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  • richardmitnick 4:17 pm on April 16, 2018 Permalink | Reply
    Tags: Accelerator Science, , , , LARP-US LHC Accelerator Research Program, , ,   

    From CERN: “LHC luminosity upgrade project moving to next phase” [2015. Really? So what is new here?] 

    Cern New Bloc

    Cern New Particle Event

    CERN New Masthead

    CERN

    29 Oct 2015 [Really?]

    1
    29 October 2015. This week more than 230 scientists and engineers from around the world met at CERN1 to discuss the High-Luminosity LHC – a major upgrade to the Large Hadron Collider (LHC) that will increase the accelerator’s discovery potential from 2025.

    After a four year long design study the project is now moving into its second phase, which will see the development of industrial prototypes for various parts of the accelerator.

    Luminosity is a crucial indicator of performance for an accelerator. It is proportional to the number of particles colliding within a defined amount of time. Since discoveries in particle physics rely on statistics, the greater the number of collisions, the more chances physicists have to see a particle or process that they have not seen before.

    The High-Luminosity LHC will increase the luminosity by a factor of 10, delivering 10 times more collisions than the LHC would do over the same period of time.

    It will therefore provide more accurate measurements of fundamental particles and enable physicists to observe rare processes that occur below the current sensitivity level of the LHC. With this upgrade, the LHC will continue to push the limits of human knowledge, enabling physicists to explore beyond the Standard Model and Brout-Englert-Higgs mechanism.

    “The LHC already delivers proton collisions at the highest energy ever,” said CERN Director General Rolf Heuer. “The High-Luminosity LHC will produce collisions 10 times more rapidly, increasing our discovery potential and transforming the LHC into a machine for precision studies: the natural next step for the high energy frontier.”

    The increase in luminosity will mean physicists will be able to study new phenomena discovered by the LHC, such as the Higgs boson, in more detail. The High-Luminosity LHC will produce 15 million Higgs bosons per year compared to the 1.2 million in total created at the LHC between 2011 and 2012.

    Upgrading the LHC will be a challenging procedure and relies on several breakthrough technologies currently under development.

    “We have to innovate in many fields, developing cutting-edge technologies for magnets, the optics of the accelerator, superconducting radiofrequency cavities, and superconducting links,” explained Lucio Rossi, Head of the High-Luminosity LHC project.

    Some 1.2 km of the LHC will be replaced by these new technologies, which include cutting-edge 12 Tesla superconducting quadrupole magnets built using a superconducting compound of niobium and tin [built by whom?*]. These will strongly focus the beam to increase the probability of collisions occurring and will be installed at each side of the ATLAS and CMS experiments.

    There are also brand new superconducting radiofrequency cavities, called “crab cavities” [built by whom?*], which will be used to orientate the beam before the collision to increase the length of the area where the beams overlap. New electrical transfer lines, based on high temperature superconductors, will be able to carry currents of record intensities to the accelerator, up to 100,000 amps, over 100 metres.

    “The High-Luminosity LHC will use pioneering technologies – such as high field niobium-tin magnets [built by whom?] – for the first time,” said Frédérick Bordry, CERN Director for Accelerators and Technology. “This will not only increase the discovery potential of the LHC but also serve as a proof of concept for future accelerators.”

    All these technologies have been explored since 2011 in the framework of the HiLumi LHC Design Study – partly financed by the European Commission’s FP7 programme. HiLumi LHC brought together a large number of laboratories from CERN’s member states, as well as from Russia, Japan and the US. American institutes participated in the project with the support of the US LHC Accelerator Research Program (LARP), funded by the U.S. Department of Energy. Some 200 scientists from 20 countries collaborated on this first successful phase.

    The meeting this week marks the end of this hugely complex and collaborative design phase of the High-Luminosity LHC project. The project will now focus on the prototyping and industrialization of the technologies before the construction phase can begin.

    *Outside builders, such as BNL,FNAL,LBNL, SLAC, DESY, KEK, etc. deserve to be credited.

    See the full article here.

    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 New

    CMS
    CERN CMS New

    LHCb
    CERN LHCb New II

    LHC

    CERN LHC 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

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  • richardmitnick 10:12 am on April 16, 2018 Permalink | Reply
    Tags: Accelerator Science, , , , , , , Ready- Set- Go   

    From CERN ALICE: “Ready, Set, Go” 

    CERN
    CERN New Masthead

    16 April 2018
    Virginia Greco

    During the recent weeks, test, calibration and configuration activities were carried on to prepare the ALICE detector for the imminent restart of beam. In advance with respect to the original plan, the LHC is expected to deliver collisions with stable beams on 17 April.

    1
    The LHC is getting ready for injecting physics beam. The first collisions with stable beams of 2018 will be delivered between 16 and 17 of April.

    Thanks to the excellent performance exhibited by the LHC during the latest weeks, the schedule of the accelerator restarting has been compressed and collisions with stable beams will be delivered beforehand. As a consequence, the ALICE experiment has sped up its commissioning as well to be ready to take data as soon as possible.

    The operations in the experimental cavern, which included some minor repairing and interventions on the muon arm and the TPC, are concluded. Technical runs were started at the beginning of March. During them, the various detectors and systems were left working for many hours in a row – without beams in the accelerator – to check their correct functioning and their stability over time. In the first two weeks, these tests were performed only between 7 am and 11 pm and then the detector switched off, so that no crew was required to stay in the control room at night. Following this, full shifts (24 hours a day) were started and tests continued. Dry runs like these are key to the preparation for data taking, since they allow the experts to identify possible issues and glitches and to fix them in time for the restart.

    The detectors were gradually included in these common coordinated runs but only after successfully completing a reintegration procedure of their detector control system (DCS), necessary to ensure proper transitioning of detectors from normal to beam-safe running conditions.

    CERN/ALICE Detector

    ALICE Run Control Center

    The TPC and the TRD also went through an energy calibration (called “krypton calibration”) performed using a solid rubidium source, which decays into a gaseous excited state of krypton that mixes with the gas volumes of the detectors. This excited state returns to its ground state inside the detector with a known energy spectrum.

    The Data Acquisition System (DAQ) together with the Central Trigger Processor (CTP) and the High-Level Trigger (HLT), in turn, worked to get prepared for the Pb-Pb collisions that will be delivered at the end of the year, from November on. In particular, various tests have been carried out – and will be continued throughout the year whenever possible – to check, tune and improve how the full chain (from the detector signals to the final data storage) behaves when pushed to the limit of its capacity. Specifically, ‘fake’ events, carrying no meaningful information but having rates and sizes similar to those of the events expected in the future Pb-Pb collisions, were generated to put a significant load on the data channels and – partially – on the processing stages.

    After completion of two weeks of dry runs, the ALICE magnet was switched on and data from cosmic ray interactions were taken with many of the detectors until the accelerator team was ready to start test injection in the beam pipe.

    During this beam operation time, when the experts of the machine put in place their commissioning procedure, the ALICE detector has been put in a beam-safe state. In practice, only the systems that have minimal risk of being damaged when hit by the beam when switched on can actually run. The others have to stay in standby mode or run in a non-standard configuration (for example, no high voltage is applied to the detectors that normally require it).

    Collisions with unstable beams were delivered on April 12 and stable beams will be declared at some point between 16 and 17 of April. The ALICE experiment is all set and ready to start its 2018 race.

    See the full article here .

    Please help promote STEM in your local schools.

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    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/LHC Map
    CERN LHC Grand Tunnel

    CERN LHC particles


    Quantum Diaries

     
  • richardmitnick 8:58 am on April 13, 2018 Permalink | Reply
    Tags: Accelerator Science, , First LHC test collisions of 2018, , , ,   

    From CERN: “First LHC collisions of 2018” 

    Cern New Bloc

    Cern New Particle Event

    CERN New Masthead

    CERN

    12 Apr 2018
    Ana Lopes

    1
    A test collision recorded by the CMS experiment on 12 April 2018. The CMS collaboration uses these first collisions to prepare for data taking, fine-tuning and powering on various subsystems as needed. (Image: CERN)

    Proton slamming has resumed at the Large Hadron Collider (LHC). Almost a fortnight after the collider began circulating proton beams for the first time in 2018, the machine’s operations team has today steered beams into collision. While these are only test collisions, they are an essential step along the way to serious data taking, which is expected to kick off in early May.

    Achieving first test collisions is anything but an easy job. It involves round-the-clock checking and rechecking of the thousands of systems that comprise the LHC. It includes ramping up the energy of each beam to the operating value of 6.5 TeV, checking the beams’ instrumentation and optics, testing electronic feedback systems, aligning jaw-like devices called collimators that close around the beams to absorb stray particles and, finally, focusing the beams to make them collide.

    Each beam consists of packets of protons called bunches. For these test collisions, each beam contains only two “nominal” bunches, each made up of 120 billion protons. This is far fewer than the 1200 bunches per beam that will mark the start of serious data taking and particle hunting. As the year progresses, the operations team will continue to increase the number of bunches in each beam, up to the maximum of 2556.

    With today’s test collisions, the teams of the experiments located at four collision points around the LHC ring (ALICE, LHCb, CMS and ATLAS) will now be able to check and calibrate their detectors. Stay tuned for the next steps.

    Beams are back in the LHC
    29 Mar 2018
    Corinne Pralavorio

    3
    View of the LHC in 2018, before the restart of the accelerato. (Image: Maximilien Brice, Julien Ordan/CERN)

    The Large Hadron Collider is back in business! On Friday 30 March, at 12:17 pm, protons circulated in the 27-km ring for the first time in 2018. The world’s most powerful particle accelerator thus entered its seventh year of data taking and its fourth year at 13 TeV collision energy.

    Restarting an accelerator involves much more than just flicking a switch, especially as the LHC is the final link in an accelerator chain comprising five separate machines. Following the winter break, which enabled teams to carry out a whole host of maintenance operations, the machine operators gradually have brought the infrastructures and accelerators back on line. At the beginning of March, the first protons were extracted from their hydrogen bottle and injected into the Linac2, and then into the PS Booster. On 8 March, it was the turn of the Proton Synchrotron (PS) to receive beams, and then, a week later, the Super Proton Synchrotron (SPS).

    4
    Applause in the CERN Control Centre after the beam makes a first turn of the LHC loop. Sitting, the operators in charge of restarting the accelerator. Standing behind them, from left to right, Rende Steerenberg, Head of Operation, Frédérick Bordry, Director for Accelerators and Technology, Fabiola Gianotti, CERN Director-General, Rossano Giachino, from the LHC operation team, and Jörg Wenninger, in charge of the LHC operation team. (Image: CERN)

    In parallel, the teams have been checking all the LHC hardware, such as the cryogenic cooling systems, the radiofrequency cavities (which accelerate the particles), the power supplies, the magnets, the vacuum system and the safety installations. For example, no fewer than 1 560 electrical circuits had to be powered and about 10 000 tests performed. Only once all these tests had been completed could particles be injected into the LHC.

    Even so, commissioning is far from over. The first beams circulating only have one bunch of particles, which contains 20 times fewer protons than in normal operation. And their energy is limited to the injection energy of 450 GeV. Further adjustments and tests will be needed over the coming days before the energy and the number of bunches in each beam can be increased and the bunches squeezed to produce first collisions. Physics operation should start in May.

    The operation objective for 2018 is to accumulate more data than in 2017: the target is 60 inverse femtobarns (fb-1) of integrated luminosity (against 50 fb-1 in 2017). Luminosity is a measurement of the number of potential collisions per surface unit in a given period of time.

    5
    “LHC page 1” shows the status of the LHC on 30 March. The blue line on the right of the screen indicates the first beam circulating in the LHC in 2018. (Image: CERN)

    While we await collisions in the LHC, data taking is already starting elsewhere. CERN’s accelerators provide particles for a diverse array of experiments. The PS has already started supplying beams to the nuclear physics facility n_TOF and to the experiments in the East Hall. The nuclear physics programme at ISOLDE should start up on 9 April, while the Antiproton decelerator should start again in the second half of April.

    2018 is an important year for the collaborations using CERN’s accelerators, as it will be the last year of Run 2. In December, the accelerator complex will be shut down for two years of upgrade work aimed at improving performance further still and preparing for the High-Luminosity LHC.

    Accelerator hibernation ends

    9 Mar 2018
    Achintya Rao

    Today, 9 March, marks the end of CERN’s annual winter shut down. The Laboratory’s massive accelerator complex will soon begin to lumber out of its winter hibernation and resume accelerating and colliding particles.

    But while the Large Hadron Collider (LHC) has not been filled with protons since the Year-End Technical Stop (YETS) began on 4 December 2017, its tunnels and experimental caverns have been packed with people performing maintenance and repairs as well as testing components for future accelerators.

    Today, CERN’s Engineering department hands the accelerator complex back to the Beams department, who will commence hardware commissioning for 2018. This commissioning will culminate in the restart of the LHC, planned for early April.

    See the full article and following articles here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    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 LHC 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

     
  • richardmitnick 2:42 pm on April 10, 2018 Permalink | Reply
    Tags: Accelerator Science, , , , Now the question is what if there is a whole sector of undiscovered particles that cannot communicate with our standard particles but can interact with the Higgs boson?, , , , , Theorists predict that about 90 percent of Higgs bosons are created through gluon fusion   

    From Symmetry: “How to make a Higgs boson” 

    Symmetry Mag
    Symmetry

    04/10/18
    Sarah Charley

    CERN CMS Higgs Event


    CERN ATLAS Higgs Event

    It doesn’t seem like collisions of particles with no mass should be able to produce the “mass-giving” boson, the Higgs. But every other second at the LHC, they do.

    Einstein’s most famous theory, often written as E=mc2, tells us that energy and matter are two sides of the same coin.

    The Large Hadron Collider uses this principle to convert the energy contained within ordinary particles into new particles that are difficult to find in nature—particles like the Higgs boson, which is so massive that it almost immediately decays into pairs of lighter, more stable particles.

    LHC

    CERN/LHC Map

    CERN LHC Tunnel

    CERN LHC particles

    But not just any collision can create a Higgs boson.

    “The Higgs is not just created from a ‘poof’ of energy,” says Laura Dodd, a researcher at the University of Wisconsin, Madison. “Particles follow a strict set of laws that dictate how they can form, decay and interact.”

    One of these laws states that Higgs bosons can be produced only by particles that interact with the Higgs field—in other words, particles with mass.

    The Higgs field is like an invisible spider’s web that permeates all of space. As particles travel through it, some get tangled in the sticky tendrils, a process that makes them gain mass and slow down. But for other particles—such as photons and gluons—this web is completely transparent, and they glide through unhindered.

    Given enough energy, the particles wrapped in the Higgs field can transfer their energy into it and kick out a Higgs boson. Because massless particles do not interact with the Higgs field, it would make sense to say that they can’t create a Higgs. But scientists at the LHC would beg to differ.

    The LHC accelerates protons around its 17-mile circumference to just under the speed of light and then brings them into head-on collisions at four intersections along its ring. Protons are not fundamental particles, particles that cannot be broken down into any smaller constituent pieces. Rather they are made up of gluons and quarks.

    As two pepped-up protons pass through each other, it’s usually pairs of massless gluons that infuse invisible fields with their combined energy and excite other particles into existence—and that includes Higgs bosons.

    __________________________________________________________

    We know that particles follow strict rules about who can talk to whom.
    __________________________________________________________

    How? Gluons have found a way to cheat.

    “It would be impossible to generate Higgs bosons with gluons if the collisions in the LHC were a simple, one-step processes,” says Richard Ruiz, a theorist at Durham University’s Institute for Particle Physics Phenomenology.

    Luckily, they aren’t.

    Gluons can momentarily “launder” their energy to a virtual particle, which converts the gluon’s energy into mass. If two gluons produce a pair of virtual top quarks, the tops can recombine and annihilate into a Higgs boson.

    To be clear, virtual particles are not stable particles at all, but rather irregular disturbances in quantum mechanical fields that exist in a half-baked state for an incredibly short period of time. If a real particle were a thriving business, then a virtual particle would be a shell company.

    Theorists predict that about 90 percent of Higgs bosons are created through gluon fusion. The probability of two gluons colliding, creating a top quark-antitop pair and propitiously producing a Higgs is roughly one in 2 billion. However, because the LHC generates 10 million proton collisions every second, the odds are in scientists’ favor and the production rate for Higgs bosons is roughly one every two seconds.

    Shortly after the Higgs discovery, scientists were mostly focused on what happens to Higgs bosons after they decay, according to Dodd.

    “But now that we have more data and a better understanding of the Higgs, we’re starting to look closer at the collision byproducts to better understand how frequently the Higgs is produced through the different mechanisms,” she says.

    The Standard Model of particle physics predicts that almost all Higgs bosons are produced through one of four possible processes.

    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

    What scientists would love to see are Higgs bosons being created in a way that the Standard Model of particle physics does not predict, such as in the decay of a new particle. Breaking the known rules would show that there is more going on than physicists previously understood.

    “We know that particles follow strict rules about who can talk to whom because we’ve seen this time and time again during our experiments,” Ruiz says. “So now the question is, what if there is a whole sector of undiscovered particles that cannot communicate with our standard particles but can interact with the Higgs boson?”

    Scientists are keeping an eye out for anything unexpected, such as an excess of certain particles radiating from a collision or decay paths that occur more or less frequently than scientists predicted. These indicators could point to undiscovered heavy particles morphing into Higgs bosons.

    At the same time, to find hints of unexpected ingredients in the chain reactions that sometimes make Higgs bosons, scientists must know very precisely what they should expect.

    “We have fantastic mathematical models that predict all this, and we know what both sides of the equations are,” Ruiz says. “Now we need to experimentally test these predictions to see if everything adds up, and if not, figure out what those extra missing variables might be.”

    See the full article here .

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 5:35 pm on April 6, 2018 Permalink | Reply
    Tags: Accelerator Science, , , , , , ,   

    From University of Toronto: “U of T staff (ethically) hack CERN, world’s largest particle physics lab” 

    U Toronto Bloc

    University of Toronto

    1
    CERN, the international lab near Geneva, is home to the Large Hadron Collider, the world’s largest particle accelerator (photo by Claudia Marcelloni/CERN).
    U of T staff (ethically) hack CERN, world’s largest particle physics lab.
    In Geneva, where U of T scientists are on the frontier of physics with world’s largest particle accelerator.

    It takes 22 member states, more than 10,000 scientists and state-of-the-art technology for CERN to investigate the mysteries of the universe. But no matter how cutting-edge a system is, it can have vulnerabilities – and last year University of Toronto employees helped CERN find theirs.

    CERN, the European Organization for Nuclear Research, asked for help to hack its digital infrastructure last year, organizing the White Hat Challenge. Allan Stojanovic and David Auclair from U of T’s ITS Information Security Enterprise and Architecture department, along with a group of security professionals, were more than willing to answer the call.

    Passionate advocates for information security, Stojanovic and Auclair say regular testing is essential for any organization.

    “Vulnerabilities are not created, they are discovered,” says Stojanovic. “Just because something has been working, doesn’t mean there wasn’t a flaw in it all along.”

    Their director, Mike Wiseman, supported their participation in the challenge. “This competition was an opportunity to bring experts together to exercise their skill as well as give CERN a valuable test of their infrastructure.”

    Stojanovic first heard about the challenge during a presentation at a Black Hat digital security conference. He jumped at the opportunity, immediately approaching the presenter, Stefan Lüders, CERN’s security manager.

    Stojanovic put together a group of eight industry professionals (pen testers, consultants, Computer Information Systems administrators and programmers), set goals for the test and created a ten-day timeline.

    Any penetration test involves three main stages: scoping, reconnaissance and scanning. Before the scanning stage begins, testers are not allowed to interact with the system directly, but try to learn everything they can about it.

    During the “scoping” stage, testers define what is “in scope” and specify what IP spaces and domains they can and cannot probe during the testing. The “recon” stage is exactly what it sounds like: reconnaissance. The testers try to find out everything they can about the domains that are in scope, helping guide them towards potential weaknesses.

    With scoping and recon complete, the team was able to officially begin the scanning stage. Scanning is like a huge treasure hunt, beginning with a broad search and gradually narrowing it down, burrowing deeper and deeper into the most interesting areas and letting go of the others.

    This went on for nine days. It was a gruelling process – the team would find a tiny foothold, investigate it, but nothing significant would emerge. This happened again and again.

    Finally, Stojanovic was woken up one day by a short message, “I got it!” Someone on the team had solved the puzzle – a breakthrough generated by multiple late nights of patient analysis.

    Details of the breakthrough are kept secret due to a confidentiality agreement with CERN. But after more than two weeks of work, the team revealed weaknesses in CERN’s security infrastructure and provided important recommendations on how to improve it.

    CERN’s security group was then able to roll out fixes and address the identified vulnerabilities before U of T’s formal report even hit their desks.

    Stojanovic hopes that his team’s success will encourage educators to use penetration testing as a pedagogical tool. “It’s a lot of really fantastic experience,” he says, adding that these are the hands-on skills that new security professionals are going to need in the fast-growing information security industry.

    Stojanovic hopes that other institutions, including U of T, will follow CERN’s lead in opening themselves up to testing of this nature.

    And this won’t be the last CERN will see of U of T – Lüders has already asked for round two.

    The U of T at CERN

    Working on a small piece of the world’s largest experiment, it’s easy to lose sight of the big picture.

    Kyle Cormier, a University of Toronto grad student in particle physics, is a member of U of T’s research group at CERN, the sprawling international lab on the French-Swiss border that is home to the largest particle accelerator, the Large Hadron Collider.

    His job? Researching a silicon microchip for a planned upgrade to the 7,000-tonne Atlas detector, one of four major experiments at the LHC. He has designed, tested and redesigned the chip to withstand extreme cold and radiation exposure – all so that it can read data from proton collisions without needing a tune-up for at least a decade.

    It may not sound glamorous, but it’s the type of precise, exacting work that led CERN researchers to the 2012 discovery of the Higgs boson, a particle that had been theorized in the 1960s.

    “If you’re on a big hike up a mountain, you’re stepping over root branches working your way up,” Cormier says.

    2
    Professor Pekka Sinervo and U of T students, including Vincent Pascuzzi, Joey Carter, Laurelle Veloce, Kyle Cormier (seated right), at CERN outside Geneva (photo by Geoffrey Vendeville)

    At first glance, CERN, a collection of low-slung concrete buildings on the outskirts of Geneva, doesn’t look like a state-of-the-art, multibillion-dollar research facility. But deep underground, the accelerator races protons around a 27-kilometre ring until they are travelling nearly the speed of light and then smashes them together. Like crash scene investigators looking for clues in rubble, scientists analyze the debris from the collisions, which send subatomic particles flying in every direction.

    CERN scientists used this method to detect the Higgs boson in 2012, a particle explaining why others have mass. Now they’re digging even deeper, investigating questions such as the nature of dark matter.

    The mysterious type of matter, which makes up more than a quarter of the universe, has puzzled scientists since the first clues about its existence arose in the 1930s through astronomical observation and calculations.

    “We’re at the point where we’ve looked where the light’s brightest,” says Pekka Sinervo, a professor of experimental high energy physics at U of T. “Now we’re looking in all the dark corners that are hard to investigate.”

    3

    Researchers may still be a long way off from answering the dark matter riddle, but some breakthrough is just a matter of time, says Laurelle Veloce, who is also studying particle physics at U of T and working at CERN.

    “You just put one foot in front of the other and eventually you know someone will find something,” she says.

    The U of T research group is the largest Canadian team working on the Atlas experiment, with 17 graduate students, four postdocs and six faculty members. Over the summer, undergraduate students can take a summer course at CERN.

    Olivier Arnaez, now a U of T postdoc, spent years searching for the Higgs. When CERN researchers had gathered enough statistical evidence to confirm the discovery of a new particle, there was no eureka moment, he recalls – just relief.

    “We were happy because we knew we could sleep soon,” he says, “which didn’t happen because we then had to investigate more properties of the Higgs.” The celebrations involved litres of champagne and Nobel prizes for the theorists who proposed the Higgs mechanism decades earlier.

    Years of research at CERN haven’t been without setbacks, however. Only nine days after the first successful beam tests in 2008, a soldering error caused an accident that put the project behind schedule by more than 18 months. And last year, researchers who thought they had discovered another new particle admitted they had misinterpreted the data.

    But researchers are still hopeful and morale remains high, says Sinervo.

    “We’re trying to do things every day that nobody has ever done before,” he says.

    Engineering a microchip to work for 10 years without the need for repair, as his student Cormier is doing, is no small feat, he adds. “That’s like how you build spaceships for a moonshot.

    “We know that there is going to be some discovery over the horizon,” Sinervo says. “How far do we have to go to reach it? That’s something we don’t know.”

    See the full article here .

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    U Toronto Campus

    Established in 1827, the University of Toronto has one of the strongest research and teaching faculties in North America, presenting top students at all levels with an intellectual environment unmatched in depth and breadth on any other Canadian campus.

    Established in 1827, the University of Toronto has one of the strongest research and teaching faculties in North America, presenting top students at all levels with an intellectual environment unmatched in depth and breadth on any other Canadian campus.

     
  • richardmitnick 4:37 pm on April 6, 2018 Permalink | Reply
    Tags: Accelerator Science, , , , , , , ,   

    From DESY: “Electron beams that chop themselves” 

    DESY
    DESY

    2018/04/06

    First experimental proof of self-modulation of particle bunches.

    1
    View through the plasma cell along the flight path of the electron beam. Visible in the middle is the pink glow of the plasma. Credit: DESY, Johannes Engel.

    In a multi-national effort a team of researchers from DESY, the Lawrence Berkeley National Laboratory (LBNL) and other institutes have demonstrated a remarkable feature of self-organisation in a particle beam that can be of great use for a future generation of compact accelerators: Using the high quality electron beam at DESY’s PITZ facility, the scientists could show that long electron bunches can chop themselves into a row of shorter bunches when they fly through a cloud of electrically charged gas, called a plasma.

    At the same time the electrons’ energies were seen to be modulated along each bunch. These results are the experimental proof of a novel plasma acceleration concept pursued by the AWAKE (Advanced Wakefield Experiment) collaboration at the European particle physics lab CERN in Geneva. The team led by DESY scientist Matthias Groß presents its findings in the journal Physical Review Letters.

    Particle accelerators at the energy frontier like the Large Hadron Collider (LHC) at CERN are extremely costly to build and operate.

    LHC

    CERN/LHC Map

    CERN LHC Tunnel

    CERN LHC particles

    Nevertheless there is strong interest to increase available beam energies even further to refine the standard model of particle physics and discover physics beyond. Plasma wakefield accelerators could be the answer to this problem. Today’s bulky structures could be replaced with millimetre-sized plasmas enabling several orders of magnitude stronger acceleration.

    To accelerate an electron bunch in this way the plasma electrons are separated from the plasma molecules, forming a so-called plasma wakefield that creates an immense accelerating field. The separation of electrons and molecules in the plasma can be achieved through a high-energy bunch of charged particles. Using proton bunches is very attractive since sufficient energy can be stored in a proton beam to drive a plasma accelerator and generate electron bunches with energies in the LHC regime of tera-electronvolts (TeV) in a single stage. The AWAKE experiment is hosted by CERN to investigate this promising scheme. However, proton bunches as they are generated in today’s accelerators are much too long to be useful in plasma accelerators. Therefore, the generation of suitable proton bunches from a conventional accelerator is a key issue for the AWAKE setup.

    CERN AWAKE

    CERN AWAKE

    2
    A self-modulated electron bunch. Credit: DESY

    This task can be accomplished by utilising the so-called self-modulation instability. In this case a plasma wave is initiated at or near the front of the bunch and the resulting electric fields lead to the desired re-organisation of the particle bunches in the beam. This self-modulation effect was described in theory and simulation, but so far only indirect indications were observed in experiment. This is where the unique capabilities of the PITZ facility comes into play, explains group leader Frank Stephan: “The combination of a flexible photocathode laser, high electron beam quality and excellent diagnostics made it possible to demonstrate this effect unambiguously for the first time.” The measurements showed that an incident long electron bunch split itself into three smaller bunches.

    1
    DESY PITZ

    ”The breakthrough results described in our manuscript can be scaled directly to the proton regime and thus open the path to validate the self-modulation scheme towards the next-generation of high-energy physics accelerators at CERN,” emphasises main author Matthias Groß. “Our positive results show that the self-modulation can be practically used in experiments and that unwanted effects like beam hosing, which tend to destroy particle bunches, can be kept under control. This experimental data has been eagerly anticipated in the plasma wakefield accelerator community, especially by the AWAKE collaboration, for several years. The presented achievement is a further example where a plasma wakefield theory based prediction is directly validated in experiment. And looking ahead, our special cross shaped plasma cell which was utilized to gain these results may be of great interest to other groups working on beam-driven plasma wakefield acceleration as well.”

    See the full article here .

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    desi

    DESY is one of the world’s leading accelerator centres. Researchers use the large-scale facilities at DESY to explore the microcosm in all its variety – from the interactions of tiny elementary particles and the behaviour of new types of nanomaterials to biomolecular processes that are essential to life. The accelerators and detectors that DESY develops and builds are unique research tools. The facilities generate the world’s most intense X-ray light, accelerate particles to record energies and open completely new windows onto the universe. 
That makes DESY not only a magnet for more than 3000 guest researchers from over 40 countries every year, but also a coveted partner for national and international cooperations. Committed young researchers find an exciting interdisciplinary setting at DESY. The research centre offers specialized training for a large number of professions. DESY cooperates with industry and business to promote new technologies that will benefit society and encourage innovations. This also benefits the metropolitan regions of the two DESY locations, Hamburg and Zeuthen near Berlin.

     
  • richardmitnick 2:44 pm on April 5, 2018 Permalink | Reply
    Tags: Accelerator Science, , , , , , Particle Physicists begin to invent reasons to build next larger Particle Collider, , ,   

    From BBC via Back Reaction: “Particle Physicists begin to invent reasons to build next larger Particle Collider” 

    BBC
    BBC

    Back Reaction

    April 04, 2018

    2
    Sabine Hossenfelder

    Nigel Lockyer, the director of Fermilab [FNAL], recently spoke to BBC about the benefits of building a next larger particle collider, one that reaches energies higher than the Large Hadron Collider (LHC).

    Nigel Lockyer

    ,

    Such a new collider could measure more precisely the properties of the Higgs-boson. But that’s not all, at least according to Lockyer. He claims he knows there is something new to discover too:

    “Everybody believes there’s something there, but what we’re now starting to question is the scale of the new physics. At what energy does this new physics show up,” said Dr Lockyer. “From a simple calculation of the Higgs’ mass, there has to be new science. We just can’t give up on everything we know as an excuse for where we are now.”

    First, let me note that “everybody believes” is an argument ad populum. It isn’t only non-scientific, it is also wrong because I don’t believe it, qed. But more importantly, the argument for why there has to be new science is wrong.

    To begin with, we can’t calculate the Higgs mass; it’s a free parameter that is determined by measurement. Same with the Higgs mass as with the masses of all other elementary particles. But that’s a matter of imprecise phrasing, and I only bring it up because I’m an ass.

    The argument Lockyer is referring to are calculations of quantum corrections to the Higgs-mass. I.e., he is making the good, old, argument from naturalness.

    If that argument were right, we should have seen supersymmetric particles already. We didn’t. That’s why Giudice, head of the CERN theory division, has recently rung in the post-naturalness era. Even New Scientist took note of that. But maybe the news hasn’t yet arrived in the USA.

    Naturalness arguments never had a solid mathematical basis. But so far you could have gotten away saying they are handy guides for theory development. Now, however, seeing that these guides were bad guides in that their predictions turned out incorrect, using arguments from naturalness is no longer scientifically justified. If it ever was. This means we have no reason to expect new science, not in the not-yet analyzed LHC data and not at a next larger collider.

    Of course there could be something new. I am all in favor of building a larger collider and just see what happens. But please let’s stick to the facts: There is no reason to think a new discovery is around the corner.

    I don’t think Lockyer deliberately lied to BBC. He’s an experimentalist and probably actually believes what the theorists tell him. He has all reasons for wanting to believe it. But really he should know better.

    Much more worrisome than Lockyer’s false claim is that literally no one from the community tried to correct it. Heck, it’s like the head of NASA just told BBC we know there’s life on Mars! If that happened, astrophysicists would collectively vomit on social media. But particle physicists? They all keep their mouth shut if one of theirs spreads falsehoods. And you wonder why I say you can’t trust them?

    Meanwhile Gordon Kane, a US-Particle physicist known for his unswerving support of super-symmetry, has made an interesting move: he discarded of naturalness arguments altogether.

    You find this in a paper which appeared on the arXiv today. It seems to be a promotional piece that Kane wrote together with Stephen Hawking some months ago to advocate the Chinese Super Proton Proton Collider (SPPC) [So far, the Chinese physics community thinks this is a waste of money.].

    Kane has claimed for 15 years or so that the LHC would have to see supersymmetric particles because of naturalness. Now that this didn’t work out, he has come up with a new reason for why a next larger collider should see something:

    “Some people have said that the absence of superpartners or other phenomena at LHC so far makes discovery of superpartners unlikely. But history suggests otherwise. Once the [bottom] quark was found, in 1979, people argued that “naturally” the top quark would only be a few times heavier. In fact the top quark did exist, but was forty-one times heavier than the [bottom] quark, and was only found nearly twenty years later. If superpartners were forty-one times heavier than Z-bosons they would be too heavy to detect at LHC and its upgrades, but could be detected at SPPC.”

    Indeed, nothing forbids superpartners to be forty-one times heavier than Z-bosons. Neither is there anything that forbids them to be four-thousand times heavier, or four billion times heavier. Indeed, they don’t even have to be there at all. Isn’t it beautiful?

    Leaving aside that just because we can’t calculate the masses doesn’t mean they have to be near the discovery-threshold, the historical analogy doesn’t work for several reasons.

    Most importantly, quarks come in pairs that are SU(2) doublets. This means once you have the bottom quark, you know it needs to have a partner. If there wouldn’t be one, you’d have to discontinue the symmetry of the standard model which was established with the lighter 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

    Supersymmetry, on contrast, has no evidence among the already known particles speaking in its favor.

    Standard model of Supersymmetry DESY

    Physicists also knew since the early 1970s that the weak nuclear force violates CP-invariance, which requires (at least) three generations of quarks. Because of this, the existence of both the bottom and top quark were already predicted in 1973.

    Finally, for anomaly cancellation to work you need equally many leptons as quarks, and the tau and tau-neutrino (third generation of leptons) had been measured already in 1975 and 1977, respectively. (We also know the top quark mass can’t be too far away from the bottom quark mass, and the Higgs mass has to be close by the top quark mass, but this calculation wasn’t available in the 1970s.)

    In brief this means if the top quark had not been found, the whole standard model wouldn’t have worked. The standard model, however, works just fine without supersymmetric particles.

    Of course Gordon Kane knows all this. But desperate times call for desperate measures I guess.

    In the Kane-Hawking pamphlet we also read:

    “In addition, a supersymmetric theory has the remarkable property that it can relate physics at our scale, where colliders take data, with the Planck scale, the natural scale for a fundamental physics theory, which may help in the efforts to find a deeper underlying theory.”

    I don’t disagree with this. But it’s a funny statement because for 30 years or so we have been told that supersymmetry has the virtue of removing the sensitivity to Planck scale effects. So, actually the absence of naturalness holds much more promise to make that connection to higher energy. In other words, I say, the way out is through.

    I wish I could say I’m surprised to see such wrong claims boldly being made in public. But then I only just wrote two weeks ago that the lobbying campaign is likely to start soon. And, lo and behold, here we go.

    See the full article here .

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  • richardmitnick 10:45 am on April 5, 2018 Permalink | Reply
    Tags: A Second 'Big Bang' Could End Our Universe in an Instant, Accelerator Science, , , , , , , , , Thanks to The Higgs Boson   

    From Harvard via Science Alert: “A Second ‘Big Bang’ Could End Our Universe in an Instant, Thanks to The Higgs Boson” 

    Harvard University
    Harvard University

    ScienceAlert

    Science Alert

    Well, that’s just great.

    1
    A Black Hole Artist Concept. (NASA/JPL-Caltech)

    5 APR 2018
    JEREMY BERKE, BUSINESS INSIDER

    Our universe may end the same way it was created: with a big, sudden bang. That’s according to new research from a group of Harvard physicists, who found that the destabilization of the Higgs boson – a tiny quantum particle that gives other particles mass – could lead to an explosion of energy that would consume everything in the known universe and upend the laws of physics and chemistry.

    As part of their study, published last month in the journal Physical Review D, the researchers calculated when our universe could end.

    It’s nothing to worry about just yet. They settled on a date 10139 years from now, or 10 million trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion years in the future. And they’re at least 95 percent sure – a statistical measure of certainty – that the universe will last at least another 1058 years.

    The Higgs boson, discovered in 2012 by researchers smashing subatomic protons together at the Large Hadron Collider, has a specific mass.

    LHC

    CERN/LHC Map

    CERN LHC Tunnel

    CERN LHC particles

    CERN CMS Higgs Event

    CERN ATLAS Higgs Event

    If the researchers are correct, that mass could change, turning physics on its head and tearing apart the elements that make life possible, according to the New York Post.

    And rather than burning slowly over trillions of years, an unstable Higgs boson could create an instantaneous bang, like the Big Bang that created our universe.

    The researchers say a collapse could be driven by the curvature of space-time around a black hole, somewhere deep in the universe. When space-time curves around super-dense objects, like a black hole, it throws the laws of physics out of whack and causes particles to interact in all sorts of strange ways.

    The researchers say the collapse may have already begun – but we have no way of knowing, as the Higgs boson particle may be far away from where we can analyse it, within our seemingly infinite universe. “It turns out we’re right on the edge between a stable universe and an unstable universe,” Joseph Lykken, a physicist from the Fermi National Accelerator Laboratory who was not involved in the study, told the Post.

    He added: “We’re sort of right on the edge where the universe can last for a long time, but eventually, it should go ‘boom.'”

    See the full article here .

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    Harvard University campus
    Harvard is the oldest institution of higher education in the United States, established in 1636 by vote of the Great and General Court of the Massachusetts Bay Colony. It was named after the College’s first benefactor, the young minister John Harvard of Charlestown, who upon his death in 1638 left his library and half his estate to the institution. A statue of John Harvard stands today in front of University Hall in Harvard Yard, and is perhaps the University’s best known landmark.

    Harvard University has 12 degree-granting Schools in addition to the Radcliffe Institute for Advanced Study. The University has grown from nine students with a single master to an enrollment of more than 20,000 degree candidates including undergraduate, graduate, and professional students. There are more than 360,000 living alumni in the U.S. and over 190 other countries.

     
  • richardmitnick 2:10 pm on April 4, 2018 Permalink | Reply
    Tags: A new era of precision for antimatter research, Accelerator Science, , , , , , , ,   

    From CERN ALPHA: “A new era of precision for antimatter research” 

    Cern New Bloc

    Cern New Particle Event

    CERN New Masthead

    CERN ALPHA

    4 Apr 2018
    Ana Lopes

    1
    ALPHA experiment (Image: Maximilien Brice/CERN)

    The ALPHA collaboration has reported the most precise direct measurement of antimatter ever made, revealing the spectral structure of the antihydrogen atom in unprecedented colour. The result, published today in Nature, is the culmination of three decades of research and development at CERN, and opens a completely new era of high-precision tests between matter and antimatter.

    The humble hydrogen atom, comprising a single electron orbiting a single proton, is a giant in fundamental physics, underpinning the modern atomic picture. Its spectrum is characterised by well-known spectral lines at certain wavelengths, corresponding to the emission of photons of a certain frequency or colour when electrons jump between different orbits. Measurements of the hydrogen spectrum agree with theoretical predictions at the level of a few parts in a quadrillion (1015) — a stunning achievement that antimatter researchers have long sought to match for antihydrogen.

    Comparing such measurements with those of antihydrogen atoms, which comprise an antiproton orbited by a positron, tests a fundamental symmetry called charge-parity-time (CPT) invariance. Finding any slight difference between the two would rock the foundations of the Standard Model of particle physics and perhaps shed light on why the universe is made up almost entirely of matter, even though equal amounts of antimatter should have been created in the Big Bang.

    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

    Until now, however, it has been all but impossible to produce and trap sufficient numbers of delicate antihydrogen atoms, and to acquire the necessary optical interrogation technology, to make serious antihydrogen spectroscopy possible.

    The ALPHA team makes antihydrogen atoms by taking antiprotons from CERN’s Antiproton Decelerator (AD) and binding them with positrons from a sodium-22 source.

    CERN Antiproton Decelerator

    Next it confines the resulting antihydrogen atoms in a magnetic trap, which prevents them from coming into contact with matter and annihilating. Laser light is then shone onto the trapped antihydrogen atoms, their response measured and finally compared with that of hydrogen.

    In 2016, the ALPHA team used this approach to measure the frequency of the electronic transition between the lowest-energy state and the first excited state (the so-called 1S to 2S transition) of antihydrogen with a precision of a couple of parts in ten billion, finding good agreement with the equivalent transition in hydrogen. The measurement involved using two laser frequencies — one matching the frequency of the 1S–2S transition in hydrogen and another “detuned” from it — and counting the number of atoms that dropped out of the trap as a result of interactions between the laser and the trapped atoms.

    The latest result from ALPHA takes antihydrogen spectroscopy to the next level, using not just one but several detuned laser frequencies, with slightly lower and higher frequencies than the 1S–2S transition frequency in hydrogen. This allowed the team to measure the spectral shape, or spread in colours, of the 1S–2S antihydrogen transition and get a more precise measurement of its frequency. The shape matches that expected for hydrogen extremely well, and ALPHA was able to determine the 1S–2S antihydrogen transition frequency to a precision of a couple of parts in a trillion—a factor of 100 better than the 2016 measurement.

    “The precision achieved in the latest study is the ultimate accomplishment for us,” explains Jeffrey Hangst, spokesperson for the ALPHA experiment. “We have been trying to achieve this precision for 30 years and have finally done it.”

    Although the precision still falls short of that for ordinary hydrogen, the rapid progress made by ALPHA suggests hydrogen-like precision in antihydrogen — and thus unprecedented tests of CPT symmetry — are now within reach. “This is real laser spectroscopy with antimatter, and the matter community will take notice,” adds Hangst. “We are realising the whole promise of CERN’s AD facility; it’s a paradigm change.”


    ALPHA spokesperson Jeffrey Hangst explains the new results. (Video: Jacques Fichet/CERN)

    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 LHC 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

     
  • richardmitnick 11:22 am on March 29, 2018 Permalink | Reply
    Tags: Accelerator Science, , CERN experiment sees hints of a rare kaon decay, , NA62 experiment, , ,   

    From CERN: “CERN experiment sees hints of a rare kaon decay” 

    Cern New Bloc

    Cern New Particle Event

    CERN New Masthead

    CERN

    27 Mar 2018
    Ana Lopes

    1
    NA62 experiment in CERN’s North Area. (Image: NA62/CERN)

    What if the odds of an event occurring were about one in ten billion? This is the case for the decay of a positively charged particle known as a kaon into another positively charged particle called a pion and a neutrino–antineutrino pair. Yet, such a rare event, which has never been observed with certainty, is something that particle physicists really want to get their hands on. The reason? The Standard Model predicts such one-in-ten-billion odds with an uncertainty of less than ten percent. A deviation from this prediction, revealed by a precise measurement of the decay, could therefore be a clear indicator of physics beyond 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.


    Standard Model of Particle Physics from Symmetry Magazine

    In a seminar taking place today at CERN, the NA62 collaboration reports a candidate event of this ultra-rare kaon decay found using a new “in-flight decay” approach. While this single event cannot be used to probe beyond-Standard-Model physics, it demonstrates that the approach works well and can be applied to catch more events in the next run of data-taking, which kicks off in mid-April. The result was also presented earlier this month at the Rencontres de Moriond conference in La Thuile, Italy.

    To look for kaon decays, the NA62 team first makes beams rich in kaons by firing high-energy protons from the Super Proton Synchrotron (SPS) accelerator into a beryllium target.

    CERN Super Proton Synchrotron

    The collision creates a beam of nearly one billion particles per second, only about 6% of which are kaons. Next, the team sends the beam through a Cherenkov detector, which positively identifies the kaons from the Cherenkov radiation that they produce. A silicon-pixel detector then determines the momentum of the kaons with a time resolution of 100 picoseconds (1 picosecond is one trillionth of a second). A device called a straw tracker, placed inside a vacuum tank, in turn measures the momentum of the charged daughter particles into which the kaons decay, and another Cherenkov detector called RICH determines the particles’ type. Other devices known as calorimeters reject unwanted background events with photons and muons.

    In their analysis of data taken over the course of 2016, the NA62 team identified a candidate event of the decay of a positively charged kaon into a positively charged pion and a neutrino–antineutrino pair that escapes undetected. The result allowed the researchers to put an upper limit on the relative frequency, or “branching fraction”, of the decay of 14 in 10 billion. The result is compatible with the Standard-Model prediction, which is 8.4 in 100 billion (with an uncertainty of 1), but more data is needed to probe beyond-Standard-Model theories, which predict deviations from the Standard-Model value.

    3
    NA62’s candidate event of a rare kaon decay. Octagons show hits in the RICH detector. Circles show predicted “Cherenkov rings” for positively charged pion (π+), positively charged muon (μ+) and antielectron (e+) decay particles. (Image: NA62/CERN)

    This is not the first time that hints of this decay have been observed. Several candidate events have been previously reported by the E949 experiment and its predecessor E787 at Brookhaven National Laboratory in Long Island, New York. These candidate events have been used to infer a branching fraction of 17.3 in 100 billion (with an uncertainty of about 11), which is consistent, within large errors, with the Standard-Model prediction.

    But there is a difference between the Brookhaven experiments and NA62: whereas the former observed the kaon decays with the particles at rest in a target, NA62 observes them while the particles are in flight within the vacuum tank. This new in-flight approach has advantages because it provides much more room for detection and background-event immunity.

    The NA62 team expects to identify more events of the rare kaon decay in the ongoing analysis of a twenty-fold-larger dataset taken in 2017, and it will begin taking data again in mid-April for a record number of 218 days. If all goes to plan, the collaboration should be able to measure the branching fraction of the decay with a small enough uncertainty to make a precise test of the Standard Model.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    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 LHC 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

     
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