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  • richardmitnick 11:58 am on October 30, 2014 Permalink | Reply
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    From LC Newsline: “The future of Higgs physics” 

    Linear Collider Collaboration header
    Linear Collider Collaboration

    30 October 2014
    Joykrit Mitra

    In 2012, the ATLAS and CMS experiments at CERN’s Large Hadron Collider announced the discovery of the Higgs boson. The Higgs was expected to be the final piece of the particular jigsaw that is the Standard Model of particle physics, and its discovery was a monumental event.

    higgs
    Event recorded with the CMS detector in 2012 at a proton-proton centre of mass energy of 8 TeV. The event shows characteristics expected from the decay of the SM Higgs boson to a pair of photons (dashed yellow lines and green towers). Image: L. Taylor, CMS collaboration /CERN

    sm
    The Standard Model of elementary particles, with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    CERN ATLAS New
    CERN ATLAS

    CERN CMS New
    CDERN CMS

    But more precise studies of it are needed than the LHC is able to provide. That is why, years earlier, a machine like the International Linear Collider had been envisioned as a Higgs factory, and the Higgs discovery set the stage for its possible construction.

    ILC schematic
    ILC schematic

    Over the years, instruments for probing the universe have become more sophisticated. More refined data has hinted that aspects of the Standard Model are incomplete. If built, a machine such as the ILC will help reveal how wide a gulf there is between the universe and our understanding of it by probing the Higgs to unprecedented levels. And perhaps, as some physicists think, it will uproot the Standard Model and make way for an entirely new physics.

    In the textbook version, the Higgs boson is a single particle, and its alleged progenitor, the mysterious Higgs field that pervades every point in the universe, is a single field. But this theory is still to be tested.

    “We don’t know whether the Higgs field is one field or many fields,” said Michael Peskin of SLAC’s Theoretical Physics Group. “We’re just now scratching the surface at the LHC.”

    The LHC collides proton beams together, and the collision environment is not a clean one. Protons are made up of quarks and gluons, and in an LHC collision it’s really these many component parts – not the larger proton – that interact. During a collision, there are simply too many components in the mix to determine the initial energies of each one. Without knowing them, it’s not possible to precisely calculate properties of the particles generated from the collision. Furthermore, Higgs events at the LHC are exceptionally rare, and there is so much background that the amount of data that scientists have to sift through to glean information on the Higgs is astronomical.

    “There are many ways to produce an event that looks like the Higgs at the LHC,” Peskin said. “Lots of other things happen that look exactly like what you’re trying to find.”

    The ILC, on the other hand, would collide electrons and positrons, which are themselves fundamental particles. They have no component parts. Scientists would know their precise initial energy states and there will be significantly fewer distractions from the measurement standpoint. The ILC is designed to be able to accelerate particle beams up to energies of 250 billion electronvolts, extendable eventually to 500 billion electronvolts. The higher the particles’ energies, the larger will be the number of Higgs events. It’s the best possible scenario to probe the Higgs.

    If the ILC is built, physicists will first want to test whether the Higgs particle discovered at the LHC indeed has the properties predicted by the Standard Model. To do this, they plan to study Higgs couplings with known subatomic particles. The higher a particle’s mass, the proportionally stronger its coupling ought to be with the Higgs boson. The ILC will be sensitive enough to detect and accurately measure Higgs couplings with light particles, for instance with charm quarks. Such a coupling can be detected at the LHC in principle but is very difficult to measure accurately.

    The ILC can also help measure the exact lifetime of the Higgs boson. The more particles the Higgs couples to, the faster it decays and disappears. A difference between the measured lifetime and the projected lifetime—calculated from the Standard Model—could reveal what fraction of possible particles—or the Higgs’ interactions with them— we’ve actually discovered.

    “Maybe the Higgs interacts with something new that is very hard to detect at a hadron collider, for example if it cannot be observed directly, like neutrinos,” speculated John Campbell of Fermilab’s Theoretical Physics Department.

    These investigations could yield some surprises. Unexpected vagaries in measurement could point to yet undiscovered particles, which in turn would indicate that the Standard Model is incomplete. The Standard Model also has predictions for the coupling between two Higgs bosons, and physicists hope to study this as well to check if there are indeed multiple kinds of Higgs particles.

    “It could be that the Higgs boson is only a part of the story, and it has explained what’s happened at colliders so far,” Campbell said. “The self-coupling of the Higgs is there in the Standard Model to make it self-consistent. If not the Higgs, then some other thing has to play that role that self-couplings play in the model. Other explanations could also provide dark matter candidates, but it’s all speculation at this point.”

    image
    3D plot showing how dark matter distribution in our universe has grown clumpier over time. (Image: NASA, ESA, R. Massey from California Institute of Technology)

    The Standard Model has been very self-consistent so far, but some physicists think it isn’t entirely valid. It ignores the universe’s
    accelerating expansion caused by dark energy, as well as the mysterious dark matter that still allows matter to clump together and galaxies to form. There is speculation about the existence of undiscovered mediator particles that might be exchanged between dark matter and the Higgs field. The Higgs particle could be a likely gateway to this unknown physics.

    With the LHC set to be operational again next year, an optimistic possibility is that a new particle or two might be dredged out from trillions of collision events in the near future. If built, the ILC would be able to build on such discoveries, just as in case of the Higgs boson, and provide a platform for more precise investigation.

    The collaboration between a hadron collider like the LHC and an electron-positron collider of the scale of the ILC could uncover new territories to be explored and help map them with precision, making particle physics that much richer.

    See the full article here.

    The Linear Collider Collaboration is an organisation that brings the two most likely candidates, the Compact Linear Collider Study (CLIC) and the International Liner Collider (ILC), together under one roof. Headed by former LHC Project Manager Lyn Evans, it strives to coordinate the research and development work that is being done for accelerators and detectors around the world and to take the project linear collider to the next step: a decision that it will be built, and where.

    Some 2000 scientists – particle physicists, accelerator physicists, engineers – are involved in the ILC or in CLIC, and often in both projects. They work on state-of-the-art detector technologies, new acceleration techniques, the civil engineering aspect of building a straight tunnel of at least 30 kilometres in length, a reliable cost estimate and many more aspects that projects of this scale require. The Linear Collider Collaboration ensures that synergies between the two friendly competitors are used to the maximum.

    Linear Collider Colaboration Banner

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  • richardmitnick 2:52 pm on October 16, 2014 Permalink | Reply
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    From LC Newsline: “Full ILC-type cryomodule makes the grade” 

    Linear Collider Collaboration header
    Linear Collider Collaboration

    16 October 2014
    Joykrit Mitra

    For the first time, the ILC gradient specification of 31.5 megavolts per metre has been achieved on average across all of the eight cavities assembled in an ILC-type cryomodule. A team at Fermilab reached the milestone earlier this month. It is an achievement for scientists, engineers and technicians at Fermilab and Jefferson Lab in Virginia as well as their domestic and international partners in superconducting radio-frequency (SRF) technologies.

    The cryomodule, called CM2, was developed and assembled to advance superconducting radio-frequency technology and infrastructure at Americas-region laboratories. The CM2 milestone achievement has been nearly a decade in the making, since US scientists started participating in ILC research and development in 2006.

    cryo
    CM2 cryomodule being assembled at Fermilab’s Industrial Center Building (2011). Photo: Reidar Hahn

    “We’ve reached this important milestone and it was a long time coming,” said Elvin Harms, who leads the cryomodule testing programme at Fermilab. “It’s the first time in the world this has been achieved.”

    An accelerating gradient is a measure of how much of an energy boost particle bunches receive as they zip through an accelerator. Cavities with higher gradients boost particle bunches to higher energies over shorter distances. In an operational ILC, all 16,000 of its cavities would be housed in cryomodules, which would keep the cavities cool when operating at a temperature of 2 kelvins. While cavities can achieve high gradients as standalones, when they are assembled together in a cryomodule unit, the average gradient drops significantly.

    The road to the 31.5 MV/m milestone has been a long and arduous one. Between 2008 and 2010, all of the eight cavities in CM2 had individually been pushed to gradients above 35 MV/m at Jefferson Lab in tests in which the cavities were electropolished and vertically oriented. They were among 60 cavities evaluated globally for the prospects of reaching the ILC gradient. This evaluation was known as the S0 Global Design Effort. It was a build-up to the S1-Global Experiment, which put to the test the possibility of reaching 31.5 MV/m across an entire cryomodule. The final assembly of the S1 cryomodule setup took place at KEK in Japan, between 2010 and 2011. In S1, seven nine-cell 1.3-gigahertz niobium cavities strung together inside a cryomodule achieved an average gradient of 26 MV/m. An ILC-type cryomodule consists of eight such cavities.

    cm2
    CM2 in its home at Fermilab’s NML building, as part of the future Advanced Superconducting Test Accelerator. Photo: Reidar Hahn

    But the ILC community has taken big strides since then. Americas region teams acquired significant expertise in increasing cavity gradients: all CM2 cavities were vertically tested in the United States, initially at Jefferson Lab, and were subjected to additional horizontal tests at Fermilab. Further, cavities manufactured by private vendors in the United States have improved in quality: three of the eight cavities that make up the CM2 cryomodule were fabricated locally.

    Hands-on experience played a major role in improving the overall CM2 gradient. In 2007, a kit for Fermilab’s Cryomodule 1, or CM1, arrived from DESY, and by 2010, when CM1 was operational, the workforce had adopted a production mentality, which was crucial for the work they did on CM2.

    “I would like to congratulate my Fermilab colleagues for their persistence in carrying out this important work and for the quality of their work, which is extremely high,” said the SRF Institute at Jefferson Lab’s Rongli Geng, who led the ILC high-gradient cavity project there from 2007 to 2012. “We are glad to be able to contribute to this success.”

    But achieving the gradient is only the first step, Harms said. “There is still a lot of work left to be done. We need to look at CM2’s longer term performance. And we need to evaluate it thoroughly.”

    Among other tasks, the CM2 group will gently push the gradients higher to determine the limits of the technology and continue to understand and refine it. They plan to power and check the magnet—manufactured at Fermilab— that will be used to focus the particle beam passing through the cryomodule. Also in the works is a plan to study the rate at which the CM2 can be cooled down to 2 kelvins and warmed up again. Finally, they expect to send an actual electron beam through CM2 in 2015 to understand better how the beam and cryomodule respond in that setup.

    Scientists at Fermilab also expect that CM2 will be used in the Advanced Superconducting Test Accelerator currently under construction at Fermilab’s NML building, where CM2 is housed. The SRF technology developed for CM2 also has applications for light source instruments such as LCLS-II at SLAC in the United States and DESY’s XFEL.

    And it’s definitely a viable option for a future machine like the ILC.

    See the full article here.

    The Linear Collider Collaboration is an organisation that brings the two most likely candidates, the Compact Linear Collider Study (CLIC) and the International Liner Collider (ILC), together under one roof. Headed by former LHC Project Manager Lyn Evans, it strives to coordinate the research and development work that is being done for accelerators and detectors around the world and to take the project linear collider to the next step: a decision that it will be built, and where.

    Some 2000 scientists – particle physicists, accelerator physicists, engineers – are involved in the ILC or in CLIC, and often in both projects. They work on state-of-the-art detector technologies, new acceleration techniques, the civil engineering aspect of building a straight tunnel of at least 30 kilometres in length, a reliable cost estimate and many more aspects that projects of this scale require. The Linear Collider Collaboration ensures that synergies between the two friendly competitors are used to the maximum.

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  • richardmitnick 2:30 pm on October 16, 2014 Permalink | Reply
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    From LC Newsline: “Calorimeters enjoy beam time” 

    Linear Collider Collaboration header
    Linear Collider Collaboration

    16 October 2014
    Barbara Warmbein

    There are prototypes and there are prototypes. Some are needed to verify that a chosen detection technology actually works, some help scientists test one technology against another, some help them design sturdy detector infrastructure with little material budget, working power supply and cooling, while others set out to prove that it is possible to have full detector functionality with all electronics set up like in the final detector. And then there are those that do it all at the same time.

    calice
    CALICE crowd around detector setup in the T9 beamline at CERN. All images by Katsushige Kotera

    The CALICE collaboration’s analogue hadronic calorimeter, or AHCAL, is an example of the last type. It is a prototype for a calorimeter – a subdetector that measures the energies of passing particles – that might one day be part of the ILD detector. It would work together with trackers, electromagnetic calorimeter and muon system to record, reconstruct, track and identify every particle produced in the collisions at the future ILC. The CALICE scientists are currently testing a prototype that takes a close look at detector infrastructure like cooling and power supply while at the same time comparing different kinds of silicon photomultipliers or SiPMs. These do the actual job of detection, and the collaboration is testing the latest and much advanced commercial silicon photomultipliers (SiPMs) from Russia, Ireland, Japan and Germany.

    fd
    Flying detectors: after craning the hadronic calorimeter into its test beam destination…
    in
    …it gets installed and set up before starting its data taking run.

    The HCAL prototype consists of one module, which corresponds to a slice of one sector of the future calorimeter barrel of the final detector. It has 1000 channels per square metre and it shares the space in the test beam area with CALICE electromagnetic calorimeter prototype modules from Japan – a true collaboration that also shares the same readout electronics. It’s also the first time that these calorimeters are taking data in a hadron beam after a few runs in electron beams at DESY in Germany.

    …it gets installed and set up before starting its data taking run.

    See the full article here.

    The Linear Collider Collaboration is an organisation that brings the two most likely candidates, the Compact Linear Collider Study (CLIC) and the International Liner Collider (ILC), together under one roof. Headed by former LHC Project Manager Lyn Evans, it strives to coordinate the research and development work that is being done for accelerators and detectors around the world and to take the project linear collider to the next step: a decision that it will be built, and where.

    Some 2000 scientists – particle physicists, accelerator physicists, engineers – are involved in the ILC or in CLIC, and often in both projects. They work on state-of-the-art detector technologies, new acceleration techniques, the civil engineering aspect of building a straight tunnel of at least 30 kilometres in length, a reliable cost estimate and many more aspects that projects of this scale require. The Linear Collider Collaboration ensures that synergies between the two friendly competitors are used to the maximum.

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  • richardmitnick 10:52 am on July 24, 2014 Permalink | Reply
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    From LC Newsline: “Another record for ATF2″ 

    Linear Collider Collaboration header
    Linear Collider Collaboration

    24 July 2014
    Rika Takahashi

    Last month, LC NewsLine reported the achievement of the world’s smallest beam size of 55 nanometres at the ATF2 facility at KEK. At two international conferences held in June and July, the next record of 44 nanometres was reported by Kiyoshi Kubo and Shigeru Kuroda.

    The beam line at ATF2 is designed as a prototype of the final focus system of the ILC, with basically the same optics, similar beam energy spread, natural chromaticity and tolerances of magnetic field errors.

    ILC schematic
    ILC schematic

    For linear colliders, realising an extremely small and stable beam is essential. At the ILC, the design vertical beam size and required position stability at the interaction point is at the nanometer level. The target beam size at ATF is 37 nanometres. Because of the difference in the beam energy, 37 nanometres at ATF will correspond to smaller than 5 nanometres at the ILC, the specification for the ILC design.. The result presented at ICHEP and IPAC was just one step away from the target size.

    Kubo said the most important factor of the improvement was the stabilisation of the beam orbit by improving the feedback system. “We installed a new magnet for better feedback and improved the software, which worked to stabilise the beam. The beam was stable for 30 to 60 minutes without tuning in most cases.”

    “Also, we removed as much possible strong wakefield sources on every weekend when we stop the operation,” said Kuroda. “To put it in a nutshell, the further stabilisation of the beam and reduction of wakefield,” said Kuroda about the contributing factors.

    The beam size is still slightly larger than the target size of 37 nanometres. ATF is now under summer shut-down, and the scientists are planning to work on the remaining issues in the autumn this year.

    See the full article here.

    The Linear Collider Collaboration is an organisation that brings the two most likely candidates, the Compact Linear Collider Study (CLIC) and the International Liner Collider (ILC), together under one roof. Headed by former LHC Project Manager Lyn Evans, it strives to coordinate the research and development work that is being done for accelerators and detectors around the world and to take the project linear collider to the next step: a decision that it will be built, and where.

    Some 2000 scientists – particle physicists, accelerator physicists, engineers – are involved in the ILC or in CLIC, and often in both projects. They work on state-of-the-art detector technologies, new acceleration techniques, the civil engineering aspect of building a straight tunnel of at least 30 kilometres in length, a reliable cost estimate and many more aspects that projects of this scale require. The Linear Collider Collaboration ensures that synergies between the two friendly competitors are used to the maximum.

    Linear Collider Colaboration Banner


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  • richardmitnick 1:16 pm on June 12, 2014 Permalink | Reply
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    From Symmetry: “Researchers imagine the accelerators of the future” 

    Symmetry

    June 12, 2014
    Sarah Charley

    At the LHC Physics Conference in New York, experts looked to the next steps in collider physics.

    In the late 1800s, many scientists thought that the major laws of physics had been discovered—that all that remained to be resolved were a few minor details.

    Then in 1896 came the discovery of the first fundamental particle, the electron, followed by the discovery of atomic nuclei and revolutions in quantum physics and relativity. Modern particle physics had just begun, said Natalie Roe, the Director of the Physics Division at Lawrence Berkeley National Laboratory, at the recent Large Hadron Collider Physics Conference in New York.

    Since then, physicists have discovered a slew of new elementary particles and have developed a model that accurately describes the fundamental components of matter. But this time, they know that there is more left to find—if only they can reach it. In a presentation and a panel discussion chaired by New York Times science reporter Dennis Overbye, experts at the LHCP Conference discussed the future of collider-based particle physics research.

    The discovery of a Higgs boson bolstered physicists’ confidence in the Standard Model—our best understanding of matter at its most fundamental level. But the Standard Model does not answer important questions such as why the Higgs boson is so light or why neutrinos have mass, nor does it account for dark matter and dark energy, which astronomical observations indicate make up the majority of the known universe.

    sm
    The Standard Model of elementary particles, with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    “We know that the Standard Model is not a complete theory because many outstanding questions remain,” said CERN physicist Fabiola Gianotti, the former head of the ATLAS experiment at the LHC, at the LHCP Conference. “We must ask, at what energy scales do these questions find their answers?”

    CERN ATLAS New
    ATLAS at the LHC

    CERN LHC Grand Tunnel

    CERN LHC Map
    LHC at CERN

    The LHC will access an energy level higher than any previous accelerator, up to 13 trillion electronvolts, when it restarts in 2015. Scientists are already thinking about what could come next, such as the proposed International Linear Collider or hadron colliders under discussion in Europe and Asia.

    ILC schematic
    ILC design

    CERN CLIC
    CLIC design at CERN

    Building any proposed future accelerator will not be easy, “and none of them are cheap,” Gianotti said. However, one should not discount the opportunities that technological advances can afford.

    Gianotti pointed out that, in a 1954 presentation to the American Physical Society, Nobel Laureate Enrico Fermi estimated that an accelerator capable of accessing up to an energy of 3 trillion electronvolts would need to encircle the Earth and would cost about $170 billion.

    Thanks to the development of colliders and superconducting magnets, the 17-mile-long LHC has reached an energy level more than twice as high for a small fraction of Fermi’s estimated cost.

    Whatever the next step may be, physicists must look toward the future as an international community, panelists said.

    “The world has become more global, and we have contributed to that,” said Sergio Bertolucci, research director at CERN. “Things have changed.”

    According to scientists at the LHCP Conference, the discovery of the Higgs boson by a large international collaboration marked an era in which the big questions are tackled not by one nation, but by a global community.

    See the full article here.

    Symmetry is a joint Fermilab/SLAC publication.



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  • richardmitnick 3:19 pm on May 1, 2014 Permalink | Reply
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    From LC Newsline: “From UK News from CERN: Speaking up for CLIC” 

    Linear Collider Collaboration header
    Linear Collider Collaboration

    1 May 2014
    Stephanie Hills, STFC’s UK Communications and Innovation Officer

    The CLIC accelerator collaboration has elected a new spokesperson. Phil Burrows of the University of Oxford succeeds Roberto Corsini of CERN.

    pb
    Phil Burrows is the new CLIC accelerator spokesman. Image: Jesus College, Oxford

    Over the next three years, Burrows will be engaging with the institutes that are members of CLIC and helping to ensure that CLIC’s R&D programme pushes ahead during the critical phase ahead of the next update of the European strategy for particle physics. Corsini will continue his technical leadership of CLIC/CTF3.

    Burrows, who is an expert on fast-feedback and feed-forward beam correction systems (studied at KEK’s ATF2 and CERN’s CTF3 test facilities for future linear colliders) and on the machine-detector interface, is the first non-CERN CLIC accelerator spokesman. “I hope to cultivate the collaboration spirit and maximise opportunities for the international CLIC accelerator collaboration,” he says. The CTF3 test facility will probably stop operating in its current mode within the next couple of years, so changes are ahead for CLIC. “There are several promising avenues to explore, including exploring opportunities for novel applications of CLIC technologies.”

    The most recent European strategy for particle physics was published in 2013. Recognising the international collaborations that will be needed to make scientific advances, it sets out the future priorities for European particle physics research. The strategy is due to be updated in 2018, and that’s likely to be the timescale for decisions on the future direction for CLIC. With other potential successors to the Large Hadron Collider (LHC) on the table, Burrows says there will be tough decisions to be made about the best choice for the next big particle physics machine in Europe. “Any future proposed project would be expensive to build. We might be able to afford one in Europe, but definitely not two or more.”

    “CLIC remains the only viable technology today that could take us to multi-TeV centre of mass electron-positron collisions,” he says. “But we need more LHC results to assess whether it is the right machine to take us into new areas of physics research. LHC results over the next few years of running at higher energy and luminosity will be key to determining the way forward.”

    Using the CLIC Test Facility (CTF3), the key concepts of CLIC have already been tested and proved. Probably the most innovative element of the CLIC design is that it has two beams – a drive beam and a main beam. “We’ve demonstrated that it is possible to transfer energy from the drive beam and feed it to the main beam,” says Burrows. “Now we need to work on more of the technical implementation and system optimization, not least how to mass produce the components that we need – essential for keeping the cost of the project as low as possible.”

    CLIC collider
    CLIC

    For the next few years, the focus is definitely on CLIC R&D, but Phil will undoubtedly have more than half an eye on results coming out of the LHC when it starts operating again in 2015.

    See the full article here.

    The Linear Collider Collaboration is an organisation that brings the two most likely candidates, the Compact Linear Collider Study (CLIC) and the International Liner Collider (ILC), together under one roof. Headed by former LHC Project Manager Lyn Evans, it strives to coordinate the research and development work that is being done for accelerators and detectors around the world and to take the project linear collider to the next step: a decision that it will be built, and where.

    Some 2000 scientists – particle physicists, accelerator physicists, engineers – are involved in the ILC or in CLIC, and often in both projects. They work on state-of-the-art detector technologies, new acceleration techniques, the civil engineering aspect of building a straight tunnel of at least 30 kilometres in length, a reliable cost estimate and many more aspects that projects of this scale require. The Linear Collider Collaboration ensures that synergies between the two friendly competitors are used to the maximum.

    Linear Collider Colaboration Banner


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  • richardmitnick 2:49 pm on May 1, 2014 Permalink | Reply
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    From LC Newsline: “Loops and legs for ILC” 

    Linear Collider Collaboration header

    Linear Collider Collaboration

    1 May 2014
    Rika Takahashi

    The International Linear Collider will provide an experimental environment of unprecedented precision. One of the important issues at ILC experiments is the measurement of fundamental parameters with high precision, to match with the precision level of the experiment. The discovery of the Higgs particle brought demands on the ability to make predictions to a new level. Driven by those demands from the experimental results, scientists have been making efforts to develop techniques to calculate what will happen when particles collide, and these techniques have made big leaps in recent years. Sill, more studies are needed for ILC. Scientists gathered at Weimar, Germany for the Loops and Legs in Quantum Field Theory to tackle this challenging task.

    This bi-annual workshop on elementary particle theory was organised by the theory group of DESY in Zeuthen. “For more than 20 years this meeting brings together about 100 scientists from all over the world to discuss the latest achievements on precise calculations for high energy particle physics in experiment, theory, computational technology and the associated mathematics. This year the focus was on precision LHC processes, but also those at the ILC. Many talks were dealing with Higgs-physics and challenges for the future. It is needless to say that very many of the burning questions ultimately will request the ILC to be decided,” said DESY theorist Johannes Bluemlein.

    So, what are loops and legs?

    For particle physics studies, scientists use Feynman diagrams that show what happens when elementary particles collide.
    feyman
    Image: Kaori Kurokawa

    feynman 2
    In this Feynman diagram, an electron and a positron annihilate, producing a photon (represented by the blue sine wave) that becomes a quark–antiquark pair, after which the antiquark radiates a gluon (represented by the green helix).

    feynman 3

    The real deal

    feynman man
    The man himself, Dr. Richard Feynman. Nobel Laureat, comedian, general all around good guy

    When two particles collide and produce two new particles, the diagram has two inbound lines and two outbound lines. “We call the diagram showing this reaction ‘four legs.’ If three particles are produced, ‘five legs,’” said Junpei Fujimoto, a scientist at KEK. The higher the energy of the experiment, the larger the numbers of legs are expected. “For former electron-positron experiments up to 90′s, calculations for four-leg diagrams were enough to provide the reference for the experiments. But for the ILC experiments, we need precise multi-leg calculation to successfully compare theory and experiment,” he said.

    For rough estimations, the diagrams have only branches and legs. But in order to get more accurate predictions, the diagrams will have circular shaped lines. Those are called ‘loops’. “When loops are involved, the difficulty level of the calculation goes up drastically. To make precise theoretical predictions, we need to have knowledge of the higher loop computation, which is not easy. It is important to discuss about the new ideas and formulas, new way of calculations or new findings.”

    Fujimoto is a member of the GRACE group, which is working on constructing the systems to calculate Feynman amplitudes including loop diagrams. The group’s final goal is to construct the fully automatic computation system of multi-loop integrals. “We confirmed that the GRACE system is successfully working for one-loop calculation for both the Standard Model and the supersymmetric Standard Model. Now, we need to have a crack at the multi-loop integrals. I hope to have good worldwide cooperation for this challenge”.

    sm
    The Standard Model of elementary particles, with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    ssm
    Supersymmetry, or SUSY for short, states that there is an undiscovered bosonic counterpart to every fermion in the Standard Model, and an undiscovered fermionic counterpart to every boson. (image credit: T. Kondo)

    In addition to the need of discussion, Fujimoto has another aim to attend the Weimar meeting.

    “I wanted to report the latest information on ILC in Japan to prominent theorists in the world. ILC is really moving forward, and we have a good chance to start the experiment in the next decade. The power of the people who came to the Weimar meeting is quite important to the ILC’s success, and I wanted to remind them of that.”

    Participants know very well that some calculations demanded by ILC are quite tough, and also request much CPU power. Nevertheless now it is just the time to start consideration to attack such a huge calculations, and to seek a new way to overcome.

    See the full article here.

    The Linear Collider Collaboration is an organisation that brings the two most likely candidates, the Compact Linear Collider Study (CLIC) and the International Liner Collider (ILC), together under one roof. Headed by former LHC Project Manager Lyn Evans, it strives to coordinate the research and development work that is being done for accelerators and detectors around the world and to take the project linear collider to the next step: a decision that it will be built, and where.

    Some 2000 scientists – particle physicists, accelerator physicists, engineers – are involved in the ILC or in CLIC, and often in both projects. They work on state-of-the-art detector technologies, new acceleration techniques, the civil engineering aspect of building a straight tunnel of at least 30 kilometres in length, a reliable cost estimate and many more aspects that projects of this scale require. The Linear Collider Collaboration ensures that synergies between the two friendly competitors are used to the maximum.

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  • richardmitnick 3:06 pm on March 6, 2014 Permalink | Reply
    Tags: , , LCC-Linear Collider Collaboration, ,   

    From LC Newsline: “Strengthening Asian capability in SCRF technology” 

    Linear Collider Collaboration header

    6 March 2014
    Rika Takahashi

    Sixteen thousand – that’s the number of the superconducting radiofrequency (SCRF) accelerating cavities needed to build the 500-Giga-electronvolt linear collider. The fabrications of these 16 000 cavities will be divided between the three regions of Europe, the Americas, and Asia. This week, encouraging news about SCRF cavity fabrication came form Asia.

    “This is our first in-house SCRF cavity,” said Takayuki Saeki, SCRF specialist at the KEK laboratory in Japan. KEK has been working on a study for industrialisation of the SCRF cavity at a facility called CFF (Cavity Fabrication Facility) established in 2011. CFF is equipped with a press machine, vertical lathe, electron-beam welding machine, chemical treatment room, and surface inspection machine, where most of the cavity fabrication processes are done in a one-stop shop. At CFF, scientists are aiming for a high performance and high yield rate, for reducing the fabrication cost, establishing mass-production processes, and preparing the fixtures needed.

    Prior to the first cavity called KEK-001, they produced a test cavity, KEK-000. “The aim of the KEK-000 was basically to gain experience with cavity fabrication, and learn the basics. This time, we focused more on mass-production,” said Saeki.

    “We used the different technique to weld the equatorial part of the cavity cells for the KEK-001. We chose the technique best suitable for mass production aiming for cost reduction,” said Saeki. Scientists also adopted a cost-effective fabrication technique for the cavity end parts, which have complicated structures with components such as beam pipe, higher order mode RF coupler, power port, flanges. “We thoroughly investigate the all welding locations to determine the desirable parameters, using niobium plates and pipes. I think it worked very well.” The performance test on KEK-001 will be conducted in a few months.

    Another good news from KEK is the success in the vertical test of a single cell cavity made out of large-grain niobium, which reached the record accelerating gradient of 45 Megavolts per metre. Several major laboratories have investigated the use of large-grain and single-crystal material in the past years. Large-grain and single-crystal niobium is an alternative material to poly-crystalline, or fine-grain niobium for superconducting cavities, that has potential advantages such as reduced costs and better reproducibility in performance.

    cavity
    large grain 9-cell superconducting cavity (PKU4) Image: Peking University

    Last year, a 9-cell niobium SCRF cavity made of large-grain niobium achieved an accelerating gradient of 32.6 MV/m at Peking University (PKU), Beijing, China, in cooperation with KEK. The fabrication of the cavity was finished with careful control of machining, better field flatness tuning, improved surface treatment and electron beam welding.The multiple surface treatment and performance tests on this cavity were carried out by KEK. This cavity, called PKU4, is the first cavity which has reached the requirement for the ILC both in accelerating gradient and intrinsic quality factor in China.

    cryo
    ILC-type cryomodule to be tested at IHEP Beijing. image: IHEP

    There are more advancements on SCRF technology in China. The Institute of High Energy Physics (IHEP), Beijing, is progressing the system assembly of the cryomodule, composed of composed of a 9-cell cavity housed in a cryostat, which maintains the cavity to very low temperature to realise superconductivity. It is now getting ready for the cold performance test later this year. This system will be a prototype to demonstrate full functioning for the ILC SCRF system requirement.

    These activities and progresses indicate that China has the capability to manufacture superconducting cavities and the SCRF system integration for the ILC. “International collaboration is the key for the success for the ILC construction. And PKU4’s success is a very important milestone for superconducting technology development in China, and also for the China-Japan collaboration,” said Akira Yamamoto, regional director for Asia at the Linear Collider Collaboration. Asia is getting ready for the ILC construction.

    See the full article here.

    The Linear Collider Collaboration is an organisation that brings the two most likely candidates, the Compact Linear Collider Study (CLIC) and the International Liner Collider (ILC), together under one roof. Headed by former LHC Project Manager Lyn Evans, it strives to coordinate the research and development work that is being done for accelerators and detectors around the world and to take the project linear collider to the next step: a decision that it will be built, and where.

    Some 2000 scientists – particle physicists, accelerator physicists, engineers – are involved in the ILC or in CLIC, and often in both projects. They work on state-of-the-art detector technologies, new acceleration techniques, the civil engineering aspect of building a straight tunnel of at least 30 kilometres in length, a reliable cost estimate and many more aspects that projects of this scale require. The Linear Collider Collaboration ensures that synergies between the two friendly competitors are used to the maximum.

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  • richardmitnick 12:00 pm on February 20, 2014 Permalink | Reply
    Tags: , , , LCC-Linear Collider Collaboration, ,   

    From LC Newsline: “Future Colliders: A strategic perspective” 

    Linear Collider Collaboration header

    20 February 2014
    Harry Weerts

    hw
    Harry Weerts is the Americas Regional Director for the Linear Collider Collaboration

    Over the past decades, colliders have defined the energy frontier in particle physics. Both electron-positron, proton-(anti)proton as well as electron-proton colliders have played complementary roles in fully mapping out the constituents and forces in the Standard Model (SM).

    sm
    The Standard Model of elementary particles, with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    pc
    Particle collisions could reveal new physics territories. Image: Norman Graf, SLAC

    We are now at a point where all predicted SM constituents have been found at colliders. Currently only one collider, the Large Hadron Collider (LHC) is running and will run for a while. The last remaining, predicted field/particle in the SM was found at the LHC in 2012 and with increased luminosity and raising the energy to 14 teraelectronvolts (TeV), the LHC will be the field’s only tool to study the Higgs boson. Especially raising the energy will also enable extending the reach for searching for new physics beyond the SM (BSM).

    Trying to explain the SM and its features and parameters leads us to expect new physics and therefore new particles. There are theoretical expectations that such particles are at the TeV-level energy scale, but in principle they could be at any scale above one TeV and even that depends on their interaction strength. In an ideal world the only way to directly produce such particles/fields in our labs is in colliders. Assuming that we need to go beyond the LHC, we would like a collider or colliders that can reach from a few hundred GeV to very high energies, ultimately if one is allowed to dream the Planck scale of 1019 gigaelectronvolts (GeV).

    The above reasoning has led to many studies of future colliders at rather different stages of completion or maturity. It is also the driving scientific force behind a worldwide accelerator R&D programme trying to achieve higher accelerating gradients, especially for linear colliders and to achieve higher magnetic fields, for circular colliders. This programme driven by the high-energy physics (HEP) community which needs to build ever higher energy colliders at affordable cost, has led to technologies that enabled other fields of science in obtaining their goals (the European XFEL at DESY, Germany and LCLS II at SLAC, US). These fields often industrialise those technologies before HEP can do it and in that way contribute to possible future machines for HEP. In that way all participating fields of science benefit and contribute.

    The studies of future HEP colliders mentioned above are very important aspects of HEP. Over the last two decades several of these studies have been undertaken and some are just being started now. They all aim at proposing a future collider and requiring the development of new technologies to be able to reach the energies aimed at. Typically these technologies do not exist at the start of the study, but are anticipated to be within reach, given sufficient research, development and funding. These studies are also on extremely different time scales of possible realisation of concepts. Currently there are four studies worldwide: ILC, CLIC, FCC and a muon collider. The International Linear Collider (ILC), an electron-positron collider at 500 Gev and possibly upgraded to 1 TeV is the most mature with a Technical Design Report (TDR) and the most established superconducting RF technology. A candidate site has also been identified in Japan to possibly locate the machine. CLIC (Compact Linear Collider) is an eletron-positron collider concept based on two beam acceleration aiming to reach about 3TeV and with a completed Conceptual Design Report (CDR), aiming for a TDR around 2019. A multi-TeV muon collider is under discussion and an active R&D programme of how to cool muons, an essential ingredient, is in progress. Recently the study of a Future Circular Collider (FCC) aiming at about 100TeV centre-of-mass energy for proton-proton collisions has started. It is being pursued both in Europe and in China and will require the development of new superconducting high field magnets (of about 16-20 teslas). The FCC study at least in Europe aims for a CDR around 2018. From a HEP perspective, one can argue about which one of these should be pursued and each of us in HEP has their preference. However there is a strategic aspect associated with this conundrum that cannot be ignored and that is the time scale involved in realising any of these machines. In the most optimistic scenario, the LHC will have a high luminosity run and will run until sometime in the 2030’s. The only option mentioned above that has any chance of some overlap with LHC and/or be accumulating data around that time is the ILC. Even that assumes that the ILC will be realised in Japan on a technically limited schedule without financial or political delays.

    So it seems that if HEP wants to continue energy frontier physics with complementary to the LHC, precision exploration of the Higgs and explore BSM physics at weak scales above about 200 GeV, unexplored by the LHC, then the ILC is the natural next energy frontier machine for HEP. Any other option will take at least another decade beyond 2030 before it could be realised. That would result in an extended period of time without a running energy frontier machine in HEP.

    See the full article here.

    The Linear Collider Collaboration is an organisation that brings the two most likely candidates, the Compact Linear Collider Study (CLIC) and the International Liner Collider (ILC), together under one roof. Headed by former LHC Project Manager Lyn Evans, it strives to coordinate the research and development work that is being done for accelerators and detectors around the world and to take the project linear collider to the next step: a decision that it will be built, and where.

    Some 2000 scientists – particle physicists, accelerator physicists, engineers – are involved in the ILC or in CLIC, and often in both projects. They work on state-of-the-art detector technologies, new acceleration techniques, the civil engineering aspect of building a straight tunnel of at least 30 kilometres in length, a reliable cost estimate and many more aspects that projects of this scale require. The Linear Collider Collaboration ensures that synergies between the two friendly competitors are used to the maximum.

    Linear Collider Colaboration Banner


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  • richardmitnick 12:53 pm on February 6, 2014 Permalink | Reply
    Tags: , , LCC-Linear Collider Collaboration   

    From LC Newsline: “The year 2014 – The real starting year of the ILC?” 

    Linear Collider Collaboration header

    6 February 2014
    Rika Takahashi

    Close to the end of the year 2013, we had encouraging news for the ILC. On 24 December, the Japanese cabinet released the government budget decision for fiscal year 2014 – which includes an official budget for the International Linear Collider. The amount of the budget is 50 million yen, about half a million US dollars, which might not seem a lot at first glance. However, this budget is highly significant in a symbolical way towards the realisation of the ILC, since this budget represents a qualitative change in the status of the ILC in the Japanese government. It means that the ILC is now recognised as a formal project.

    ilc
    Proposed ILC

    This budget will be used by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) to investigate and analyse the requirements and issues for the realisation of the ILC, and for collecting objective data which serves as the basis for the future governmental decision.

    Along with this development at the government level, the Japanese research community is also taking a next step. On 6 February, KEK announced the creation of an office responsible for the ILC project, the ILC Planning Office. The office will be headed by Atsuto Suzuki, Director General of KEK.

    KEK has been playing a leading role in research and development efforts for the ILC. “With the national budget officially allocated, the ILC project now needs the driving force to bring forward the project. The new office, the Planning Office for the International Linear Collider, will coordinate and integrate efforts on planning, scheduling, and managing research activities. It will also take care of internal and external cooperation and coordination as well as handling discuss the desirable way to organize future international laboratory, or the way to manage it, the research activities already going on,” said Suzuki.
    The new office is just a section in the KEK organisation, but this is merely a starting point. “I am planning to expand this office to a pan-Japan organisation with a participation of all the researchers and engineers in Japan, and ultimately, make it into an international ILC pre-laboratory,” he said.
    Suzuki aims to deepen the industry-academia collaboration, which is currently carried out through the cooperation with the Advanced Accelerator Association Promoting Science and Technology (AAA). “We will have a new facility in KEK towards the industrialisation of the superconducting cavities. The new office is also in charge of the industry-academia collaboration,” said Suzuki.

    In addition, the expert panel established under MEXT started their discussions on the issues pointed out by Science Council of Japan last summer, such as scrutinising the cost evaluation or calculating the number of scientists and engineers needed to build the accelerator and facility, or how to distribute the cost internationally.

    “With all these developments, I think we can say that the year 2014 will be a real starting year for the ILC as a project,” says Suzuki. They will work on the detailed accelerator design, and issues to manage the international laboratory if it is built in Japan.

    Suzuki says, “We will do our best to appeals to relevant counterpart such as OECD to make the ILC project endorsed as an international project under the aegis of an appropriate international organisation like OECD or UNESCO, to solidify the foundation for the government to start the international negotiations as soon as possible.”

    February has traditionally been a memorial month for the ILC project. The release ceremony of the Reference Design Report took place in February 2007, and the new organisation for the realisation of the project, the Linear Collider Collaboration, was also established in February in 2013. This new office in KEK may well become another memorial event for “ILC February.”

    See the full article here.

    The Linear Collider Collaboration is an organisation that brings the two most likely candidates, the Compact Linear Collider Study (CLIC) and the International Liner Collider (ILC), together under one roof. Headed by former LHC Project Manager Lyn Evans, it strives to coordinate the research and development work that is being done for accelerators and detectors around the world and to take the project linear collider to the next step: a decision that it will be built, and where.

    Some 2000 scientists – particle physicists, accelerator physicists, engineers – are involved in the ILC or in CLIC, and often in both projects. They work on state-of-the-art detector technologies, new acceleration techniques, the civil engineering aspect of building a straight tunnel of at least 30 kilometres in length, a reliable cost estimate and many more aspects that projects of this scale require. The Linear Collider Collaboration ensures that synergies between the two friendly competitors are used to the maximum.

    Linear Collider Colaboration Banner


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