 000 Open Access articles free of charge.

    Hosted at CERN, under the oversight of international governance, SCOAP3 is primarily funded through the re-direction of budgets previously used by libraries to purchase journal subscriptions, to instead support Open Access publications. Funding Agencies in some research-intensive countries provide some additional support.

    Following the success of the first three years, the growth of the SCOAP3 partnership, and the increasing policy requirements for, and global commitment to, Open Access, CERN has now signed contracts with 10 scientific publishers and learned societies for a three-year extension of the initiative, from January 2017 to December 2019.

    “With its success, SCOAP3 has shown that its model of global cooperation is sustainable, in the same broad and participative way we build and operate large collaborations in particle physics,” said CERN Director for Research and Computing, Eckhard Elsen. “As a scientist I am impressed by how SCOAP3 partners played a pioneering role in advancing Open Access and I look forward to even larger partnership in the upcoming years.”

    See the full article here.

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    Meet CERN in a variety of places:

    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 LHC Map
    CERN LHC Grand Tunnel

    CERN LHC particles

    Quantum Diaries

     
  • richardmitnick 10:39 am on September 20, 2016 Permalink | Reply
    Tags: Accelerator Science, , , , Luminosity vs. Energy, ,   

    From Don Lincoln at FNAL- “Accelerator Science: Luminosity vs. Energy” 

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    Sep 19, 2016

    FNAL Don Lincoln
    Don Lincoln

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    In the world of high energy physics there are several parameters that are important when one constructs a particle accelerator. Two crucial ones are the energy of the beam and the luminosity, which is another word for the number of particles in the beam. In this video, Fermilab’s Dr. Don Lincoln explains the differences and the pros and cons. He even works in an unexpected sporting event.

    Watch, enjoy, learn.

    See the full article here .

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 2:03 pm on September 16, 2016 Permalink | Reply
    Tags: Accelerator Science, , , ,   

    From Symmetry: “The secret lives of long-lived particles” 

    Symmetry Mag

    Symmetry

    09/16/16
    Sarah Charley

    A theoretical species of particle might answer nearly every question about our cosmos—if scientists can find it.

    1
    ATLAS collaboration

    The universe is unbalanced.

    Gravity is tremendously weak. But the weak force, which allows particles to interact and transform, is enormously strong. The mass of the Higgs boson is suspiciously petite. And the catalog of the makeup of the cosmos? Ninety-six percent incomplete.

    Almost every observation of the subatomic universe can be explained by the Standard Model of particle physics—a robust theoretical framework bursting with verifiable predictions.

    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 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 because of these unsolved puzzles, the math is awkward, incomplete and filled with restrictions.

    A few more particles would solve almost all of these frustrations. Supersymmetry (nicknamed SUSY for short) is a colossal model that introduces new particles into the Standard Model’s equations.

    Standard model of Supersymmetry DESY
    Standard model of Supersymmetry DESY

    It rounds out the math and ties up loose ends. The only problem is that after decades of searching, physicists have found none of these new friends.

    But maybe the reason physicists haven’t found SUSY (or other physics beyond the Standard Model) is because they’ve been looking through the wrong lens.

    “Beautiful sets of models keep getting ruled out,” says Jessie Shelton, a theorist at the University of Illinois, “so we’ve had to take a step back and consider a whole new dimension in our searches, which is the lifetime of these particles.”

    In the past, physicists assumed that new particles produced in particle collisions would decay immediately, almost precisely at their points of origin. Scientists can catch particles that behave this way—for example, Higgs bosons—in particle detectors built around particle collision points. But what if new particles had long lifetimes and traveled centimeters—even kilometers—before transforming into something physicists could detect?

    This is not unprecedented. Bottom quarks, for instance, can travel a few tenths of a millimeter before decaying into more stable particles. And muons can travel several kilometers (with the help of special relativity) before transforming into electrons and neutrinos. Many theorists are now predicting that there may be clandestine species of particles that behave in a similar fashion. The only catch is that these long-lived particles must rarely interact with ordinary matter, thus explaining why they’ve escaped detection for so long. One possible explanation for this aloof behavior is that long live particles dwell in a hidden sector of physics.

    “Hidden-sector particles are separated from ordinary matter by a quantum mechanical energy barrier—like two villages separated by a mountain range,” says Henry Lubatti from the University of Washington. “They can be right next to each other, but without a huge boost in energy to get over the peak, they’ll never be able to interact with each other.”

    High-energy collisions generated by the Large Hadron Collider could kick these hidden-sector particles over this energy barrier into our own regime. And if the LHC can produce them, scientists should be able to see the fingerprints of long-lived particles imprinted in their data.

    CERN/LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    Long-lived particles jolted into our world by the LHC would most likely fly at close to the speed of light for between a few micrometers and a few hundred thousand kilometers before transforming into ordinary and measurable matter. This incredibly generous range makes it difficult for scientists to pin down where and how to look for them.

    But the lifetime of a subatomic particle is much like that of any living creature. Each type of particle has an average lifespan, but the exact lifetime of an individual particle varies. If these long-lived particles can travel thousands of kilometers before decaying, scientists are hoping that they’ll still be able to catch a few of the unlucky early-transformers before they leave the detector. Lubatti and his collaborators have also proposed a new LHC surface detector, which would extend their search range by many orders of magnitude.

    Because these long-lived particles themselves don’t interact with the detector, their signal would look like a stream of ordinary matter spontaneously appearing out of nowhere.

    “For instance, if a long lived particle decayed into quarks while inside the muon detector, it would mimic the appearance of several muons closely clustered together,” Lubatti says. “We are triggering on events like this in the ATLAS experiment.” After recording the events, scientists use custom algorithms to reconstruct the origins of these clustered particles to see if they could be the offspring of an invisible long-lived parent.

    If discovered, this new breed of matter could help answer several lingering questions in physics.

    “Long-lived particles are not a prediction of a single new theory, but rather a phenomenon that could fit into almost all of our frameworks for beyond-the-Standard-Model physics,” Shelton says.

    In addition to rounding out the Standard Model’s mathematics, inert long-lived particles could be cousins of dark matter—an invisible form of matter that only interacts with the visible cosmos through gravity. They could also help explain the origin of matter after the Big Bang.

    “So many of us have spent a lifetime studying such a tiny fraction of the universe,” Lubatti says. “We’ve understood a lot, but there’s still a lot we don’t understand—an enormous amount we don’t understand. This gives me and my colleagues pause.”

    See the full article here .

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 5:31 pm on September 15, 2016 Permalink | Reply
    Tags: Accelerator Science, , , Pixel detector, U.S. CMS FPIX team   

    From FNAL: “The world’s latest (and greatest) pixel detector” 

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    September 14, 2016
    Steve Nahn

    This article, and the work it represents, is dedicated to our dear friend and colleague Gino Bolla.

    There’s a new pixel detector in the world, and it’s one of our own.

    1
    This close-up shows three disks in one half cylinder, a quarter of the full FPIX detector.

    The Forward Pixel detector, part of the CMS Phase 1 upgrade, is taking shape out at SiDet. The new device lies at the heart of the CMS detector, providing micron-scale resolution on charged particle trajectories, which in turn provides precision position measurements of the proton-proton collisions. This detector is composed of 672 modules, each of which has 16 readout chips. Each chip reads out the signal from charge deposited on one of an array of 52×80 pixels.

    That means nearly 45 million pixels to sample at 100 kHz, the nominal trigger rate of CMS. The modules are mounted onto inner and outer custom carbon fiber “half-disks,” and three inner-outer pairs are mounted in the custom carbon fiber support structure, called a “half-cylinder.” The half-cylinder also brings the innovative dual-phase carbon dioxide cooling fluid and power to the half-disks and carries the data away via optical fibers.

    In addition to the physical detector, there are also the external components, such as the power supply and interlock system and the Data Acquisition system. To say it is a complex apparatus is a rather gross understatement. Though it is based on the original detector, this version supplies an extra layer of tracking with less mass and is more capable of handling the increased instantaneous luminosity expected in LHC Run 2 and Run 3, which will bring us up to 2023.

    Over the last three years, the U.S. CMS FPIX team, including contributions from 21 institutions, has designed, prototyped, extensively tested, and fabricated the detector components. They are in the last stages of assembly and on time for installation during the upcoming winter technical stop of the LHC. The entire enterprise exploited the unique strengths of this dispersed team. For example, the sensors were procured by the University of Kansas; the data-concentrator ASIC was designed by Rutgers University; the modules were assembled at Purdue University and the University of Nebraska and tested by x-ray exposure at Kansas State University and the University of Illinois-Chicago.

    Kansas State, Vanderbilt University, the University of Mississippi and Cornell University are developing data acquisition and control systems, while Fermilab has focused on mechanical structure, microelectronics and integration. And right now it is all coming together at SiDet.

    Over the past six months, modules have been arriving at SiDet, where a small army of students, postdocs, faculty (and even a project manager, when they let him) have been testing the modules at 17 degrees and at -20 degrees Celsius. In parallel a team of talented technicians and engineers has been assembling the mechanical structure. It hasn’t been without hiccups, notably the initially low yield of modules due to splinters (from cutting up wafers) damaging readout chips and the discovery of a whole new (to us, anyway) potential failure mode. This mode, known as “hot cracking,” is when impurities in the small stainless steel tubing spread out around stress lines during the molten cooling phase of laser welding, forming cracks only a handful of microns wide but several hundred long, which initially withstand pressure testing but may fail after extended thermal cycling.

    However, due to the dedication and talents of the teams involved, these problems have been overcome. We are well on the way to sending this new detector to CERN. If you have time, you should head out to SiDet to see it before it goes and gets buried deep in the heart of CMS, but you’ll have to hurry! The first of four half-cylinders complete with modules has been tested and is at CERN already, with the second one following this week, and the third and fourth within the next few weeks. Look for one of the people in the photo above, who will be happy to show you the fruits of their labor.

    See the full article here .

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 4:13 pm on September 13, 2016 Permalink | Reply
    Tags: Accelerator Science, , D+ mesons, , , Strong interaction   

    From FNAL: “CDF can’t stop being charming” 

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    September 8, 2016
    Jeffrey Appel

    FNAL/Tevatron map
    FNAL/Tevatron map

    FNAL/Tevatron CDF detector
    FNAL/Tevatron CDF detector

    Good news: there is a theory to describe the strong interaction, the interactions that bind the constituents of protons and neutrons together and create the strong force. Bad news: Calculations using the theory can be made in only a limited selection of natural phenomena.

    Quantitative predictions for interactions beyond that subset depend on measurements. This can be either for direct use or to help guide the theory about the inputs used in calculations, such as the distributions of the quark and gluon constituents inside protons and neutrons. Using the production of particles containing heavy charm and bottom quarks helps especially with gluon distributions.

    CDF is now reporting new measurements of the rate of production at the Tevatron of D+ mesons, which contain charm quarks. Furthermore, the new measurements are made in the region where the D+ mesons have the smallest momentum transverse to the incident beams. This is the region that is the hardest to calculate using the theory of strong interactions and has never been explored in proton-antiproton collisions.

    1
    This plot shows the measures, in bins of momentum transverse to incident protons, of the average probability of producing a D+ meson at the Tevatron. Shown as bands are the averages predicted in the same bins by the latest theoretical calculations.

    To probe such small transverse momenta, CDF physicists examined all types of interactions of the incoming protons and antiprotons, not just those selected to study rare occurrences.

    The results of this new analysis appear in the figure. The measurements lie within the band of uncertainty of the theoretical predictions. Using the results here, theorists can reduce the size of the band of uncertainty. They might also be able to improve the general trend of the predictions to agree better with the trends in the measurements.

    This measurement is an example of CDF’s continuing effort to produce unique and useful results that complement and supplement those of the LHC. These help improve our understanding of the fundamental forces of nature.

    Learn more.

    See the full article here .

    Please help promote STEM in your local schools.

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    FNAL Icon
    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 12:18 pm on September 12, 2016 Permalink | Reply
    Tags: Accelerator Science, , CERN HIE-ISOLDE, First physics experiment at HIE-ISOLDE begins, ,   

    From CERN: “First physics experiment at HIE-ISOLDE begins” 

    Cern New Bloc

    Cern New Particle Event

    CERN New Masthead

    CERN

    CERN ISOLDE New
    CERN ISOLDE

    1
    Miniball is one of two detection stations receiving beams from HIE-ISOLDE. It’s a very efficient gamma detector array, and will be permanently linked to the beams from HIE-ISOLDE (Image: CERN)

    This weekend the first physics experiment started running using radioactive beams from the newly upgraded HIE-ISOLDE facility. ISOLDE, the nuclear research facility at CERN, allows many different experiments to study the properties of atomic nuclei.

    The upgrade means the machine can now reach an energy of 5.5MeV per nucleon (MeV/u.), making ISOLDE the only facility in the world capable of investigating nuclei from the middle to heavy end of this energy range.

    The experiment is ready to go after the second of two cryomodules (containing the accelerating cavities)was installed – marking the end of the installation of phase one of HIE-ISOLDE.

    The HIE-ISOLDE (High Intensity Energy-ISOLDE) Project is a major upgrade of the ISOLDE facility, which will increase the energy, intensity and quality of the beams delivered to scientists.

    “It’s a major breakthrough. This is the result of eight years of development and manufacturing. This would not have been possible without the dedication of the technical staff at CERN. But what makes us most proud isn’t that we built a machine, but that we have attracted enthusiastic users to do forefront physics. We are looking forward to this exciting high intensity period,” says Yacine Kadi , leader of the HIE-ISOLDE project.

    2
    The tunnel at HIE-ISOLDE now contains two cryomodules – a unique set up that marks the end of phase one for the HIE-ISOLDE installation. By Spring 2018 the project will have four cryomodules installed and will be able to reach higher energy up to 10 MeV/u a broader range of nuclear physics (Image: Erwin Siesling/ CERN)

    This is the second physics run of the project (the first radioactive beam was run on 22 October 2015) but then the machine only had one cryomodule and was capable of running at an energy of just 4.3MeV/u.

    Now, with the second cryostat coupled on, the machine is capable of reaching up to 5.5 MeV/u and can investigate the structure of heavier isotopes.

    “It is a universal machine that can accelerate and investigate all nuclei from mass number 6 to mass 224 or more and at variable energies,” explains Maria Borge, leader of the ISOLDE group. “This year we’re investigating nuclei with mass number from 9 to 142 – these experiments can only be done at this moment at ISOLDE. At CERN.”

    HIE-ISOLDE will be capable of investigating nuclei of all masses when the additional two cryomodules are installed in 2018, as the machine will be able to accelerating them up to energies of 10MeV/u.

    The further upgrades mean that, while ISOLDE can currently collect information about the collective properties of isotopes, eventually researchers will be able to use the machine at higher intensities to investigate the properties of individual particles. This can be done at the moment for lower masses, but has never been done before for heavier isotopes.

    “The community has grown a lot recently, as people are attracted by the possibilities new higher energies bring. It’s a energy domain that’s not explored much, since no other facility in world can deliver pure beams at these energies,” Borge says.

    HIE-ISOLDE will run from now until mid-November. All but one of the seven different experiments planned during this time will use the Miniball detection station. The first experiment will investigate Tin, a special element with two double magic isotopes.


    Eight years since the start of the HIE-ISOLDE project, a new accelerator is in place taking nuclear physics at CERN to higher energies. The first physics run last year marked the start of the project, but after a new cryomodule was installed physicists are able to reach a greater energy of up to 5.5.MeV/u. With physicists setting their sights on even higher energies of 10 MeV/u in the future, they will continue to commission more HIE-ISOLDE accelerating cavities and beamlines in the years to come. (Video: Christoph Madsen/CERN)

    See the full article here.

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    Meet CERN in a variety of places:

    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 LHC Map
    CERN LHC Grand Tunnel

    CERN LHC particles

    Quantum Diaries

     
  • richardmitnick 9:16 am on September 9, 2016 Permalink | Reply
    Tags: Accelerator Science, , CERN DIRAC, ,   

    From Physics: “Synopsis: Strange Mesonic Atoms Detected” 

    Physics LogoAbout Physics

    Physics Logo 2

    Physics

    September 8, 2016
    Michael Schirber

    1
    DIRAC Collaboration, Phys. Rev. Lett. (2016)

    1
    The Dimeson Relativistic Atom Complex (DIRAC) is an experiment to help physicists gain a deeper insight into the fundamental force called the strong force. CERN

    An atom is normally a nucleus surrounded by electrons. But physicists have observed several exotic atoms comprising other particles, such as mesons (two-quark particles). Following earlier hints, a new analysis of data from the DIRAC experiment at CERN finds the first conclusive evidence of an atom made up of a π meson (containing up and down quarks) and a K meson (containing up and strange quarks). Further study of these strange dimesons should give insight into how quarks interact at relatively low energies.

    Meson-containing atoms, such as kaonic hydrogen (proton plus K) and pionium (two oppositely charged π mesons), are bound together by electromagnetic forces. However, strong force interactions between quarks cause the atoms to decay. Precise measurements of these decay lifetimes would place important constraints on the probabilities of low-energy quark scattering, which cannot be calculated directly.

    The DIRAC experiment was built to detect and characterize πK atoms (as well as ππ atoms). To create these bound states, the researchers fire a high-energy proton beam into a thin metal sheet. Collisions between protons and metal nuclei occasionally produce πK atoms, and some of these atoms collide with other nuclei, causing them to dissociate into unbound πK pairs. DIRAC is designed to detect these pairs using a double-arm mass spectrometer. Previous results showed evidence of πK atoms, but the underlying statistical significance was too low to claim a detection. The DIRAC collaboration has now combined data from trials using different metal sheets and has improved estimates of the background from πK pairs unrelated to atoms. The team reports the detection of over 300 πK atoms. Additional analysis is continuing to extract the lifetime of the πK decay.

    This research is published in Physical Review Letters.

    See the full article here .

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    Physicists are drowning in a flood of research papers in their own fields and coping with an even larger deluge in other areas of physics. How can an active researcher stay informed about the most important developments in physics? Physics highlights a selection of papers from the Physical Review journals. In consultation with expert scientists, the editors choose these papers for their importance and/or intrinsic interest. To highlight these papers, Physics features three kinds of articles: Viewpoints are commentaries written by active researchers, who are asked to explain the results to physicists in other subfields. Focus stories are written by professional science writers in a journalistic style and are intended to be accessible to students and non-experts. Synopses are brief editor-written summaries. Physics provides a much-needed guide to the best in physics, and we welcome your comments (physics@aps.org).

     
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