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Sample records for na akceleratorze lhc

  1. LHC physics

    National Research Council Canada - National Science Library

    Binoth, T

    2012-01-01

    "Exploring the phenomenology of the Large Hadron Collider (LHC) at CERN, LHC Physics focuses on the first years of data collected at the LHC as well as the experimental and theoretical tools involved...

  2. Študij sevalnih poškodb silicijevih detektorjev za eksperimente z visoko luminoznostjo na trkalniku LHC

    CERN Document Server

    Žontar, Dejan; Mikuž, Marko

    1998-01-01

    Radiation damage of the silicon bulk will play an important role in the vertex detectors in the future experiments at LHC. To study its macroscopic effects, high resistivity p-n-n diodes were irradiated with neutrons at the TRIGA research reactor of Jožef Stefan Institute in Ljubljana. Irradiation fluences were in the range from 10^13 to 2.5x10^14 cm2 of equivalent 1 MeV neutrons. Development of effective doping concentration and reverse current during and after irradiations was studied under controlled conditions (bias, temperature). Long term annealing of effective doping concentration was studied to determine the dynamics of the process responsible. Results obtained from a set of unbiased diodes kept at 20"C gave conclusive evidence that, at least during the initial stage, time development can be described by a first order process. Flux dependence of defect creation has been checked in the flux range from 2x10^8 to approx 5x10^15 n/cm2s. No significant difference among the samples was observed in a...

  3. LHC report

    CERN Multimedia

    CERN. Geneva

    2010-01-01

    This week's Report, by Gianluigi Arduini,  will be included in the LHC Physics Day, dedicated to the reviews of the LHC physics results presented at ICHEP 2010. Seehttp://indico.cern.ch/conferenceDisplay.py?confId=102669 

  4. The LHC

    CERN Multimedia

    2002-01-01

    The LHC will use the latest technologies on an enormous scale. 8000 superconducting magnets will keep the beams on track. The entire 27 km ring will be cooled by 700 000 litres of liquid helium to a temperature of -271 degrees Celsius , making the LHC the world's largest superconducting installation. Conventional superconducting wire will form the magnet coils, while high-temperature superconductors will carry a total of 2 300 000 amperes from the power supplies into the magnet cryostat

  5. LHC magnets

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Preparations for the LHC proton collider to be built in CERN's LEP tunnel continue to make good progress. In particular development work for the high field superconducting magnets to guide the almost 8 TeVproton beams through the 'tight' curve of the 27-kilometre ring are proceeding well, while the magnet designs and lattice configuration are evolving in the light of ongoing experience. At the Evian LHC Experiments meeting, this progress was covered by Giorgio Brianti

  6. LHC milestone

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    At the December meeting of CERN's Council, the Organization's Governing Body, the delegates from the 16 Member States unanimously agreed that the LHC proton-proton collider proposed for the 27-kilometre LEP tunnel is the 'right machine for the advance of the subject and of the future of CERN'

  7. LHC Create

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    LHC Create is an upcoming 2-day workshop held at IdeaSquare in November. Participants from CERN and IPAC school of design will compete to design an exhibit that explains why CERN does what it does. The winner will have their exhibit fully realised and made available to experiments, institutes, and tourism agencies around the world.

  8. LHC Supertable

    International Nuclear Information System (INIS)

    Pereira, M.; Lahey, T.E.; Lamont, M.; Mueller, G.J.; Teixeira, D.D.; McCrory, E.S.

    2012-01-01

    LHC operations generate enormous amounts of data. This data is being stored in many different databases. Hence, it is difficult for operators, physicists, engineers and management to have a clear view on the overall accelerator performance. Until recently the logging database, through its desktop interface TIMBER, was the only way of retrieving information on a fill-by-fill basis. The LHC Supertable has been developed to provide a summary of key LHC performance parameters in a clear, consistent and comprehensive format. The columns in this table represent main parameters that describe the collider operation such as luminosity, beam intensity, emittance, etc. The data is organized in a tabular fill-by-fill manner with different levels of detail. Particular emphasis was placed on data sharing by making data available in various open formats. Typically the contents are calculated for periods of time that map to the accelerator's states or beam modes such as Injection, Stable Beams, etc. Data retrieval and calculation is triggered automatically after the end of each fill. The LHC Supertable project currently publishes 80 columns of data on around 100 fills. (authors)

  9. LHC Supertable

    CERN Document Server

    Pereira, M; Lamont, M; Muller, GJ; Teixeira, D D; McCrory, ES

    2011-01-01

    LHC operations generate enormous amounts of data. This data is being stored in many different databases. Hence, it is difficult for operators, physicists, engineers and management to have a clear view on the overall accelerator performance. Until recently the logging database, through its desktop interface TIMBER, was the only way of retrieving information on a fill-by-fill basis. The LHC Supertable has been developed to provide a summary of key LHC performance parameters in a clear, consistent and comprehensive format. The columns in this table represent main parameters that describe the collider’s operation such as luminosity, beam intensity, emittance, etc. The data is organized in a tabular fill-by-fill manner with different levels of detail. Particular emphasis was placed on data sharing by making data available in various open formats. Typically the contents are calculated for periods of time that map to the accelerator’s states or beam modes such as Injection, Stable Beams, etc. Data retrieval and ...

  10. LHC Startup

    CERN Document Server

    AUTHOR|(CDS)2067853

    2008-01-01

    The Large Hadron Collider will commence operations in the latter half of 2008. The plans of the LHC experiments ALICE, ATLAS, CMS and LHCb are described. The scenario for progression of luminosity and the strategies of these 4 experiments to use the initial data are detailed. There are significant measurements possible with integrated luminosities of 1, 10 and 100 pb^-1. These measurements will provide essential calibration and tests of the detectors, understanding of the Standard Model backgrounds and a first oportunity to look for new physics.

  11. LHC Report

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    During last week the commissioning effort has been devoted to beam development work, required to accelerate beams with nominal bunch intensity to 3.5 TeV. Significant progress has been done with the commissioning of the systems required to control the beam size and bunch length during the ramp and accelerate the beam with reproducible characteristics. The setting-up of the collimation system for the operation with higher intensity is presently ongoing with the aim of delivering physics with nominal bunch intensity towards the end of next week. For more information about the LHC and a video of the presentation recently done by LHC operators, please visit: http://lpcc.web.cern.ch/LPCC/ http://indico.cern.ch/categoryDisplay.py?categId=2687

  12. HL-LHC Accelerator

    CERN Document Server

    Zimmermann, F

    2013-01-01

    The tentative schedule, key ingredients, as well as progress of pertinent R&D and component prototypes for the LHC luminosity upgrade, "HL-LHC," are reviewed. Also alternative scenarios based on performance-improving consolidations (PICs) instead of a full upgrade are discussed. Tentative time schedules and expected luminosity evolutions for the different scenarios are sketched. The important role of HL-LHC development as a step towards a future HE-LHC or VHE-LHC is finally highlighted. Presented at "Higgs & Beyond" Conference Tohoku University, Sendai 7 June 2013.

  13. Safe LHC beam commissioning

    International Nuclear Information System (INIS)

    Uythoven, J.; Schmidt, R.

    2007-01-01

    Due to the large amount of energy stored in magnets and beams, safety operation of the LHC is essential. The commissioning of the LHC machine protection system will be an integral part of the general LHC commissioning program. A brief overview of the LHC Machine Protection System will be given, identifying the main components: the Beam Interlock System, the Beam Dumping System, the Collimation System, the Beam Loss Monitoring System and the Quench Protection System. An outline is given of the commissioning strategy of these systems during the different commissioning phases of the LHC: without beam, injection and the different phases with stored beam depending on beam intensity and energy. (author)

  14. LHC synchronization test successful

    CERN Multimedia

    The synchronization of the LHC's clockwise beam transfer system and the rest of CERN's accelerator chain was successfully achieved last weekend. Tests began on Friday 8 August when a single bunch of a few particles was taken down the transfer line from the SPS accelerator to the LHC. After a period of optimization, one bunch was kicked up from the transfer line into the LHC beam pipe and steered about 3 kilometres around the LHC itself on the first attempt. On Saturday, the test was repeated several times to optimize the transfer before the operations group handed the machine back for hardware commissioning to resume on Sunday. The anti-clockwise synchronization systems will be tested over the weekend of 22 August.Picture:http://lhc-injection-test.web.cern.ch/lhc-injection-test/

  15. Some LHC milestones...

    CERN Multimedia

    2008-01-01

    October 1995 The LHC technical design report is published. This document details the operation and the architecture of the future accelerator. November 2000 The first of the 1232 main dipole magnets for the LHC are delivered. May 2005 The first interconnection between two magnets of the accelerator is made. To carry out the 1700 interconnections of the LHC, 123 000 operations are necessary. February 2006 The new CERN Control Centre, which combines all the control rooms for the accelerators, the cryogenics and the technical infrastructure, starts operation. The LHC will be controlled from here. October 2006 Construction of the largest refrigerator in the world is complete. The 27 km cryogenic distribution line inside the LHC tunnel will circulate helium in liquid and gas phases to provide cryogenic conditions for the superconducting magnets of the accelerator. November 2006 Magnet production for the LHC is complete. The last of t...

  16. Towards LHC experiments

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    As plans for the LHC proton collider to be built in CERN's 27-kilometre LEP tunnel take shape, interest widens to bring in the experiments exploiting the big machine. The first public presentations of 'expressions of interest' for LHC experiments featured from 5-8 March at Evian-les-Bains on the shore of Lake Geneva, some 50 kilometres from CERN, at the special Towards the LHC Experimental Programme' meeting

  17. LHC superconducting strand

    CERN Multimedia

    Patrice Loiez

    1999-01-01

    This cross-section through a strand of superconducting matieral as used in the LHC shows the 8000 Niobium-Titanium filaments embedded like a honeycomb in copper. When cooled to 1.9 degrees above absolute zero in the LHC accelerator, these filaments will have zero resistance and so will carry a high electric current with no energy loss.

  18. The physics behind LHC

    CERN Multimedia

    CERN. Geneva

    2006-01-01

    What do physicists want to discover with experiments at the LHC? What is the Higgs boson? What are the new phenomena that could be observed at the LHC?I will try to answer these questions using language accessible also to non-experts. Organiser(s): L. Alvarez-Gaume / PH-THNote: * Tea & coffee will be served at 16:00.

  19. The LHC is safe

    CERN Document Server

    CERN. Geneva; Alvarez-Gaumé, Luís

    2008-01-01

    Concerns have been expressed from time to time about the safety of new high-energy colliders, and the LHC has been no exception. The LHC Safety Assessment Group (LSAG)(*) was asked last year by the CERN management to review previous LHC safety analyses in light of additional experimental results and theoretical understanding. LSAG confirms, updates and extends previous conclusions that there is no basis for any conceivable threat from the LHC. Indeed, recent theoretical and experimental developments reinforce this conclusion. In this Colloquium, the basic arguments presented by LSAG will be reviewed. Cosmic rays of much higher effective centre-of-mass energies have been bombarding the Earth and other astronomical objects for billions of years, and their continued existence shows that the Earth faces no dangers from exotic objects such as hypothetical microscopic black holes that might be produced by the LHC - as discussed in a detailed paper by Giddings and Mangano(**). Measurements of strange particle produc...

  20. LHC Report: LHC hit the target!

    CERN Multimedia

    Enrico Bravin for the LHC team

    2016-01-01

    Last week, the accumulated integrated luminosity reached the target value for 2016 of 25 fb-1 in both ATLAS and CMS.   The integrated luminosity delivered to ATLAS and CMS reached (and already passed!) 25 fb-1– the target for the whole year! Tuesday, 30 August was just a regular day for the 2016 LHC run. However,  on that day, the integrated luminosity delivered to ATLAS and CMS reached 25 fb-1 – the target for the whole year! How did we get here? A large group of committed scientists and technical experts work behind the scenes at the LHC, ready to adapt to the quirks of this truly impressive machine. After the push to produce as many proton-proton collisions as possible before the summer conferences, several new ideas and production techniques (such as Bunch Compression Multiple Splitting, BCMS) have been incorporated in the operation of LHC in order to boost its performance even further. Thanks to these improvements, the LHC was routinely operated with peak luminos...

  1. The LHC babies

    CERN Multimedia

    Laëtitia Pedroso

    2011-01-01

    With the machine restart and first collisions at 3.5 TeV, 2009 and 2010 were two action-packed years at the LHC. The events were a real media success, but one important result that remained well hidden was the ten births in the LHC team over the same period. The mothers – engineers, cryogenics experts and administrative assistants working for the LHC – confirm that it is possible to maintain a reasonable work-life balance. Two of them tell us more…   Verena Kain (left) and Reyes Alemany (right) in the CERN Control Centre. With the LHC running around the clock, LHC operations engineers have high-pressure jobs with unsociable working hours. These past two years, which will undoubtedly go down in the annals of CERN history, the LHC team had their work cut out, but despite their high-octane professional lives, several female members of the team took up no less of a challenge in their private lives, creating a mini-baby-boom by which the LHC start-up will also be remembe...

  2. LHC preparations change gear

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    After the formal approval by CERN Council in December (January, page 1) of the LHC protonproton collider for CERN's 27- kilometre LEP tunnel, preparations for the new machine change gear. Lyndon Evans becomes LHC Project Leader, and CERN's internal structure will soon be reorganized to take account of the project becoming a definite commitment. On the experimental side, the full Technical Proposals for the big general purpose ATLAS and CMS detectors were aired at a major meeting of the LHC Committee at CERN in January. These Technical Proposals are impressive documents each of some several hundred pages. (Summaries of the detector designs will appear in forthcoming issues of the CERN Courier.) The ALICE heavy ion experiment is not far behind, and plans for other LHC experiments are being developed. Playing an important role in this groundwork has been the Detector Research and Development Committee (DRDC), founded in 1990 to foster detector development for the LHC experimental programme and structured along the lines of a traditional CERN Experiments Committee. Established under the Director Generalship of Carlo Rubbia and initially steered by Research Director Walter Hoogland, the DRDC has done sterling work in blazing a trail for LHC experiments. Acknowledging that the challenge of LHC experimentation needs technological breakthroughs as well as specific detector subsystems, DRDC proposals have covered a wide front, covering readout electronics and computing as well as detector technology. Its first Chairman was Enzo larocci, succeeded in 1993 by Michal Turala. DRDC's role was to evaluate proposals, and make recommendations to CERN's Research Board for approval and resource allocation, not an easy task when the LHC project itself had yet to be formally approved. Over the years, a comprehensive portfolio of detector development has been built up, much of which has either led to specific LHC detector subsystems for traditional detector tasks

  3. Conference: STANDARD MODEL @ LHC

    CERN Multimedia

    2012-01-01

    HCØ institute Universitetsparken 5 DK-2100 Copenhagen Ø Denmark Room: Auditorium 2 STANDARD MODEL @ LHC Niels Bohr International Academy and Discovery Center 10-13 April 2012 This four day meeting will bring together both experimental and theoretical aspects of Standard Model phenomenology at the LHC. The very latest results from the LHC experiments will be under discussion. Topics covered will be split into the following categories:     * QCD (Hard,Soft & PDFs)     * Vector Boson production     * Higgs searches     * Top Quark Physics     * Flavour physics

  4. HL-LHC alternatives

    CERN Document Server

    Tomás, R; White, S

    2014-01-01

    The HL-LHC parameters assume unexplored regimes for hadron colliders in various aspects of accelerator beam dynamics and technology. This paper reviews three alternatives that could potentially improve the LHC performance: (i) the alternative filling scheme 8b+4e, (ii) the use of a 200 MHz RF system in the LHC and (iii) the use of proton cooling methods to reduce the beam emittance (at top energy and at injection). The alternatives are assessed in terms of feasibility, pros and cons, risks versus benefits and the impact on beam availability.

  5. The Lhc beam commissioning

    International Nuclear Information System (INIS)

    Redarelli, S.; Bailey, R.

    2008-01-01

    The plans for the Lhc proton beam commissioning are presented. A staged commissioning approach is proposed to satisfy the request of the Lhc experiments while minimizing the machine complexity in early commissioning phases. Machine protection and collimation aspects will be tackled progressively as the performance will be pushed to higher beam intensities. The key parameters are the number of bunches, k b , the proton intensity pe bunch, N, and the β in the various interaction points. All together these parameters determine the total beam power and the complexity of the machine. We will present the proposed trade off between the evolution of these parameters and the Lhc luminosity performance.

  6. The super-LHC

    CERN Document Server

    Mangano, Michelangelo L

    2010-01-01

    We review here the prospects of a long-term upgrade programme for the Large Hadron Collider (LHC), CERN laboratory's new proton-proton collider. The super-LHC, which is currently under evaluation and design, is expected to deliver of the order of ten times the statistics of the LHC. In addition to a non-technical summary of the principal physics arguments for the upgrade, I present a pedagogical introduction to the technological challenges on the accelerator and experimental fronts, and a review of the current status of the planning.

  7. LHC brochure (Italian version)

    CERN Multimedia

    Lefevre, Christiane

    2011-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which started up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  8. LHC brochure (German version)

    CERN Multimedia

    Lefevre, Christiane

    2011-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which will start-up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  9. LHC brochure (French version)

    CERN Multimedia

    Lefevre, C

    2010-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which started up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  10. LHC brochure (Danish version)

    CERN Multimedia

    Lefevre, C

    2010-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which started up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  11. LHC brochure (English version)

    CERN Multimedia

    Lefevre, C

    2010-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which started up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  12. LHC brochure (French version)

    CERN Multimedia

    Marcastel, Fabienne

    2014-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which started up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  13. LHC brochure (English version)

    CERN Multimedia

    AUTHOR|(CDS)2070305

    2014-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which started up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  14. CERN confirms LHC schedule

    CERN Document Server

    2003-01-01

    The CERN Council held its 125th session on 20 June. Highlights of the meeting included confirmation that the LHC is on schedule for a 2007 start-up, and the announcement of a new organizational structure in 2004.

  15. LHC Brochure (german version)

    CERN Multimedia

    Vanoli, C.

    2006-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which will start-up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  16. LHC brochure (German version)

    CERN Multimedia

    Lefevre, C

    2008-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which will start-up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  17. CERN recognises LHC suppliers

    CERN Multimedia

    2002-01-01

    CERN has just presented the first awards recognising LHC suppliers. The Russian institute BINP, the Belgian firm Cockerill-Sambre and the US company Wah-Chang are the recipients of the first 'Golden Hadrons'.

  18. LHC Luminosity Performance

    CERN Document Server

    AUTHOR|(CDS)2091107; Fuchsberger, Kajetan; Papotti, Giulia

    This thesis adresses several approaches with the common goal of assessing, understanding and improving the luminosity of the Large Hadron Collider (LHC). To better exploit existing margins for maximum luminosity while fulfilling the requirements of the LHC experiments, new techniques for luminosity levelling are studied and developed to an operational state, such as changing the crossing angle or $\\beta^*$ (beam size) at the interaction points with the beams in collisions. In 2017 LHC operation, the crossing angle reduction in collisions improved the integrated luminosity by $\\mathrm{\\sim} 2\\,\\mathrm{fb^{-1}}$ ($\\mathrm{\\sim} 4\\,\\mathrm{\\%}$ of the yearly production). For additional diagnostics, a new method for measuring beam sizes and orbits for each circulating bunch using the luminosity measurement during beam separation scans is shown. The results of these Emittance Scans improved the understanding of the LHC luminosity reach and of the orbit offsets introduced by beam-beam long-range effects.

  19. LHC brochure (German version)

    CERN Multimedia

    Marcastel, Fabienne

    2014-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which started up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  20. LHC brochure (Spanish version)

    CERN Multimedia

    Lefevre, C

    2008-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which will start-up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  1. LHC: seven golden suppliers

    CERN Multimedia

    2005-01-01

    The fourth CERN Golden Hadron awards saw seven of the LHC's best suppliers receive recognition for the high quality of their work, compliance with delivery deadlines, flexibility and adaptability to the demanding working conditions of the project. The representatives of the seven companies which received awards during the Golden Hadron ceremony, standing with Lyn Evans, LHC Project Leader. 'The Golden Hadron awards are a symbol of our appreciation of not only the quality and timely delivery of components but also the collaborative and flexible way the firms have contributed to this very difficult project,' said Lyn Evans, head of the LHC project. The awards went to Kemppi-Kempower (Finland), Metso Powdermet (Finland), Transtechnik (Germany), Babcock Noell Nuclear (Germany), Iniziative Industriali (Italy), ZTS VVU Kosice (Slovakia), and Jehier (France). Babock Noell Nuclear (BNN) successfully produced one-third (416 cold dipole masses) of the LHC's superconducting dipole magnets, one of the most critical an...

  2. LHC First Beam 2008

    CERN Multimedia

    Tuura, L

    2008-01-01

    The CMS Centre played a major part in the LHC First Beam Event on September 10th 2008: it was a central point for CMS, hosting journalists from all over the world and providing live link-ups to collaborating institutes as well as, of course, monitoring events as they happened at Point 5. It was also a venue for celebration as the beam completed circuits of the LHC in both directions, passing successfully through the detector (Courtesy of Lassi Tuura)

  3. submitter LHC experiments

    CERN Document Server

    Tanaka, Shuji

    2001-01-01

    Large Hadron Collider (LHC) is under construction at the CERN Laboratory in Switzerland. Four experiments (ATLAS, CMS, LHCb, ALICE) will try to study the new physics by LHC from 2006. Its goal to explore the fundamental nature of matter and the basic forces. The PDF file of the transparency is located on http://www-atlas.kek.jp/sub/documents/lepsymp-stanaka.pdf.

  4. Future of LHC

    CERN Document Server

    Dova, Maria-Teresa; The ATLAS collaboration

    2018-01-01

    The High-Luminosity LHC aims to provide a total integrated luminosity of 3000 fb-1 from p-p collisions at  14 TeV over the course of 10 years. The upgraded ATLAS detector must be able to cope well with increased occupancies and data rates. The large data samples at the High-Luminosity LHC will enable precise measurements of the Higgs boson and other Standard Model particles, as well as searches for new phenomena BSM.

  5. LHC Report: astounding availability

    CERN Multimedia

    Andrea Apollonio for the LHC team

    2016-01-01

    The LHC is off to an excellent start in 2016, having already produced triple the luminosity of 2015. An important factor in the impressive performance so far this year is the unprecedented machine availability.   LHC integrated luminosity in 2011, 2012, 2015 and 2016 and the prediction of the 2016 performance foreseen at the start of the year. Following the 2015-2016 end of year shutdown, the LHC restarted beam operation in March 2016. Between the restart and the first technical stop (TS1) in June, the LHC's beam intensity was successively increased, achieving operation with 2040 bunches per beam. The technical stop on 7-8 June was shortened to maximise the time available for luminosity production for the LHC experiments before the summer conferences. Following the technical stop, operation resumed and quickly returned to the performance levels previously achieved. Since then, the LHC has been running steadily with up to 2076 bunches per beam. Since the technical stop, a...

  6. LHC INAUGURATION, LHC Fest highlights: exhibition time!

    CERN Multimedia

    2008-01-01

    David Gross, one of the twenty-one Nobel Laureates who have participated in the project.Tuesday 21 October 2008 Accelerating Nobels Colliding Charm, Atomic Cuisine, The Good Anomaly, A Quark Somewhere on the White Paper, Wire Proliferation, A Tale of Two Liquids … these are just some of the titles given to artworks by Physics Nobel Laureates who agreed to make drawings of their prize-winning discoveries (more or less reluctantly) during a special photo session. Science photographer Volker Steger made portraits of Physics Nobel Laureates and before the photo sessions he asked them to make a drawing of their most important discovery. The result is "Accelerating Nobels", an exhibition that combines unusual portraits of and original drawings by twenty-one Nobel laureates in physics whose work is closely related to CERN and the LHC. This exhibition will be one of the highlights of the LHC celebrations on 21 October in the SM18 hall b...

  7. LHC detectors trigger/DAQ at LHC

    CERN Document Server

    Sphicas, Paris

    1998-01-01

    At its design luminosity, the LHC will deliver hundreds of millions of proton-proton interactions per second. Storage and computing limitations limit the number of physics events that can be recorded to about 100 per second. The selection will be carried out by the Trigger and data acquisition systems of the experiments. This lecture will review the requirements, architectures and various designs currently considered.

  8. LHC Report: LHC smashes collision records

    CERN Multimedia

    Sarah Charley

    2016-01-01

    The Large Hadron Collider is now producing more than a billion proton-proton collisions per second.   The LHC is colliding protons at a faster rate than ever before: approximately 1 billion times per second. Since April 2016, the LHC has delivered more than 30 inverse femtobarns (fb-1) to both ATLAS and CMS. This means that around 2.4 quadrillion (2.4 million billion) collisions have been seen by each of the experiments this year. The inverse femtobarn is the unit of measurement for integrated luminosity, indicating the cumulative number of potential collisions. This compares with the total of 33.2 fb-1 produced between 2010 and 2015. The unprecedented performance this year is the result of both the incremental increases in collision rate and the sheer amount of time the LHC has been up and running. This comes after a slow start-up in 2015, when scientists and engineers still needed to learn how to operate the machine at a much higher energy. “With more energy, the machine is much more sen...

  9. Electronics for LHC experiments

    International Nuclear Information System (INIS)

    Bourgeois, Francois

    1995-01-01

    Full text: A major effort is being mounted to prepare the way handling the high interaction rates expected from CERN's new LHC proton-proton collider (see, for example, November, page 6). September saw the First Workshop on Electronics for LHC Experiments, organized by Lisbon's Particle Physics Instrumentation Laboratory (LIP) on behalf of CERN's LHC Electronics Review Board (LERB - March, page 2). Its purpose was not only for the LERB to have a thorough review of ongoing activities, but also to promote cross fertilization in the engineering community involved in electronics design for LHC experiments. The Workshop gathered 187 physicists and engineers from 20 countries including USA and Japan. The meeting comprised six sessions and 82 talks, with special focus on radiation-hard microelectronic processes, electronics for tracking, calorimetry and muon detectors, optoelectronics, trigger and data acquisition systems. Each topic was introduced by an invited speaker who reviewed the requirements set by the particular detector technology at LHC. At the end of each session, panel discussions were chaired by each invited speaker. Representatives from four major integrated circuit manufacturers covered advanced radiation hard processes. Two talks highlighted the importance of obsolescence and quality systems in the long-lived and demanding environment of LHC. The Workshop identified areas and encouraged efforts for rationalization and common developments within and between the different detector groups. As a result, it will also help ensure the reliability and the long term maintainability of installed equipment. The proceedings of the Workshop are available from LIP Lisbon*. The LERB Workshop on Electronics for LHC Experiments will become a regular event, with the second taking place in Hungary, by Lake Balaton, from 23-27 September 1996. The Hungarian institutes KFKIRMKI have taken up the challenge of being as successful as LIP Lisbon in the organization

  10. LHC physics results and prospects

    CERN Document Server

    Kono, Takanori; The ATLAS collaboration

    2018-01-01

    This talk presents the latest results from LHC Run-2 as of May 2018 which include Standard Model measurements, Higgs boson properties and beyond Standard Model search results. The prospects for future LHC runs are also shown.

  11. Commissioning of the LHC

    CERN Multimedia

    CERN. Geneva

    2007-01-01

    The LHC construction is now approaching the end and it is now time to prepare for commissioning with beam. The behavior of a proton storage ring is much different to that of LEP, which profited from strong radiation damping to keep the beam stable. Our last experience with a hadron collider at CERN goes back more than 15 years when the proton-antiproton collider last operated. Ppbar taught us a lot about the machine physics of bunched beam proton storage rings and was essential input for the design of the LHC. After a short presentation of where we stand today with machine installation and hardware commissioning, I will discuss the main machine physics issues that will have to be dealt with in the LHC.

  12. Electronics at LHC

    CERN Document Server

    Hall, Geoffrey

    1998-01-01

    An overview of the electronic readout systems planned for use in the CMS and ATLAS experiments at the LHC will be given, with an emphasis on the motivations for the designs adopted and major technologies to be employed, specially those which are specific to LHC. At its design luminosity, the LHC will deliver hundreds of millions of proton-proton interactions per second. Storage and computing limitations limit the number of physics events that can be recorded to about 100 per second. The selection will be carried out by the Trigger and data acquisition systems of the experiments. This lecture will review the requirements, architectures and various designs currently considered. Introduction. Structure of gauge theories. The QED and QCD examples. Chiral theories. The electroweak theory. Spontaneous symmetry breaking. The Higgs machanism.Gauge boson and fermion masses. Yukawa coupling. Charges current couplings. The Cabibbo-Kobayashi-Maskawa matrix and CP violation. neutral current couplings. the Clashow-Iliopoul...

  13. LHC bending magnet coil

    CERN Multimedia

    A short test version of coil of wire used for the LHC dipole magnets. The high magnetic fields needed for guiding particles around the Large Hadron Collider (LHC) ring are created by passing 12’500 amps of current through coils of superconducting wiring. At very low temperatures, superconductors have no electrical resistance and therefore no power loss. The LHC is the largest superconducting installation ever built. The magnetic field must also be extremely uniform. This means the current flowing in the coils has to be very precisely controlled. Indeed, nowhere before has such precision been achieved at such high currents. Magnet coils are made of copper-clad niobium–titanium cables — each wire in the cable consists of 9’000 niobium–titanium filaments ten times finer than a hair.

  14. Lectures on LHC physics

    CERN Document Server

    Plehn, Tilman

    2015-01-01

    With the discovery of the Higgs boson, the LHC experiments have closed the most important gap in our understanding of fundamental interactions, confirming that such interactions between elementary particles can be described by quantum field theory, more specifically by a renormalizable gauge theory. This theory is a priori valid for arbitrarily high energy scales and does not require an ultraviolet completion. Yet, when trying to apply the concrete knowledge of quantum field theory to actual LHC physics - in particular to the Higgs sector and certain regimes of QCD - one inevitably encounters an intricate maze of phenomenological know-how, common lore and other, often historically developed intuitions about what works and what doesn’t. These lectures cover three aspects to help understand LHC results in the Higgs sector and in searches for physics beyond the Standard Model: they discuss the many facets of Higgs physics, which is at the core of this significantly expanded second edition; then QCD, to the deg...

  15. The LHC in numbers

    CERN Multimedia

    Alizée Dauvergne

    2010-01-01

    What makes the LHC the biggest particle accelerator in the world? Here are some of the numbers that characterise the LHC, and their equivalents in terms that are easier for us to imagine.   Feature Number Equivalent Circumference ~ 27 km   Distance covered by beam in 10 hours ~ 10 billion km a round trip to Neptune Number of times a single proton travels around the ring each second 11 245   Speed of protons first entering the LHC 299 732 500 m/s 99.9998 % of the speed of light Speed of protons when they collide 299 789 760 m/s 99.9999991 % of the speed of light Collision temperature ~ 1016 °C ove...

  16. UFOs in the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Grob, Laura [CERN, Geneva (Switzerland); Technische Universitaet Darmstadt (Germany)

    2016-07-01

    In the Large Hadron Collider (LHC) localized and recurring beam losses have been observed, which usually persist for several hundred microseconds. With increasing beam energy these losses were found to pose a serious risk to the machine availability, as some of these events can cause quenches in the superconducting magnets. The current understanding is that these losses are caused by falling microparticles that interact with the proton beam. To describe these so-called UFOs (unidentified falling objects) and their dynamics, a model was developed starting from the approach that only gravitational and electrostatic forces act on a neutrally charged particle. However, the model's results cannot reproduce the actual data from the LHC's beam loss monitors (BLMs), which indicates a more complex UFO dynamic. Experimental studies and further analysis of the BLM data are planned to investigate the UFO dynamics in greater detail and to understand origins and release mechanisms for microparticles in the LHC beam pipe.

  17. Cryogenics will cool LHC

    International Nuclear Information System (INIS)

    Anon.

    2001-01-01

    Results of the investigation into the cryogenic regulating line (QRL) performed by the LHC laboratory are presented. It is projected that eight cryogenic units located in five places around the LHC ring will provide superconducting magnets by liquid helium through eight cryogenic regulating lines of 3.2 km each. All QRL zones remain to be independent. CERN uses three test units with the aim of the certification of chosen constructions and verification of their thermal and mechanical efficiency before starting full-scale production [ru

  18. LHC-ILC synergy

    CERN Document Server

    Godbole, Rohini M

    2006-01-01

    I will begin by making a few general comments on the synergy between the Large Hadron Collider (LHC) which will go in action in 2007 and the International Linear Collider (ILC) which is under planning. I will then focus on the synergy between the LHC and the PLC option at the ILC, which is expected to be realised in the later stages of the ILC program. In this I will cover the possible synergy in the Higgs sector (with and without CP violation), in the determination of the anomalous vector boson couplings and last but not the least, in the search for extra dimensions and radions.

  19. The LHC detector challenge

    CERN Document Server

    Virdee, Tejinder S

    2004-01-01

    The Large Hadron Collider (LHC) from CERN, scheduled to come online in 2007, is a multi-TeV proton-proton collider with vast detectors. Two of the more significant detectors for LHC are ATLAS and CMS. Currently, both detectors are more than 65% complete in terms of financial commitment, and the experiments are being assembled at an increasing pace. ATLAS is being built directly in its underground cavern, whereas CMS is being assembled above ground. When completed, both detectors will aid researchers in determining what lies at the high-energy frontier, in particular the mechanism by which particles attain mass. (Edited abstract).

  20. LHC beampipe interconnection

    CERN Document Server

    Particle beams circulate for around 10 hours in the Large Hadron Collider (LHC). During this time, the particles make four hundred million revolutions of the machine, travelling a distance equivalent to the diameter of the solar system. The beams must travel in a pipe which is emptied of air, to avoid collisions between the particles and air molecules (which are considerably bigger than protons). The beam pipes are pumped down to an air pressure similar to that on the surface of the moon. Much of the LHC runs at 1.9 degrees above absolute zero. When material is cooled, it contracts. The interconnections must absorb this contraction whilst maintaining electrical connectivity.

  1. LHC Commissioning and First Operation

    OpenAIRE

    Myers, S

    2010-01-01

    A description is given of the repair of the LHC after the accident of September 2008. The LHC hardware and beam commissioning and initial operation are reviewed both in terms of beam and hardware performance. The implemented machine protection measures and their impact on LHC operation are presented.

  2. LHC challenges and upgrade options

    Energy Technology Data Exchange (ETDEWEB)

    Bruning, O [CERN AB/ABP, Y03600, 1211 Geneva 23 (Switzerland)], E-mail: Oliver.Bruning@cern.ch

    2008-05-15

    The presentation summarizes the key parameters of the LHC collider. Following a discussion of the main challenges for reaching the nominal machine performance the presentation identifies options for increasing the operation tolerances and the potential performance reach of the LHC by means of future hardware upgrades of the LHC and its injector complex.

  3. LHC challenges and upgrade options

    International Nuclear Information System (INIS)

    Bruning, O

    2008-01-01

    The presentation summarizes the key parameters of the LHC collider. Following a discussion of the main challenges for reaching the nominal machine performance the presentation identifies options for increasing the operation tolerances and the potential performance reach of the LHC by means of future hardware upgrades of the LHC and its injector complex

  4. LHC Report: Summer temperatures in the LHC

    CERN Multimedia

    Jan Uythoven for the LHC Team

    2012-01-01

    The LHC experiments have finished their data-taking period before the summer conferences. The machine has already delivered substantially more collisions to the experiments this year than in the whole of 2011. The LHC has now started a six-day Machine Development period, which will be followed by the second Technical Stop of the year.   The number of collisions delivered to the experiments is expressed in integrated luminosity. In 2011, the integrated luminosity delivered to both ATLAS and CMS was around 5.6 fb-1. On Monday 18 June, experiments finished taking data before the summer conferences and the integrated luminosity for 2012 so far is about 6.6 fb-1, well above the unofficial target of 5 fb-1. The LHC’s performance over the last week of running was so efficient that the injection kicker magnets – which heat up due to the circulating beam – did not have time to cool down between the subsequent fills. As the time constants for warming up and cooli...

  5. CERN: LHC magnets

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    With test magnets for CERN's LHC proton-proton collider regularly attaining field strengths which show that 10 Tesla is not forbidden territory, attention turns to why and where quenches happen. If 'training' can be reduced, superconducting magnets become easier to commission

  6. LHC status report

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Following the great success of the first 3.5 TeV collisions in all four LHC experiments on 30 March, the focus of the LHC commissioning teams has turned to consolidating the beam injection and acceleration procedures.   During the last two weeks, the operators have adopted a cycle of beam commissioning studies by day and the preparation and delivery of collisions during the night shifts. The injection and acceleration processes for the beams are by now well established and almost all feedback systems, which are an essential ingredient for establishing reliable and safe machine operation, have been commissioned. Thanks to special current settings for the quadrupoles that are situated near the collision points, the LHC luminosity at high energy has been increased by a factor of 5 in three of the four experiments. Similar improvements are under way for the fourth experiment. The next steps include adjustments of the LHC machine protection and collimation devices, which will ensure 'stable beam' co...

  7. Fully transparent LHC

    CERN Multimedia

    2008-01-01

    Thanks to the first real signals received from the LHC while in operation before the incident, the experiments are now set to make the best use of the data they have collected. Report from the LHCC open session.The September open session of the LHCC (LHC Experiments Committee) came just a few days after the incident that occurred at the LHC. The packed auditorium was a testament to the huge interest raised by Lyn Evans’ talk about the status of the machine and the plans for the future. After being told that the actual consequences of the incident will be clear only once Sector 3-4 has been warmed up, the audience focussed on the reports from the experiments. For the first time, the reports showed performance results of the various detectors with particles coming from the machine and not just from cosmic rays or tests and simulations. "The first days of LHC beam exceeded all expectations and the experiments made extensive and rapid use of the data they collected", says ...

  8. Higgs physics at LHC

    OpenAIRE

    Unal, G

    2006-01-01

    This is a review of Higgs physics at LHC. The topics covered are the search of the Standard Model Higgs boson (with emphasis on the low mass region), the measurements of the Higgs boson properties (mass, width, spin, CP and couplings) and the Higgs sector of the MSSM.

  9. Mobilizing for the LHC

    CERN Multimedia

    2008-01-01

    A follow-up report on the incident that occurred in LHC Sector 3-4 was published on 5 December. It confirms that the accelerator will be restarted in the summer of 2009. From now until then, the teams will be pulling out all the stops to repair the sector and enhance the operational safety of the machine.

  10. LHC: forwards and onwards

    CERN Multimedia

    2008-01-01

    Following the recent incident in Sector 3-4, which has brought the start-up of the LHC to a halt, the various teams are working hard to establish the cause, evaluate the situation and plan the necessary repairs. The LHC will be started up again in spring 2009 following the winter shutdown for the maintenance of all the CERN installations. The LHC teams are at work on warming up Sector 3-4 and establishing the cause of the serious incident that occurred on Friday, 19 September. Preliminary investigations suggest that the likely cause of the problem was a faulty electrical connection between two magnets. The connections probably melted, leading to a mechanical failure and a large leak of helium into the tunnel. However, the teams will not be able to carry out a full evaluation and assess the repairs needed until the sector has been warmed up again and inspected. "We are not worried about repairing the magnets as spare parts are available", said Lyn Evans, the LHC Project Leade...

  11. LHC Report: Ion Age

    CERN Multimedia

    John Jowett for the LHC team

    2013-01-01

    The LHC starts the New Year facing a new challenge: proton-lead collisions in the last month before the shutdown in mid-February.    Commissioning this new and almost unprecedented mode of collider operation is a major challenge both for the LHC and its injector chain. Moreover, it has to be done very quickly to achieve a whole series of physics goals, requiring modifications of the LHC configuration, in a very short time. These include a switch of the beam directions halfway through the run, polarity reversals of the ALICE spectrometer magnet and Van der Meer scans.    The Linac3 team kept the lead source running throughout the end-of-year technical stop, and recovery of the accelerator complex was very quick. New proton and lead beams were soon ready, with a bunch filling pattern that ensures they will eventually match up in the LHC. The LEIR machine has even attained a new ion beam intensity record.  On Friday 11 January the first single bunches o...

  12. Higgs physics at LHC

    Indian Academy of Sciences (India)

    The large hadron collider (LHC) and its detectors, ATLAS and CMS, are being built to study TeV scale physics, and to fully understand the electroweak symmetry breaking mechanism. The Monte-Carlo simulation results for the standard model and minimal super symmetric standard model Higgs boson searches and ...

  13. Electronics for LHC Experiments

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    This document gathers the abstracts of most presentations made at this workshop on electronics for the large hadron collider (LHC) experiments. The presentations were arranged into 6 sessions: 1) electronics for tracker, 2) trigger electronics, 3) detector control systems, 4) data acquisition, 5) electronics for calorimeters and electronics for muons, and 6) links, power systems, grounding and shielding, testing and quality assurance.

  14. CERN: LHC magnets

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1992-08-15

    With test magnets for CERN's LHC proton-proton collider regularly attaining field strengths which show that 10 Tesla is not forbidden territory, attention turns to why and where quenches happen. If 'training' can be reduced, superconducting magnets become easier to commission.

  15. Electronics for LHC Experiments

    International Nuclear Information System (INIS)

    2004-01-01

    This document gathers the abstracts of most presentations made at this workshop on electronics for the large hadron collider (LHC) experiments. The presentations were arranged into 6 sessions: 1) electronics for tracker, 2) trigger electronics, 3) detector control systems, 4) data acquisition, 5) electronics for calorimeters and electronics for muons, and 6) links, power systems, grounding and shielding, testing and quality assurance

  16. ATLAS. LHC experiments

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    In Greek mythology, Atlas was a Titan who had to hold up the heavens with his hands as a punishment for having taken part in a revolt against the Olympians. For LHC, the ATLAS detector will also have an onerous physics burden to bear, but this is seen as a golden opportunity rather than a punishment. The major physics goal of CERN's LHC proton-proton collider is the quest for the long-awaited£higgs' mechanism which drives the spontaneous symmetry breaking of the electroweak Standard Model picture. The large ATLAS collaboration proposes a large general-purpose detector to exploit the full discovery potential of LHC's proton collisions. LHC will provide proton-proton collision luminosities at the aweinspiring level of 1034 cm2 s~1, with initial running in at 1033. The ATLAS philosophy is to handle as many signatures as possible at all luminosity levels, with the initial running providing more complex possibilities. The ATLAS concept was first presented as a Letter of Intent to the LHC Committee in November 1992. Following initial presentations at the Evian meeting (Towards the LHC Experimental Programme') in March of that year, two ideas for generalpurpose detectors, the ASCOT and EAGLE schemes, merged, with Friedrich Dydak (MPI Munich) and Peter Jenni (CERN) as ATLAS cospokesmen. Since the initial Letter of Intent presentation, the ATLAS design has been optimized and developed, guided by physics performance studies and the LHC-oriented detector R&D programme (April/May, page 3). The overall detector concept is characterized by an inner superconducting solenoid (for inner tracking) and large superconducting air-core toroids outside the calorimetry. This solution avoids constraining the calorimetry while providing a high resolution, large acceptance and robust detector. The outer magnet will extend over a length of 26 metres, with an outer diameter of almost 20 metres. The total weight of the detector is 7,000 tonnes. Fitted with its end

  17. LHC Nobel Symposium Proceedings

    Science.gov (United States)

    Ekelöf, Tord

    2013-12-01

    In the summer of 2012, a great discovery emerged at the Large Hadron Collider (LHC) at CERN in Geneva. A plethora of new precision data had already by then been collected by the ATLAS and CMS experiments at LHC, providing further extensive support for the validity of the Standard Model of particle physics. But what now appeared was the first evidence for what was not only the last unverified prediction of the Standard Model, but also perhaps the most decisive one: the prediction made already in 1964 of a unique scalar boson required by the theory of François Englert and Peter Higgs on how fundamental particles acquire mass. At that moment in 2012, it seemed particularly appropriate to start planning a gathering of world experts in particle physics to take stock of the situation and try to answer the challenging question: what next? By May 2013, when the LHC Nobel Symposium was held at the Krusenberg Mansion outside Uppsala in Sweden, the first signs of a great discovery had already turned into fully convincing experimental evidence for the existence of a scalar boson of mass about 125 GeV, having properties compatible with the 50-year-old prediction. And in October 2013, the evidence was deemed so convincing that the Swedish Royal Academy of Sciences awarded the Nobel Prize in Physics to Englert and Higgs for their pioneering work. At the same time the search at the LHC for other particles, beyond those predicted by the Standard Model, with heavier masses up to—and in some cases beyond—1 TeV, had provided no positive result. The triumph of the Standard Model seems resounding, in particular because the mass of the discovered scalar boson is such that, when identified with the Higgs boson, the Standard Model is able to provide predictions at energies as high as the Planck mass, although at the price of accepting that the vacuum would be metastable. However, even if there were some feelings of triumph, the ambience at the LHC Nobel Symposium was more one of

  18. 2008 LHC Open Days LHC magnets on display

    CERN Multimedia

    2008-01-01

    Over the last few years you’ve probably seen many of the 15 m long blue LHC dipole magnets being ferried around the site. Most of them are underground now, but on the LHC Open Days on 5 and 6 April the magnets will also play a central role on the surface. Installation of one of the LHC dipole magnets on the Saint-Genis roundabout on 7 March. The LHC dipole testing facility with several magnets at various stages of testing. The 27 km ring of the LHC consists of 1232 double-aperture superconducting dipole magnets, 360 short straight sections (SSS) and 114 special SSS for the insertion regions. On the Open Day, you will be able to "Follow the LHC magnets" through different stages around the site, culminating in their descent into the tunnel. Discover all the many components that have to be precisely integrated in the magnet casings, and talk to the engine...

  19. LHC forward physics

    Energy Technology Data Exchange (ETDEWEB)

    Cartiglia, N. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Royon, C. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). et al.

    2015-10-02

    The goal of this report is to give a comprehensive overview of the rich field of forward physics, with a special attention to the topics that can be studied at the LHC. The report starts presenting a selection of the Monte Carlo simulation tools currently available, chapter 2, then enters the rich phenomenology of QCD at low, chapter 3, and high, chapter 4, momentum transfer, while the unique scattering conditions of central exclusive production are analyzed in chapter 5. The last two experimental topics, Cosmic Ray and Heavy Ion physics are presented in the chapter 6 and 7 respectively. Chapter 8 is dedicated to the BFKL dynamics, multiparton interactions, and saturation. The report ends with an overview of the forward detectors at LHC. Each chapter is correlated with a comprehensive bibliography, attempting to provide to the interested reader with a wide opportunity for further studies.

  20. LHC Forward Physics

    CERN Document Server

    Akiba, K.

    2016-10-17

    The goal of this report is to give a comprehensive overview of the rich field of forward physics, with a special attention to the topics that can be studied at the LHC. The report starts presenting a selection of the Monte Carlo simulation tools currently available, chapter 2, then enters the rich phenomenology of QCD at low, chapter 3, and high, chapter 4, momentum transfer, while the unique scattering conditions of central exclusive production are analyzed in chapter 5. The last two experimental topics, Cosmic Ray and Heavy Ion physics are presented in the chapter 6 and 7 respectively. Chapter 8 is dedicated to the BFKL dynamics, multiparton interactions, and saturation. The report ends with an overview of the forward detectors at LHC. Each chapter is correlated with a comprehensive bibliography, attempting to provide to the interested reader with a wide opportunity for further studies.

  1. LHC Report: machine development

    CERN Multimedia

    Rogelio Tomás García for the LHC team

    2015-01-01

    Machine development weeks are carefully planned in the LHC operation schedule to optimise and further study the performance of the machine. The first machine development session of Run 2 ended on Saturday, 25 July. Despite various hiccoughs, it allowed the operators to make great strides towards improving the long-term performance of the LHC.   The main goals of this first machine development (MD) week were to determine the minimum beam-spot size at the interaction points given existing optics and collimation constraints; to test new beam instrumentation; to evaluate the effectiveness of performing part of the beam-squeezing process during the energy ramp; and to explore the limits on the number of protons per bunch arising from the electromagnetic interactions with the accelerator environment and the other beam. Unfortunately, a series of events reduced the machine availability for studies to about 50%. The most critical issue was the recurrent trip of a sextupolar corrector circuit –...

  2. The LHC superconducting cavities

    CERN Document Server

    Boussard, Daniel; Häbel, E; Kindermann, H P; Losito, R; Marque, S; Rödel, V; Stirbet, M

    1999-01-01

    The LHC RF system, which must handle high intensity (0.5 A d.c.) beams, makes use of superconducting single-cell cavities, best suited to minimizing the effects of periodic transient beam loading. There will be eight cavities per beam, each capable of delivering 2 MV (5 MV/m accelerating field) at 400 MHz. The cavities themselves are now being manufactured by industry, using niobium-on-copper technology which gives full satisfaction at LEP. A cavity unit includes a helium tank (4.5 K operating temperature) built around a cavity cell, RF and HOM couplers and a mechanical tuner, all housed in a modular cryostat. Four-unit modules are ultimately foreseen for the LHC (two per beam), while at present a prototype version with two complete units is being extensively tested. In addition to a detailed description of the cavity and its ancillary equipment, the first test results of the prototype will be reported.

  3. LHC, Astrophysics and Cosmology

    Directory of Open Access Journals (Sweden)

    Giulio Auriemma

    2014-12-01

    Full Text Available In this paper we discuss the impact on cosmology of recent results obtained by the LHC (Large Hadron Collider experiments in the 2011-2012 runs, respectively at √s = 7 and 8 TeV. The capital achievement of LHC in this period has been the discovery of a spin-0 particle with mass 126 GeV/c2, very similar to the Higgs boson of the Standard Model of Particle Physics. Less exciting, but not less important, negative results of searches for Supersymmetric particles or other exotica in direct production or rare decays are discussed in connection with particles and V.H.E. astronomy searches for Dark Matter.

  4. Cryogenics for LHC experiments

    CERN Multimedia

    2001-01-01

    Cryogenic systems will be used by LHC experiments to maximize their performance. Institutes around the world are collaborating with CERN in the construction of these very low temperature systems. The cryogenic test facility in hall 180 for ATLAS magnets. High Energy Physics experiments have frequently adopted cryogenic versions of their apparatus to achieve optimal performance, and those for the LHC will be no exception. The two largest experiments for CERN's new flagship accelerator, ATLAS and CMS, will both use large superconducting magnets operated at 4.5 Kelvin - almost 270 degrees below the freezing point of water. ATLAS also includes calorimeters filled with liquid argon at 87 Kelvin. For the magnets, the choice of a cryogenic version was dictated by a combination economy and transparency to emerging particles. For the calorimeters, liquid argon was selected as the fluid best suited to the experiment's physics requirements. High Energy Physics experiments are the result of worldwide collaborations and...

  5. MPI@LHC Talk.

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00392933; The ATLAS collaboration

    2016-01-01

    Draft version of talk for MPI@LHC, regarding the topic of "Monte Carlo Tuning @ ATLAS". The talk introduces the event generator chain, concepts of tuning, issues/problems with over tuning, and then proceeds to explain 3(4) tunes performed at ATLAS. A 4th tune known as A15-MG5aMC@NLO(-TTBAR) is also included, but is awaiting note approval.

  6. LHC Magnet test failure

    CERN Multimedia

    2007-01-01

    "On Tueday, March 22, a Fermilab-built quadrupole magnet, one of an "inner triplet" of three focusing magnets, failed a high-pressure test at Point 5 in the tunnel of the LHC accelerator at CERN. Since Tuesday, teams at CERN and Fermilab have worked closely together to address the problem and have identified the cause of the failure. Now they are at work on a solution.:" (1 page)

  7. The LHC on Google

    CERN Multimedia

    2009-01-01

    Where in the world could the LHC outdo Barack Obama in the popularity stakes? On Google, of course! The famous search engine has just published its Top Ten "most popular" and "fastest rising" searches for 2008 in each of 34 countries. Surprise, surprise, the term "Large Hadron Collider" was the 6th fastest rising topic in the United Kingdom and the 10th fastest in New Zealand. In the UK, "Large Hadron Collider" even beat "Obama" into 7th place!

  8. Lectures on LHC physics

    CERN Document Server

    Plehn, Tilman

    2012-01-01

    When we try to advance from a solid knowledge of field theory to LHC physics we usually encounter a frustrating problem: in particular Higgs physics and QCD techniques appear as a impenetrable granite block of phenomenological know-how, common lores, and historically grown intuition what works and what does not. I hope this lecture can drill a few holes into the rock and put you into a position to digest advanced writeups as well as some first research papers on the topic.

  9. The LHC project

    CERN Multimedia

    CERN. Geneva

    2002-01-01

    At the halfway point in the construction of the LHC, the project is now moving from the design and procurement phase to the installation phase, which officially started on 1st March. An overview of the progress of the project is given and the final schedule for installation and commissioning is discussed. The talk will be given in English but questions can be taken in French.

  10. LHC Report: Beam on

    CERN Multimedia

    Rossano Giachino for the LHC Team

    2012-01-01

    The powering tests described in the last edition of the Bulletin were successfully finished at the end of the first week of March opening the way for 4 TeV operations this year. The beam was back in the machine on Wednesday 14 March. The first collisions at 4 TeV are scheduled for the first week of April.   The first beam of 2012 is dumped after making a few rounds in the LHC. The magnet powering tests were followed by the machine checkout phase. Here the operations team in collaboration with the equipment groups performs a sequence of tests to ensure the readiness of the LHC for beam. The tests include driving all the LHC systems – beam dump, injection, collimation, RF, power converters, magnet circuits, vacuum, interlocks, controls, timing and synchronization – through the operational cycle. The “checkout phase” is really a massive de-bugging exercise, which is performed with the objective of ensuring the proper functioning of the whole machine and t...

  11. LHC Report: imaginative injectors

    CERN Multimedia

    Pierre Freyermuth for the LHC team

    2016-01-01

    A new bunch injection scheme from the PS to the SPS allowed the LHC to achieve a new peak luminosity record.   Figure 1: PSB multi-turn injection principle: to vary the parameters during injection with the aim of putting the newly injected beam in a different region of the transverse phase-space plan. The LHC relies on the injector complex to deliver beam with well-defined bunch populations and the necessary transverse and longitudinal characteristics – all of which fold directly into luminosity performance. There are several processes taking place in the PS Booster (PSB) and the Proton Synchrotron (PS) acting on the beam structure in order to obtain the LHC beam characteristics. Two processes are mainly responsible for the beam brightness: the PSB multi-turn injection and the PS radio-frequency (RF) gymnastics. The total number of protons in a bunch and the transverse emittances are mostly determined by the multi-turn Booster injection, while the number of bunches and their time spacin...

  12. LHC Report: Rocky XIV

    CERN Multimedia

    Mike Lamont for the LHC Team

    2012-01-01

    The LHC has been in luminosity production mode for the last couple of weeks. Peak luminosities have ranged between 6 and a record 7.74 x 1033 cm -2 s-1. Integrated luminosities per fill have been healthy, with 170 inverse picobarn per fill reached on five occasions in the last two weeks.  The total integrated luminosity for the year has passed 14 inverse femtobarns.   Injected bunch currents have peaked at an average of  1.69 x 1011 protons per bunch on average - a remarkable achievement for both the injectors and the LHC: the injectors to be able to produce good quality beam at these intensities; the LHC for being able to cope with these intensities without excessive losses. Peak performance from day to day depends strongly on the beam sizes and bunch intensities delivered by the injectors. It is a continual challenge to keep the Booster, PS and SPS optimally tuned while they deliver beams to their other wide range of users. Despite the excel...

  13. LHC Dipoles Accelerate

    CERN Multimedia

    2001-01-01

    Andrezej Siemko (left), Peter Sievers (centre), and Lucio Rossi (right), have the exciting challenge of preparing and testing 2000 magnets for the LHC. The LHC is going to require a lot of powerful magnets by the time it begins operation in 2006. More specifically, it is going to need 130 special magnets, 400 quadrupoles, and a whopping 1250 dipoles! Preparing and testing these magnets for the conditions they will encounter in the LHC is not an easy task. But evaluation of the most recently received magnet, from the German company Noell, is showing that while the monumental task of receiving and testing nearly 2000 magnets is going to be exhausting, the goals are definitely attainable. At the moment and over the next year, pre-series magnets (the magnets that CERN uses to fine tune performance) are arriving slowly (90 in total will arrive), but by 2003 the rate of series magnet arrival will accelerate to 9 per week, that's over 450 in a single year! And working with these magnets when they arrive is tough. ...

  14. LHC luminosity upgrade detector challenges

    CERN Multimedia

    CERN. Geneva; de Roeck, Albert; Bortoletto, Daniela; Wigmans, Richard; Riegler, Werner; Smith, Wesley H

    2006-01-01

    LHC luminosity upgrade: detector challenges The upgrade of the LHC machine towards higher luminosity (1035 cm -2s-1) has been studied over the last few years. These studies have investigated scenarios to achieve the increase in peak luminosity by an order of magnitude, as well as the physics potential of such an upgrade and the impact of a machine upgrade on the LHC DETECTORS. This series of lectures will cover the following topics: • Physics motivation and machine scenarios for an order of magnitude increase in the LHC peak luminosity (lecture 1) • Detector challenges including overview of ideas for R&D programs by the LHC experiments: tracking and calorimetry, other new detector developments (lectures 2-4) • Electronics, trigger and data acquisition challenges (lecture 5) Note: the much more ambitious LHC energy upgrade will not be covered

  15. LHC goes global

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1995-09-15

    As CERN's major project for the future, the LHC sets a new scale in world-wide scientific collaboration. As well as researchers and engineers from CERN's 19 European Member States, preparations for the LHC now include scientists from several continents. Some 50 per cent of the researchers involved in one way or another with preparations for the LHC experimental programme now come from countries which are not CERN Member States. Underlining this enlarged international involvement is the recent decision by the Japanese Ministry of Education, Science and Culture ('Monbusho') to accord CERN a generous contribution of five billion yen (about 65 million Swiss francs) to help finance the construction of the LHC. This money will be held in a special fund earmarked for construction of specific LHC components and related activities. To take account of the new situation, CERN is proposing to set up a totally new 'Associate State' status. This is foreseen as a flexible bilateral framework which will be set up on a case-by-case basis to adapt to different circumstances. This proposal was introduced to CERN Council in June, and will be further discussed later this year. These developments reflect CERN's new role as a focus of world science, constituting a first step towards a wider level of international collaboration. At the June Council session, as a first step, Japan was unanimously elected as a CERN Observer State, giving them the right to attend Council meetings. Introducing the topic at the Council session, Director General Chris Llewellyn Smith sketched the history of Japanese involvement in CERN research. This began in 1957 and has gone on to include an important experiment at the LEAR low energy antiproton ring using laser spectroscopy of antiprotonic helium atoms, the new Chorus neutrino experiment using an emulsion target, and a major contribution to the Opal experiment at the LEP electronpositron collider. In welcoming the development, many Council delegates looked

  16. LHC goes global

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    As CERN's major project for the future, the LHC sets a new scale in world-wide scientific collaboration. As well as researchers and engineers from CERN's 19 European Member States, preparations for the LHC now include scientists from several continents. Some 50 per cent of the researchers involved in one way or another with preparations for the LHC experimental programme now come from countries which are not CERN Member States. Underlining this enlarged international involvement is the recent decision by the Japanese Ministry of Education, Science and Culture ('Monbusho') to accord CERN a generous contribution of five billion yen (about 65 million Swiss francs) to help finance the construction of the LHC. This money will be held in a special fund earmarked for construction of specific LHC components and related activities. To take account of the new situation, CERN is proposing to set up a totally new 'Associate State' status. This is foreseen as a flexible bilateral framework which will be set up on a case-by-case basis to adapt to different circumstances. This proposal was introduced to CERN Council in June, and will be further discussed later this year. These developments reflect CERN's new role as a focus of world science, constituting a first step towards a wider level of international collaboration. At the June Council session, as a first step, Japan was unanimously elected as a CERN Observer State, giving them the right to attend Council meetings. Introducing the topic at the Council session, Director General Chris Llewellyn Smith sketched the history of Japanese involvement in CERN research. This began in 1957 and has gone on to include an important experiment at the LEAR low energy antiproton ring using laser spectroscopy of antiprotonic helium atoms, the new Chorus neutrino experiment using an emulsion target, and a major contribution to the Opal experiment at the LEP electronpositron collider. In welcoming the

  17. PDF4LHC recommendations for LHC Run II

    NARCIS (Netherlands)

    Butterworth, Jon; Carrazza, Stefano; Cooper-Sarkar, Amanda; Roeck, Albert de; Feltesse, Joel; Forte, Stefano; Gao, Jun; Glazov, Sasha; Huston, Joey; Kassabov, Zahari; McNulty, Ronan; Morsch, Andreas; Nadolsky, Pavel; Radescu, Voica; Rojo, Juan; Thorne, Robert S.

    2015-01-01

    We provide an updated recommendation for the usage of sets of parton distribution functions (PDFs) and the assessment of PDF and PDF+$\\alpha_s$ uncertainties suitable for applications at the LHC Run II. We review developments since the previous PDF4LHC recommendation, and discuss and compare the new

  18. RF upgrade program in LHC injectors and LHC machine

    International Nuclear Information System (INIS)

    Jensen, E.

    2012-01-01

    The main themes of the RF upgrade program are: the Linac4 project, the LLRF-upgrade and the study of a tuning-free wide-band system for PSB, the upgrade of the SPS 800 MHz amplifiers and beam controls and the upgrade of the transverse dampers of the LHC. Whilst LHC Splice Consolidation is certainly the top priority for LS1, some necessary RF consolidation and upgrade is necessary to assure the LHC performance for the next 3- year run period. This includes: 1) necessary maintenance and consolidation work that could not fit the shorter technical stops during the last years, 2) the upgrade of the SPS 200 MHz system from presently 4 to 6 cavities and possibly 3) the replacement of one LHC cavity module. On the longer term, the LHC luminosity upgrade requires crab cavities, for which some preparatory work in SPS Coldex must be scheduled during LS1. (author)

  19. LNV Higgses at LHC

    Science.gov (United States)

    Maiezza, Alessio; Nemevšek, Miha; Nesti, Fabrizio

    2016-06-01

    Lepton number is a fundamental symmetry that can be probed at the LHC. Here, we study the Higgs sector of theories responsible for neutrino mass generation. After a brief discussion of simple see-saw scenarios, we turn to theories where heavy Majorana neutrino mass is protected by a gauge symmetry and focus on the Left-Right symmetric theory. There, the SM-like Higgs boson can decay to a pair of heavy neutrinos and provide enough information to establish the origin of neutrino mass.

  20. Thermometry for the LHC

    International Nuclear Information System (INIS)

    Buhler, S.; Junquera, T.; Thermeau, J.P.

    1999-01-01

    The LHC project will use about 8000 thermometers to control the temperature of magnets. These thermometers will be operated at a temperature ranging from 1.6 K to 300 K and their calibration should be better than 0.25%. A small cryogenic thermometer calibration facility has been designed and tested. To select the cryogenic temperature sensors, an irradiation program is being performed to expose at high neutron fluences (>10 15 n/cm 2 ) the following thermometers: carbon resistors, Ge, thin film, RhFe and Pt. The resistance shifts under radiation of the different sensors at liquid helium are presented. (authors)

  1. QCD probes at LHC

    CERN Document Server

    Da Silveira, G. Gil

    2018-01-01

    The LHC experiments have reported new results with respect to the dynamics of the strong interactions in $pp$, $p$A, and AA collisions over the past years. In proton-proton collisions, the data analyses have focused in exploring the nature of underlying events and double parton scattering at high energies. For large systems, the heavy-ion collisions have provided new insights on physics aspects related to azimuthal correlations, jet quenching, and particle production, such as antiprotons. This Letter reports the recent results from the ATLAS, CMS, and LHCb Collaborations on these various topics and highlights its relevant findings for the high-energy community.

  2. First LHC beam in 2017

    CERN Multimedia

    ATLAS Collaboration

    2017-01-01

    Impressions from the ATLAS control room while waiting for the very first 2017 LHC beams, from the traditional croissants in the morning to the "beam splashes" in the evening. The shift crew, online experts, run coordinators and management are looking forward to the next steps of the LHC restart.

  3. Status of the LHC machine

    International Nuclear Information System (INIS)

    Faugeras, P.

    1997-01-01

    The report represents itself a set of diagrams, characterizing: the LHC main parameters for proton-proton collisions and lead ion collisions, parameters of SC dipole and quadrupole magnets and outlines of their designs, LHC cryogenic systems, injection complex and detectors [ru

  4. Le futur du project LHC

    CERN Multimedia

    Heyoka

    2007-01-01

    Since 2004, and specitally during the long study in 2005, we used the results of the LHC Project to evaluate differents parameters of the machiene (LHC). The final choices for the design of the machine are based partly on these results. (1,5 page)

  5. LHC Cryogenics on the mend

    CERN Multimedia

    2004-01-01

    On 29 September, repairs began on the LHC cryogenic distribution line, or QRL, to replace a faulty part that occurs in the hundreds of elements of the line that are already on-site. The Accelerator Technology Department is designing a work programme to finish the repairs as soon as possible and minimize delays to the rest of the LHC project.

  6. First LHC beam in 2017

    CERN Multimedia

    ATLAS Collaboration

    2017-01-01

    Impressions from the ATLAS control room while waiting for the very first 2017 LHC beams, from the traditional croissants in the morning to the "beam splashes" in the evening. The shift crew, online experts, run coordinators and management are looking forward the next steps of the LHC restart.

  7. Support for the LHC experiments

    CERN Document Server

    Butin, François; Gastal, M; Lacarrère, D; Macina, D; Perrot, A L; Tsesmelis, E; Wilhelmsson, M; CERN. Geneva. TS Department

    2008-01-01

    Experimental Area Teams have been put in place and charged with the general co-ordination and management of the LHC experimental areas and of the zones in the LHC tunnel hosting near-beam detectors of the experiments. This organization is responsible for the in situ co-ordination of work with the aim of providing a structure that enables the experiment collaborations and accelerator groups to carry out their work effectively and safely. This presentation will review some key elements in the support given to the LHC experimental areas and, given the track record and successful implementation during the LHC installation and commissioning phase, will argue that such an organization structure will be required also for the period of LHC exploitation for physics.

  8. Section of LHC beampipe

    CERN Multimedia

    2009-01-01

    A short section of the LHC beampipe including beam screen. Particle beams circulate for around 10 hours in the Large Hadron Collider (LHC). During this time, the particles make four hundred million revolutions of the machine, travelling a distance equivalent to the diameter of the solar system. The beams must travel in a pipe which is emptied of air, to avoid collisions between the particles and air molecules (which are considerably bigger than protons). The beam pipes are pumped down to an air pressure similar to that on the surface of the moon. Emptying the air from the two 27 km long Large Hadron Collider beam-pipes is equivalent in volume to emptying the nave of the Notre Dame cathedral in Paris. Initially, the air pressure is reduced by pumping. Then, cold sections of the beam-pipe are further emptied using the temperature gradient across special beam-screens inside the tube where particles travel. The warm sections are emptied using a coating called a getter that works like molecular fly-paper. This va...

  9. LHC beampipe section

    CERN Multimedia

    A short section of the LHC beam-pipe including beam screen. In the LHC, particles circulate under vacuum. The vacuum chamber can be at room temperature (for example, in the experimental areas), or at cryogenic temperature, in the superconductive magnets. This piece is located in the superconductive magnets. The outer pipe is the vacuum chamber, which is in contact with the magnets, at cryogenic temperature (1.9K). It is called the “cold bore”. The inner tube is the beam screen. Its main goal is to protect the magnets from the heat load coming from the synchrotron radiation. Indeed, when high energy protons’ trajectory is bent, photons are emitted by the beam. They are intercepted by the beam screen. The temperature of the beam screen is kept between 5 and 20K by a circulation of gaseous helium in the small pipes on both sides of the beam screen. As those surfaces are at cryogenic temperature. The residual gas present in the accelerator is sticking on the surfaces. This phenomenon called “adsorption”...

  10. CERN: LHC progress

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    The push for CERN's next major project, the LHC proton collider to be built in the 27-kilometre LEP tunnel, is advancing on a wide front. For the machine itself, there has been considerable progress in the detailed design. While the main thrust is for proton-proton collisions, heavy ions are also on the LHC collision menu. On the experimental side, proposals are coming into sharper focus. For the machine, the main aim is for the highest possible proton collision energies and collision rates in the confines of the existing LEP tunnel, and the original base design looked to achieve these goals in three collision regions. Early discussions on the experimental programme quickly established that the most probable configuration would have two collision regions rather than three. This, combined with hints that the electronics of several detectors would have to handle several bunch crossings at a time, raised the question whether the originally specified bunch spacing of 15 ns was still optimal

  11. LHC Power Distribution

    CERN Document Server

    Pedersen, J

    1999-01-01

    The power distribution for the LHC machine and its experiments will be realised making extensive use of the existing infrastructure for the LEP. The overall power requirement is approximately the same, about 125 MW. The load distribution will however change. The even points will loose in importance and the points 1 and 5 will, due to the installation of ATLAS and CMS, gain. A thorough reorganisation of the 18 kV distribution will thus be necessary. Due to the important cryogenic installations required for the LHC, the 3.3 kV distribution system, supplying mainly cryogenic compressors, will be extended with a number of new substations. The important number of new surface buildings, underground caverns and other underground structures all will receive general service installations: Lighting and power. The new injection tunnels will require complete installations: A.C. supplies for the power converters and for general service, and D.C. cabling for the magnets of the beam line. Special safe power installations ar...

  12. Vacuum system for LHC

    International Nuclear Information System (INIS)

    Groebner, O.

    1995-01-01

    The Large Hadron Collider (LHC) which is planned at CERN will be housed in the tunnel of the Large Electron Positron collider (LEP) and will store two counter-rotating proton beams with energies of up to 7 TeV in a 27 km accelerator/storage ring with superconducting magnets. The vacuum system for the LHC will be at cryogenic temperatures (between 1.9 and 20 K) and will be exposed to synchrotron radiation emitted by the protons. A stringent limitation on the vacuum is given by the energy deposition in the superconducting coils of the magnets due to nuclear scattering of the protons on residual gas molecules because this may provoke a quench. This effect imposes an upper limit to a local region of increased gas density (e.g. a leak), while considerations of beam lifetime (100 h) will determine more stringent requirements on the average gas density. The proton beam creates ions from the residual gas which may strike the vacuum chamber with sufficient energy to lead to a pressure 'run-away' when the net ion induced desorption yield exceeds a stable limit. These dynamic pressure effects will be limited to an acceptable level by installing a perforated 'beam screen' which shields the cryopumped gas molecules at 1.9 K from synchrotron radiation and which also absorbs the synchrotron radiation power at a higher and, therefore, thermodynamically more efficient temperature. (author)

  13. LHC progress report

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Last weekend saw a record physics fill with a tenfold increase in instantaneous luminosity (event rate from collisions), marking an important milestone for the LHC. This physics fill did not only establish luminosities above 1.1 x 1028 cm-2 s-1 in all four experiments but was also kept in "stable beam" mode for a new record length of 30 hours. The particle physics experiments were able to more than double the total number of events so far recorded at 3.5 TeV.   The LHC screen indicating that squeezed stable beams have been achieved for the first time. The very successful weekend had been preceded by hard work on the accelerator side. A factor 5 improvement in luminosity was achieved by "squeezing" (reducing) the beam sizes at all four interaction points. This process, one of the most complex stages in the operation of the accelerator, was finalised the week before. Once the machine is "squeezed", the experimental insertions become aperture bot...

  14. LHC Capabilities for Quarkonia

    CERN Document Server

    Petrushanko, Sergey

    2008-01-01

    The measurement of the charmonium and bottomonium resonances in nucleus-nucleus collisions provides crucial information on high-density QCD matter. First, the suppression of quarkonia production is generally agreed to be one of the most direct probes of quark-gluon plasma formation. The observation of anomalous J/$\\psi$ suppression at the CERN-SPS and at RHIC is well established but the clarification of some important remaining questions requires equivalent studies of the $\\Upsilon$ family, only possible at the LHC energies. Second, the production of heavy-quarks proceeds mainly via gluon-gluon fusion processes and, as such, is sensitive to saturation of the gluon density at low-x in the nucleus. Measured departures from the expected vacuum quarkonia cross-sections in Pb+Pb collisions at the LHC will thus provide valuable information not only on the thermodynamical state of the produced partonic medium, but also on the initial-state modifications of the nuclear parton distribution functions. The capabilities ...

  15. LHC Report: Rocky Recovery

    CERN Multimedia

    Mike Lamont for the LHC Team

    2011-01-01

    The last technical stop finished on Friday 8 July, but the machine returned to its pre-stop performance level over a week later.   Efficiency of LHC fills between 16 July and 20 July, 2011. The cryogenics team had the entire ring cold by Saturday morning and the usual post-technical stop tests with circulating beams started soon after. Unfortunately, they were interrupted by a major perturbation to CERN’s electrical network caused by an impressive thunderstorm that swept over the Pays de Gex. There were major knock-on effects, including the loss of cooling to the cryogenics and an inevitable recovery period once normal service had been re-established. The beams were circulating again by Tuesday afternoon and the post-technical stop checks continued, beefed up with further tests to address a number of issues related to the power cut.  Before the stop, the LHC had managed to get 1380 bunches per beam into collisions and the plan was to ramp back up relatively quickly to this leve...

  16. LHC Injection Beam Quality During LHC Run I

    CERN Document Server

    AUTHOR|(CDS)2079186; Kain, Verena; Stapnes, Steinar

    The LHC at CERN was designed to accelerate proton beams from 450 GeV to 7 TeV and collide them in four large experiments. The 450 GeV beam is extracted from the last pre-accelerator, the SPS, and injected into the LHC via two 3 km long transfer lines, TI 2 and TI 8. The injection process is critical in terms of preservation of beam quality and machine protection. During LHC Run I (2009-2013) the LHC was filled with twelve high intensity injections per ring, in batches of up to 144 bunches of 1.7*10^11 protons per bunch. The stored beam energy of such a batch is already an order of magnitude above the damage level of accelerator equipment. Strict quality and machine protection requirements at injection have a significant impact on operational efficiency. During the first years of LHC operation, the injection phase was identified as one of the limiting factors for fast LHC turnaround time. The LHC Injection Quality Check (IQC) software framework was developed as a part of this thesis to monitor the beam quality...

  17. Tracking detectors for the sLHC, the LHC upgrade

    CERN Document Server

    Sadrozinski, Hartmut F W

    2005-01-01

    The plans for an upgrade of the Large Hadron Collider (LHC) to the Super-LHC (sLHC) are reviewed with special consideration of the environment for the inner tracking system. A straw-man detector upgrade for ATLAS is presented, which is motivated by the varying radiation levels as a function of radius, and choices for detector geometries and technologies are proposed, based on the environmental constraints. A few promising technologies for detectors are discussed, both for sensors and for the associated front-end electronics. On-going research in silicon detectors and in ASIC technologies will be crucial for the success of the upgrade.

  18. LHC-B: a dedicated LHC collider beauty experiment

    International Nuclear Information System (INIS)

    Erhan, S.

    1995-01-01

    LHC-B is a forward detector optimized for the study of CP-violation and other rare phenomena in the decays of beauty particles at the LHC. An open geometry forward detector design, with good mass, vertex resolution and particle identification, will facilitate the collection of a large numbers of event samples in diverse B decay channels and allow for a thorough understanding of the systematic uncertainties. With the expected large event statistics, LHC-B will be able to test the closure of the unitarity triangle and make sensitive tests of the Standard Model description of CP-violation. Here we describe the experiment and summarize its anticipated performance. (orig.)

  19. Keeping HL-LHC accountable

    CERN Multimedia

    2015-01-01

    This week saw the cost and schedule of the High Luminosity LHC (HL-LHC) and LHC Injectors Upgrade (LIU) projects come under close scrutiny from the external review committee set up for the purpose.    HL-LHC, whose implementation requires an upgrade to the CERN injector complex, responds directly to one of the key recommendations of the updated European Strategy for Particle Physics, which urges CERN to prepare for a ‘major luminosity upgrade’, a recommendation that is also perfectly in line with the P5 report on the US strategy for the field. Responding to this recommendation, CERN set up the HL-LHC project in 2013, partially supported by FP7 funding through the HiLumi LHC Design Study (2011-2015), and coordinated with the American LARP project, which oversees the US contribution to the upgrade. A key element of HL-LHC planning is a mechanism for receiving independent expert advice on all aspects of the project.  To this end, several technical reviews h...

  20. Physics Validation of the LHC Software

    CERN Multimedia

    CERN. Geneva

    2004-01-01

    The LHC Software will be confronted to unprecedented challenges as soon as the LHC will turn on. We summarize the main Software requirements coming from the LHC detectors, triggers and physics, and we discuss several examples of Software components developed by the experiments and the LCG project (simulation, reconstruction, etc.), their validation, and their adequacy for LHC physics.

  1. Dissecting an LHC dipole

    CERN Multimedia

    2004-01-01

    The cold mass of a 15-metre main dipole magnet has some fifteen different components. All the main components are manufactured under CERN's direct responsibility. Four of them transit through CERN before being shipped to the dipole assembly contractors, namely the cable, which constitutes the magnet's superconducting core (see Bulletin 14/2004), the beam screens, the heat exchanger tubes and the cold bore beam tubes. The two latter components transit via Building 927 where they undergo part of the production process. The 58-mm diameter heat exchanger tubes will remove heat from the magnets using superfluid helium. The 53-mm diameter cold bore tubes will be placed under vacuum to allow the twin beams to circulate around the LHC.

  2. Beam Scraping for LHC Injection

    CERN Document Server

    Burkhardt, H; Fischer, C; Gras, J-J; Koschik, A; Kramer, Daniel; Pedersen, S; Redaelli, S

    2007-01-01

    Operation of the LHC will require injection of very high intensity beams from the SPS to the LHC. Fast scrapers have been installed and will be used in the SPS to detect and remove any existing halo before beams are extracted, to minimize the probability for quenching of superconducting magnets at injection in the LHC. We briefly review the functionality of the scraper system and report about measurements that have recently been performed in the SPS on halo scraping and re-population of tails.

  3. CERN LHC dipole prototype success

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    In a crash programme, the first prototype superconducting dipole magnet for CERN's LHC protonproton collider was successfully powered for the first time at CERN on 14 April, eventually sailing to 9T, above the 8.65T nominal LHC field, before quenching for the third time. The next stage is to install the delicate measuring system for making comprehensive magnetic field maps in the 10 m long, 50 mm diameter twin-apertures of the magnet. These measurements will check that the required LHC field quality has been achieved at both the nominal and injection fields

  4. PDF4LHC recommendations for LHC Run II

    CERN Document Server

    Butterworth, Jon; Cooper-Sarkar, Amanda; De Roeck, Albert; Feltesse, Joel; Forte, Stefano; Gao, Jun; Glazov, Sasha; Huston, Joey; Kassabov, Zahari; McNulty, Ronan; Morsch, Andreas; Nadolsky, Pavel; Radescu, Voica; Rojo, Juan; Thorne, Robert

    2016-01-01

    We provide an updated recommendation for the usage of sets of parton distribution functions (PDFs) and the assessment of PDF and PDF+$\\alpha_s$ uncertainties suitable for applications at the LHC Run II. We review developments since the previous PDF4LHC recommendation, and discuss and compare the new generation of PDFs, which include substantial information from experimental data from the Run I of the LHC. We then propose a new prescription for the combination of a suitable subset of the available PDF sets, which is presented in terms of a single combined PDF set. We finally discuss tools which allow for the delivery of this combined set in terms of optimized sets of Hessian eigenvectors or Monte Carlo replicas, and their usage, and provide some examples of their application to LHC phenomenology.

  5. LHC Report: Tests of new LHC running modes

    CERN Document Server

    Verena Kain for the LHC team

    2012-01-01

    On 13 September, the LHC collided lead ions with protons for the first time. This outstanding achievement was key preparation for the planned 2013 operation in this mode. Outside of two special physics runs, the LHC has continued productive proton-proton luminosity operation.   Celebrating proton-ion collisions. The first week of September added another 1 fb-1 of integrated luminosity to ATLAS’s and CMS’s proton-proton data set. It was a week of good and steady production mixed with the usual collection of minor equipment faults. The peak performance was slightly degraded at the start of the week but thanks to the work of the teams in the LHC injectors the beam brightness – and thus the LHC peak performance – were restored to previous levels by the weekend. The LHC then switched to new running modes and spectacularly proved its potential as a multi-purpose machine. This is due in large part to the LHC equipment and controls, which have been designed wi...

  6. To the LHC and beyond

    CERN Document Server

    Rodgers, Peter

    2004-01-01

    CERN was conceived in 1949 as a new European laboratory to halt the exodus of physics talent from Europe to North America. In 1954, the new lab formally came into existence upon ratification of the resolution by the first 12 European member states. To further strengthen its position as the top particle-physics laboratory in the world, the CERN council agreed a new seven-point strategy. Completing the Large Hadron Collider (LHC) on schedule in 2007 is the top priority, followed by consolidating the lab's infrastructure to guarantee reliable operation of the LHC; examining the lab's experimental program apart from the LHC; coordinating research in Europe; building a new injector for the LHC in 2006; increasing R&D on the Compact Linear Collider (CLIC); and working on a long-term strategy for the lab. CERN expects to complete half of these at the end of 2008. (Edited abstract).

  7. High Luminosity LHC Project Description

    CERN Document Server

    Apollinari, Giorgio; Rossi, Lucio

    2014-01-01

    The High Luminosity LHC (HL-LHC) is a novel configuration of the Large Hadron Collider, aiming at increasing the luminosity by a factor five or more above the nominal LHC design, to allow increasing the integrated luminosity, in the high luminosity experiments ATLAS and CMS, from the 300 fb-1 of the LHC original design up to 3000 fb-1 or more. This paper contains a short description of the main machine parameters and of the main equipment that need to be developed and installed. The preliminary cost evaluation and the time plan are presented, too. Finally, the international collaboration that is supporting the project, the governance and the project structure are discussed, too.

  8. Coming Soon: LHC's Big Chill

    CERN Multimedia

    2003-01-01

    Installation of the LHC cryogenic distribution line has begun. The line is crucial to the project, as it is to be used to distribute the liquid helium for cooling the superconducting magnets down to 1.8 K.

  9. The Workflow of LHC Papers

    CERN Multimedia

    CERN. Geneva

    2012-01-01

    Finally, the talk will focus on how the institutional repository (CDS) is being linked to the HEP disciplinary archive (INSPIRE) in order to provide users with a central access point to reach LHC results.

  10. NNLO corrections for LHC processes

    CERN Document Server

    Caola, Fabrizio

    2015-01-01

    To fully profit from the remarkable achievements of the experimental program at the LHC, very precise theoretical predictions for signal and background processes are required. In this contribution, I will review some of the recent progress in fully exclusive next-to-next-toleading-order (NNLO) QCD computations. As an example of the phenomenological relevance of these results, I will present LHC predictions for t-channel single-top production and Higgs boson production in association with one hard jet.

  11. The LHC personnel safety system

    International Nuclear Information System (INIS)

    Ninin, P.; Valentini, F.; Ladzinski, T.

    2011-01-01

    Large particle physics installations such as the CERN Large Hadron Collider require specific Personnel Safety Systems (PSS) to protect the personnel against the radiological and industrial hazards. In order to fulfill the French regulation in matter of nuclear installations, the principles of IEC 61508 and IEC 61513 standard are used as a methodology framework to evaluate the criticality of the installation, to design and to implement the PSS.The LHC PSS deals with the implementation of all physical barriers, access controls and interlock devices around the 27 km of underground tunnel, service zones and experimental caverns of the LHC. The system shall guarantee the absence of personnel in the LHC controlled areas during the machine operations and, on the other hand, ensure the automatic accelerator shutdown in case of any safety condition violation, such as an intrusion during beam circulation. The LHC PSS has been conceived as two separate and independent systems: the LHC Access Control System (LACS) and the LHC Access Safety System (LASS). The LACS, using off the shelf technologies, realizes all physical barriers and regulates all accesses to the underground areas by identifying users and checking their authorizations.The LASS has been designed according to the principles of the IEC 61508 and 61513 standards, starting from a risk analysis conducted on the LHC facility equipped with a standard access control system. It consists in a set of safety functions realized by a dedicated fail-safe and redundant hardware guaranteed to be of SIL3 class. The integration of various technologies combining electronics, sensors, video and operational procedures adopted to establish an efficient personnel safety system for the CERN LHC accelerator is presented in this paper. (authors)

  12. LHC magnet string in 1994

    CERN Multimedia

    1994-01-01

    On 6-7 December 1994, a string of powerful superconducting magnets for CERN's next particle accelerator, the Large Hadron Collider (LHC), ran successfully at 8.36 tesla for 24 hours. This magnetic field is 100 000 times that of the Earth and is required to keep beams of protons travelling on the correct circular path over 27 km at 7 TeV in the new LHC accelerator.

  13. LHC: from hot to cold

    CERN Multimedia

    2006-01-01

    The first cryogenic feedbox designed to supply electricity to the superconducting magnets of one arc has just been installed at Point 8 of the LHC. This latest milestone is the reward for the joint efforts of the AT and TS Departments at CERN, the IHEP Institute in Moscow and CERN’s industrial partners who collaborated in its manufacture, and is a precursor to the forthcoming cool down of the first 3.3 km sector of the LHC.

  14. LHC Results Highlights (CLASHEP 2013)

    CERN Document Server

    Gonzalez, O.

    2015-05-22

    The good performance of the LHC provided enough data at 7 TeV and 8 TeV to allow the experiments to perform very competitive measurements and to expand the knowledge about the fundamental interaction far beyond that from previous colliders. This report summarizes the highlights of the results obtained with these data samples by the four large experiments, covering all the topics of the physics program and focusing on those exploiting the possibilities of the LHC.

  15. LHC an unprecedented technological challenge

    International Nuclear Information System (INIS)

    Baruch, J.O.

    2002-01-01

    This article presents the future LHC (large hadron collider) in simple terms and gives some details concerning radiation detectors and supra-conducting magnets. LHC will take the place of the LEP inside the 27 km long underground tunnel near Geneva and is scheduled to operate in 2007. 8 years after its official launching the LHC project has piled up 2 year delay and has exceeded its initial budget (2 milliard euros) by 18%. Technological challenges and design difficulties are the main causes of these shifts. The first challenge has been carried out successfully, it was the complete clearing out of the LEP installation. In order to release 14 TeV in each proton-proton collision, powerful magnetic fields (8,33 Tesla) are necessary. 1248 supra-conducting 15 m-long bipolar magnets have to be built. 30% of the worldwide production of niobium-titanium wires will be used each year for 5 years in the design of these coils. The global cryogenic system will be gigantic and will use 94 tons of helium. 4 radiation detectors are being built: ATLAS (a toroidal LHC apparatus), CMS (compact muon solenoid), ALICE (a large ion collider experiment) and LHC-b (large hadron collider beauty). The 2 first will search after the Higgs boson, ALICE will be dedicated to the study of the quark-gluon plasma and LHC-b will gather data on the imbalance between matter and anti-matter. (A.C.)

  16. LHC Olympics flex physicists' brains

    CERN Multimedia

    2006-01-01

    Physicists from around the world met at CERN to strengthen their data-deciphering skills at the second LHC Olympics workshop. Physicists gather for the second LHC Olympics workshop. Coinciding with the kick-off of the winter Olympics in Turin, more than 70 physicists gathered at CERN from across the globe for the second LHC Olympics workshop on 9-10 February. Their challenge, however, involved brains rather than brawn. As the switch-on date for the LHC draws near, scientists excited by the project want to test and improve their ability to decipher the unprecedented amount of data that the world's biggest and most powerful particle accelerator is expected to generate. The LHC Olympics is a coordinated effort to do just that, minus the gold, silver and bronze of the athletics competition. 'In some ways, the LHC is not a precision instrument. It gives you the information that something is there but it's hard to untangle and interpret what it is,' said University of Michigan physicist Gordy Kane, who organiz...

  17. The LHC at level best

    CERN Multimedia

    Katarina Anthony

    2013-01-01

    On 10 March, a team of CERN surveyors descended into the LHC tunnel. Their aim: to take measurements of the height of the LHC magnets to see how geological shifts might be affecting the machine and to take reference positions of the machine before the interconnects are opened.    CERN surveyors take levelling measurements of the LHC magnets during LS1. The LHC tunnel is renowned for its geological stability: set between layers of sandstone and molasse, it has allowed the alignment of the world’s largest accelerators to be within sub-millimetre precision. But even the most stable of tunnels can be affected by geological events. To ensure the precise alignment of the LHC, the CERN survey team performs regular measurements of the vertical position of the magnets (a process known as “levelling”). Over the past month, the team has been taking measurements of the LHC before the temperature of the magnets reaches 100 K, beyond which there may be some mechanic...

  18. Last cast for the LHC

    CERN Multimedia

    2005-01-01

    The first major contract signed for the LHC is drawing to a close. Belgian firm Cockerill Sambre (a member of the Arcelor Group) has just completed production of 50,000 tonnes of steel sheets for the accelerator's superconducting magnet yokes, in what has proved to be an exemplary partnership with CERN. Philippe Lebrun, Head of the AT Department, Lyn Evans, LHC Project Leader, and Lucio Rossi, Head of the AT-MAS Group, in front of the last batch of steel for the LHC at Cockerill Sambre. It was a bright red-letter day at the end of May, when Belgian firm Cockerill Sambre of the Arcelor Group marked the completion of one of the largest contracts for the LHC machine by casting the last batch of steel sheets for the LHC superconducting magnet yokes in the presence of LHC Project Leader Lyn Evans, AT Department Head Philippe Lebrun, Magnets and Superconductors (AT-MAS) Group Leader Lucio Rossi and Head of the AT-MAS Group's components centre Francesco Bertinelli. The yokes constitute approximately 80% of the acc...

  19. The LHC on the table

    CERN Multimedia

    2002-01-01

    How many dipoles have been manufactured so far? How many have been delivered? To find out, you can now consult the LHC Progress Dashboard on the web. The dashboard tracks progress with regard to manufacture and delivery of thirty different types of LHC components. Do you want to know everything about progress on LHC construction? The LHC's engineers have recently acquired a very useful tracking tool precisely for that purpose. This is the LHC Progress Dashboard which makes it possible to track work progress in graph form. In the interests of transparency, the LHC Project Management has decided to make it accessible to the public on the web. You can now consult normalized graphs for each of the thirty different types of components that form part of machine construction, such as the cold masses of the dipole magnets, the vacuum chambers and the octupoles, etc. The graphs show: in blue: the contractual delivery curves, i.e. the delivery schedules to which the suppliers have committed themselves in their contra...

  20. The High Luminosity LHC Project

    Science.gov (United States)

    Rossi, Lucio

    The High Luminosity LHC is one of the major scientific project of the next decade. It aims at increasing the luminosity reach of LHC by a factor five for peak luminosity and a factor ten in integrated luminosity. The project, now fully approved and funded, will be finished in ten years and will prolong the life of LHC until 2035-2040. It implies deep modifications of the LHC for about 1.2 km around the high luminosity insertions of ATLAS and CMS and relies on new cutting edge technologies. We are developing new advanced superconducting magnets capable of reaching 12 T field; superconducting RF crab cavities capable to rotate the beams with great accuracy; 100 kA and hundred meter long superconducting links for removing the power converter out of the tunnel; new collimator concepts, etc... Beside the important physics goals, the High Luminosity LHC project is an ideal test bed for new technologies for the next hadron collider for the post-LHC era.

  1. LHC Report: Take Five

    CERN Multimedia

    Mike Lamont for the LHC Team

    2011-01-01

    The LHC is continuing to perform well and an integrated luminosity of over 5fb-1 has now been delivered to ATLAS and CMS. While keeping a close eye on beam induced heating and vacuum quality, the bunch current has been gently raised to over 1.4x1011 protons per bunch. This has given a peak luminosity of 3.6x1033 cm-2s-1. Some long fills have helped production and recent high points include 120pb-1 delivered in one fill and 580pb-1 delivered in one week.   Time has also been devoted to some special physics runs for TOTEM and ALFA. In these runs, the beam is de-squeezed to a ß* of 90 m in ATLAS and CMS. This is instead of the usual 1m ß*, and gives a larger beam size at interaction points. The increased beam size results in a reduced beam divergence at the interaction points. This permits TOTEM and ALFA to probe low-angle scattering and allows them to measure the total cross section of proton-proton interactions and the absolute luminosity cal...

  2. Tracking the LHC halo

    CERN Multimedia

    Antonella Del Rosso

    2015-01-01

    In the LHC, beams of 25-ns-spaced proton bunches travel at almost the speed of light and pass through many different devices installed along the ring that monitor their properties. During their whirling motion, beam particles might interact with the collimation instrumentation or with residual gas in the vacuum chambers and this creates the beam halo – an annoying source of background for the physics data. Newly installed CMS sub-detectors are now able to monitor it.   The Beam Halo Monitors (BHM) are installed around the CMS rotating shielding. The BHM are designed and built by University of Minnesota, CERN, Princeton University, INFN Bologna and the National Technical University of Athens. (Image: Andrea Manna). The Beam Halo Monitor (BHM) is a set of 20 Cherenkov radiators – 10-cm-long quartz crystals – installed at each end of the huge CMS detector. Their design goal is to measure the particles that can cause the so-called “machine-induced...

  3. LHC magnet support post

    CERN Multimedia

    1995-01-01

    A prototype magnet support for the Large Hadron Collider (LHC). The magnet supports have to bridge a difference in temperature of 300 degrees. Electrical connections, instrumentation and the posts on which the magnets stand are the only points where heat transfer can happen through conduction. They are all carefully designed to draw off heat progressively. The posts are made of 4 mm thick glass-fibre– epoxy composite material. Each post supports 10 000 kg of magnet and leaks just 0.1 W of heat. This piece required a long development period which started in the early ’90s and continued until the end of the decade. The wires next to the support post are wires from strain gauges, which are employed to measure the stress level in the material when the support is mechanically loaded. These supports are mechanically optimized to withstand a weight of up to 100Kn (10 tons) while being as thin as possible to minimize conduction heat to magnets. This is the reason why the stress measurement was extensively done...

  4. LHC on the bus

    CERN Multimedia

    Laëtitia Pedroso

    2010-01-01

    On 15 December, an airport bus will be transformed in the image of CERN. The bus will be seen by the thousands of travellers arriving in Geneva, informing them of the possibility to visit CERN.   Sketch of the bus. The good relationship between Geneva International Airport and CERN started several years ago. In 2004 the airport put advertising space in the arrivals area at CERN's disposal free of charge. Now, starting on 15 December, a 40-foot long bus will display a giant sticker advertisement depicting CERN as it takes passengers over the airport tarmac to their planes. This is no ordinary sticker, and it was no mean task to attach it to the bus. The task of producing and attaching it was entrusted to Geneva-based specialists Mathys SA. With the ski season opening on 15 December, there will be many travellers arriving at the airport, and the bus will be ready to receive them. When one thinks of CERN, the subjects that naturally come to mind are the LHC, the mysteries of the Universe...

  5. Power to the LHC

    CERN Multimedia

    2016-01-01

    It’s March already, and time for the LHC to wake up from its short winter break. The first of 7000 powering tests began on 4 March: the first step on the way to the first beams of 2016. It’s a tight schedule, with the powering tests scheduled for just 12 days before moving on to machine checkout and then commissioning with beam around Easter.   Last year marked a great start to Run 2. The objective for the year was to establish proton-proton collisions at 13 TeV with 25 ns bunch spacing, and in that we were successful, delivering four inverse femtobarns (4 fb-1) of data to the experiments. This was a great result but, to put it into context, the goal for the whole of Run 2 is to deliver 100 fb-1 by the end of 2018, so we still have a long way to go. 2015 was a learning year, and by the time we switched off for the end-of-year break, we had learned a great deal about how to operate this superb machine at the new higher energy, with shorter bunch spacing allowing us to get many ...

  6. LHC Report: Ticking over

    CERN Multimedia

    Mike Lamont for the LHC Team

    2012-01-01

    The past two weeks have seen luminosity production rates vary somewhat but the overall upwards slope has remained steady. Over 17 fb-1 have been delivered to both ATLAS and CMS; LHCb is also doing well, with around 1.6 fb-1 delivered so far in 2012. The proton physics production also slotted in a five-day machine development period (Monday 8 to Saturday 13 October).   When producing the LHC beam in the PS, some parasitic low-intensity satellite bunches are formed 25 ns from the main bunches, which are spaced by 50 ns. ALICE, whose detector is designed to work with relatively low collision rates, has been taking data from satellite-main collisions. The population of these satellites has recently been increased thanks to gentle tweaks by the PS radio frequency experts. This has increased the peak luminosity in ALICE and will help them to reach their proton-proton integrated luminosity goal for the year. The October machine development programme was a mixed bag. While some studies were aimed at sho...

  7. Illuminating the LHC

    CERN Multimedia

    2004-01-01

    For the first time ever, on 29 September the LHC ring will be visible above ground. Spotlights aimed at the sky will light up the 27 km path of the ring to celebrate CERN's 50th anniversary. Also, everyone born in 1954 is invited to come to blow out birthday candles on a cake. To see the display, you can come to departure station for the gondola at Crozet*, France, starting at 18:30. There will be music, official speeches and food stands. At 20:00 the ring will light up, and to wrap it up at 21:15 there will be the cake and videoconferences with Robert Aymar, the Director-General of CERN, and the inventor of the Web, Tim Berners-Lee. The event is organized by the Department of Justice, Police and Security of the Canton of Geneva, Switzerland, in collaboration with communes of the Canton of Geneva, the Communauté des communes du Pays de Gex and the Préfecture de l'Ain. More information on the schedule for the night. * The event initially planned at Divonne has been moved to Crozet.

  8. LHC vacuum system

    CERN Document Server

    Gröbner, Oswald

    1999-01-01

    The Large Hadron Collider (LHC) project, now in the advanced construction phase at CERN, comprises two proton storage rings with colliding beams of 7-TeV energy. The machine is housed in the existing LEP tunnel with a circumference of 26.7 km and requires a bending magnetic field of 8.4 T with 14-m long superconducting magnets. The beam vacuum chambers comprise the inner 'cold bore' walls of the magnets. These magnets operate at 1.9 K, and thus serve as very good cryo-pumps. In order to reduce the cryogenic power consumption, both the heat load from synchrotron radiation emitted by the proton beams and the resistive power dissipation by the beam image currents have to be absorbed on a 'beam screen', which operates between 5 and 20 K and is inserted inside the vacuum chamber. The design of this beam screen represents a technological challenge in view of the numerous and often conflicting requirements and the very tight mechanical tolerances imposed. The synchrotron radiation produces strong outgassing from the...

  9. Crystals in the LHC

    CERN Multimedia

    Antonella Del Rosso

    2012-01-01

    Bent crystals can be used to deflect charged particle beams. Their use in high-energy accelerators has been investigated for almost 40 years. Recently, a bent crystal was irradiated for the first time in the HiRadMat facility with an extreme particle flux, which crystals would have to withstand in the LHC. The results were very encouraging and confirmed that this technology could play a major role in increasing the beam collimation performance in future upgrades of the machine.   UA9 bent crystal tested with a laser. Charged particles interacting with a bent crystal can be trapped in channelling states and deflected by the atomic planes of the crystal lattice (see box). The use of bent crystals for beam manipulation in particle accelerators is a concept that has been well-assessed. Over the last three decades, a large number of experimental findings have contributed to furthering our knowledge and improving our ability to control crystal-particle interactions. In modern hadron colliders, su...

  10. The LHC collimators

    CERN Document Server

    Bertarelli, A

    2004-01-01

    In the framework of the LHC Collimator project, TS department has been assigned the task to design the series collimators and to manufacture prototypes to be tested in summer 2004. Their concept must comply with a very demanding specification, entailing a temperature on the collimating jaws not exceeding 50ºC in steady conditions and an unparalleled overall geometrical stability of 25 micro m on a 1200 mm span, meeting, at the same time, the challenging deadlines required by the project schedule. To respond to these tough and sometimes conflicting constraints, the chosen design appeals to a mixture of traditional and innovative technologies, largely drawing from LEP collimator experience. The specification imposes a low-Z material for the collimator jaws, directing the design towards graphite or such novel materials as 2-D and 3-D Carbon/Carbon composites. An accurate mechanical design has allowed to considerably reduce the mechanical play and to optimize the geometrical stability. The mechanical lay-out a...

  11. LHC Report: Level best

    CERN Multimedia

    Mike Lamont for the LHC team

    2012-01-01

    The LHCb experiment is special: there is a limit to the number of the events the detector can handle per bunch crossing. Consequently the maximum luminosity provided in 2012 has been around 4 x1032 cm-2s-1 (compared to the maximum of 7.7 x1033 cm-2s-1 seen by ATLAS and CMS). Nonetheless LHCb still wants to integrate as much luminosity as possible.    To meet LHCb's requirements a luminosity leveling technique is used. A machine setup is chosen that would give a peak luminosity well above the required maximum if the beams are collided head-on at LHCb's interaction point. This peak luminosity is then reduced to the required maximum by moving the two beams transversely apart at the interaction point. As the beam current goes down during a fill, the beams can be moved together in small increments to keep the collision rate constant throughout the fill. In practice, when the LHC goes into collisions in LHCb, the initial luminosity is safely below LHCb's demanded le...

  12. LHC Report: a record start for LHC ion operation

    CERN Multimedia

    Jan Uythoven for the LHC Team

    2011-01-01

    After the technical stop, the LHC switched over to ion operation, colliding lead-ions on lead-ions. The recovery from the technical stop was very smooth, and records for ion luminosity were set during the first days of ion operation.   The LHC technical stop ended on the evening of Friday, 11 November. The recovery from the technical stop was extremely smooth, and already that same evening ion beams were circulating in the LHC. ‘Stable beams’ were declared the same night, with 2 x 2 bunches of ions circulating in the LHC, allowing the experiments to have their first look at ion collisions this year. However, the next step-up in intensity – colliding 170 x 170 bunches – was postponed due to a vacuum problem in the PS accelerator, so the collisions on Sunday, 13 November were confined to 9 x 9 bunches. The vacuum problem was solved, and on the night of Monday, 14 November, trains of 24 lead bunches were injected into the LHC and 170 x 170 bunches were brough...

  13. LHC collimator controls for a safe LHC operation

    International Nuclear Information System (INIS)

    Redaelli, S.; Assmann, R.; Losito, R.; Donze, M.; Masi, A.

    2012-01-01

    The Large Hadron Collider (LHC) collimation system is designed to protect the machine against beam losses and consists of 108 collimators, 100 of which are movable, located along the 27 km long ring and in the transfer lines. The cleaning performance and machine protection role of the system depend critically on accurate jaw positioning. A fully redundant control system has been developed to ensure that the collimators dynamically follow optimum settings in all phases of the LHC operational cycle. Jaw positions and collimator gaps are interlocked against dump limits defined redundantly as functions of time, beam energy and the β functions, which describe the focusing property of the beams. In this paper, the architectural choices that guarantee a safe LHC operation are presented. Hardware and software implementations that ensure the required performance are described. (authors)

  14. Le LHC, un tunnel cosmique

    CERN Multimedia

    CERN. Geneva

    2009-01-01

    Et si la lumière au bout du tunnel du LHC était cosmique ? En d’autres termes, qu’est-ce que le LHC peut nous apporter dans la connaissance de l’Univers ? Car la montée en énergie des accélérateurs de particules nous permet de mieux appréhender l’univers primordial, chaud et dense. Mais dans quel sens dit-on que le LHC reproduit des conditions proches du Big bang ? Quelles informations nous apporte-t-il sur le contenu de l’Univers ? La matière noire est-elle détectable au LHC ? L’énergie noire ? Pourquoi l’antimatière accumulée au CERN est-elle si rare dans l’Univers ? Et si le CERN a bâti sa réputation sur l’exploration des forces faibles et fortes qui opèrent au sein des atomes et de leurs noyaux, est-ce que le LHC peut nous apporter des informations sur la force gravitationnelle qui gouverne l’évolution cosmique ? Depuis une trentaine d’années, notre compréhension de l’univers dans ses plus grandes dimensions et l’appréhension de son comportement aux plus peti...

  15. Scenarios for the LHC Upgrade

    CERN Document Server

    Scandale, Walter

    2008-01-01

    The projected lifetime of the LHC low-beta quadrupoles, the evolution of the statistical error halving time, and the physics potential all call for an LHC luminosity upgrade by the middle of the coming decade. In the framework of the CARE-HHH network three principal scenarios have been developed for increasing the LHC peak luminosity by more than a factor of 10, to values above 1035 cm−2s−1. All scenarios imply a rebuilding of the high-luminosity interaction regions (IRs) in combination with a consistent change of beam parameters. However, their respective features, bunch structures, IR layouts, merits and challenges, and luminosity variation with β∗ differ substantially. In all scenarios luminosity leveling during a store would be advantageous for the physics experiments. An injector upgrade must complement the upgrade measures in the LHC proper in order to provide the beam intensity and brightness needed as well as to reduce the LHC turnaround time for higher integrated luminosity.

  16. Physics at LHC and beyond

    CERN Document Server

    2014-01-01

    The topics addressed during this Conference are as follows. ---An overview of the legacy results of the LHC experiments with 7 and 8 TeV data on Standard Model physics, Scalar sector and searches for New Physics. ---A discussion of the readiness of the CMS, ATLAS, and LHCb experiments for the forthcoming high-energy run and status of the detector upgrades ---A review of the most up-to-date theory outcome on cross-sections and uncertainties, phenomenology of the scalar sector, constraints and portals for new physics. ---The presentation of the improvements and of the expected sensibilities for the Run 2 of the LHC at 13 TeV and beyond. ---A comparison of the relative scientific merits of the future projects for hadron and e+e- colliders (HL-LHC, HE-LHC, ILC, CLIC, TLEP, VHE-LHC) towards precision measurements of the Scalar boson properties and of the Electroweak-Symmetry-Breaking parameters, and towards direct searches for New Physics.

  17. Heavy feet for the LHC

    CERN Document Server

    2003-01-01

    The first 800 jacks (adjustable supports) for one sector of the LHC have arrived from India in recent weeks. After the final acceptance of the preseries jacks at the end of October, they can now be used to support the LHC cryo-magnets. How do you move the weight of eight adult Indian elephants by the breadth of a human hair? If you are a surveyor at CERN who has to adjust the 32 ton LHC dipoles with a resolution of 1/20 of a millimetre, you use the 80 kg jacks which were designed and are being procured by the Centre for Advanced Technology (CAT) in India. The jacks are undergoing final pre-shipment inspection by CAT engineers in India. More than 800 jacks have arrived in recent weeks from India, enough to equip the first sector of the LHC (one octant of the ring). For all the cryo-magnets (dipoles and quadrupoles) of the LHC 7000 jacks are needed in total. They are now being continuously delivered to CERN up to mid-2005. The close collaboration between the Department of Atomic Energy (DAE) in India and CE...

  18. Hybrid beams in the LHC

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    The first proton-ion beams were successfully circulated in the LHC a couple of weeks ago. Everything went so smoothly that the LHC teams had planned the first p-Pb collisions for Wednesday, 16 November. Unfortunately, a last-minute problem with a component of the PS required for proton acceleration prevented the LHC teams from making these new collisions. However, the way is open for a possible physics run with proton-lead collisions in 2012.   Members of the LHC team photographed when the first hybrid beams got to full energy. The proton and lead beams are visible on the leftmost screen up on the wall (click to enlarge the photo). The technical challenge of making different beams circulate in the LHC is by no means trivial. Even if the machine is the same, there are a number of differences when it is operated with beams of protons, beams of lead or beams of proton and lead. Provided that the beams are equal, irrespective of whether they consist of protons or lead nuclei, they revolve at the...

  19. The LHC and its successors

    CERN Multimedia

    Anaïs Schaeffer

    2012-01-01

    Not too long before the first long technical stop of the LHC, engineers and physicists are already working on the next generation of accelerators: HL-LHC and LHeC. The first would push proton-proton collisions to an unprecedented luminosity rate; the second would give a second wind to electron-proton collisions.   The ring-ring configuration of the LHeC would need this type of magnets, currently being studied for possible future use. In one year, the LHC will begin to change. During the first long shutdown, from December 2012 to late 2014, the machine will go through a first phase of major upgrades, with the objective of running at 7 TeV per beam at the beginning of 2015. With this long technical stop and the two others that will follow (in 2018 and 2022), a new project will see the light of day. Current plans include the study of something that looks more like a new machine rather than a simple upgrade: the High Luminosity LHC (HL-LHC). Much more powerful than the current machine, the HL-...

  20. Technological challenges for the LHC

    CERN Multimedia

    CERN. Geneva; Rossi, Lucio; Lebrun, Philippe; Bordry, Frederick; Mess, Karl Hubert; Schmidt, Rüdiger

    2003-01-01

    For the LHC to provide particle physics with proton-proton collisions at the centre of mass energy of 14 TeV with a luminosity of 1034 cm-2s-1, the machine will operate with high-field dipole magnets using NbTi superconductors cooled to below the lambda point of helium. In order to reach design performance, the LHC requires both, the use of existing technologies pushed to the limits as well as the application of novel technologies. The construction follows a decade of intensive R&D and technical validation of major collider sub-systems. The first lecture will focus on the required LHC performance, and on the implications on the technologies. In the following lectures several examples for LHC technologies will be discussed: the superconducting magnets to deflect and focus the beams, the cryogenics to cool the magnets to a temperature below the lambda point of helium along most of the LHC circumference, the powering system supplying about 7000 magnets connected in 1700 electrical circuits with a total curr...

  1. Computer graphic of LHC in the tunnel

    CERN Multimedia

    1996-01-01

    A computer-generated image of the LHC particle accelerator at CERN in the tunnel originally built for the LEP accelerator that was closed in 2000. The cross-section of an LHC superconducting dipole magnet is also seen.

  2. The HL-LHC accelerator physics challenges

    CERN Document Server

    Fartoukh, S

    2014-01-01

    We review the conceptual baseline of the HL-LHC project, putting into perspective the main beam physics challenges of this new collider in comparison with the existing LHC, and the series of solutions and possible mitigation measures presently envisaged.

  3. The HL-LHC Accelerator Physics Challenges

    Science.gov (United States)

    Fartoukh, S.; Zimmermann, F.

    The conceptual baseline of the HL-LHC project is reviewed, putting into perspective the main beam physics challenges of this new collider in comparison with the existing LHC, and the series of solutions and possible mitigation measures presently envisaged.

  4. The HL-LHC accelerator physics challenges

    CERN Document Server

    Fartoukh, S

    2015-01-01

    The conceptual baseline of the HL-LHC project is reviewed, putting into perspective the main beam physics challenges of this new collider in comparison with the existing LHC, and the series of solutions and possible mitigation measures presently envisaged.

  5. Dashboard for the LHC experiments

    International Nuclear Information System (INIS)

    Andreeva, J; Cirstoiu, C; Miguel, M D F D; Ivanchenko, A; Gaidioz, B; Herrala, J; Janulis, M; Maier, G; Maguire, E J; Rivera, R P; Rocha, R; Saiz, P; Sidorova, I; Belov, S; Berejnoj, A; Kodolova, O; Chen, Y; Chen, T; Chiu, S; Munro, C

    2008-01-01

    In this paper we present the Experiment Dashboard monitoring system, which is currently in use by four Large Hadron Collider (LHC) experiments. The goal of the Experiment Dashboard is to monitor the activities of the LHC experiments on the distributed infrastructure, providing monitoring data from the virtual organization (VO) and user perspectives. The LHC experiments are using various Grid infrastructures (LCG/EGEE, OSG, NDGF) with correspondingly various middleware flavors and job submission methods. Providing a uniform and complete view of various activities like job processing, data movement and publishing, access to distributed databases regardless of the underlying Grid flavor is the challenging task. In this paper we will describe the Experiment Dashboard concept, its framework and main monitoring applications

  6. The LHC road at CERN

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    To explore the 1 TeV energy scale where fundamental particle interactions should encounter new conditions, two major routes were proposed - a high magnetic field proton collider in the LEP tunnel, dubbed LHC for Large Hadron Collider, and the CERN Linear Collider (CLIC) to supply beams of electrons and positrons. Exploratory studies have shown that while CLIC remains a valid long-term goal, LHC appears as the most cost-effective way for CERN to enter the 1 TeV arena. High-field superconducting magnet prototype work demonstrates that a 'two-in-one' design supplying the 10 tesla fields needed to handle LHC's 8 TeV proton beams (collision energy 16 TeV) is a practical proposition. (orig./HSI).

  7. The first LHC insertion quadrupole

    CERN Multimedia

    2004-01-01

    An important milestone was reached in December 2003 at the CERN Magnet Assembly Facility. The team from the Accelerator Technology - Magnet and Electrical Systems group, AT-MEL, completed the first special superconducting quadrupole for the LHC insertions which house the experiments and major collider systems. The magnet is 8 metres long and contains two matching quadrupole magnets and an orbit corrector, a dipole magnet, used to correct errors in quadrupole alignment. All were tested in liquid helium and reached the ultimate performance criteria required for the LHC. After insertion in the cryostat, the superconducting magnet will be installed as the Q9 quadrupole in sector 7-8, the first sector of the LHC to be put in place in 2004. Members of the quadrupole team, from the AT-MEL group, gathered around the Q9 quadrupole at its inauguration on 12 December 2003 in building 181.

  8. The LHC inauguration in pictures

    CERN Multimedia

    2008-01-01

    The LHC inauguration ceremony was a memorable experience for everyone who attended. On Tuesday 21 October the ceremony hall, SMA18, was filled with over 1500 invited guests, VIPs included Swiss President Pascal Couchepin, French Prime Minister François Fillon and several ministers from CERN’s Member States and around the world. You can watch a video of the highlights of the ceremony at http://cds.cern.ch/record/1136012 The Heads of Delegations from all the Member and Observer States pose with the Director-General. "The LHC is a marvel of modern technology, which would not have been possible without the continuous support of our Member States," said the Director-General in his opening speech. "This is an opportunity for me to thank them on behalf of the world’s particle physics community." The LHC inauguration ceremony officially marked the end of 24 years of conception, development, constru...

  9. The LHC goes 3G

    CERN Multimedia

    Anaïs Schaeffer

    2013-01-01

    A new telecommunications network has been installed in the LHC tunnel to facilitate operations during the long shutdown. Anyone using a smartphone, tablet or laptop computer will now be able to access the Internet from the tunnel.   Results of a download (green) and upload (yellow) test carried out in the LHC tunnel using the new Universal Mobile Telecommunications System (UMTS). The first long shutdown has officially begun, and the teams are about to enter the various tunnels around the Laboratory. It’s a good opportunity to talk telecommunications. As you can well imagine, even the highest of high-tech smartphones remains stubbornly silent and unresponsive 100 metres below the ground. Except at CERN… The IT-CS Group has implemented an impressive state-of-the-art solution to tackle this problem - a new Universal Mobile Telecommunications System (UMTS), better known as “3G”, covering the entire 27-km circumference of the LHC tunnel. Established on th...

  10. Inclusive production at LHC energies

    International Nuclear Information System (INIS)

    Merino, C.; Pajares, C.; Shabelski, Yu.M.

    2011-01-01

    We consider the first LHC data for pp collisions in the framework of Regge theory. The integral cross sections and inclusive densities of secondaries are determined by the Pomeron exchange, and we present the corresponding predictions for them. The first measurements of inclusive densities in the midrapidity region are in agreement with these predictions. The contribution of the baryon-number transfer due to String Junction diffusion in the rapidity space is at the origin of the differences in the inclusive spectra of particle and antiparticle in the central region, and this effect could be significant at LHC energies. We discuss the first data of ALICE and LHCb collaborations on the baryon/antibaryon asymmetry at LHC. (orig.)

  11. Parton distributions with LHC data

    DEFF Research Database (Denmark)

    Ball, R.D.; Deans, C.S.; Del Debbio, L.

    2013-01-01

    We present the first determination of parton distributions of the nucleon at NLO and NNLO based on a global data set which includes LHC data: NNPDF2.3. Our data set includes, besides the deep inelastic, Drell-Yan, gauge boson production and jet data already used in previous global PDF determinati......We present the first determination of parton distributions of the nucleon at NLO and NNLO based on a global data set which includes LHC data: NNPDF2.3. Our data set includes, besides the deep inelastic, Drell-Yan, gauge boson production and jet data already used in previous global PDF...... fraction of the proton. We also present collider PDF sets, constructed using only data from HERA, the Tevatron and the LHC, but find that this data set is neither precise nor complete enough for a competitive PDF determination....

  12. Searches for SUSY at LHC

    International Nuclear Information System (INIS)

    Kharchilava, A.

    1997-01-01

    One of the main motivations of experiments at the LHC is to search for SUSY particles. The talk is based on recent analyses, performed by CMS Collaboration, within the framework of the Supergravity motivated minimal SUSY extension of the Standard Model. The emphasis is put on leptonic channels. The strategies for obtaining experimental signatures for strongly and weakly interacting sparticles productions, as well as examples of determination of SUSY masses and model parameters are discussed. The domain of parameter space where SUSY can be discovered is investigated. Results show, that if SUSY is of relevance at Electro-Weak scale it could hardly escape detection at LHC. (author)

  13. HL-LHC tracking challenge

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    We organize on the Kaggle platform a data science competition to stimulate both the ML and HEP communities to renew core tracking algorithms in preparation of the next generation of particle detectors at the LHC. In a nutshell : one event has 100.000 3D points ; how to associate the points onto 10.000 unknown approximately helicoidal trajectories ? avoiding combinatorial explosion ? you have a few seconds. But we do give you 100.000 events to train on. We ran ttbar+200 minimum bias event into ACTS a simplified (yet accurate) simulation of a generic LHC silicon detectors, and wrote out the reconstructed hits, with matching truth. ...

  14. Diffraction dissociation at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Jenkovszky, Laszlo [Bogolyubov Institute for Theoretical Physics (BITP), Ukrainian National Academy of Sciences 14-b, Metrolohichna str., Kiev, 03680, Ukraine and Wigner Research Centre for Physics, Hungarian Academy of Sciences 1525 Budapest, POB 49 (Hungary); Orava, Risto [Institute of Physics, Division of Elementary Particle Physics, P.O. Box 64 (Gustaf Haellstroeminkatu 2a), FI-00014 University of Helsinki, Finland and CERN, CH-1211 Geneva 23 (Switzerland); Salii, Andrii [Bogolyubov Institute for Theoretical Physics (BITP), Ukrainian National Academy of Sciences 14-b, Metrolohichna str., Kiev, 03680 (Ukraine)

    2013-04-15

    We report on recent calculations of low missing mass single (SD) and double (DD) diffractive dissociation at LHC energies. The calculations are based on a dual-Regge model, dominated by a single Pomeron exchange. The diffractively excited states lie on the nucleon trajectory N*, appended by the isolated Roper resonance. Detailed predictions for the squared momentum transfer and missing mass dependence of the differential and integrated single-and double diffraction dissociation in the kinematical range of present and future LHC measurements are given.

  15. Diffraction dissociation at the LHC

    International Nuclear Information System (INIS)

    Jenkovszky, László; Orava, Risto; Salii, Andrii

    2013-01-01

    We report on recent calculations of low missing mass single (SD) and double (DD) diffractive dissociation at LHC energies. The calculations are based on a dual-Regge model, dominated by a single Pomeron exchange. The diffractively excited states lie on the nucleon trajectory N*, appended by the isolated Roper resonance. Detailed predictions for the squared momentum transfer and missing mass dependence of the differential and integrated single-and double diffraction dissociation in the kinematical range of present and future LHC measurements are given.

  16. Searching dark matter at LHC

    International Nuclear Information System (INIS)

    Nojiri, Mihoko M.

    2007-01-01

    We now believe that the dark matter in our Universe must be an unknown elementary particle, which is charge neutral and weakly interacting. The standard model must be extended to include it. The dark matter was likely produced in the early universe from the high energy collisions of the particles. Now LHC experiment starting from 2008 will create such high energy collision to explore the nature of the dark matter. In this article we explain how dark matter and LHC physics will be connected in detail. (author)

  17. LHC Report: The beam is back at the LHC

    CERN Multimedia

    Reyes Alemany

    2015-01-01

    A series of sector beam tests paved the way for the start-up of the LHC in 2008 and 2009. These tests and the follow-up of the issues that arose were part of the process that led to a smooth start-up with beam.   Given this experience, sector tests were scheduled to take place several weeks before the 2015 start-up. On the weekend of 6-9 March, beam from the SPS was injected into both LHC injection regions, followed by a first pass through the downstream LHC sectors. For the clockwise LHC beam (called “beam 1”) this meant passing through ALICE and into Sector 2-3, while the anticlockwise beam (called “beam 2”) was threaded through LHCb and all the way from Point 8 to Point 6, where it was extracted by the beam dump kickers onto the beam dump block. The dry runs in the previous weeks were mainly targeted at preparation for the sector tests. The systems tested included: injection, timing, synchronisation and beam instrumentation. The beam interlock ...

  18. High Luminosity LHC (HL-LHC) general infographics

    CERN Multimedia

    Landua, Fabienne

    2016-01-01

    The High-Luminosity LHC, which is expected to be operational after 2025, will increase the LHC’s luminosity by a factor of 10. To achieve this major upgrade, several technologies, some of which are completely innovative, are being developed.

  19. From the LHC to Future Colliders

    DEFF Research Database (Denmark)

    De Roeck, A.; Ellis, J.; Grojean, C.

    2010-01-01

    Discoveries at the LHC will soon set the physics agenda for future colliders. This report of a CERN Theory Institute includes the summaries of Working Groups that reviewed the physics goals and prospects of LHC running with 10 to 300/fb of integrated luminosity, of the proposed sLHC luminosity up...

  20. Budker INP in the LHC Machine (2)

    CERN Multimedia

    2001-01-01

    The main BINP contributions to the LHC machine are magnets for transfer lines (26 MCHF) and bus- bar sets (23 MCHF). Budker INP is also responsible for construction of some other LHC magnets and vacuum parts. In total, the contribution to the LHC machine will reach about 90 MCHF.

  1. LHC Report: Back in operation

    CERN Multimedia

    2016-01-01

    With the machine back in their hands since Friday, 4 March, the LHC operators are now performing the powering tests on the magnets. This is a crucial step before receiving the first beams and restarting Run 2 for physics.   A Distribution Feed-Box (DFB) brings power to the LHC magnets and maintains the stability of the current in the superconducting circuits. The LHC was the last machine to be handed back to operators after the completion of maintenance work carried out during the Year-End Technical Stop (YETS) that had started on 14 December 2015. During the eleven weeks of scheduled maintenance activities, several operations took place in all the accelerators and beam lines. They included the maintenance in several points of the cryogenic system, the replacement of 18 magnets in the Super Proton Synchrotron; an extensive campaign to identify and remove thousands of obsolete cables; the replacement of the LHC beam absorbers for injection (TDIs) that are used to absorb the SPS b...

  2. LHC machine: Status and plan

    International Nuclear Information System (INIS)

    Pojer, M.

    2013-01-01

    The LHC Run I was successfully concluded in March 2012. An incredible amount of data has been collected and the performance continuously improved during these three years. Important information on the limitations of the machine also emerged, which will be used to further increase the potential of the machine in the coming years. (authors)

  3. Perturbative QCD for the LHC

    International Nuclear Information System (INIS)

    Glover, N.

    2008-01-01

    The need for predictions of standard model processes at the LHC at leading order and beyond is motivated. Recent developments in computing scattering amplitudes are reviewed. I describe the limitations of tree-level predictions, and how they may be improved at next-to-leading order. The current status of the field is discussed. (author)

  4. LHC Report: focus on luminosity

    CERN Document Server

    Reyes Alemany Fernandez for the LHC team

    2016-01-01

    The intensity ramp-up of the LHC beams resumed last Friday after the main powering system of the PS accelerator was put back in service.    The image above shows the last twenty four hours of fill #4947 in the machine. The LHC operations team kept the beams of this fill in the machine for a record 35 and a half hours.  Beams are back in the LHC. On Friday, the accelerator resumed the intensity ramp-up, reaching 1752 bunches per beam last week-end. The intensity ramp-up was interrupted on 20 May because of a problem with the PS’s main power supply (see box). A steady increase in the total number of bunches per beam is required to check out all aspects of beam operation and make sure the LHC is fully safe before the nominal number of bunches per beam can be brought into collision. At present, four intensity steps have been completed: 313, 601, 889, and 1177 bunches per beam. The qualification of the next step with 1752 bunches is in progress. At every s...

  5. LHC and the neutrino paradigm

    CERN Multimedia

    CERN. Geneva

    2011-01-01

    I argue that LHC may shed light on the nature of neutrino mass through the probe of the seesaw mechanism. The smoking gun signature is lepton number violation through the production of same sign lepton pairs, a collider analogy of the neutrinoless double beta decay. I discuss this in the context of L-R symmetric theories, which predicted neutrino mass long before experiment and led to the seesaw mechanism. A WR gauge boson with a mass in a few TeV region could easily dominate neutrinoless double beta decay, and its discovery at LHC would have spectacular signatures of parity restoration and lepton number violation. I also discuss the collider signatures of the three types of seesaw mechanism, and show how in the case of Type II one can measure the PMNS mixing matrix at the LHC, complementing the low energy probes. Finally, I give an example of a simple realistic SU(5) grand unified theory that predicts the hybrid Type I + III seesaw with a weak fermion triplet at the LHC energies. The seminar will be fol...

  6. Post-LHC accelerator magnets

    International Nuclear Information System (INIS)

    Gourlay, Stephen A.

    2001-01-01

    The design and practicality of future accelerators, such as hadron colliders and neutrino factories being considered to supercede the LHC, will depend greatly on the choice of superconducting magnets. Various possibilities will be reviewed and discussed, taking into account recent progress and projected improvements in magnet design and conductor development along with the recommendations from the 2001 Snowmass workshop

  7. LHC physics: challenges for QCD

    OpenAIRE

    Frixione, S.

    2003-01-01

    I review the status of the comparisons between a few measurements at hadronic colliders and perturbative QCD predictions, which emphasize the need for improving the current computations. Such improvements will be mandatory for a satisfactory understanding of high-energy collisions at the LHC

  8. Higgs physics at the LHC

    CERN Document Server

    Mariotti, Chiara

    2017-01-01

    The first measurements of the mass, the width, and the couplings of the newly discovered Higgs boson at LHC at 7 and 8 TeV center of mass energy will be reviewed. Recent results at 13 TeV center of mass energy will be presented. Finally, searches for additional Higgs bosons in models beyond the standard model will be summarised.

  9. Parton distributions with LHC data

    NARCIS (Netherlands)

    Ball, Richard D.; Bertone, Valerio; Carrazza, Stefano; Deans, Christopher S.; Debbio, Luigi Del; Forte, Stefano; Guffanti, Alberto; Hartland, Nathan P.; Latorre, Jose I.; Rojo, Juan; Ubiali, Maria

    2013-01-01

    We present the first determination of parton distributions of the nucleon at NLO and NNLO based on a global data set which includes LHC data: NNPDF2.3. Our data set includes, besides the deep inelastic, Drell-Yan, gauge boson production and jet data already used in previous global PDF

  10. The history of the LHC

    CERN Multimedia

    CERN. Geneva

    2010-01-01

    Abstract: From the civil engineering, to the manufacturing of the various magnet types, each building block of this extraordinary machine required ambitious leaps in innovation. This lecture will review the history of the LHC project, focusing on the many challenges -- scientific, technological, managerial -- that had to be met during the various phases of R&D, industrialization, construction, installation and commissioning.

  11. LHC: Past, Present, and Future

    CERN Document Server

    Landsberg, Greg

    2013-01-01

    In this overview talk, I give highlights of the first three years of the LHC operations at high energy, spanning heavy-ion physics, standard model measurements, and searches for new particles, which culminated in the discovery of the Higgs boson by the ATLAS and CMS experiments in 2012. I'll discuss what we found about the properties of the new particle in 10 months since the discovery and then talk about the future LHC program and preparations to the 2015 run at the center-of-mass energy of ~13 TeV. These proceedings are meant to be a snapshot of the LHC results as of May 2013 - the time of the conference. Many of the results shown in these proceedings have been since updated (sometimes significantly) just 4 months thereafter, when these proceedings were due. Nevertheless, keeping this writeup in sync with the results shown in the actual talk has some historical value, as, for one, it tells the reader how short is the turnaround time to update the results at the LHC. To help an appreciation of this fact, I b...

  12. SPS in training for LHC

    CERN Document Server

    2003-01-01

    On 8 and 9 September the new beam extraction system of the SPS and the downstream transfer line were successfully commissioned and tested. Using this extraction, a beam will be sent towards LHC in 2004 and to the CNGS facility in 2006.

  13. Keeping the LHC in power

    CERN Multimedia

    CERN Bulletin

    2013-01-01

    The critical safety equipment around the LHC, including the machine protection systems, is connected to Uninterruptible Power Supplies (UPS).  In case of mains failure, the UPS systems continue to power, for a limited time, these critical systems and ensure a safe shutdown of the accelerator. This week, work began to upgrade and replace over 100 UPS systems in the LHC.   The new UPS installations. For the LHC, even a perturbation on the mains is more than just an inconvenience: it often results in beam dumps and, in some cases, requires an energy extraction from superconducting circuits. When this occurs, machine protection systems, and in particular the Quench Protection System, must remain active to correctly carry out the shutdown procedure. With the UPS systems, 10 minutes of crucial power can be provided to the protection systems during this critical phase. There are currently two UPS systems in place in each one of the 32 LHC UPS zones. Originally one was used as a backup if ...

  14. LHC magnets: the great descent

    CERN Multimedia

    2005-01-01

    A first dipole magnet was delivered to its final location in the LHC tunnel on Monday, 7 March. This achievement coincides with another important milestone in the installation of the future collider, the completion of the delivery of half the dipole magnets.

  15. Connecting LHC, ILC, and quintessence

    International Nuclear Information System (INIS)

    Chung, Daniel J.H.; Everett, Lisa L.; Kong, Kyoungchul; Matchev, Konstantin T.

    2007-01-01

    If the cold dark matter consists of weakly interacting massive particles (WIMPs), anticipated measurements of the WIMP properties at the Large Hadron Collider (LHC) and the International Linear Collider (ILC) will provide an unprecedented experimental probe of cosmology at temperatures of order 1 GeV. It is worth emphasizing that the expected outcome of these tests may or may not be consistent with the picture of standard cosmology. For example, in kination-dominated quintessence models of dark energy, the dark matter relic abundance can be significantly enhanced compared to that obtained from freeze out in a radiation-dominated universe. Collider measurements then will simultaneously probe both dark matter and dark energy. In this article, we investigate the precision to which the LHC and ILC can determine the dark matter and dark energy parameters under those circumstances. We use an illustrative set of four benchmark points in minimal supergravity in analogy with the four LCC benchmark points. The precision achievable together at the LHC and ILC is sufficient to discover kination-dominated quintessence, under the assumption that the WIMPs are the only dark matter component. The LHC and ILC can thus play important roles as alternative probes of both dark matter and dark energy

  16. Parton distributions with LHC data

    CERN Document Server

    Ball, Richard D.; Carrazza, Stefano; Deans, Christopher S.; Del Debbio, Luigi; Forte, Stefano; Guffanti, Alberto; Hartland, Nathan P.; Latorre, Jose I.; Rojo, Juan; Ubiali, Maria

    2013-01-01

    We present the first determination of parton distributions of the nucleon at NLO and NNLO based on a global data set which includes LHC data: NNPDF2.3. Our data set includes, besides the deep inelastic, Drell-Yan, gauge boson production and jet data already used in previous global PDF determinations, all the relevant LHC data for which experimental systematic uncertainties are currently available: ATLAS and LHCb W and Z lepton rapidity distributions from the 2010 run, CMS W electron asymmetry data from the 2011 run, and ATLAS inclusive jet cross-sections from the 2010 run. We introduce an improved implementation of the FastKernel method which allows us to fit to this extended data set, and also to adopt a more effective minimization methodology. We present the NNPDF2.3 PDF sets, and compare them to the NNPDF2.1 sets to assess the impact of the LHC data. We find that all the LHC data are broadly consistent with each other and with all the older data sets included in the fit. We present predictions for various ...

  17. A table-top LHC

    CERN Multimedia

    Barbara Warmbein

    2011-01-01

    Many years ago, when ATLAS was no more than a huge empty underground cavern and Russian artillery shell casings were being melted down to become part of the CMS calorimetry system, science photographer Peter Ginter started documenting the LHC’s progress. He was there when special convoys of equipment crossed the Jura at night, when cranes were lowering down detector slices and magnet coils were being wound in workshops. Some 18 years of LHC history have been documented by Ginter, and the result has just come out as a massive coffee table book full of double-page spreads of Ginter’s impressive images.   The new coffee table book, LHC: the Large Hadron Collider. Published by the Austrian publisher Edition Lammerhuber in cooperation with CERN and UNESCO Publishing, LHC: the Large Hadron Collider is an unusual piece in the company’s portfolio. As the publisher’s first science book, LHC: the Large Hadron Collider weighs close to five kilos and comes in a s...

  18. PHOBOS in the LHC era

    Energy Technology Data Exchange (ETDEWEB)

    Steinberg, Peter, E-mail: peter.steinberg@bnl.gov

    2015-01-15

    The PHOBOS experiment ran at the RHIC collider from 2000 to 2005, under the leadership of Wit Busza. These proceedings summarize selected PHOBOS results, highlighting their continuing relevance amidst the wealth of new results from the lead–lead program at the Large Hadron Collider (LHC)

  19. Dark Matter Searches at LHC

    CERN Document Server

    Terashi, Koji; The ATLAS collaboration

    2017-01-01

    This talk will present dark matter searches at the LHC in the PIC2017 conference. The main emphasis is placed on the direct dark matter searches while the interpretation of searches for SUSY and invisible Higgs signals for the dark matter is also presented.

  20. ELECTRONICS FOR CALORIMETERS AT LHC

    International Nuclear Information System (INIS)

    Radeka, V.

    2001-01-01

    Some principal design features of front-end electronics for calorimeters in experiments at the LHC will be highlighted. Some concerns arising in the transition from the research and development and design phase to the construction will be discussed. Future challenges will be indicated

  1. LHC Accelerator Fault Tracker - First Experience

    CERN Document Server

    Apollonio, Andrea; Roderick, Chris; Schmidt, Ruediger; Todd, Benjamin; Wollmann, Daniel

    2016-01-01

    Availability is one of the key performance indicators of LHC operation, being directly correlated with integrated luminosity production. An effective tool for availability tracking is a necessity to ensure a coherent capture of fault information and relevant dependencies on operational modes and beam parameters. At the beginning of LHC Run 2 in 2015, the Accelerator Fault Tracking (AFT) tool was deployed at CERN to track faults or events affecting LHC operation. Information derived from the AFT is crucial for the identification of areas to improve LHC availability, and hence LHC physics production. For the 2015 run, the AFT has been used by members of the CERN Availability Working Group, LHC Machine coordinators and equipment owners to identify the main contributors to downtime and to understand the evolution of LHC availability throughout the year. In this paper the 2015 experience with the AFT for availability tracking is summarised and an overview of the first results as well as an outlook to future develo...

  2. LHC? Of course we’ve heard of the LHC!

    CERN Multimedia

    2009-01-01

    Well, more or less. After its first outing in Meyrin (see last Bulletin issue), our street poll hits the streets of Divonne-les-Bains and the corridors of the University of Geneva. While many have heard of the LHC, the raison d’être of this "scientific whatsit" often remains a mystery.On first questioning, the "man-in-the-street" always pleads ignorance. "Lausanne Hockey Club?" The acronym LHC is not yet imprinted on people’s minds. "Erm, Left-Handed thingamajig?" But as soon as we mention the word "CERN", the accelerator pops straight into people’s minds. Variously referred to as "the circle" or "the ring", it makes you wonder whether people would have been so aware of the LHC if it had been shaped like a square. Size is another thing people remember: "It’s the world’s biggest. Up to now…" As for its purpose, well that’s another kettle of fish. &...

  3. LHC Report: Beams are back in the LHC

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    The LHC has shaken itself awake after the winter break, and, as the snow melts on the lower slopes, the temperature in the magnets has dropped to a chilly 1.9 K once more.   Following the cool-down, the last few weeks have seen an intense few tests of the magnets, power supplies and associated protection systems. These tests, referred to as hardware commissioning, have been completed in record time. At the same time the other accelerator systems have been put through the preparatory machine checkout. In parallel, the injectors (LINAC2, Booster, PS and SPS) have also come out of the technical stop in order to prepare to deliver beam to the LHC very early in the season. Of particular note here was the remarkably seamless transition to POPS, the PS's new main power supply system. All this work culminated in the LHC taking beam again for the first time in 2011 on Saturday, 19 February. The careful preparation paid off, with circulating beams being rapidly re-established. There then followed a programme ...

  4. LHC beam energy in 2012

    International Nuclear Information System (INIS)

    Siemko, A.; Charifouline, Z.; Dahlerup-Petersen, K.; Denz, R.; Ravaioli, E.; Schmidt, R.; Verweij, A.

    2012-01-01

    The interconnections between the LHC main magnets are made of soldered joints (splices) of two superconducting cables stabilized by a copper bus bar. The measurements performed in 2009 in the whole machine, in particular in sector 3-4 during the repair after the 2008 accident, demonstrated that there is a significant fraction of defective copper bus bar joints in the machine. In this paper, the limiting factors for operating the LHC at higher energies with defective 13 kA bus bar joints are briefly reviewed. The experience gained during the 2011 run, including the quench statistics and dedicated quench propagation tests impacting on maximum safe energy are presented. The impact of the by-pass diode contact resistance issue is also addressed. Finally, a proposal for running at the highest possible safe energy compatible with the pre-defined risk level is presented. (authors)

  5. Electroweak Physics at the LHC

    CERN Document Server

    Sommer, Philip; The ATLAS collaboration

    2018-01-01

    With the large integrated luminosities recorded at the LHC and the excellent understanding of the LHC detectors, it is possible to measure electroweak observables to the highest precision. A review of the measurement of the $W$ boson mass by the ATLAS Collaboration as well as a new measurement of the electroweak mixing angle with the CMS detector are presented. Special emphasis is put on a discussion of the modelling uncertainties and the potential of the latest low-$\\mu$ runs, recorded at the end of 2017 by both collaboration. In addition, the latest measurements of multi-boson final states as well as the electroweak production of single gauge bosons at 13 TeV are summarised. The study of these processes can be used to constrain anomalous gauge couplings in an effective field theory approach, allowing to bridge tests of the electroweak sector of the Standard Models also to Higgs boson production.

  6. Electroweak Physics at the LHC

    CERN Document Server

    Sommer, Philip; The ATLAS collaboration

    2018-01-01

    With the high integrated luminosities recorded at the LHC and the very good understanding of the LHC detectors, it is possible to measure electroweak observables to the highest precision. In this talk, we review the measurement of the W boson mass by the ATLAS Collaboration as well as the new measurement of the electroweak mixing angle with the CMS detector. Special focus is drawn on a discussion of the modeling uncertainties and the physics potential of the latest low-mu runs, recorded at the end of 2017 by both collaboration. In addition, we will present the latest measurements of multi-boson final states as well as the electroweak production of single gauge bosons at 13 TeV. The study of these processes can be used to constrain anomalous gauge couplings in an effective field theory approach, allowing to bridge tests of the electroweak sector of the Standard Models also to the Higgs-boson production.

  7. Slice of LHC dipole wiring

    CERN Multimedia

    Dipole model slice made in 1994 by Ansaldo. The high magnetic fields needed for guiding particles around the Large Hadron Collider (LHC) ring are created by passing 12’500 amps of current through coils of superconducting wiring. At very low temperatures, superconductors have no electrical resistance and therefore no power loss. The LHC is the largest superconducting installation ever built. The magnetic field must also be extremely uniform. This means the current flowing in the coils has to be very precisely controlled. Indeed, nowhere before has such precision been achieved at such high currents. 50’000 tonnes of steel sheets are used to make the magnet yokes that keep the wiring firmly in place. The yokes constitute approximately 80% of the accelerator's weight and, placed side by side, stretch over 20 km!

  8. Operational beams for the LHC

    CERN Document Server

    Papaphilippou, Y.; Rumolo, G.; Manglunki, D.

    2014-01-01

    The variety of beams, needed to set-up in the injectors as requested in the LHC, are reviewed, in terms of priority but also performance expectations and reach during 2015. This includes the single bunch beams for machine commissioning and measurements (probe, Indiv) but also the standard physics beams with 50 ns and 25 ns bunch spacing and their high brightness variants using the Bunch Compression Merging and Splitting (BCMS) scheme. The required parameters and target performance of special beams like the doublet for electron cloud enhancement and the more exotic 8b$\\oplus$4e beam, compatible with some post-scrubbing scenarios are also described. The progress and plans for the LHC ion production beams during 2014-2015 are detailed. Highlights on the current progress of the setting up of the various beams are finally presented with special emphasis on potential performance issues across the proton and ion injector chain.

  9. Reliability issues at the LHC

    CERN Multimedia

    CERN. Geneva. Audiovisual Unit; Gillies, James D

    2002-01-01

    The Lectures on reliability issues at the LHC will be focused on five main Modules on five days. Module 1: Basic Elements in Reliability Engineering Some basic terms, definitions and methods, from components up to the system and the plant, common cause failures and human factor issues. Module 2: Interrelations of Reliability & Safety (R&S) Reliability and risk informed approach, living models, risk monitoring. Module 3: The ideal R&S Process for Large Scale Systems From R&S goals via the implementation into the system to the proof of the compliance. Module 4: Some Applications of R&S on LHC Master logic, anatomy of risk, cause - consequence diagram, decomposition and aggregation of the system. Module 5: Lessons learned from R&S Application in various Technologies Success stories, pitfalls, constrains in data and methods, limitations per se, experienced in aviation, space, process, nuclear, offshore and transport systems and plants. The Lectures will reflect in summary the compromise in...

  10. LHC Beam Energy in 2012

    CERN Document Server

    Siemko, A; Dahlerup-Petersen, K; Denz, R; Ravaioli, E; Schmidt, R; Verweij, A

    2012-01-01

    The interconnections between the LHC main magnets are made of soldered joints (splices) of two superconducting cables stabilized by a copper bus bar. The measurements performed in 2009 in the whole machine, in particular in sector 3-4 during the repair after the 2008 accident, demonstrated that there is a significant fraction of defective copper bus bar joints in the machine. In this paper, the limiting factors for operating the LHC at higher energies with defective 13 kA bus bar joints are briefly reviewed. The experience gained during the 2011 run, including the quench statistics and dedicated quench propagation tests impacting on maximum safe energy are presented. The impact of the by-pass diode contact resistance issue is also addressed. Finally, a proposal for running at the highest possible safe energy compatible with the pre-defined risk level is presented.

  11. The LHC at the AAAS

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    The American Association for the Advancement of Science held its annual meeting in the Walter E. Washington Convention Center in Washington D.C. last week.   Veteran science writer Tim Radford introduces LHC scientists during a media briefing at the AAAS annual meeting. Left to right: Felicitas Pauss, Tom LeCompte, Yves Schutz and Nick Hadley. As the world’s largest popular science meeting, the AAAS meeting is a major event in the calendar of science journalists.  At this year’s LHC session, CERN’s coordinator for international relations, Felicitas Pauss, opened the discussion, paving the way for Tom LeCompte of ATLAS, Joe Incandela of CMS, Yves Schutz of ALICE and Monica Pepe-Altarelli of LHCb to report on the status of the first year’s analysis from their experiments.    

  12. Photodetection in the LHC experiments

    International Nuclear Information System (INIS)

    Joram, C.

    2012-01-01

    The challenging requirements on photodetection in the LHC experiments have motivated large-scale R and D efforts on various detector technologies, which started already in the 1990s. The state-of-the-art of the LEP era would not have allowed satisfying the demanding needs, particularly from calorimetry and particle identification. After almost two decades of intense development, construction and integration efforts, the LHC and its four major experiments are performing in a just exemplary manner, in many respects exceeding the expectations. Hundreds of thousands of photodetectors with millions of readout channels contribute to this success story. This article aims at reviewing the main activities in photodetection, the initial achieved performance as well as some consolidation and first upgrade efforts.

  13. LHC technical data goes mobile

    CERN Multimedia

    Jordan Juras

    2010-01-01

    The Computerized Maintenance Management System (CMMS), which has been in use at CERN for many years, has recently been enhanced with an innovative new feature for managing and exploiting existing information regarding the LHC: a system to read the barcodes on the LHC components and easily obtain data and information on the many thousands of items of equipment that make up the accelerator. The feature will eventually be made available for any other scientific instrumentation located at CERN.   Example of a magnet's barcode Systems like CERN's CMMS, which is based on an Enterprise Asset Management (EAM) system from Infor, are today standard practice in organizations managing large volumes of information about their facilities. However, the way in which CERN has adapted its system is rather unique: the CMMS not only manages the manufacturing, installation, maintenance and disposal of the components of CERN’s infrastructure but now has the potential to provide equipment information interact...

  14. Beam Loss Monitors at LHC

    CERN Document Server

    Dehning, B.

    2016-01-01

    One of the main functions of the LHC beam loss measurement system is the protection of equipment against damage caused by impacting particles creating secondary showers and their energy dissipation in the matter. Reliability requirements are scaled according to the acceptable consequences and the frequency of particle impact events on equipment. Increasing reliability often leads to more complex systems. The downside of complexity is a reduction of availability; therefore, an optimum has to be found for these conflicting requirements. A detailed review of selected concepts and solutions for the LHC system will be given to show approaches used in various parts of the system from the sensors, signal processing, and software implementations to the requirements for operation and documentation.

  15. The TOTEM project at LHC

    International Nuclear Information System (INIS)

    Buenerd, M.

    1996-01-01

    The TOTEM (TOTal cross section and Elastic scattering Measurement) collaboration at the LHC aims at measuring the total, elastic scattering over a large range of 4-momentum transfer, and single diffractive scattering and double Pomeron exchange cross sections in proton-proton collisions at 10 to 14 TeV center of mass energies. The physics motivations are outlined, the beam optics requirements are presented together with a first solution for a dedicated insertion. The instrumental aspects are only quoted qualitatively. (author)

  16. LHC magnet quench protection system

    Science.gov (United States)

    Coull, L.; Hagedorn, D.; Remondino, V.; Rodriguez-Mateos, F.

    1994-07-01

    The quench protection system for the superconducting magnets of the CERN Large Hadron Collider (LHC) is described. The system is based on the so called 'cold diode' concept. In a group of series connected magnets if one magnet quenches then the magnetic energy of all the magnets will be dissipated in the quenched magnet so destroying it. This is avoided by by-passing the quenched magnet and then rapidly de-exciting the unquenched magnets. For the LHC machine it is foreseen to use silicon diodes situated inside the cryostat as by-pass elements - so called 'cold diodes'. The diodes are exposed to some 50 kGray of radiation during a 10 year operation life-time. The high energy density of the LHC magnets (500 kJ/m) coupled with the relatively slow propagation speed of a 'natural' quench (10 to 20 m/s) can lead to excessive heating of the zone where the quench started and to high internal voltages. It is therefore necessary to detect quickly the incipient quench and fire strip heaters which spread the quench out more quickly over a large volume of the magnet. After a quench the magnet chain must be de-excited rapidly to avoid spreading the quench to other magnets and over-heating the by-pass diode. This is done by switching high-power energy-dump resistors in series with the magnets. The LHC main ring magnet will be divided into 16 electrically separated units which has important advantages.

  17. LHC magnet quench protection system

    International Nuclear Information System (INIS)

    Coull, L.; Hagedorn, D.; Remondino, V.; Rodriguez-Mateos, F.

    1994-01-01

    The quench protection system for the superconducting magnets of the CERN Large Hadron Collider (LHC) is described. The system is based on the so called ''cold diode'' concept. In a group of series connected magnets if one magnet quenches then the magnetic energy of all the magnets will be dissipated in the quenched magnet so destroying it. This is avoided by by-passing the quenched magnet and then rapidly de-exciting the unquenched magnets. For the LHC machine it is foreseen to use silicon diodes situated inside the cryostat as by-pass elements--so called ''cold diodes''. The diodes are exposed to some 50 kGray of radiation during a 10 year operation life-time. The high energy density of the LHC magnets (500 kJ/m) coupled with the relatively slow propagation speed of a ''natural'' quench (10 to 20 m/s) can lead to excessive heating of the zone where the quench started and to high internal voltages. It is therefore necessary to detect quickly the incipient quench and fire strip heaters which spread the quench out more quickly over a large volume of the magnet. After a quench the magnet chain must be de-excited rapidly to avoid spreading the quench to other magnets and over-heating the by-pass diode. This is done by switching high-power energy-dump resistors in series with the magnets. The LHC main ring magnet will be divided into 16 electrically separated units which has important advantages

  18. Discovery Physics at the LHC

    CERN Document Server

    Höcker, A

    2006-01-01

    Introductory lecture to the phenomenology of, and the LHC search for physics beyond the Standard Model (BSM). The first lecture discusses the empirical and theoretical reasons that require BSM physics, and how Supersymmetry, extra dimension and little Higgs models can cope with these. The second lecture introduces the experimental approaches adopted by ATLAS and CMS to search for BSM physics signals, and to measure some of their properties.

  19. LHC Detectors and Early Physics

    CERN Document Server

    Dissertori, Guenther

    2010-01-01

    In this review I sketch the basic criteria and boundary conditions which have guided the design of the LHC detectors. The discussion will concentrate on the so-called general-purpose experiments, ATLAS and CMS. After an overview of the detector's characteristics and performance, I will elaborate on the expected measurements of hard processes, with emphasis on jet and vector boson production, i.e., tests of Quantum Chromodynamics (QCD) and Electroweak Physics.

  20. In Particular: Podcasting the LHC

    CERN Document Server

    Holmes, Tova Ray; The ATLAS collaboration

    2016-01-01

    "In Particular" is a podcast about physics and the process of discovering physics at the high energy frontier. Produced by members of the ATLAS Collaboration, the show tells the stories of particle physics from the ground level. Aimed at science enthusiasts interested in understanding what drives LHC physicists and what their work entails, "In Particular" gives a voice directly to the researchers. Details about the philosophy, production, and goals of the show will be presented.

  1. The LHC magnets' trip underground

    CERN Multimedia

    2002-01-01

    Buildings SMI 2 and SDI 2 are currently a big blue construction at the end of the Meyrin site. When they are finished, in 2003, they will be the departure point from where the magnets for the LHC will be lowered down into the tunnel. View of the new building at the end of the Meyrin site. If you live in neighbouring France, you have probably noticed a new blue steel construction that has changed the view from Saint Genis Pouilly since last March. It's the first of two contiguous buildings, SMI 2 and SDI 2, which will make it possible to prepare and lower the 1232 dipole magnets, the 400 short straight sections and some 60 insertion magnets down into the TI2 tunnel, and from there, to their final location in the LHC tunnel. According to Paul Faugeras, Technical Co-ordinator for the LHC machine, 'the installation of the magnets will start in early 2004, and hopefully everything will be done by October 2006'. The first part of the magnets' journey will take place on surface. The 15 metre-long dipole magnets a...

  2. Half way round the LHC

    CERN Multimedia

    CERN Bulletin

    The LHC operations teams are preparing the machine for circulating beams and things are going very smoothly. ALICE and LHCb are getting used to observing particle tracks coming from the LHC beams. During the weekend of 7-8 November, CMS also  saw its first signals from beams dumped just upstream of  the experiment cavern.   Operators in the CMS control room observe the good performance of their detector. Particles are smoothly making their way around the 27 km circumference of the LHC. Last weekend (7-8 November), the first bunches of injection energy protons completed their journey (anti-clockwise) through three octants of the LHC’s circumference and were dumped in a collimator just before entering the CMS cavern. The particles produced by the impact of the protons on the tertiary collimators (used to stop the beam) left their tracks in the calorimeters and the muon chambers of the experiment. The more delicate inner detectors were switched off for protection reasons....

  3. The LHC quench protection system

    CERN Multimedia

    2009-01-01

    The new quench protection system (QPS) has the crucial roles of providing an early warning for any part of the superconducting coils and busbars that develop high resistance, as well as triggering the switch-off of the machine. Over 2000 new detectors will be installed around the LHC to make sure every busbar segment between magnets is monitored and protected. One of the major consolidation activities for the LHC is the addition of two new detectors to the quench protection system. A magnet quench occurs when part of the superconducting cable becomes normally-conducting. When the protection system detects an increased resistance the huge amount of energy stored in the magnet chains is safely extracted and ‘dumped’ into specially designed resistors. In the case of the main dipole chain, the stored energy in a single LHC sector is roughly the same as the kinetic energy of a passenger jet at cruising speed. The first new detector is designed to monitor the superconducting...

  4. Heatwave warning for the LHC

    CERN Multimedia

    Anaïs Schaeffer

    2013-01-01

    Engineers have been able to start warming up the first sectors of the LHC where the tests on the superconductor circuits have been completed. Raising the temperature from 1.9 K to 300 K is a remarkable but delicate process.   Filling the first liquid-helium truck for external storage. The first update on LS1, published in the previous edition of the Bulletin, announced the start of the Electrical Quality Assurance (ElQA) tests on the LHC magnets. These tests began on 22 February and have already been completed in two Sectors: “The integrity of the magnets’ electrical insulation has been fully verified in sectors 4-5 and 5-6,” reports Mirko Pojer, Engineer in Charge of the LHC. “This is vital in order for the magnets to function properly at the nominal current, which we should reach in 2015. The ElQA team has also run other tests, in particular to verify the electrical insulation between the coils. Fortunately, we have not detected any major problems so...

  5. Latest news from the LHC

    CERN Document Server

    CERN Bulletin

    2010-01-01

    Last week the LHC passed the threshold of 3 pb-1 total integrated luminosity delivered to the experiments, of which about half was delivered in just one week. These excellent results were achieved by operating the machine with up to 50 nominal bunches per beam.   After a very successful week that saw intense beams circulating for long periods (a total of 76.5 hours of stable beams, corresponding to about 40% of the time), there has been a technical stop this week. Over the coming days, experts will work on bunch trains with 150 ns spacing between bunches (the current minimum spacing is 1000 ns). This will involve making the necessary changes throughout the injector chain, as well as in the LHC itself. In the LHC, bunch trains imply working with a crossing angle throughout the machine cycle, in order to avoid unwanted parasitic collisions, which means that the whole process of injection, ramp and squeeze will have to be re-commissioned. The task also includes re-commissioning all the protection syste...

  6. LHC gets the ball rolling

    CERN Multimedia

    2007-01-01

    A technique involving a small ball with a transmitter embedded inside it has been successfully tested in Sector 7-8. The ball is sent through the LHC beam pipes to check the LHC interconnections. The multidisciplinary team responsible for the RF ball project to check the interconnections. From left to right: Rhodri Jones (AB/BI), Eva Calvo (AB/BI), Francesco Bertinelli (AT/MCS), Sonia Bartolome Jimenez (TS/IC), Sylvain Weisz (TS/IC), Paul Cruikshank (AT/VAC), Willemjan Maan (AT/VAC), Alain Poncet (AT/MCS), Marek Gasior (AB/BI). During the tests the ball is inserted very carefully into the vacuum chamber.A game of ping-pong at the LHC? On 13 September a rather unusual test was carried out in Sector 7-8 of the accelerator. A ball just a bit smaller than a ping-pong ball was carefully introduced into one of the accelerator’s two vacuum pipes, where it travelled 800 metres in the space of a few mi...

  7. Cryogenics for HL-LHC

    Science.gov (United States)

    Tavian, L.; Brodzinski, K.; Claudet, S.; Ferlin, G.; Wagner, U.; van Weelderen, R.

    The discovery of a Higgs boson at CERN in 2012 is the start of a major program of work to measure this particle's properties with the highest possible precision for testing the validity of the Standard Model and to search for further new physics at the energy frontier. The LHC is in a unique position to pursue this program. Europe's top priority is the exploitation of the full potential of the LHC, including the high-luminosity upgrade of the machine and detectors with an objective to collect ten times more data than in the initial design, by around 2030. To reach this objective, the LHC cryogenic system must be upgraded to withstand higher beam current and higher luminosity at top energy while keeping the same operation availability by improving the collimation system and the protection of electronics sensitive to radiation. This chapter will present the conceptual design of the cryogenic system upgrade with recent updates in performance requirements, the corresponding layout and architecture of the system as well as the main technical challenges which have to be met in the coming years.

  8. LHC Report: a brief deceleration

    CERN Multimedia

    Rossano Giachino & Markus Albert

    2015-01-01

    The LHC has now transitioned from powering tests to the machine checkout phase. This phase involves the full-scale tests of all systems in preparation for beam. Early last Saturday morning, during the ramp-down, an earth fault developed in the main dipole circuit. Full evaluation of the situation is ongoing.   The various systems are put through their operational paces from the CCC. This includes important tests of the beam dump system and full-scale tests of the beam interlock system (BIS) and its many inputs from other systems around the ring. All magnetic circuits are driven through the ramp, squeeze, ramp-down, and pre-cycle along with the collimators and RF. Instrumentation, feedbacks, and the control system are also stress tested. Inevitably there is some final frantic debugging but, up to now, things seem to be in reasonable shape. The machine checkout is an important coming together of all LHC systems. During this final phase before beam, the operations team tests all of the LHC subsystem...

  9. LHC Report: Timeout is over!

    CERN Multimedia

    Jan Uythoven for the LHC Team

    2012-01-01

    Over the last two weeks the LHC has been collecting luminosity at a steady pace, but not delivering the canonical 1 fb-1 per week. This is because machine timeouts were necessary to solve some beam-stability problems. Also, the beam development programme was moved forward, taking advantage of a timeout caused by an emergency ramp-down of the CMS solenoid magnet. With all these problems solved and with good injector performance, the past week has seen the LHC back to new record luminosities.   Previous LHC reports have mentioned that the peak luminosity at the beginning of the “stable beams” period had gone down by about 10% with respect to previous records. This is explained by the reduction of bunch intensities, as higher bunch intensities were leading to beam instabilities and important beam losses. When beams become unstable, octupole magnets can be used to correct them. These magnets can be powered at two different polarities and several days were needed to find new optimu...

  10. Switch on to the LHC!

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    The LHC is preparing to collide beams at 3.5 TeV for the first time ever! Be part of the event and follow live what goes on at the world’s most powerful particle accelerator by connecting to LHC1. Hereafter we give you a key to understand the display as well as a typical event display from the ATLAS and CMS experiments. Click on the image to enlarge it 1. This is the energy of beams. 1 TeV=1000 GeV. The LHC set the energy world’s record of 3.48 TeV per beam, today, 19 March 2010. 2. Intensity of, respectively, B1 (blue) and B2 (red). 3. The information in these boxes can vary. Operators display the graphs that are relevant to the specific operation. 4. Most of the flags are set automatically. They provide a quick summary of the machine status. In order to have collisions the ‘Stable Beams’ flag must be set to green. 5. Here operators write down their messages to the experiments. Often, they write the ongoing activity, followed by the plan for the coming hou...

  11. The LHC on an envelope

    CERN Multimedia

    2007-01-01

    The series of envelopes featuring CERN issued this summer was a huge success. The French postal services of the Pays de Gex will shortly be launching the second set of pre-paid envelopes issued in collaboration with the Laboratory this year, this time highlighting the LHC. Five thousand envelopes describing the accelerator’s capabilities will go on sale on 12 November, and some of the packs will even contain a small sample of the cables from the heart of the LHC magnets. The sets of ten pre-paid envelopes will tell you everything about CERN’s flagship accelerator, from its astounding technical capabilities to its spin-offs in the fields of technology and human resources. Each envelope will feature a different attribute or spin-off of the LHC. People will be invited to consult CERN’s public website for more detailed explanations if they want to know more. The new envelopes will be available from five post offices in the Pays ...

  12. The LHC in an envelope

    CERN Multimedia

    2007-01-01

    The series of envelopes featuring CERN issued this summer was a huge success. The French postal services of the Pays de Gex will shortly be launching the second set of pre-paid envelopes issued in collaboration with the Laboratory this year, this time highlighting the LHC. Five thousand envelopes describing the accelerator’s capabilities will go on sale on 12 November, and some of the packs will even contain a small sample of the cables from the heart of the LHC magnets. The sets of ten pre-paid envelopes will tell you everything about CERN’s flagship accelerator, from its astounding technical capabilities to its spin-offs in the fields of technology and human resources. Each envelope will feature a different attribute or spin-off of the LHC. People will be invited to consult CERN’s public website for more detailed explanations if they want to know more. The new envelopes will be available from five post offices in the Pays de Gex (Ferney-Voltaire, Prévessin...

  13. Warmer amps for the LHC

    CERN Multimedia

    Anaïs Schaeffer

    2012-01-01

    CERN is working together with an Italian company to develop superconducting cables that can function at temperatures of up to 25 K (-248°C). This will make it possible to move LHC magnet power supplies out of the tunnel, protecting them from exposure to the showers of very high-energy particles produced by the accelerator.   Figure 1: devices of this type, which measure approximately 10 metres in length, are inserted between the accelerating magnets at different points along the LHC. When it comes to consuming electricity, the magnets that steer particles through large accelerators can be characterised with just one word: greedy. For the LHC, the total current can reach 1.5 million amps. At the present time, this current is brought in via copper cables of up to 10 cm in diameter. In the tunnel, these cables connect the current leads - which provide the transition between the ambient-temperature cables and the magnets in their bath of superfluid helium - to the power supply. In the a...

  14. Detector technologies for LHC experiments

    CERN Document Server

    Hansl-Kozanecka, Traudl

    1999-01-01

    Abstract The Large Hadron Collider (LHC) at CERN will provide proton-proton collisions ata centre-of-mass energy of 14 TeV with a design luminosity of 10^34cm^-2s^-1. The exploitation of the rich physics potential is illustrated using the expected performance of the two general-purpose detectors ATLAS and CMS.The lecture introduces the physics motivation for experiments at the LHC energy.The design parameters and expected performance of the LHC machine are then discussed, followed by the design objectives for the detectors. The technical solutions are presented for each detector system (calorimetry, muon system, inner tracker, trigger). For each system the requirements, the technology choices and the achieved and expected performance are discussed. Lectures given at Herbstschule fu:r Hochenergiephysik, Maria Laach, 1999Copies of the transparencies are available in reduced format (black-and-white) from the secretariats of ATLAS and CMS (1999-093 Talk). A full-size colour version is available for consultation.e...

  15. QCD@LHC International Conference

    CERN Document Server

    2016-01-01

    The particle physics groups of UZH and ETH will host the QCD@LHC2016 conference (22.8.-26.8., UZH downtown campus), which is part of an annual conference series bringing together theorists and experimentalists working on hard scattering processes at the CERN LHC, ranging from precision studies of Standard Model processes to searches for new particles and phenomena. The format of the conference is a combination of plenary review talks and parallel sessions, with the latter providing a particularly good opportunity for junior researchers to present their results. The conference will take place shortly after the release of the new data taken by the LHC in sping 2016 at a collision energy of 13TeV, expected to more than double the currently available data set. It will be one of the first opportunities to discuss these data in a broader context, and we expect the conference to become a very lively forum at the interface of phenomenology and experiment.

  16. The latest from the LHC

    CERN Multimedia

    2009-01-01

    Work on closing up sectors in the LHC tunnel. The foreseen shutdown work on the LHC is proceeding well, including the powering tests with the new quench protection system. However, during the past week vacuum leaks have been found in two "cold" sectors of the LHC. The leaks were found in Sectors 8-1 and 2-3 while they were being prepared for the electrical tests on the copper stabilizers at around 80 K. In both cases the leak is at one end of the sector, where the electrical feedbox, DFBA, joins Q7, the final magnet in the sector. Unfortunately, the repair necessitates a partial warm-up of both sectors. This involves the end sub-sector being warmed to room temperature, while the adjacent sub-sector "floats" in temperature and the remainder of the sector is kept at 80 K. As the leak is from the helium circuit to the insulating vacuum, the repair work will have no impact on the vacuum in the beam pipe. However the intervention wil...

  17. Important step towards the LHC

    CERN Document Server

    2001-01-01

    The TI2 tunnel, one of the two tunnels that will transfer protons from the SPS to the LHC, broke through into the LEP/LHC ring on 15 May. TI2 will carry clockwise-moving protons from under the Laboratory's West Area to Point 2, future home of the ALICE experiment. It is coming up to 16:00 on 15 May and a group of some 50 people, fully kitted out in boots, helmets, and masks is intently watching a point on the wall in front of them. They are down in the LEP/LHC tunnel waiting for civil engineers to excavate the last few centimetres separating them from the TI2 transfer tunnel. The noise of machines begins, and just five minutes later the wall comes tumbling down. The excavator breaks through right on target, bringing a two-year project to a happy conclusion. Later, the survey team published the outstanding result that the tunnel junction was made within 6 millimetres of target. TI2 measures 2648 metres in length and three metres in diameter. Around 32,000 cubic metres of rock have been excavated to make it, so...

  18. LHC Inner Triplet Powering Strategy

    CERN Document Server

    Bordry, Frederick

    2001-01-01

    In order to achieve a luminosity in excess of 10**34 cm**-2s**-1 at the Large Hadron Collider (LHC), special high gradient quadrupoles are required for the final focusing triplets. These low-b triplets, located in the four experimental insertions (ATLAS, CMS, ALICE, LHC-B), consist of four wide-aperture superconducting magnets: two outer quadrupoles, Q1 and Q3, with a maximum current of 7 kA and a central one divided into two identical magnets, Q2a and Q2b, with a maximum current of 11.5 kA. To optimise the powering of these mixed quadrupoles, it was decided to use two nested high-current power converters : [8kA, 8V] and [6kA, 8V]. This paper presents the consequence of the interaction between the two galvanically coupled circuits. A control strategy, using two independent, standard, LHC digital controllers, to decouple the two systems is proposed and described. The converter protection during the discharge of the magnet energy due to quenches or interlocks of the magnets are discussed. Simulation and experim...

  19. Robust Tracking at the High Luminosity LHC

    CERN Document Server

    Woods, Natasha Lee; The ATLAS collaboration

    2018-01-01

    The High Luminosity LHC (HL-LHC) aims to increase the LHC data-set by an order of magnitude in order to increase its potential for discoveries. Starting from the middle of 2026, the HL-LHC is expected to reach the peak instantaneous luminosity of 7.5×10^34cm^-2s^-1 which corresponds to about 200 inelastic proton-proton collisions per beam crossing. To cope with the large radiation doses and high pileup, the current ATLAS Inner Detector will be replaced with a new all-silicon Inner Tracker. In this talk the expected performance of tracking and vertexing with the HL-LHC tracker is presented. Comparison is made to the performance with the Run2 detector. Ongoing developments of the track reconstruction for the HL-LHC are also discussed.

  20. Review of LHC dark matter searches

    International Nuclear Information System (INIS)

    Kahlhoefer, Felix

    2017-02-01

    This review discusses both experimental and theoretical aspects of searches for dark matter at the LHC. An overview of the various experimental search channels is given, followed by a summary of the different theoretical approaches for predicting dark matter signals. A special emphasis is placed on the interplay between LHC dark matter searches and other kinds of dark matter experiments, as well as among different types of LHC searches.

  1. Gravitino LSP scneario at the LHC

    International Nuclear Information System (INIS)

    Heisig, Jan

    2010-05-01

    In this thesis we discuss the phenomenology of the gravitino LSP scenario at the large hadron collider (LHC) experiment. We concentrate on a long-lived stau NLSP which gives rise to a prominent signature in the LHC detector as a 'slow muon'. We discuss the production channels and compute the cross sections for direct production via the Drell-Yan process. On this basis we claim a conservative estimation of the discovery potential for this scenario at the LHC. (orig.)

  2. Review of LHC dark matter searches

    Energy Technology Data Exchange (ETDEWEB)

    Kahlhoefer, Felix

    2017-02-15

    This review discusses both experimental and theoretical aspects of searches for dark matter at the LHC. An overview of the various experimental search channels is given, followed by a summary of the different theoretical approaches for predicting dark matter signals. A special emphasis is placed on the interplay between LHC dark matter searches and other kinds of dark matter experiments, as well as among different types of LHC searches.

  3. QCD and hard diffraction at the LHC

    International Nuclear Information System (INIS)

    Albrow, Michael G.; Fermilab

    2005-01-01

    As an introduction to QCD at the LHC I given an overview of QCD at the Tevatron, emphasizing the high Q 2 frontier which will be taken over by the LHC. After describing briefly the LHC detectors I discuss high mass diffraction, in particular central exclusive production of Higgs and vector boson pairs. I introduce the FP420 project to measure the scattered protons 420 m downstream of ATLAS and CMS

  4. Highlights from LHC experiments and future perspectives

    International Nuclear Information System (INIS)

    Campana, P.

    2016-01-01

    The experiments at LHC are collecting a large amount of data in a kinematic of the (x, Q 2 ) variables never accessed before. Boosted by LHC analyses, Quantum Chromodynamics (QCD) is experiencing an impressive progress in the last few years, and even brighter perspectives can be foreseen for the future data taking. A subset of the most recent results from the LHC experiments in the area of QCD (both perturbative and soft) are reviewed

  5. LHC computing (WLCG) past, present, and future

    CERN Document Server

    Bird, I G

    2016-01-01

    The LCG project, and the WLCG Collaboration, represent a more than 10-year investment in building and operating the LHC computing environment. This article gives some of the history of how the WLCG was constructed and the preparations for the accelerator start-up. It will discuss the experiences and lessons learned during the first 3 year run of the LHC, and will conclude with a look forwards to the planned upgrades of the LHC and the experiments, discussing the implications for computing.

  6. Physics programmes of the restarted LHC

    International Nuclear Information System (INIS)

    Tokushuku, Katsuo

    2011-01-01

    Experimental programs at the Large Hadron Collider (LHC) have started. On March 30th in 2010, proton beams collided at 7 TeV in the LHC, at the highest center-of-mass energy the humankind has ever produced. The machine will be operated almost continuously until the end of 2011, providing many collision data to explore new physics in the TeV region. The LHC has recovered from the unfortunate helium-leak incident in September 2009. In this article, after describing the history of the consolidation works in the LHC, physics prospects from the 2 year run are discussed. (author)

  7. The LHC access system LACS and LASS

    CERN Document Server

    Ninin, P

    2005-01-01

    The LHC complex is divided into a number of zones with different levels of access controls.Inside the interlocked areas, the personnel protection is ensured by the LHC Access System.The system is made of two parts:the LHC Access Safety System and the LHC Access Control System. During machine operation,the LHC Access Safety System ensures the collective protection of the personnel against the radiation hazards arising from the operation of the accelerator by interlocking the LHC key safety elements. When the beams are off, the LHC Access Control System regulates the access to the accelerator and its many subsystems.It allows a remote, local or automatic operation of the access control equipment which verifies and identifies all users entering the controlled areas.The global architecture of the LHC Access System is now designed and is being validated to ensure that it meets the safety requirements for operation of the LHC.A pilot installation will be tested in the summer 2005 to validate the concept with the us...

  8. Abort Gap Cleaning for LHC Run 2

    Energy Technology Data Exchange (ETDEWEB)

    Uythoven, Jan [CERN; Boccardi, Andrea [CERN; Bravin, Enrico [CERN; Goddard, Brennan [CERN; Hemelsoet, Georges-Henry [CERN; Höfle, Wolfgang [CERN; Jacquet, Delphine [CERN; Kain, Verena [CERN; Mazzoni, Stefano [CERN; Meddahi, Malika [CERN; Valuch, Daniel [CERN; Gianfelice-Wendt, Eliana [Fermilab

    2014-07-01

    To minimize the beam losses at the moment of an LHC beam dump the 3 μs long abort gap should contain as few particles as possible. Its population can be minimised by abort gap cleaning using the LHC transverse damper system. The LHC Run 1 experience is briefly recalled; changes foreseen for the LHC Run 2 are presented. They include improvements in the observation of the abort gap population and the mechanism to decide if cleaning is required, changes to the hardware of the transverse dampers to reduce the detrimental effect on the luminosity lifetime and proposed changes to the applied cleaning algorithms.

  9. LHC related projects and studies - Part (II)

    International Nuclear Information System (INIS)

    Rossi, L.; De Maria, R.

    2012-01-01

    The session was devoted to address some aspects of the HL-LHC (High Luminosity LHC) project and explore ideas on new machines for the long term future. The session had two parts. The former focused on some of the key issues of the HL-LHC projects: beam current limits, evolution of the collimation system, research plans for the interaction region magnets and crab cavities. The latter explored the ideas for the long term future projects (LHeC and HE-LHC) and how the current research-development program for magnets and RF structures could fit in the envisaged scenarios

  10. Physics possibilities at LHC/SSC

    International Nuclear Information System (INIS)

    Hinchliffe, I.

    1991-01-01

    This document reviews some recent work on physics simulations for SSC/LHC. Included are reviews of some of the recent developments in physics simulations for the SSC/LHC and comments upon the requirements that are placed upon detectors by the need to extract specific physics signatures. The material in the various EOI/LOI documents submitted to the SCC Laboratory and the work done at the Aachen LHC workshop are discussed. In the following discussion 1 SSC (LHC) year corresponds to an integrated luminosity of 10 (100) fb -1 . 41 refs., 14 figs

  11. LHC crab-cavity aspects and strategy

    International Nuclear Information System (INIS)

    Calaga, R.; Tomas, R.; Zimmermann, F.

    2010-01-01

    The 3rd LHC Crab Cavity workshop (LHC-CC09) took place at CERN in October 2009. It reviewed the current status and identified a clear strategy towards a future crab-cavity implementation. Following the success of crab cavities in KEK-B and the strong potential for luminosity gain and leveling, CERN will pursue crab crossing for the LHC upgrade. We present a summary and outcome of the variousworkshop sessions which have led to the LHC crab-cavity strategy, covering topics like layout, cavity design, integration, machine protection, and a potential validation test in the SPS.

  12. Abort Gap Cleaning for LHC Run 2

    CERN Document Server

    Uythoven, J; Bravin, E; Goddard, B; Hemelsoet, GH; Höfle, W; Jacquet, D; Kain, V; Mazzoni, S; Meddahi, M; Valuch, D

    2015-01-01

    To minimise the beam losses at the moment of an LHC beam dump the 3 μs long abort gap should contain as few particles as possible. Its population can be minimised by abort gap cleaning using the LHC transverse damper system. The LHC Run 1 experience is briefly recalled; changes foreseen for the LHC Run 2 are presented. They include improvements in the observation of the abort gap population and the mechanism to decide if cleaning is required, changes to the hardware of the transverse dampers to reduce the detrimental effect on the luminosity lifetime and proposed changes to the applied cleaning algorithms.

  13. SUSY confronts LHC results - LHC results confront SUSY?

    International Nuclear Information System (INIS)

    Feigl, B.; Zeppenfeld, D.; Rzenak, H.

    2014-01-01

    Two of the key points of the LHC research program are searches for supersymmetry on the one hand and Higgs boson searches on the other hand. Though usually treated separately, if supersymmetry is realized in nature, the searches might be entangled. We first give a brief status of the validity of supersymmetric models. Then we discuss how Higgs boson searches might be affected by the existence of supersymmetric particles not yet directly detected. We focus on the search channels with the Higgs boson decay mode H → WW where data driven background estimation methods are applied. (authors)

  14. The LHC's peta-bytes

    International Nuclear Information System (INIS)

    Malek, Fairouz

    2013-01-01

    As the LHC generates each second billions of billions of collisions between protons, each of these collisions generates about a megabyte of data. The author first recalls the different detectors which record traces of collisions, outlines that the Higgs boson is rarely produced by these collisions, and moreover, disintegrates into two Z bosons. This means that the detection rate is very low. She outlines the huge number of data generated by each experiment, and evokes how they are processed, and outlines the associated required computing capacities

  15. Hard QCD Measurements at LHC

    CERN Document Server

    Pasztor, Gabriella

    2018-01-01

    The rich proton-proton collision data of the LHC allow to study QCD processes in a previously unexplored region with ever improving precision. This paper summarises recent results of the ATLAS, CMS and LHCb Collaborations using primarily multi-jet and vector boson plus jet data collected at $\\sqrt s$ = 8 and 13 TeV. Comparisons to higher-order theoretical calculations and sophisticated Monte Carlo predictions are presented, as well as the impact of the data on the determination of the parton distribution functions and the measurement of the strong coupling constant, $\\alpha_s$.

  16. Record current in the LHC

    CERN Multimedia

    On 19 December, just before CERN's end-of-year break, Sector 4-5, which had been cooled to 1.9 K, beat the LHC current record for 2007. The current was raised to 8500 amperes in the main magnets. The current of the dipole circuit was repeatedly ramped up and quenches were provoked. The magnets were maintained at 4.5 K over the holiday period so that they could be quickly brought back down to the nominal temperature after the shutdown. The testing of the sector has now resumed.

  17. LHC Status and Upgrade Challenges

    Science.gov (United States)

    Smith, Jeffrey

    2009-11-01

    The Large Hadron Collider has had a trying start-up and a challenging operational future lays ahead. Critical to the machine's performance is controlling a beam of particles whose stored energy is equivalent to 80 kg of TNT. Unavoidable beam losses result in energy deposition throughout the machine and without adequate protection this power would result in quenching of the superconducting magnets. A brief overview of the machine layout and principles of operation will be reviewed including a summary of the September 2008 accident. The current status of the LHC, startup schedule and upgrade options to achieve the target luminosity will be presented.

  18. The TOTEM Detector at LHC

    OpenAIRE

    Ruggiero, G; Antchev, G; Aspell, P; Atanassov, I; Avati, V; Berardi, V; Berretti, M; Bozzo, M; Brücken, E; Buzzo, A; Cafagna, F; Calicchio, M; Catanesi, M G; Ciocci, M A; Csanád, M

    2010-01-01

    The TOTEM experiment, small in size compared to the others at the LHC, is dedicated to the measurement of the total proton-proton cross-section with the luminosity-independent method and to the study of elastic and diffractive scattering. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the interaction point IP5, two tracking telescopes, T1 and T2, are installed on each side in the pseudo-rapidity region between 3.1 and 6.5, and Roman Pot (RP) stations...

  19. Radiation Levels around the LHC

    CERN Document Server

    Mala, P; Calviani, M; Nordt, A

    2013-01-01

    This work discuss on the radiation levels measured around the LHC machine during the 2012 operational year. The doses and particle fluences are measured primarily by RadMon detectors – about 300 RadMons are installed around the accelerator – and by thermoluminescent detectors. In addition, BLMs, IG5/PMI ionisation chambers as well as FGCs can be used for corresponding cumulated dose evaluations. The probability of SEE depends directly on the high-energy hadron (HEH) fluence, so this is the main parameter that is calculated based on RadMons counts.

  20. The LHC's equipment all in step

    CERN Multimedia

    2005-01-01

    Over 80% of the control equipment for the LHC will be connected by a special communication network known as WorldFIP, which has been chosen for its very precise timing, excellent operating performance and robustness in difficult environments. Over 350 kilometres of this network are currently being installed in the LHC tunnel and checked for compliance with the required standards.

  1. Physics with heavy ions at LHC

    International Nuclear Information System (INIS)

    Safarik, K.

    2004-01-01

    We discuss the motivation to study heavy ion collisions at LHC, and the experimental conditions under which detectors will have to operate. A short description of the detectors under construction is given. Physics performance is illustrated in two examples, which will become accessible at LHC energies, jet quenching and heavy-flavor production. (author)

  2. LHC Experiments: refinements for the restart

    CERN Multimedia

    2009-01-01

    As the LHC restart draws closer, the Bulletin will be taking a look at how the six LHC experiments are preparing and what they have been up to since last September. In this issue we start with a roundup of the past 10 months of activity at CMS and ATLAS, both technical work and outreach activities.

  3. Wie passt der LHC in den Physikunterricht?

    CERN Document Server

    AUTHOR|(CDS)2084439; Woithe, Julia; Brown, Alex; Jende, Konrad

    2017-01-01

    Der LHC bietet sich als aktuelles und prominentes Beispiel der Grundlagenforschung an, im Unterricht behandelt zu werden. Der Artikel gibt einen kurzen Überblick über Komponenten und Funktionsweise des LHC. Zudem wird auf hilfreiche Ressourcen und Anknüpfungspunkte zum Curriculum verwiesen.

  4. Standard Model at the LHC 2017

    CERN Document Server

    2017-01-01

    The SM@LHC 2017 conference will be held May 2-5, 2017 at Nikhef, Amsterdam. The meeting aims to bring together experimentalists and theorists to discuss the phenomenology, observational results and theoretical tools for Standard Model physics at the LHC.

  5. Parton Distribution Benchmarking with LHC Data

    NARCIS (Netherlands)

    Ball, Richard D.; Carrazza, Stefano; Debbio, Luigi Del; Forte, Stefano; Gao, Jun; Hartland, Nathan; Huston, Joey; Nadolsky, Pavel; Rojo, Juan; Stump, Daniel; Thorne, Robert S.; Yuan, C. -P.

    2012-01-01

    We present a detailed comparison of the most recent sets of NNLO PDFs from the ABM, CT, HERAPDF, MSTW and NNPDF collaborations. We compare parton distributions at low and high scales and parton luminosities relevant for LHC phenomenology. We study the PDF dependence of LHC benchmark inclusive cross

  6. Partons and jets at the LHC

    Indian Academy of Sciences (India)

    Partons and jets at the LHC. DAVISON E SOPER. Institute of Theoretical Science, University of Oregon, Eugene, OR 97403-5203, USA. Abstract. I review some issues related to short distance QCD and its relation to the experimental program of the large hadron collider (LHC) now under construction in Geneva. Keywords.

  7. Protons on the doorstep of the LHC

    CERN Multimedia

    Mertens, Volker

    2005-01-01

    The first of the two new beam transfer lines to the LHC was successfully commissioned in autumn 2004. At the first attempt a low-intensity proton beam passed down the line to a few meters before the LHC tunnel (3 pages)

  8. The last LHC dipole magnet is lowered

    CERN Multimedia

    Claudia Marcelloni

    2007-01-01

    A ceremony is held as the last of 1746 superconducting magnets is lowered into the 27-km circumference tunnel that houses the LHC. The LHC project leader, Lyn Evans, changes a banner reading ‘first magnet for the LHC’ to ‘last magnet for the LHC’ in his native Welsh.

  9. PS, SL and LHC Auditoria change names

    CERN Multimedia

    2003-01-01

    Following the replacement of the PS, SL and LHC Divisions by the AB and AT Divisions, the Auditoria are also changing their names. PS Auditorium is renamed AB Meyrin SL Auditorium is renamed AB Prévessin LHC Auditorium is renamed AT

  10. Prospects on electroweak physics from the LHC

    International Nuclear Information System (INIS)

    Vikas, Pratibha

    2001-01-01

    The abundant production of gauge bosons, gauge boson pairs and top quarks at the LHC will offer the opportunity for comprehensive and challenging tests of theoretical predictions in the electroweak sector. Some issues which influence these measurements followed by prospects on some possible measurements by the ATLAS and CMS experiments at the Large Hadron Collider (LHC), at CERN are discussed. (author)

  11. HL-LHC parameter space and scenarios

    International Nuclear Information System (INIS)

    Bruning, O.S.

    2012-01-01

    The HL-LHC project aims at a total integrated luminosity of approximately 3000 fb -1 over the lifetime of the HL-LHC. Assuming an exploitation period of ca. 10 years this goal implies an annual integrated luminosity of approximately 200 fb -1 to 300 fb -1 per year. This paper looks at potential beam parameters that are compatible with the HL-LHC performance goals and discusses briefly potential variation in the parameter space. It is shown that the design goal of the HL-LHC project can only be achieved with a full upgrade of the injector complex and the operation with β* values close to 0.15 m. Significant margins for leveling can be achieved for β* values close to 0.15 m. However, these margins can only be harvested during the HL-LHC operation if the required leveling techniques have been demonstrated in operation

  12. Helium Inventory Management For LHC Cryogenics

    CERN Document Server

    Pyarali, Maisam

    2017-01-01

    The LHC is a 26.7 km circumference ring lined with superconducting magnets that operate at 1.9 K. These magnets are used to control the trajectory of beams of protons traveling in opposite directions and collide them at various experimental sites across the LHC where their debris is analyzed. The focus of this paper is the cryogenic system that allows the magnets to operate in their superconducting states. It aims to highlight the operating principles of helium refrigeration and liquefaction, with and without nitrogen pre-cooling; discuss the various refrigerators and liquefiers used at CERN for both LHC and Non-LHC applications, with their liquefaction capacities and purposes; and finally to deliberate the management of the LHC inventory and how it contributes to the strategic decision CERN makes regarding the inventory management during the Year-End Technical Stop (YETS), Extended Year-End Technical Stop (EYETS) and long shutdowns.

  13. Looking back over the LHC Project

    CERN Multimedia

    2007-01-01

    Have you always wanted to delve into the history of the phenomenal LHC Project? Well, now you can. A chronological history of the LHC Project is now available on the web. It traces the Project's key milestones, from its first approval in 1994 to the most recent spectacular transport operations for detector components. The photographs used to illustrate these events are linked to the CDS database, allowing visitors who wish to do so the opportunity to download them or to search for photographs associated with subjects that are of interest to them. To explore the history of the LHC Project, go to the CERN Public Welcome page and click on 'LHC Milestones' or simply go directly to the following link: http://cern.ch/LHC-Milestones/

  14. The latest from the LHC

    CERN Multimedia

    2009-01-01

    View of the LHC tunnel after the repairs.Three weeks ago vacuum leaks occurred in both Sector 8-1 and 2-3 (See previous update). While the cause and exact locations of the leaks are still unknown, it is suspected that they occurred in both cases from a flexible hose in the liquid helium transport circuits, which vented helium into the vacuum insulation. In Sector 8-1 the leaks occurred while it was being maintained at 80 K in order to perform the resistance measurements on the copper part of the superconducting busbars. Less than 24 hours later a similar leak occurred in Sector 2-3 while it was being warmed from superconducting temperatures to 80 K to perform the busbar resistance measurement. Both leaks happened where the final magnet of the sector (known as Q7) joins the electrical feedbox (called the DFBA). The end vacuum subsectors – a 200-metre stretch of the LHC sealed off by vacuum barriers – will be warmed to room temp...

  15. The Latest from the LHC

    CERN Multimedia

    In SM18 six magnets have been cold tested with good results. It has also been a good week for cyostating with five more magnets completed. In sector 3-4 interconnection work and welding has started in the area damaged on 19 September last year. Interconnection work is also ongoing on the replacement magnet for the faulty dipole removed from sector 1-2. Three separate teams are now working in the three sectors to install the new DN200 pressure release nozzles. In total 27 magnets have been completed so far, with 34 nozzles welded. A new study is also underway to include a similar pressure release system for both the stand-alone magnets (SAMs) and the triplet magnets. All about Chamonix At the public session of the LHCC (the LHC experiments committee) held Wednesday, 18 February Steve Myers, Director for Accelerators and Technology, reviewed the discussions on the LHC at the Chamonix workshop. He explained the scenarios being studied to implement the machine consolidation measures and resume operation. The ...

  16. Elastic scattering at the LHC

    CERN Document Server

    Kaspar, Jan; Deile, M

    The seemingly simple elastic scattering of protons still presents a challenge for the theory. In this thesis we discuss the elastic scattering from theoretical as well as experimental point of view. In the theory part, we present several models and their predictions for the LHC. We also discuss the Coulomb-hadronic interference, where we present a new eikonal calculation to all orders of alpha, the fine-structure constant. In the experimental part we introduce the TOTEM experiment which is dedicated, among other subjects, to the measurement of the elastic scattering at the LHC. This measurement is performed primarily with the Roman Pot (RP) detectors - movable beam-pipe insertions hundreds of meters from the interaction point, that can detect protons scattered to very small angles. We discuss some aspects of the RP simulation and reconstruction software. A central point is devoted to the techniques of RP alignment - determining the RP sensor positions relative to each other and to the beam. At the end we pres...

  17. Forward Physics at the LHC

    CERN Document Server

    Martin, A D; Khoze, V A

    2009-01-01

    We review two inter-related topics. First, we consider the behaviour of "soft" scattering observables, such as sigma_{tot}, dsigma_{el}/dt, dsigma_{SD}/dtdM^2, particle multiplicities etc., at high-energy proton-(anti)proton colliders. We emphasize the sizeable effects of absorption on high-energy `soft' processes, and, hence, the necessity to include multi-Pomeron-Pomeron interactions in the usual multi-channel eikonal description. We describe a multi-component model which has been tuned to the available data for soft processes in the CERN-ISR to Tevatron energy range, and which therefore allows predictions to be made for `soft' observables at the LHC. The second topic concerns the calculation of the rate of exclusive processes of the form pp --> p+A+p at high energy colliders, where A is a heavy system. In particular, we discuss the survival probability of the rapidity gaps (denoted by the + signs) to both eikonal and enhanced soft rescattering effects. At the LHC energy, the most topical case is when A is ...

  18. LHC Report: A tough restart

    CERN Multimedia

    Jan Uythoven for the LHC team

    2012-01-01

    The third LHC Technical Stop of five days took place in the week of September 17. Getting back to normal operation after a technical stop  can sometimes be difficult, with debugging, testing and requalification required on the systems that have seen interventions. Folding in a selection of other problems can make for a frustrating time.   The new injector magnet is transported to the LHC. Photo: TE/ABT group. The restart experienced over the last days was one of the tougher ones. Many problems occurred, both small and large, one after the other; in the end it took until Sunday afternoon, 9 days after the end of the technical stop, to have a physics fill in the machine that delivered an initial luminosity similar to those before the technical stop. Most problems encountered were, in fact, not related to the technical stop. The technical stop consisted of the usual maintenance and consolidation of the various systems, but two items stand out: the replacement of the mirrors an...

  19. TOTEM, a different LHC experiment

    CERN Multimedia

    CERN. Geneva

    2008-01-01

    TOTEM will pursue a physics program (complementary to that of the other LHC detectors) spanning a wide range from total cross-section and elastic scattering measurements to the study of diffractive and forward phenomena. The TOTEM program will lead to a better understanding of the fundamental aspects of strong interactions. For the first time at hadron colliders, the very forward rapidity range, containing 90% of the energy flow and explored in high-energy cosmic ray experiments, is covered, allowing the search for unusual phenomena hinted at by cosmic ray experiments. The technical implementation of all TOTEM detectors is described. Silicon sensors housed in so-called Roman pots allow measurements of elastic and diffractive protons at distances as small as 1 mm from the beam centre. A scheme to tag events from Double-Pomeron-Exchange by diffractive protons on both sides transforms the LHC into an almost clean “gluon” collider, where the centre-of-mass energy is determined by the momentum losses of the ...

  20. The LHC Lead Injector Chain

    CERN Document Server

    Beuret, A; Blas, A; Burkhardt, H; Carli, Christian; Chanel, M; Fowler, A; Gourber-Pace, M; Hancock, S; Hourican, M; Hill, C E; Jowett, John M; Kahle, K; Küchler, D; Lombardi, A M; Mahner, E; Manglunki, Django; Martini, M; Maury, S; Pedersen, F; Raich, U; Rossi, C; Royer, J P; Schindl, Karlheinz; Scrivens, R; Sermeus, L; Shaposhnikova, Elena; Tranquille, G; Vretenar, Maurizio; Zickler, T

    2004-01-01

    A sizeable part of the LHC physics programme foresees lead-lead collisions with a design luminosity of 1027 cm-2 s-1. This will be achieved after an upgrade of the ion injector chain comprising Linac3, LEIR, PS and SPS machines [1,2]. Each LHC ring will be filled in 10 min by almost 600 bunches, each of 7×107 lead ions. Central to the scheme is the Low Energy Ion Ring (LEIR) [3,4], which transforms long pulses from Linac3 into high-brilliance bunches by means of multi-turn injection, electron cooling and accumulation. Major limitations along the chain, including space charge, intrabeam scattering, vacuum issues and emittance preservation are highlighted. The conversion from LEAR (Low Energy Antiproton Ring) to LEIR involves new magnets and power converters, high-current electron cooling, broadband RF cavities, and a UHV vacuum system with getter (NEG) coatings to achieve a few 10-12 mbar. Major hardware changes in Linac3 and the PS are also covered. An early ion scheme with fewer bunches (but each at nominal...

  1. LHC Report: Positive ion run!

    CERN Multimedia

    Mike Lamont for the LHC Team

    2011-01-01

    The current LHC ion run has been progressing very well. The first fill with 358 bunches per beam - the maximum number for the year - was on Tuesday, 15 November and was followed by an extended period of steady running. The quality of the beam delivered by the heavy-ion injector chain has been excellent, and this is reflected in both the peak and the integrated luminosity.   The peak luminosity in ATLAS reached 5x1026 cm-2s-1, which is a factor of ~16 more than last year's peak of 3x1025 cm-2s-1. The integrated luminosity in each of ALICE, ATLAS and CMS is now around 100 inverse microbarn, already comfortably over the nominal target for the run. The polarity of the ALICE spectrometer and solenoid magnets was reversed on Monday, 28 November with the aim of delivering another sizeable amount of luminosity in this configuration. On the whole, the LHC has been behaving very well recently, ensuring good machine availability. On Monday evening, however, a faulty level sensor in the cooling towe...

  2. LHC Report: plumbing new heights

    CERN Multimedia

    John Jowett for the LHC team

    2015-01-01

    Following the end of the arduous 2015 proton run on 4 November, the many teams working on the LHC and its injector complex are naturally entitled to a calmer period before the well-earned end-of-year break. But that is not the way things work.       The CCC team after stable heavy-ion beams are declared in the LHC. Instead, the subdued frenzy of setting up the accelerators for a physics run has started again, this time for heavy-ion beams, with a few additional twists of the time-pressure knob. In this year’s one-month run, the first week was devoted to colliding protons at 2.51 TeV per beam to provide reference data for the subsequent collisions of lead nuclei (the atomic number of lead is Z=82, compared to Z=1 for protons) at the unprecedented energy of 5.02 TeV in the centre of mass per nucleon pair. The chain of specialised heavy-ion injectors, comprising the ECR ion source, Linac3 and the LEIR ring, with its elaborate bunch-forming and c...

  3. The TOTEM Detector at LHC

    CERN Document Server

    Ruggiero, G; Aspell, P; Atanassov, I; Avati, V; Berardi, V; Berretti, M; Bozzo, M; Brücken, E; Buzzo, A; Cafagna, F; Calicchio, M; Catanesi, M G; Ciocci, M A; Csanád, M; Csörgö, T; Deile, M; Dénes, E; Dimovasili, E; Doubek, M; Eggert, K; Ferro, F; Garcia, F; Giani, S; Greco, V; Grzanka, L; Heino, J; Hilden, T; Janda, M; Kaspar, J; Kopal, J; Kundrát, V; Kurvinen, K; Lami, S; Latino, G; Lauhakangas, R; Lippmaa, E; Lokajícek, M; Lo Vetere, M; Lucas Rodriguez, F; Macrí, M; Magazzù, G; Minutoli, S; Niewiadomski, H; Notarnicola, G; Novak, T; Oliveri, E; Oljemark, F; Orava, R; Oriunno, M; Österberg, K; Palazzi, P; Pedreschi, E; Petäjäjärvi, J; Quinto, M; Radermacher, E; Radicioni, E; Ravotti, F; Robutti, E; Ropelewski, L; Rummel, A; Saarikko, H; Sanguinetti, G; Santroni, A; Scribano, A; Sette, G; Snoeys, W; Spearman, W; Spinella, F; Ster, A; Taylor, C; Trummal, A; Turini, N; Vacek, V; Vitek, M; Whitmore, J; Wu, J

    2010-01-01

    The TOTEM experiment, small in size compared to the others at the LHC, is dedicated to the measurement of the total proton–proton cross-sections with a luminosity-independent method and to the study of elastic and diffractive scattering at the LHC. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the IP5 interaction point, two tracking telescopes, T1 and T2, will be installed on each side in the pseudo-rapidity region between 3.1 and 6.5, and Roman Pot stations will be placed at distances of 147 and 220 m from IP5. The telescope closest to the interaction point (T1, centred at z=9 m) consists of Cathode Strip Chambers (CSC), while the second one (T2, centred at 13.5 m), makes use of Gas Electron Multipliers (GEM). The proton detectors in the Roman Pots are silicon devices designed by TOTEM with the specific objective of reducing down to a few tens of microns the insensitive area at the edge. High efficiency as close as possible to the physical detector boundary is an...

  4. The LHC Computing Grid Project

    CERN Multimedia

    Åkesson, T

    In the last ATLAS eNews I reported on the preparations for the LHC Computing Grid Project (LCGP). Significant LCGP resources were mobilized during the summer, and there have been numerous iterations on the formal paper to put forward to the CERN Council to establish the LCGP. ATLAS, and also the other LHC-experiments, has been very active in this process to maximally influence the outcome. Our main priorities were to ensure that the global aspects are properly taken into account, that the CERN non-member states are also included in the structure, that the experiments are properly involved in the LCGP execution and that the LCGP takes operative responsibility during the data challenges. A Project Launch Board (PLB) was active from the end of July until the 10th of September. It was chaired by Hans Hoffmann and had the IT division leader as secretary. Each experiment had a representative (me for ATLAS), and the large CERN member states were each represented while the smaller were represented as clusters ac...

  5. The LHC taken with philosophy

    CERN Multimedia

    2009-01-01

    "Whether or not scientists at the LHC will find the Higgs boson, they will learn something about the secrets of Nature that will greatly advance human understanding". These are the words of Anthony Grayling, Professor of Philosophy at Birkbeck College, University of London, and presenter of the forthcoming BBC series "Exchanges at the Frontier". He visited CERN to prepare for his next interview with Jim Virdee, CMS Spokesperson.Grayling’s interview with Virdee is part of a series of events at Welcome Trust Collection in London: five of the biggest names in the world of science will discuss the social impact of their discoveries. These events will be broadcast to over 40 million people worldwide in December 2009 by the BBC World Service in the framework of the Exchanges at the Frontier series. Grayling has been following the LHC via the media but his tour of the CMS experiment increased his philosophical awareness of the international cooperation that has enabled it be bu...

  6. The LHC Superconducting RF System

    CERN Document Server

    Boussard, Daniel

    1999-01-01

    The European Laboratory for Particle Physics (CERN), the largest high energy physics laboratory worldwide, is constructing the Large Hadron Collider (LHC) in the existing 27 km circumference LEP (Large Electron Positron) collider tunnel. For the LHC, superconducting cavities, operating at 4.5 K, will provide the required acceleration field for ramping the beam energy up to 7 TeV and for keeping the colliding proton beams tightly bunched. Superconducting cavities were chosen, not only because of their high acceleration field leading to a small contribution to the machine impedance, but also because of their high stored energy which minimises the effects of periodic transient beam loading associated with the high beam intensity (0.5 A). There will be eight single-cell cavities per beam, each delivering 2 MV (5.3 MV/m) at 400 MHz. The cavities themselves are now being manufactured by industrial firms, using niobium on copper technology which gives full satisfaction at LEP. A complete cavity prototype assembly in...

  7. Leading lead through the LHC

    CERN Multimedia

    2011-01-01

    Three of the LHC experiments - ALICE, ATLAS and CMS - will be studying the upcoming heavy-ion collisions. Given the excellent results from the short heavy-ion run last year, expectations have grown even higher in experiment control centres. Here they discuss their plans:   ALICE For the upcoming heavy-ion run, the ALICE physics programme will take advantage of a substantial increase of the LHC luminosity with respect to last year’s heavy-ion run.  The emphasis will be on the acquisition of rarely produced signals by implementing selective triggers. This is a different operation mode to that used during the first low luminosity heavy-ion run in 2010, when only minimum-bias triggered events were collected. In addition, ALICE will benefit from increased acceptance coverage by the electromagnetic calorimeter and the transition radiation detector. In order to double the amount of recorded events, ALICE will exploit the maximum available bandwidth for mass storage at 4 GB/s and t...

  8. The LHC Low Level RF

    CERN Document Server

    Baudrenghien, Philippe; Molendijk, John Cornelis; Olsen, Ragnar; Rohlev, Anton; Rossi, Vittorio; Stellfeld, Donat; Valuch, Daniel; Wehrle, Urs

    2006-01-01

    The LHC RF consists of eight 400 MHz superconducting cavities per ring, with each cavity independently powered by a 300 kW klystron, via a circulator. The challenge for the Low Level is to cope with very high beam current (more than 1 A RF component) and achieve excellent beam lifetime (emittance growth time in excess of 25 hours). Each cavity has an associated Cavity Controller rack consisting of two VME crates which implement high gain RF Feedback, a Tuner Loop with a new algorithm, a Klystron Ripple Loop and a Conditioning system. In addition each ring has a Beam Control system (four VME crates) which includes a Frequency Program, Phase Loop, Radial Loop and Synchronization Loop. A Longitudinal Damper (dipole and quadrupole mode) acting via the 400 MHz cavities is included to reduce emittance blow-up due to filamentation from phase and energy errors at injection. Finally an RF Synchronization system implements the bunch into bucket transfer from the SPS into each LHC ring. When fully installed in 2007, the...

  9. HL-LHC updates in Japan

    CERN Multimedia

    Antonella Del Rosso

    2014-01-01

    At a recent meeting in Japan, updates on the High Luminosity LHC (HL-LHC) project were presented, including the progress made so far and the deadlines still to be met for the upgraded machine to be operational from 2020.   New magnets made with advanced superconductor Nb3Sn in the framework of the HL-LHC project. These magnets are currently under construction at CERN by the TE-MSC group. The LHC is the world’s most powerful particle accelerator, and in 2015 it will reach yet another new record for the energy of its colliding beams. One key factor of its discovery potential is its ability to produce collisions described in mathematical terms by the parameter known as “luminosity”. In 2025, the HL-LHC project will allow the total number of collisions in the LHC to increase by a factor of 10. The first step in this rich upgrade programme is the delivery of the Preliminary Design Report (PDR), which is also a key milestone of the HiLumi LHC Design Study partly fund...

  10. The whole world behind the LHC

    CERN Multimedia

    2001-01-01

    The LHC Board, which includes representatives of the non-Member State organisations directly involved in the construction of the LHC accelerator and representatives of CERN, held its fourth meeting on Monday 21 May 2001. From left to right: 1st row, A. Yamamoto (KEK, Japan), P. Pfund (FNAL, United States), L. Maiani (CERN Director-General), L. Evans (LHC Project Leader), F. Dupont (IN2P3, France), D.D. Bhawalkar (CAT, India) ; 2nd row, P. Brossier (CEA, France), N. Tyurin (IHEP, Russia), A. Skrinsky (BINP, Russia), A. Astbury (TRIUMF, Canada), P. Lebrun (LHC Division Leader, CERN); 3rd row, T. Taylor (Deputy Division Leader LHC Division, CERN), A. Shotter (TRIUMF, Canada), P. Bryant (LHC, CERN), K. Hübner (Director for Accelerators, CERN), J. van der Boon (Director of Administration, CERN). Although Canada, the United States, India, Japan and the Russian Federation are not members of CERN, they are all playing an active part in the construction of the LHC through important technical and financial co...

  11. Warm liquid calorimetry for LHC

    CERN Document Server

    Geulig,E; Wallraff,W; Bézaguet, Alain-Arthur; Cavanna, F; Cinnini, P; Cittolin, Sergio; Dreesen, P; Demoulin, M; Dunps, L; Fucci, A; Gallay, G; Givernaud, Alain; Gonidec, A; Jank, Werner; Maurin, Guy; Placci, Alfredo; Porte, J P; Radermacher, E; Samyn, D; Schinzel, D; Schmidt, W F; CERN. Geneva. Detector Research and Development Committee

    1990-01-01

    Results from the beam tests of the U/TMP "warm liquid" calorimeter show that such a technique is very promising for the LHC. Our aim is to extend this programme and design a calorimeter that can satisfy the requirements of high rates, high radiation levels, compensation, uniformity and granularity, as well as fully contain hadronic showers. We propose to construct liquid ionization chambers operated at very high fields, capable of collecting the total charge produced by ionizing particles within times comparable to the bunch crossing time of the future Collider. For this reason we plan to extend the current programme on tetramethylpentane (TMP) to tetramethylsilane (TMSi). An electromagnetic calorimeter consisting of very high field ionization chambers filled with TMSi as sensitive medium with Uranium and/or other high density material as absorber will first be built (to be followed by a full-scale calorimeter module), on which newly designed fast amplifiers and readout electronics will be tested. In addition...

  12. Small systems at the LHC

    Science.gov (United States)

    Preghenella, Roberto

    2018-02-01

    In these proceedings, I report on a selection of recent LHC results in small systems from ALICE [1], ATLAS [2] and CMS [3] experiments. Due to the fact that the investigation of QCD in small systems at high multiplicity is becoming an increasingly large subject, interesting the heavy-ion community and more in general the high-energy physics community, not all the related topics can be discussed in this paper. The focus will be given to some of the measurements addressing the physics of collective phenomena in small systems and to the recent results on strangeness enhancement in proton-proton collisions. The reader must be informed that a large number of interesting results did not find space in the discussion reported here.

  13. Diffractive processes at the LHC

    CERN Document Server

    Martin, A D; Ryskin, M G

    2009-01-01

    We present a model of high energy soft $pp$ interactions that has multi s- and t-channel components, which has been tuned to describe all the available data. The t-channel components allow matching of the soft to the hard (QCD) Pomeron. Absorptive effects are found to be large, and, for example, suppress the prediction of the total $pp$ cross section to about 90 mb at the LHC. We use the model to calculate the survival probability, S^2, of the rapidity gaps in the exclusive process pp \\to p+H+p, a process with great advantages for searching for the H \\to \\bb signal. We consider both eikonal and enhanced rescattering.

  14. Baryonic Higgs at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Duerr, Michael [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Fileviez Perez, Pavel [Case Western Reserve Univ., Cleveland, OH (United States). CERCA, Physics Dept.; Smirnov, Juri [INFN, Sezione di Firenze (Italy); Florence Univ., Sesto Fiorentino (Italy). Dept. of Physics and Astronomy

    2017-04-15

    We investigate the possible collider signatures of a new Higgs in simple extensions of the Standard Model where baryon number is a local symmetry spontaneously broken at the low scale. We refer to this new Higgs as ''Baryonic Higgs''. This Higgs has peculiar properties since it can decay into all Standard Model particles, the leptophobic gauge boson, and the vector-like quarks present in these theories to ensure anomaly cancellation. We investigate in detail the constraints from the γγ, Zγ, ZZ, and WW searches at the Large Hadron Collider, needed to find a lower bound on the scale at which baryon number is spontaneously broken. The di-photon channel turns out to be a very sensitive probe in the case of small scalar mixing and can severely constrain the baryonic scale. We also study the properties of the leptophobic gauge boson in order to understand the testability of these theories at the LHC.

  15. The TOTEM detector at LHC

    Science.gov (United States)

    Antchev, G.; Aspell, P.; Atanassov, I.; Avati, V.; Berardi, V.; Berretti, M.; Bozzo, M.; Brucken, E.; Buzzo, A.; Cafagna, F.; Calicchio, M.; Catanesi, M. G.; Ciocci, M. A.; Csanád, M.; Csörgő, T.; Deile, M.; Dénes, E.; Dimovasili, E.; Doubek, M.; Eggert, K.; Ferro, F.; Garcia, F.; Giani, S.; Greco, V.; Grzanka, L.; Heino, J.; Hilden, T.; Janda, M.; Kaˇspar, J.; Kopal, J.; Kundrat, V.; Kurvinen, K.; Lami, S.; Latino, G.; Lauhakangas, R.; Lippmaa, E.; Lokajicek, M.; Lo Vetere, M.; Lucas Rodriguez, F.; Macri`, M.; Magazzu`, G.; Minutoli, S.; Niewiadomski, H.; Notarnicola, G.; Novak, T.; Oliveri, E.; Oljemark, F.; Orava, R.; Oriunno, M.; Osterberg, K.; Palazzi, P.; Pedreschi, E.; Petajajarvi, J.; Quinto, M.; Radermacher, E.; Radicioni, E.; Ravotti, F.; Robutti, E.; Ropelewski, L.; Ruggiero, G.; Rummel, A.; Saarikko, H.; Sanguinetti, G.; Santroni, A.; Scribano, A.; Sette, G.; Snoeys, W.; Spearman, W.; Spinella, F.; Ster, A.; Taylor, C.; Trummal, A.; Turini, N.; Vacek, V.; Vitek, M.; Whitmore, J.; Wu, J.

    2010-05-01

    The TOTEM experiment, small in size compared to the others at the LHC, is dedicated to the measurement of the total proton-proton cross-sections with a luminosity-independent method and to the study of elastic and diffractive scattering at the LHC. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the IP5 interaction point, two tracking telescopes, T1 and T2, will be installed on each side in the pseudo-rapidity region between 3.1 and 6.5, and Roman Pot stations will be placed at distances of 147 and 220 m from IP5. The telescope closest to the interaction point (T1, centred at z=9 m) consists of Cathode Strip Chambers (CSC), while the second one (T2, centred at 13.5 m), makes use of Gas Electron Multipliers (GEM). The proton detectors in the Roman Pots are silicon devices designed by TOTEM with the specific objective of reducing down to a few tens of microns the insensitive area at the edge. High efficiency as close as possible to the physical detector boundary is an essential feature. It maximizes the experimental acceptance for protons scattered elastically or interactively at polar angles down to a few micro-radians at IP5. To measure protons at the lowest possible emission angles, special beam optics have been conceived to optimize proton detection in terms of acceptance and resolution. The read-out of all TOTEM subsystems is based on the custom-developed digital VFAT chip with trigger capability.

  16. The TOTEM detector at LHC

    International Nuclear Information System (INIS)

    Antchev, G.; Aspell, P.; Atanassov, I.; Avati, V.; Berardi, V.; Berretti, M.; Bozzo, M.; Brucken, E.; Buzzo, A.; Cafagna, F.; Calicchio, M.; Catanesi, M.G.; Ciocci, M.A.; Csanad, M.; Csoergo, T.; Deile, M.; Denes, E.; Dimovasili, E.; Doubek, M.; Eggert, K.

    2010-01-01

    The TOTEM experiment, small in size compared to the others at the LHC, is dedicated to the measurement of the total proton-proton cross-sections with a luminosity-independent method and to the study of elastic and diffractive scattering at the LHC. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the IP5 interaction point, two tracking telescopes, T1 and T2, will be installed on each side in the pseudo-rapidity region between 3.1 and 6.5, and Roman Pot stations will be placed at distances of 147 and 220 m from IP5. The telescope closest to the interaction point (T1, centred at z=9 m) consists of Cathode Strip Chambers (CSC), while the second one (T2, centred at 13.5 m), makes use of Gas Electron Multipliers (GEM). The proton detectors in the Roman Pots are silicon devices designed by TOTEM with the specific objective of reducing down to a few tens of microns the insensitive area at the edge. High efficiency as close as possible to the physical detector boundary is an essential feature. It maximizes the experimental acceptance for protons scattered elastically or interactively at polar angles down to a few micro-radians at IP5. To measure protons at the lowest possible emission angles, special beam optics have been conceived to optimize proton detection in terms of acceptance and resolution. The read-out of all TOTEM subsystems is based on the custom-developed digital VFAT chip with trigger capability.

  17. The TOTEM detector at LHC

    Energy Technology Data Exchange (ETDEWEB)

    Antchev, G.; Aspell, P.; Atanassov, I. [CERN, CH-1211 Geneva 23 (Switzerland); Avati, V. [CERN, CH-1211 Geneva 23 (Switzerland); Penn State University, Dept. of Physics, University Park, PA (United States); Berardi, V. [INFN Sezione di Bari and Politecnico di Bari, Bari (Italy); Berretti, M. [INFN Sezione di Pisa and Universita di Siena (Italy); Bozzo, M. [Universita di Genova and Sezione INFN, Genova (Italy); Brucken, E. [Helsinki Institute of Physics and Department of Physics, University of Helsinki (Finland); Buzzo, A. [Universita di Genova and Sezione INFN, Genova (Italy); Cafagna, F.; Calicchio, M.; Catanesi, M.G. [INFN Sezione di Bari and Politecnico di Bari, Bari (Italy); Ciocci, M.A. [INFN Sezione di Pisa and Universita di Siena (Italy); Csanad, M.; Csoergo, T. [MTA KFKI RMKI, Budapest (Hungary); Deile, M. [CERN, CH-1211 Geneva 23 (Switzerland); Denes, E. [MTA KFKI RMKI, Budapest (Hungary); Dimovasili, E. [CERN, CH-1211 Geneva 23 (Switzerland); Penn State University, Dept. of Physics, University Park, PA (United States); Doubek, M.; Eggert, K. [Penn State University, Dept. of Physics, University Park, PA (United States)

    2010-05-21

    The TOTEM experiment, small in size compared to the others at the LHC, is dedicated to the measurement of the total proton-proton cross-sections with a luminosity-independent method and to the study of elastic and diffractive scattering at the LHC. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the IP5 interaction point, two tracking telescopes, T1 and T2, will be installed on each side in the pseudo-rapidity region between 3.1 and 6.5, and Roman Pot stations will be placed at distances of 147 and 220 m from IP5. The telescope closest to the interaction point (T1, centred at z=9 m) consists of Cathode Strip Chambers (CSC), while the second one (T2, centred at 13.5 m), makes use of Gas Electron Multipliers (GEM). The proton detectors in the Roman Pots are silicon devices designed by TOTEM with the specific objective of reducing down to a few tens of microns the insensitive area at the edge. High efficiency as close as possible to the physical detector boundary is an essential feature. It maximizes the experimental acceptance for protons scattered elastically or interactively at polar angles down to a few micro-radians at IP5. To measure protons at the lowest possible emission angles, special beam optics have been conceived to optimize proton detection in terms of acceptance and resolution. The read-out of all TOTEM subsystems is based on the custom-developed digital VFAT chip with trigger capability.

  18. Scintillating Fibre Calorimetry at the LHC

    CERN Multimedia

    2002-01-01

    Good electromagnetic and hadronic calorimetry will play a central role in an LHC detector. The lead/scintillating fibre calorimeter technique provides a fast signal response well matched to the LHC rate requirements. It can be made to give equal response for electrons and hadrons (compensation) with good electromagnetic and hadronic energy resolutions.\\\\ \\\\ The aim of this R&D proposal is to study in detail the aspects that are relevant for application of this type of calorimeter in an LHC environment, including its integration in a larger system of detectors, e.g.~projective geometry, radiation hardness, light detection, calibration and stability monitoring, electron/hadron separation.....

  19. Requirements for the LHC collimation system

    CERN Document Server

    Assmann, R W; Brugger, M; Bruno, L; Burkhardt, H; Burtin, G; Dehning, Bernd; Fischer, C; Goddard, B; Gschwendtner, E; Hayes, M; Jeanneret, J B; Jung, R; Kain, V; Kaltchev, D I; Lamont, M; Schmidt, R; Vossenberg, Eugène B; Weisse, E; Wenninger, J

    2002-01-01

    The LHC requires efficient collimation during all phases of the beam cycle. Collimation plays important roles in prevention of magnet quenches from regular beam diffusion, detection of abnormal beam loss and subsequent beam abort, radiation protection, and passive protection of the superconducting magnets in case of failures. The different roles of collimation and the high beam power in the LHC impose many challenges for the design of the collimation system. In particular, the collimators must be able to withstand the expected particle losses. The requirements for the LHC collimation system are presented.

  20. Gravitino LSP scneario at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Heisig, Jan

    2010-06-15

    In this thesis we discuss the phenomenology of the gravitino LSP scenario at the large hadron collider (LHC) experiment. We concentrate on a long-lived stau NLSP which gives rise to a prominent signature in the LHC detector as a 'slow muon'. We discuss the production channels and compute the cross sections for direct production via the Drell-Yan process. On this basis we claim a conservative estimation of the discovery potential for this scenario at the LHC. (orig.)

  1. Plan of SPS to LHC transfer tunnels

    CERN Multimedia

    Laurent Guiraud

    2001-01-01

    This diagram shows the LHC and the SPS pre-accelerator (in blue) and the transfer lines that will connect them (in red). Spanning the France-Swiss border (shown by green crosses), the 27-km LHC tunnel will receive a beam that has been pre-accelerated to 450 GeV in the smaller SPS storage ring. The transfer lines will remove each beam from the SPS and inject them into the LHC where they will be accelerated to the full energy of 7 TeV.

  2. Slice through an LHC bending magnet

    CERN Multimedia

    Slice through an LHC superconducting dipole (bending) magnet. The slice includes a cut through the magnet wiring (niobium titanium), the beampipe and the steel magnet yokes. Particle beams in the Large Hadron Collider (LHC) have the same energy as a high-speed train, squeezed ready for collision into a space narrower than a human hair. Huge forces are needed to control them. Dipole magnets (2 poles) are used to bend the paths of the protons around the 27 km ring. Quadrupole magnets (4 poles) focus the proton beams and squeeze them so that more particles collide when the beams’ paths cross. There are 1232 15m long dipole magnets in the LHC.

  3. Links between astroparticle physics and the LHC

    International Nuclear Information System (INIS)

    Pinfold, James L

    2005-01-01

    Research into the fundamental nature of matter at the high energy frontier takes place in three main areas: accelerator-based particle physics, high energy astrophysics, and the cosmology of the early universe. As a consequence the study of astroparticle physics can have significant implications for collider physics at the LHC. Likewise, the LHC project provides the laboratory to perform measurements of great importance for cosmic ray astrophysics and cosmology. This paper reviews some of the important synergistic links between astroparticle and LHC physics. (topical review)

  4. Particle Physics at the LHC Start

    CERN Document Server

    Altarelli, Guido

    2011-01-01

    I present a concise review of the major issues and challenges in particle physics at the start of the LHC era. After a brief overview of the Standard Model and of QCD, I will focus on the electroweak symmetry breaking problem which plays a central role in particle physics today. The Higgs sector of the minimal Standard Model is so far just a mere conjecture that needs to be verified or discarded by the LHC. Probably the reality is more complicated. I will summarize the motivation for new physics that should accompany or even replace the Higgs discovery and a number of its possible forms that could be revealed by the LHC.

  5. HL-LHC and HE-LHC Upgrade Plans and Opportunities for US Participation

    Science.gov (United States)

    Apollinari, Giorgio

    2017-01-01

    The US HEP community has identified the exploitation of physics opportunities at the High Luminosity-LHC (HL-LHC) as the highest near-term priority. Thanks to multi-year R&D programs, US National Laboratories and Universities have taken the leadership in the development of technical solutions to increase the LHC luminosity, enabling the HL-LHC Project and uniquely positioning this country to make critical contributions to the LHC luminosity upgrade. This talk will describe the shaping of the US Program to contribute in the next decade to HL-LHC through newly developed technologies such as Nb3Sn focusing magnets or superconducting crab cavities. The experience gained through the execution of the HL-LHC Project in the US will constitute a pool of knowledge and capabilities allowing further developments in the future. Opportunities for US participations in proposed hadron colliders, such as a possible High Energy-LHC (HE-LHC), will be described as well.

  6. LHC@home gets new home

    CERN Multimedia

    Oates, John

    2007-01-01

    "The distributed computing project LHC@home is moving to London from Cern in Switzerland. Researchers at Qeen Mary University have been trialling the system since June, but are now ready for the offical launch" (1 page)

  7. Beam-gas Background Observations at LHC

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00214737; The ATLAS collaboration; Alici, Andrea; Lazic, Dragoslav-Laza; Alemany Fernandez, Reyes; Alessio, Federico; Bregliozzi, Giuseppe; Burkhardt, Helmut; Corti, Gloria; Guthoff, Moritz; Manousos, Athanasios; Sjoebaek, Kyrre; D'Auria, Saverio

    2017-01-01

    Observations of beam-induced background at LHC during 2015 and 2016 are presented in this paper. The four LHC experiments use the non-colliding bunches present in the physics-filling pattern of the accelerator to trigger on beam-gas interactions. During luminosity production the LHC experiments record the beam-gas interactions using dedicated background monitors. These data are sent to the LHC control system and are used to monitor the background levels at the experiments during accelerator operation. This is a very important measurement, since poor beam-induced background conditions can seriously affect the performance of the detectors. A summary of the evolution of the background levels during 2015 and 2016 is given in these proceedings.

  8. Japanese contributions to CERN-LHC

    International Nuclear Information System (INIS)

    Kondo, Takahiko; Shintomi, Takakazu; Kimura, Yoshitaka

    2001-01-01

    The Large Hadron Collider (LHC) is now under construction at CERN, Geveva, to study frontier researches of particle physics. The LHC is the biggest superconducting accelerator using the most advanced cryogenics and applied superconductivities. The accelerator and large scale detectors for particle physics experiments are being constructed by collaboration with European countries and also by participation with non-CERN countries worldwide. In 1995, the Japanese government decided to take on a share in the LHC project with funding and technological contributions. KEK contributes to the development of low beta insertion superconducting quadrupole magnets and of components of the ATLAS detector by collaboration with university groups. Some Japanese companies have received contracts for technically key elements such as superconducting cable, cold compressor, nonmagnetic steel, polyimide film, and so on. An outline of the LHC project and Japanese contributions are described. (author)

  9. Superconducting magnet development for the LHC upgrades

    International Nuclear Information System (INIS)

    Rossi, Lucio

    2012-01-01

    LHC is now delivering proton and heavy ion collisions at the highest energy. Upgrading the LHC beyond its design performance is a long term program that started during the LHC construction, with some fundamental R and D programs. The upgrade program is based on a vigorous superconductor and magnet R and D, aimed at increasing the field in accelerator magnets from 8 T to 12 T for the luminosity upgrade, with the scope of increasing the collider luminosity by a factor 5 to 10 from 2022. The upgrade program might continue with the LHC energy upgrade, which would require magnets producing field in the range of 16-20 T. The results obtained so far and the future challenges are discussed together with the possible plan to reach the goals. (author)

  10. Optical fibres bringing the LHC into focus

    CERN Multimedia

    2003-01-01

    New components are being added to CERN's optical fibre network, which will transport the torrents of data produced by the LHC. 1500 kilometres of cables will be installed in the tunnels and at ground level.

  11. LHC: Collisions on course for 2007

    CERN Document Server

    2006-01-01

    In the LHC tunnel and caverns, a particle accelerator and detectors are rapidly taking shape. At last week's Council meeting, delegates took stock of the year's progress towards first collisions in 2007.

  12. Impedance and collective effects in the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Gareyte, J [European Organization for Nuclear Research, Geneva (Switzerland)

    1996-08-01

    After a review of the main LHC parameters, and a brief description of the RF and vacuum systems, the coupling impedances of the main machine elements are given, as well as the resulting thresholds for instabilities. (author)

  13. Collaborators await European approval of LHC

    CERN Multimedia

    Sweet, William N

    1994-01-01

    Physicists are awaiting the authorization of the proposed $2.5 billion European LHC. Germany, France, the UK and Switzerland are still arguing on how much extra contributions host countries should provide for the proton-proton collider's construction.

  14. LHC Interaction Region Upgrade Phase I

    CERN Document Server

    Ostojic, R

    2009-01-01

    The LHC is starting operation with beam in 2008. The primary goal of CERN and the LHC community is to ensure that the collider is operated efficiently, maximizing its physics reach, and to achieve the nominal performance in the shortest term. Since several years the community has been discussing the directions for upgrading the experiments, in particular ATLAS and CMS, the LHC machine and the CERN proton injector complex. A well substantiated and coherent scenario for the first phase of the upgrade, which is foreseen in 2013, is now approved by CERN Council. In this paper, we present the goals and the proposed conceptual solution for the Phase-I upgrade of the LHC interaction regions. This phase relies on the mature Nb-Ti superconducting magnet technology, with the target of increasing the luminosity by a factor of 2-3 with respect to the nominal luminosity of 1034 cm-2s-1, while maximising the use of the existing infrastructure.

  15. Physics motivations for SSC/LHC detectors

    International Nuclear Information System (INIS)

    Hinchliffe, I.

    1993-06-01

    In this talk, I review the some of the physics goals and simulation work done in the SSC and LHC experimental proposal. I select the processes that illustrate the strengths and weaknesses the proposed detectors

  16. Supersymmetry Breaking, Gauge Mediation, and the LHC

    International Nuclear Information System (INIS)

    Shih, David

    2015-01-01

    Gauge mediated SUSY breaking (GMSB) is a promising class of supersymmetric models that automatically satisfies the precision constraints. Prior work of Meade, Seiberg and Shih in 2008 established the full, model-independent parameter space of GMSB, which they called 'General Gauge Mediation' (GGM). During the first half of 2010-2015, Shih and his collaborators thoroughly explored the parameter space of GGM and established many well-motivated benchmark models for use by the experimentalists at the LHC. Through their work, the current constraints on GGM from LEP, the Tevatron and the LHC were fully elucidated, together with the possible collider signatures of GMSB at the LHC. This ensured that the full discovery potential for GGM could be completely realized at the LHC.

  17. Working on an LHC superconducting cavity

    CERN Multimedia

    Laurent Guiraud

    2000-01-01

    The delicate superconducting equipment for CERN’s LHC collider has to be assembled in ultra-clean conditions to safeguard performance. Here we see the power supply being installed on one of the superconducting cavities.

  18. UFOs in the LHC after LS1

    International Nuclear Information System (INIS)

    Baer, T.; Barnes, M.J.; Carlier, E.; Cerutti, F.; Dehning, B.; Ducimetiere, L.; Ferrari, A.; Garrel, N.; Gerardin, A.; Goddard, B.; Holzer, E.B.; Jackson, S.; Jimenez, J.M.; Kain, V.; Lechner, A.; Mertens, V.; Misiowiec, M.; Moron Ballester, R.; Nebot del Busto, E.; Norderhaug Drosdal, L.; Nordt, A.; Uythoven, J.; Velghe, B.; Vlachoudis, V.; Wenninger, J.; Zamantzas, C.; Zimmermann, F.; Fuster Martinez, N.

    2012-01-01

    UFOs (Unidentified Falling Objects) are potentially a major luminosity limitation for nominal LHC operation. With large-scale increases of the BLM thresholds, their impact on LHC availability was mitigated in the second half of 2011. For higher beam energy and lower magnet quench limits, the problem is expected to be considerably worse, though. Therefore, in 2011, the diagnostics for UFO events were significantly improved, dedicated experiments and measurements in the LHC and in the laboratory were made and complemented by FLUKA simulations and theoretical studies. In this paper, the state of knowledge is summarized and extrapolations for LHC operation after LS1 are presented. Mitigation strategies are proposed and related tests and measures for 2012 are specified. (authors)

  19. UFOs in the LHC after LS1

    CERN Document Server

    Baer, T; Carlier, E; Cerutti, F; Dehning, B; Ducimetière, L; Ferrari, A; Garrel, N; Gérardin, A; Goddard, B; Holzer, E B; Jackson, S; Jimenez, J M; Kain, V; Lechner, A; Mertens, V; Misiowiec, M; Morón Ballester, R; Nebot del Busto, E; Norderhaug Drosdal, L; Nordt, A; Uythoven, J; Velghe, B; Vlachoudis, V; Wenninger, J; Zamantzas, C; Zimmermann, F; Fuster Martinez, N

    2012-01-01

    UFOs (Unidentified Falling Objects) are potentially a major luminosity limitation for nominal LHC operation. With large-scale increases of the BLM thresholds, their impact on LHC availability was mitigated in the second half of 2011. For higher beam energy and lower magnet quench limits, the problem is expected to be considerably worse, though. Therefore, in 2011, the diagnostics for UFO events were significantly improved, dedicated experiments and measurements in the LHC and in the laboratory were made and complemented by FLUKA simulations and theoretical studies. In this paper, the state of knowledge is summarized and extrapolations for LHC operation after LS1 are presented. Mitigation strategies are proposed and related tests and measures for 2012 are specified.

  20. Magnet production for the LHC is complete!

    CERN Multimedia

    2006-01-01

    On 27 November, the LHC teams celebrated the end of production of the machine's main magnets. Some 1232 main dipole and 392 main quadrupole magnets have been manufactured in an unprecedented collaboration effort between CERN and European industry.

  1. LHC injection optics measurements at commissioning (2015)

    CERN Document Server

    Garcia-Tabares Valdivieso, Ana; Coello De Portugal - Martinez Vazquez, Jaime Maria; Garcia-Bonilla, Alba-Carolina; Langner, Andy Sven; Maclean, Ewen Hamish; Malina, Lukas; Mcateer, Meghan Jill; Persson, Tobias Hakan Bjorn; Skowronski, Piotr Krzysztof; Tomas Garcia, Rogelio; CERN. Geneva. ATS Department

    2016-01-01

    This report describes the measurement and correction process followed during the 2015 LHC injection optics commissioning which extended into Machine Developments (MDs). Results have been analyzed and compared to the 2012 measurements.

  2. The LHC test string first operational experience

    CERN Document Server

    Bézaguet, Alain-Arthur; Casas-Cubillos, J; Coull, L; Cruikshank, P; Dahlerup-Petersen, K; Faugeras, Paul E; Flemsæter, B; Guinaudeau, H; Hagedorn, Dietrich; Hilbert, B; Krainz, G; Kos, N; Lavielle, D; Lebrun, P; Leo, G; Mathewson, A G; Missiaen, D; Momal, F; Parma, Vittorio; Quesnel, Jean Pierre; Richter, D; Riddone, G; Rijllart, A; Rodríguez-Mateos, F; Rohmig, P; Saban, R I; Schmidt, R; Serio, L; Skiadelli, M; Suraci, A; Tavian, L; Walckiers, L; Wallén, E; Van Weelderen, R; Williams, L; McInturff, A

    1996-01-01

    CERN operates the first version of the LHC Test String which consists of one quadrupole and three 10-m twin aperture dipole magnets. An experimental programme aiming at the validation of the LHC systems started in February 1995. During this programme the string has been powered 100 times 35 of which at 12.4 kA or above. The experiments have yielded a number of results some of which, like quench recovery for cryogenics, have modified the design of subsystems of LHC. Others, like controlled helium leaks in the cold bore and quench propagation bewteen magnets, have given a better understanding on the evolution of the phenomena inside a string of superconducting magnets cooled at superfluid helium temperatures. Following the experimental programme, the string will be powered up and powered down in one hour cycles as a fatigue test of the structure thus simulating 20 years of operation of LHC.

  3. Literature in Focus Perspectives on LHC Physics

    CERN Multimedia

    2008-01-01

    The CERN Library invites you to a book presentation, a Literature in Focus event. The Large Hadron Collider (LHC) will be the world’s largest, highest energy and highest intensity particle accelerator. This is a timely book with several perspectives on the hoped-for discoveries from the LHC. This book provides an overview of the techniques that will be crucial for finding new physics at the LHC, as well as perspectives on the importance and implications of the discoveries. Among the accomplished contributors to this book are leaders and visionaries in the field of particle physics beyond the Standard Model, including two Nobel Laureates (Steven Weinberg and Frank Wilczek). With its blend of popular and technical contents, the book will have wide appeal, not only to physical scientists but also to those in related fields. Perspectives on LHC Physics (World Scientific Publishing) Gordon Kane and Aaron Pierce (eds.) Tuesday 12 August, 4.30pm Council Chamber Refresh...

  4. First beam splashes at the LHC

    CERN Multimedia

    CERN Bulletin

    2015-01-01

    After a two-year shutdown, the first beams of Run 2 circulated in the LHC last Sunday. On Tuesday, the LHC operators performed dedicated runs to allow some of the experiments to record their first signals coming from particles splashed out when the circulating beams hit the collimators. Powerful reconstruction software then transforms the electronic signals into colourful images.     “Splash” events are used by the experiments to test their numerous subdetectors and to synchronise them with the LHC clock. These events are recorded when the path of particles travelling in the LHC vacuum pipe is intentionally obstructed using collimators – one-metre-long graphite or tungsten jaws that are also used to catch particles that wander too far from the beam centre and to protect the accelerator against unavoidable regular and irregular beam losses. The particles sprayed out of the collision between the beam and the collimators are mostly muons. ATLAS and CMS&...

  5. LHC and CLIC LLRF final reports

    CERN Document Server

    Dexter, A; Woolley, B; Ambattu, P; Tahir, I; Syratchev, Igor; Wuensch, Walter

    2013-01-01

    Crab cavities rotate bunches from opposing beams to achieve effective head-on collision in CLIC or collisions at an adjustable angle in LHC. Without crab cavities 90% of achievable luminosity at CLIC would be lost. In the LHC, the crab cavities allow the same or larger integrated luminosity while reducing significantly the requested dynamic range of physics detectors. The focus for CLIC is accurate phase synchronisation of the cavities, adequate damping of wakefields and modest amplitude stability. For the LHC, the main LLRF issues are related to imperfections: beam offsets in cavities, RF noise, measurement noise in feedback loops, failure modes and mitigations. This report develops issues associated with synchronising the CLIC cavities. It defines an RF system and experiments to validate the approach. It reports on the development of hardware for measuring the phase performance of the RF distributions system and cavities. For the LHC, the hardware being very close to the existing LLRF, the report focuses on...

  6. VIP visit of LHC Computing Grid Project

    CERN Multimedia

    Krajewski, Yann Tadeusz

    2015-01-01

    VIP visit of LHC Computing Grid Project with Dr -.Ing. Tarek Kamel [Senior Advisor to the President for Government Engagement, ICANN Geneva Office] and Dr Nigel Hickson [VP, IGO Engagement, ICANN Geneva Office

  7. CERN - the W and the LHC

    CERN Document Server

    Rodgers, P

    2003-01-01

    Construction of the Large Hadron Collider (LHC) and its detectors at the CERN laboratory in Geneva is a challenge of Himalayan proportions. The LHC will collide protons at energies of 14 TeV (14 million million electrons volts) and two detectors - ATLAS and CMS - will survey the debris of these collisions for signs of the Higgs boson, supersymmetric particles, large extra dimensions and other evidence of new physics beyond the Standard Model. (U.K.)

  8. A worker inside the LHC tunnel

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    Technicians and engineers worked days and nights, carefully installing 20 magnets a week between 7 March 2005 and 26 April 2006. Each dipole weighs 34 tonnes and is 15 m long. Once they have been lowered down the specially constructed shaft, they begin a slow progression to their final destinations in the LHC tunnel, taking about 10 hours to arrive at the furthest point on the LHC ring.

  9. Status and prospects from the LHC

    International Nuclear Information System (INIS)

    Hawkings, Richard

    2010-01-01

    This article reviews the status of the CERN Large Hadron Collider and associated experiments as of July 2010. After a brief discussion of the progress in accelerator and experiment commissioning, the LHC physics landscape is presented, together with a selection of the experimental results achieved so far. Finally the prospects for the 2010-11 LHC physics run are reviewed, with an emphasis on possible discoveries in the Higgs and supersymmetry sectors.

  10. The LHC AC Dipole system: an introduction

    CERN Document Server

    Serrano, J; CERN. Geneva. BE Department

    2010-01-01

    The LHC AC Dipole is an instrument to study properties of the LHC lattice by inducing large transverse displacements in the beam. These displacements are generated by exciting the beam with an oscillating magnetic field at a frequency close to the tune. This paper presents the system requirements and the technical solution chosen to meet them, based of high-power audio amplifiers and a resonant parallel RLC circuit.

  11. Loss Control and Collimation for the LHC

    Science.gov (United States)

    Burkhardt, H.

    2005-06-01

    The total energy stored in the LHC is expected to reach 360 Mega Joule, which is about two orders of magnitude higher than in HERA or the Tevatron. Damage and quench protection in the LHC require a highly efficient and at the same time very robust collimation system. The currently planned system, the status of the project and the expected performance of the collimation system from injection up to operation with colliding beams will be presented.

  12. Loss Control and Collimation for the LHC

    International Nuclear Information System (INIS)

    Burkhardt, H.

    2005-01-01

    The total energy stored in the LHC is expected to reach 360 Mega Joule, which is about two orders of magnitude higher than in HERA or the Tevatron. Damage and quench protection in the LHC require a highly efficient and at the same time very robust collimation system. The currently planned system, the status of the project and the expected performance of the collimation system from injection up to operation with colliding beams will be presented

  13. Design of superconducting corrector magnets for LHC

    International Nuclear Information System (INIS)

    Baynham, D.E.; Coombs, R.C.; Ijspeert, A.; Perin, R.

    1994-01-01

    The Large Hadron Collider (LHC) will require a range of superconducting corrector magnets. This paper presents the design of sextupole and decapole corrector coils which will be included as spool pieces adjacent to reach main ring dipole. The paper gives detailed 3D field computations of the coil configurations to meet LHC beam dynamics requirements. Coil protection within a long string environment is addressed and mechanical design outlines are presented

  14. Design of superconducting corrector magnets for LHC

    Science.gov (United States)

    Baynham, D. E.; Coombs, R. C.; Ijspeert, A.; Perin, R.

    1994-07-01

    The Large Hadron Collider (LHC) will require a range of superconducting corrector magnets. This paper presents the design of sextupole and decapole corrector coils which will be included as spool pieces adjacent to each main ring dipole. The paper gives detailed 3D field computations of the coil configurations to meet LHC beam dynamics requirements. Coil protection within a long string environment is addressed and mechanical design outlines are presented.

  15. MICROCOSM - INSTALLATION OF THE LHC MODEL

    CERN Multimedia

    2002-01-01

    This week, installation of a 6m long section of the LHC starts in Microcosm. This full-scale model is the first part of a new exhibition highlighting the technological challenges and the exciting physics of the LHC era. Many people at CERN have helped with the preparations for the model and the Microcosm team would like to thank all those involved. An inauguration for the press will take place at the start of the next school term.

  16. ATLAS and the LHC in the limelight

    CERN Document Server

    Pauline Gagnon

    As we approach the starting time for the LHC, increasing visibility is given in the international press to the LHC in general and ATLAS in particular. We have noted a few of these comprehensive articles last month. Please let us know if you read about ATLAS in your favorite newspaper or magazine. The New York Times article published in the science section on May 15, 2007: Le Temps from Geneva: article published on May 9, 2007

  17. LHC suppliers win Golden Hadron awards

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    In a ceremony on 30 July, three of the 200 suppliers for the Large Hadron Collider (LHC) were presented with Golden Hadron awards. It is the third year that the awards have been presented to suppliers, not only for their technical and financial achievements but also for their compliance with contractual deadlines. This year the three companies are all involved in the supplies for the LHC's main magnet system.

  18. The LHC Transverse Damper (ADT) Performance Specification

    CERN Document Server

    Boussard, Daniel; Linnecar, Trevor Paul R; CERN. Geneva. SPS and LEP Division

    1997-01-01

    The appended document specifies the performance of the transverse damper (ADT) for the LHC. As Annex 1 of the Addendum No.1 to the Protocol of April 18, 1997; it forms part of the 1992 co-operation agreement between CERN and JINR (Dubna, Russia) concerning its participation in the LHC project. The current text is a reprint of the original version. Changes that have been agreed upon are inserted as footnotes.

  19. Delivering LHC software to HPC compute elements

    CERN Document Server

    Blomer, Jakob; Hardi, Nikola; Popescu, Radu

    2017-01-01

    In recent years, there was a growing interest in improving the utilization of supercomputers by running applications of experiments at the Large Hadron Collider (LHC) at CERN when idle cores cannot be assigned to traditional HPC jobs. At the same time, the upcoming LHC machine and detector upgrades will produce some 60 times higher data rates and challenge LHC experiments to use so far untapped compute resources. LHC experiment applications are tailored to run on high-throughput computing resources and they have a different anatomy than HPC applications. LHC applications comprise a core framework that allows hundreds of researchers to plug in their specific algorithms. The software stacks easily accumulate to many gigabytes for a single release. New releases are often produced on a daily basis. To facilitate the distribution of these software stacks to world-wide distributed computing resources, LHC experiments use a purpose-built, global, POSIX file system, the CernVM File System. CernVM-FS pre-processes dat...

  20. Introduction to the HL-LHC Project

    Science.gov (United States)

    Rossi, L.; Brüning, O.

    The Large Hadron Collider (LHC) is one of largest scientific instruments ever built. It has been exploring the new energy frontier since 2010, gathering a global user community of 7,000 scientists. To extend its discovery potential, the LHC will need a major upgrade in the 2020s to increase its luminosity (rate of collisions) by a factor of five beyond its design value and the integrated luminosity by a factor of ten. As a highly complex and optimized machine, such an upgrade of the LHC must be carefully studied and requires about ten years to implement. The novel machine configuration, called High Luminosity LHC (HL-LHC), will rely on a number of key innovative technologies, representing exceptional technological challenges, such as cutting-edge 11-12 tesla superconducting magnets, very compact superconducting cavities for beam rotation with ultra-precise phase control, new technology for beam collimation and 300-meter-long high-power superconducting links with negligible energy dissipation. HL-LHC federates efforts and R&D of a large community in Europe, in the US and in Japan, which will facilitate the implementation of the construction phase as a global project.

  1. Considerations on Energy Frontier Colliders after LHC

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, Vladimir [Fermilab

    2016-11-15

    Since 1960’s, particle colliders have been in the forefront of particle physics, 29 total have been built and operated, 7 are in operation now. At present the near term US, European and international strategies of the particle physics community are centered on full exploitation of the physics potential of the Large Hadron Collider (LHC) through its high-luminosity upgrade (HL-LHC). The future of the world-wide HEP community critically depends on the feasibility of possible post-LHC colliders. The concept of the feasibility is complex and includes at least three factors: feasibility of energy, feasibility of luminosity and feasibility of cost. Here we overview all current options for post-LHC colliders from such perspective (ILC, CLIC, Muon Collider, plasma colliders, CEPC, FCC, HE-LHC) and discuss major challenges and accelerator R&D required to demonstrate feasibility of an energy frontier accelerator facility following the LHC. We conclude by taking a look into ultimate energy reach accelerators based on plasmas and crystals, and discussion on the perspectives for the far future of the accelerator-based particle physics. This paper largely follows previous study [1] and the presenta ion given at the ICHEP’2016 conference in Chicago [2].

  2. Introduction to the HL-LHC Project

    CERN Document Server

    Rossi , L

    2015-01-01

    The Large Hadron Collider (LHC) is one of largest scientific instruments ever built. It has been exploring the new energy frontier since 2010, gathering a global user community of 7,000 scientists. To extend its discovery potential, the LHC will need a major upgrade in the 2020s to increase its luminosity (rate of collisions) by a factor of five beyond its design value and the integrated luminosity by a factor of ten. As a highly complex and optimized machine, such an upgrade of the LHC must be carefully studied and requires about ten years to implement. The novel machine configuration, called High Luminosity LHC (HL-LHC), will rely on a number of key innovative technologies, representing exceptional technological challenges, such as cutting-edge 11–12 tesla superconducting magnets, very compact superconducting cavities for beam rotation with ultra-precise phase control, new technology for beam collimation and 300-meter-long high-power superconducting links with negligible energy dissipation. HL-LHC federa...

  3. 1754 Days to the LHC and counting!

    CERN Multimedia

    2001-01-01

    At the 118th session of CERN Council, held on Friday 15 June under the chairmanship of Professor Maurice Bourquin of Switzerland, Director-General, Luciano Maiani, presented the commissioning schedule for the Large Hadron Collider (LHC) for the first time. The LHC will collide its first beams in a pilot run starting on 1 April 2006. 'We are 1754 days from the LHC', said Professor Maiani. A full seven-month physics run will begin in August 2006, and the LHC's heavy-ion programme will start in February 2007. Left to right: Lyn Evans, Luciano Maiani, Alexander Skrinsky, and Kurt Hubner with the magnets from Novosibirsk. Professor Maiani underlined to Council that the LHC is now CERN's most important single activity, accounting for over 70% of the Laboratory's resources. Moreover, with some 70% of the total LHC cost adjudicated and 30% paid, the project is very far advanced. With the adjudication this Autumn of the contracts for the 1236 fifteen metre superconducting dipole magnets, the placing of major contrac...

  4. From the LHC to Future Colliders

    Energy Technology Data Exchange (ETDEWEB)

    De Roeck, A.; Ellis, J.; /CERN; Grojean, C.; Heinemeyer, S.; /Cantabria Inst. of Phys.; Jakobs, K.; /Freiburg U.; Weiglein, G.; /Durham U., IPPP; Azuelos, G.; /TRIUMF; Dawson, S.; /Brookhaven; Gripaios, B.; /CERN; Han, T.; /Wisconsin U., Madison; Hewett, J.; /SLAC; Lancaster, M.; /University Coll. London; Mariotti, C.; /INFN, Turin; Moortgat, F.; /Zurich, ETH; Moortgat-Pick, G.; /Durham U., IPPP; Polesello, G.; /INFN, Pavia; Riemann, S.; /DESY; Assamagan, K.; /Brookhaven; Bechtle, P.; /DESY; Carena, M.; /Fermilab; Chachamis, G.; /PSI, Villigen /Taiwan, Natl. Taiwan U. /INFN, Florence /Bonn U. /CERN /Bonn U. /Freiburg U. /Oxford U. /Louvain U., CP3 /Bangalore, Indian Inst. Sci. /INFN, Milan Bicocca /Munich, Max Planck Inst. /Taiwan, Natl. Taiwan U. /Frascati /Fermilab /Warsaw U. /Florida U. /Orsay, LAL /LPSC, Grenoble /Warsaw U. /Yale U. /Stockholm U., Math. Dept. /Durham U., IPPP /DESY /Rome U. /University Coll. London /UC, San Diego /Heidelberg U. /Florida State U. /SLAC /Durham U., IPPP /Southern Denmark U., CP3-Origins /McGill U. /Durham U., IPPP; /more authors..

    2010-06-11

    Discoveries at the LHC will soon set the physics agenda for future colliders. This report of a CERN Theory Institute includes the summaries of Working Groups that reviewed the physics goals and prospects of LHC running with 10 to 300 fb{sup -1} of integrated luminosity, of the proposed sLHC luminosity upgrade, of the ILC, of CLIC, of the LHeC and of a muon collider. The four Working Groups considered possible scenarios for the first 10 fb{sup -1} of data at the LHC in which (i) a state with properties that are compatible with a Higgs boson is discovered, (ii) no such state is discovered either because the Higgs properties are such that it is difficult to detect or because no Higgs boson exists, (iii) a missing-energy signal beyond the Standard Model is discovered as in some supersymmetric models, and (iv) some other exotic signature of new physics is discovered. In the contexts of these scenarios, theWorking Groups reviewed the capabilities of the future colliders to study in more detail whatever new physics may be discovered by the LHC. Their reports provide the particle physics community with some tools for reviewing the scientific priorities for future colliders after the LHC produces its first harvest of new physics from multi-TeV collisions.

  5. gigapanorama of NA 62 cavern

    CERN Multimedia

    Brice, Maximilien

    2015-01-01

    The image shows the new rare Kaon decay experiment at CERN, called NA62. The NA62 experiment is 270 metres long and includes a 120-metre-long vacuum tank, shown here, housing several of the particle detectors. (Note: the experiment axis is a straight line, the curving of the tank is an optical effect of the photo.) Kaons are particles that decay into lighter elementary particles. The kaon decay processes are mostly well known, except for some very rare decay modes. For example, NA62 is investigating a rare decay predicted by the Standard Model in which a kaon decays into one pion and two neutrinos. This process occurs only once every 10 billion decays. The understanding of such ultra-rare decays are of great importance because they test the Standard Model in energy ranges not accessible by direct measurements. They are therefore complementary to the measurements at the LHC. ultra high definition on demand (photolab@cern.ch).

  6. LHC Report: playing with angles

    CERN Multimedia

    Mike Lamont for the LHC team

    2016-01-01

    Ready (after a machine development period), steady (running), go (for a special run)!   The crossing angles are an essential feature of the machine set-up. They have to be big enough to reduce the long-range beam-beam effect. The LHC has recently enjoyed a period of steady running and managed to set a new record for “Maximum Stable Luminosity Delivered in 7 days” of 3.29 fb-1 between 29 August and 4 September. The number of bunches per beam remains pegged at 2220 because of the limitations imposed by the SPS beam dump. The bunch population is also somewhat reduced due to outgassing near one of the injection kickers at point 8. Both limitations will be addressed during the year-end technical stop, opening the way for increased performance in 2017. On 10 and 11 September, a two day machine development (MD) period took place. The MD programme included a look at the possibility of reducing the crossing angle at the high-luminosity interaction points. The crossing angles are an ess...

  7. RF Power Generation in LHC

    CERN Document Server

    Brunner, O C; Valuch, D

    2003-01-01

    The counter-rotating proton beams in the Large Hadron Collider (LHC) will be captured and then accelerated to their final energies of 2 x 7 TeV by two identical 400 MHz RF systems. The RF power source required for each beam comprises eight 300 kW klystrons. The output power of each klystron is fed via a circulator and a waveguide line to the input coupler of a single-cell super-conducting (SC) cavity. Four klystrons are powered by a 100 kV, 40A AC/DC power converter, previously used for the operation of the LEP klystrons. A five-gap thyratron crowbar protects the four klystrons in each of these units. The technical specification and measured performance of the various high-power elements are discussed. These include the 400MHz/300kW klystrons with emphasis on their group delay and the three-port circulators, which have to cope with peak reflected power levels up to twice the simultaneously applied incident power of 300 kW. In addition, a novel ferrite loaded waveguide absorber, used as termination for port No...

  8. The LHC injection kicker magnet

    CERN Document Server

    Ducimetière, Laurent; Barnes, M J; Wait, G D

    2003-01-01

    Proton beams will be injected into LHC at 450 GeV by two kicker magnet systems, producing magnetic field pulses of approximately 900 ns rise time and up to 7.86 s flat top duration. One of the stringent design requirements of these systems is a flat top ripple of less than ± 0.5%. Both injection systems are composed of 4 travelling wave kicker magnets of 2.7 m length each, powered by pulse forming networks (PFN's). To achieve the required kick strength of 1.2 Tm, a low characteristic impedance has been chosen and ceramic plate capacitors are used to obtain 5 Omega. Conductive stripes in the aperture of the magnets limit the beam impedance and screen the ferrite. The electrical circuit has been designed with the help of PSpice computer modelling. A full size magnet prototype has been built and tested up to 60 kV with the magnet under ultra high vacuum (UHV). The pulse shape has been precision measured at a voltage of 15 kV. After reviewing the performance requirements the paper presents the magnet...

  9. The LHC, de-squeezed

    CERN Multimedia

    CERN Bulletin

    2012-01-01

    Rare processes like the Higgs production require maximizing the number of proton collisions. This is done by squeezing the beams to very small sizes. However, interesting physics processes also happen when beams are not squeezed at interaction points. Last week, a dedicated run showed that the LHC is a record-breaking machine also with de-squeezed beams.   This figure shows an online hit map of one of the ATLAS/ALFA detectors. The narrow elliptical shape is the typical signal produced by elastically scattered protons. The removal of the background (central bulge) is a challenge for both experiments. The beam squeezing parameter is known by experts as beta-star (ß*): the smaller the ß*, the stronger the squeezing. To obtain as many collisions as possible in the heart of the experiments, the ß* at full energy is 0.60 m – that is, beams are squeezed to very small beam sizes. This maximizes the rate of proton collisions as required for rare process...

  10. LHC Report: reaching high intensity

    CERN Multimedia

    Jan Uythoven

    2015-01-01

    After both beams having been ramped to their full energy of 6.5 TeV, the last two weeks saw the beam commissioning process advancing on many fronts. An important milestone was achieved when operators succeeded in circulating a nominal-intensity bunch. During the operation, some sudden beam losses resulted in beam dumps at top energy, a problem that needed to be understood and resolved.   In 2015 the LHC will be circulating around 2800 bunches in each beam and each bunch will contain just over 1 x 1011 protons. Until a few days ago commissioning was taking place with single bunches of 5 x 109 protons. The first nominal bunch with an intensity of 1 x 1011 protons was injected on Tuesday, 21 April. In order to circulate such a high-intensity bunch safely, the whole protection system must be working correctly: collimators, which protect the aperture, are set at preliminary values known as coarse settings; all kicker magnets for injecting and extracting the beams are commissioned with beam an...

  11. The latest from the LHC

    CERN Multimedia

    2009-01-01

    The consolidation campaign, managed by the Quench Protection team, is advancing well. Phase 1 of the campaign is focused on the new protection system designed to monitor the superconducting busbars. This system will be able to detect tiny electrical resistances on these busbars, similar to the one that caused the incident in Sector 3-4. Following completion of the design of the two principal electronics boards, the first order for 2500 and 500 such boards will be placed this week. The manufacture of the cable segments for the first three LHC sectors is going ahead, and the installation programme has already begun in Sector 4-5. In total, more than 230 km of various types of cables will have to be laid. The complete system will consist of a network of 2132 detectors housed in 436 crates around the machine. These will monitor the interconnections of the main dipoles and quadrupoles in the three major circuits. The detectors will precisely measure the electrical resistance of each busbar segment, including the ...

  12. LHC rap: a global phenomenon

    CERN Multimedia

    2008-01-01

    Do you think the LHC is super duper fly? Does it make you want to compose some slick rhymes and bust out some killer beats? It did for one CERN rapper, and the results have become a YouTube smash hit! Katie McAlpine will sing for the CMS party on 24 September, and for the ATLAS Fest on 4 October.The Large Hadron Rap, to give it its full name, is the brainchild of AlpineKat, AKA Katie McAlpine, who is currently working for ATLAS e-News and outreach. To date, the YouTube video rap has been viewed more than 2.5 million times, to say nothing of the media coverage. Featured in newspapers around the world, including the New York Times in the US, The Telegraph in the UK and Geneva’s very own Matin Bleu, the rap is officially a sensation! Katie wrote the inspired (and pretty accurate) physics lyrics during her commute on the number 56 bus between Geneva and CERN. After obtaining permission to film in the experiment caverns and tunnel,...

  13. Powering CERN and the LHC

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    CERN's electricity network is denser than that of the Canton of Geneva, is powered by two different national grids and has to provide users with an availability rate as close to 100% as possible. To ensure the smooth running of the machines throughout the period of LHC physics operation, the teams from the EN Department are implementing a continuous programme of consolidation and modernisation on all the Laboratory's sites, but the biggest projects will have to wait until the long technical shutdown scheduled for 2013.   An electrical installation at CERN. CERN's annual electricity consumption is around one terawatt hour (TWh), which roughly corresponds to a fifth of the consumption of the Canton of Geneva. However, during periods when all the machines are operating at the same time, our demand can reach the equivalent of a third of Geneva's total consumption. While the grid of the Geneva public utility company SIG (Services Industriels de Genève) covers distances of around 50 km, the ...

  14. LHC Report: First collisions soon

    CERN Multimedia

    Jan Uythoven for the LHC team

    2012-01-01

    On the evening of Friday 16 March beams were accelerated in the LHC at 4 TeV for the first time: a new world record! According to the schedule for the machine restart it will take another three weeks before the stable beams mode – the requirement for the detectors to start taking data – is achieved.   During the beam commissioning period the equipment teams make sure that their systems – beam instrumentation, radio frequency, beam interlock, feedback on orbit and tune, etc. – are working flawlessly with beam. Confidence in the correct functioning of all the magnets, their settings and their alignment is obtained by detailed measurements of the optics and the physical aperture. The optics measurements include the beta* of the squeezed beam at the centre of the experiments where the collisions will soon take place. This year the aim is to have a smaller beta* of 60 cm for the ATLAS and CMS experiments. As a reminder, smaller values of beta* mean thinner and m...

  15. The latest from the LHC

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    The setting-up to prepare the LHC for running with nominal ramp rates and with bunch trains instead of single-bunch injection have continued over the last two weeks. The goal is to reduce the machine filling time and increase its luminosity. Running with bunch trains requires the careful setting-up of crossing angles in order to avoid unwanted collisions on either side of the experiments.   The technical target for 2010 in terms of bunch spacing in the trains is 150 ns, which corresponds to a physical distance of about 45 m. This target will be progressively reduced next year to eventually attain the nominal value of 25 ns, equivalent to a distance of about 7.5 m between two bunches in the trains. Following initial setting-up last week, this week tests were made to check the size of the crossing angle needed to avoid parasitic collisions when 150 ns trains are injected into the machine, and to measure the aperture with the nominal crossing angle –at injection – of 170 micro radi...

  16. LHC Report: Restart preparations continue

    CERN Multimedia

    Katy Foraz for the LHC team and Julia Trummer for the RP Group

    2012-01-01

    Maintenance and consolidation work has been progressing well in both the machine and the experiments in preparation for the March restart.   A sample material is attached to the LHC (the white bag taped to the green line), to measure the radiation doses. Additional work was required around Point 5 due to the discovery and repair of a problem with the RF fingers at the connection of two beam vacuum chambers in CMS. The repair has been completed successfully and the sector is now under vacuum. In order to avoid rushing the delicate final operations required for closing the detector, the restart of the machine has been postponed by one week, from 7 March to 14 March. In the machine, the first cool-down to 1.9 K has started in several sectors ,and the cool-down of the whole machine is still planned to be finished by 21 February. The time window between 22 February and 14 March will be dedicated to powering and cryogenic tests. Since 12 December, the Radiation Protection (RP) group has been deep...

  17. Composite Leptoquarks at the LHC

    CERN Document Server

    Gripaios, Ben

    2010-01-01

    If electroweak symmetry breaking arises via strongly-coupled physics, the observed suppression of flavour-changing processes suggests that fermion masses should arise via mixing of elementary fermions with composite fermions of the strong sector. The strong sector then carries colour charge, and may contain composite leptoquark states, arising either as TeV scale resonances, or even as light, pseudo-Nambu-Goldstone bosons. The latter, since they are coupled to colour, get a mass of the order of several hundred GeV, beyond the reach of current searches at the Tevatron. The same generic mechanism that suppresses flavour-changing processes suppresses leptoquark-mediated rare processes, making it conceivable that the many stringent constraints may be evaded. The leptoquarks couple predominantly to third-generation quarks and leptons, and the prospects for discovery at LHC appear to be good. As an illustration, a model based on the Pati-Salam symmetry is described, and its embedding in models with a larger symmetr...

  18. Latest news from the LHC

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Over the past two weeks the LHC operations team has focused on pushing the LHC’s performance into new territory in terms of stored beam power. Moving to 25 bunches per beam with almost nominal bunch intensities at the end of July implied operation with a stored energy in each beam of more than 1 MJ. This corresponds to the current record for stored beam energy in existing hadron accelerators (e.g. CERN’s SPS and Fermilab’s Tevatron) and it marks an energy regime where a sudden loss of beam or operational errors can result in serious damage to equipment: an energy of 1 MJ is sufficient to melt 2 kg of copper. Extreme care and a thorough optimization of all operational procedures are therefore required in making this important transition in the machine’s performance.   The focus of the past two weeks has been on optimizing the operational procedures and the machine protection systems, with the aim of gaining experience with the reliability and reproducibility of...

  19. LHC Report: Freshly squeezed beams!

    CERN Multimedia

    Mike Lamont for the LHC Team

    2011-01-01

    After careful validation of  new machine settings, the LHC was ready for higher luminosity operation. New luminosity records have been set, but the operations team continues to wrestle with machine availability issues.   The commissioning of the squeeze to a ß* of 1 m in ATLAS and CMS described in the last Bulletin took until Wednesday, 7 September to complete. In order to validate the new set-up, beam losses were provoked in a controlled way with low intensity beams. The distribution of beam loss around the machine in these tests is known as a loss map. The loss maps showed that the collimation system is catching the large majority of beam losses as it should, and that the machine was ready for us to ramp the number of bunches back up and go to physics production. The ramp-up of the number of bunches went smoothly with fills at 264, 480, and 912 bunches on the way back to the machine’s previous record of 1380 bunches (first fill on Friday, 9 Se...

  20. LHC Report: 2 inverse femtobarns!

    CERN Multimedia

    Mike Lamont for the LHC Team

    2011-01-01

    The LHC is enjoying a confluence of twos. This morning (Friday 5 August) we passed 2 inverse femtobarns delivered in 2011; the peak luminosity is now just over 2 x1033 cm-2s-1; and recently fill 2000 was in for nearly 22 hours and delivered around 90 inverse picobarns, almost twice 2010's total.   In order to increase the luminosity we can increase of number of bunches, increase the number of particles per bunch, or decrease the transverse beam size at the interaction point. The beam size can be tackled in two ways: either reduce the size of the injected bunches or squeeze harder with the quadrupole magnets situated on either side of the experiments. Having increased the number of bunches to 1380, the maximum possible with a 50 ns bunch spacing, a one day meeting in Crozet decided to explore the other possibilities. The size of the beams coming from the injectors has been reduced to the minimum possible. This has brought an increase in the peak luminosity of about 50% and the 2 x 1033 cm...

  1. LHC Report: Ions cross protons

    CERN Multimedia

    Reyes Alemany Fernandez for the LHC team

    2013-01-01

    The LHC starts the New Year facing a new challenge: proton-lead collisions in the last month before the shutdown in mid-February.    The first stable beams were achieved on 20 January with 13 individual bunches per beam. In the next fill, the first bunch-trains were injected and stable beams were achieved with 96 proton on 120 ion bunches.  This fill was very important because we were able to study the so-called moving long-range beam-beam encounters. Long-range encounters, which are also seen in proton-proton runs, occur when the bunches in the two beams “see” each other as they travel in the same vacuum chamber at either side of the experiments.  The situation becomes more complicated with proton-lead ions because the two species have different revolution times (until the frequencies are locked at top energy- see “Cogging exercises”) and thus these encounters move. We found that this effect does not cause significant beam losses...

  2. The latest from the LHC

    CERN Multimedia

    Mathew Stracy

    As promised by the Director-General, we will start a series of regular updates detailing the status of the LHC repairs, consolidation and commissioning.As of last week all magnets in the damaged area of sector 3-4 have been removed and raised to the surface. In total 39 dipoles and 14 short straight sections are now on the surface. Four replacement magnets have been lowered and installed, and by the end of this week this figure should total seven. Cold testing replacement magnets in SM18 has resumed after the Christmas shutdown. The civil engineering work to repair the slight damage to the concrete has been completed. Outside the damaged area the Vacuum Group are cleaning some of the beam screens in situ.Both sector 1-2 and sector 5-6 are also now at room temperature and accessible. As well as routine maintenance in these sectors, one magnet from sector 1-2 which was found to have high resistance (approximately 100 nano-ohms, two orders of magnitude higher than the specified resistance) has been removed and ...

  3. The latest from the LHC

    CERN Document Server

    2009-01-01

    On 26 August, the first two fully tested crates for the new quench protection system (QPS) were installed in Sector 1-2. These are the first of 436 crates that will be installed around the ring. The two crates include detectors for both the enhanced busbar protection and the symmetric quench protection (more details). To test the crates before installation, a dedicated test bed has been created, capable of simulating all the conditions in the LHC, from a symmetric quench to an increase in busbar resistance. The teams are working two shifts a day, including weekends, to test the new crates. Two more test benches are also being built to increase the production rate. The whole task is on target for completion in mid October. Another important new task for the QPS team is to try and speed up the energy extraction from the magnets. The quicker the energy can be extracted the lower the risk of dangerously high temperatures should a quench occur. The time constant for the dipoles...

  4. The TOTEM Detector at LHC

    CERN Document Server

    Ruggiero, G; Aspell, P; Atanassov, I; Avati, V; Berardi, V; Berretti, M; Bozzo, M; Brücken, E; Buzzo, A; Cafagna, F; Calicchio, M; Catanesi, M G; Ciocci, M A; Csanád, M; Csörgö, T; Deile, M; Dénes, E; Dimovasili, E; Doubek, M; Eggert, K; Ferro, F; Garcia, F; Giani, S; Greco, V; Grzanka, L; Heino, J; Hilden, T; Janda, M; Kaspar, J; Kopal, J; Kundrát, V; Kurvinen, K; Lami, S; Latino, G; Lauhakangas, R; Lippmaa, E; Lokajícek, M; Lo Vetere, M; Lucas Rodriguez, F; Macrí, M; Magazzù, G; Minutoli, S; Niewiadomski, H; Notarnicola, G; Novak, T; Oliveri, E; Oljemark, F; Orava, R; Oriunno, M; Österberg, K; Pedreschi, E; Petäjäjärvi, J; Quinto, M; Radermacher, E; Radicioni, E; Ravotti, F; Robutti, E; Ropelewski, L; Rummel, A; Saarikko, H; Sanguinetti, G; Santroni, A; Scribano, A; Sette, G; Snoeys, W; Spearman, W; Spinella, F; Ster, A; Taylor, C; Trummal, A; Turini, N; Vacek, V; Vitek, M; Whitmore, J; Wu, J

    2010-01-01

    The TOTEM experiment, small in size compared to the others at the LHC, is dedicated to the measurement of the total proton-proton cross-section with the luminosity-independent method and to the study of elastic and diffractive scattering. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the interaction point IP5, two tracking telescopes, T1 and T2, are installed on each side in the pseudo-rapidity region between 3.1 and 6.5, and Roman Pot (RP) stations are placed at distances of 147m and 220m from IP5. The telescope closest to the interaction point (T1, centered at z = 9 m) consists of Cathode Strip Chambers (CSC), while the second one (T2, centered at 13.5 m), makes use of Gas Electron Multipliers (GEM). The proton detectors in the RPs are silicon devices designed by TOTEM with the specific objective of reducing down to a few tens of microns the insensitive area at the edge. High efficiency as close as possible to the physical detector boundary is an essential feature...

  5. The latest from the LHC

    CERN Multimedia

    2009-01-01

    The LHC will run with an energy of 3.5 TeV per beam when it starts up in November this year. The 80 K resistance measurements on the copper stabilizer of the superconducting busbars were completed in the remaining sectors, Sectors 8-1 and 2-3. No abnormally high resistance measurements were found, indicating that no further repairs are necessary for safe running. Detailed analysis of the resistance data from the entire ring determined a safe initial energy of 3.5 TeV per beam. Once a significant data sample has been collected and the operations team has gained experience in running the machine, the energy will be taken towards 5 TeV per beam. More information is available in the recent press release http://press.web.cern.ch/press/PressReleases/Releases2009/PR13.09E.html. Following the helium leaks into the insulation vacuum in Sectors 2-3 and 8-1 (see previous update) the cause of the leak in Sector 2-3 has been confirmed as the flexible hose. This has now been replaced...

  6. MSSM Forecast for the LHC

    CERN Document Server

    Cabrera, Maria Eugenia; de Austri, Roberto Ruiz

    2009-01-01

    We perform a forecast of the MSSM with universal soft terms (CMSSM) for the LHC, based on an improved Bayesian analysis. We do not incorporate ad hoc measures of the fine-tuning to penalize unnatural possibilities: such penalization arises from the Bayesian analysis itself when the experimental value of $M_Z$ is considered. This allows to scan the whole parameter space, allowing arbitrarily large soft terms. Still the low-energy region is statistically favoured (even before including dark matter or g-2 constraints). Contrary to other studies, the results are almost unaffected by changing the upper limits taken for the soft terms. The results are also remarkable stable when using flat or logarithmic priors, a fact that arises from the larger statistical weight of the low-energy region in both cases. Then we incorporate all the important experimental constrains to the analysis, obtaining a map of the probability density of the MSSM parameter space, i.e. the forecast of the MSSM. Since not all the experimental i...

  7. LHC Report: a Roman potpourri

    CERN Multimedia

    Mike Lamont for the LHC Team

    2012-01-01

    The last couple of weeks of operation have been a mixed bag, with time dedicated to TOTEM and ALFA, a floating machine development period and luminosity calibration runs. These special running periods were interleaved with some standard proton running where we’ve struggled a little to recover previous highs. The LHC has now returned to more routine operation.   The TOTEM and ALFA run required the development of special optics to produce large beam sizes and smaller angular spread at the interaction points in ATLAS and CMS. These special optics produce shallower angled proton-proton collisions than normal and thus allow experiments to probe the very small angle scattering regime. (For more information visit the TOTEM and ALFA websites.) The qualification of the new set-up at 4 TeV went well, paving the way for a 13-hour physics run for both TOTEM and ALFA with their Roman pots in position. Highlights from the 48-hour machine development period included the injection of high intensity bun...

  8. LHC Report: Omnium-gatherum

    CERN Multimedia

    Mike Lamont for the LHC team

    2012-01-01

    The last couple of weeks have seen a mixed bag of special runs, luminosity production, machine development and down-time.   Van der Meer scans were performed for ATLAS, CMS and ALICE. These scans step the beams transversely across each other and aim at a measurement of the absolute luminosity. A precise determination of the luminosity uncertainty is beneficial for many physics analyses and, indeed, measurements of important physics processes (such as top quark pair production) can be limited by luminosity errors. The scans were ultimately successful but the set-up and execution were affected by a number of technical problems. One of the main down-times was due to the replacement of an SPS dipole magnet which had developed a vacuum leak. A SPS magnet exchange is a well-practiced intervention. In this case, the whole exercise, including the pump down of the vacuum, took around 24 hours. There were also re-occuring problems with the fast switches of the SPS beam dump system. The LHC, as always, dep...

  9. The LHC Tier1 at PIC: Experience from first LHC run

    International Nuclear Information System (INIS)

    Flix, J.; Perez-Calero Yzquierdo, A.; Accion, E.; Acin, V.; Acosta, C.; Bernabeu, G.; Bria, A.; Casals, J.; Caubet, M.; Cruz, R.; Delfino, M.; Espinal, X.; Lanciotti, E.; Lopez, F.; Martinez, F.; Mendez, V.; Merino, G.; Pacheco, A.; Planas, E.; Porto, M. C.; Rodriguez, B.; Sedov, A.

    2013-01-01

    This paper summarizes the operational experience of the Tier1 computer center at Port d'Informacio Cientifica (PIC) supporting the commissioning and first run (Run1) of the Large Hadron Collider (LHC). The evolution of the experiment computing models resulting from the higher amounts of data expected after there start of the LHC are also described. (authors)

  10. Mark the date! LHC inauguration and LHC-Fest CERN, Tuesday 21 October 2008

    CERN Document Server

    2008-01-01

    "For a long time we will remember the year 2008, an important year for CERN. as it marks the achievement of the LHC, a great tool for future discoveries, and the completion of exceptional works that demanded the commitment and motivation of many… a remarkable motivation," declared Director-General Robert Aymar during a recent interview. To celebrate this historical milestone in this very important "Big Science" project, CERN has organised two events on October 21: the LHC official inauguration and the LHC-fest. The LHC official inauguration will take place from 14h00 to 18h00, at Point 18 of the Laboratory, in the presence of the highest representatives from the member states of CERN and representatives from the other communities and authorities of the countries participating in the LHC adventure. 300 members from the international press are also expected, giving a total of 1500 guests. The ceremony will be broadcast live in the Lab...

  11. Energy Deposition in Adjacent LHC Superconducting Magnets from Beam Loss at LHC Transfer Line Collimators

    CERN Document Server

    Beavan, S; Kain, V

    2006-01-01

    Injection intensities for the LHC are over an order of magnitude above the damage threshold. The collimation system in the two transfer lines is designed to dilute the beam sufficiently to avoid damage in case of accidental beam loss or mis-steered beam. To maximise the protection for the LHC most of the collimators are located in the last 300 m upstream of the injection point where the transfer lines approach the LHC machine. To study the issue of possible quenches following beam loss at the collimators part of the collimation section in one of the lines, TI 8, together with the adjacent part of the LHC has been modeled in FLUKA. The simulated energy deposition in the LHC for worst-case accidental losses and as well as for losses expected during a normal filling is presented.

  12. HL-LHC kicker magnet (MKI)

    CERN Multimedia

    Brice, Maximilien

    2018-01-01

    HL-LHC kicker magnet (MKI): last vacuum test, preparation for transport to LHC transfer line in underground tunnel.The LHC injection kicker systems (MKIs) generate fast field pulses to inject the clockwise rotating beam at Point 2 and the anti-clockwise rotating beam at Point 8: there are eight MKI magnets installed in total. Each MKI magnet contains a high purity alumina tube: if an MKI magnet is replaced this tube requires conditioning with LHC beam: until it is properly conditioned, there can be high vacuum pressure due to the beam. This high pressure can also cause electrical breakdowns in the MKI magnets. A special coating (Cr2O3) has been applied to the inside of the alumina tube of an upgraded MKI magnet – this is expected to greatly reduce the pressure rise with beam. In addition, HL-LHC beam would result in excessive heating of the MKI magnets: the upgraded design includes modifications that will reduce heating, and move the power deposition to parts that will be easier to cool. Experience during 2...

  13. Academic Training: The LHC machine /experiment interface

    CERN Multimedia

    Françoise Benz

    2005-01-01

    2004-2005 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 18, 19, 20, 21 & 22 April from 11.00 to 12.00 hrs - Main Auditorium, bldg. 500 The LHC machine /experiment interface S. TAPPROGGE, Univ. of Mainz, D, R. ASSMANN, CERN-AB E. TSESMELIS and D. MACINA, CERN-TS This series of lectures will cover some of the major issues at the boundary between the LHC machine and the experiments: 1) The physics motivation and expectations of the experiments regarding the machine operation. This will include an overview of the LHC physics programme (in pp and PbPb collisions), of the experimental signatures (from high pT objects to leading nucleons) and of the expected trigger rates as well as the data sets needed for specific measurements. Furthermore, issues related to various modes of operation of the machine (e.g. bunch spacings of 25 ns. vs. 75 ns.) and special requirements of the detectors for their commissioning will be described. 2) The LHC machine aspects: introduction of the main LHC parameters and discu...

  14. Performance of the LHC Pre-Injectors

    CERN Document Server

    Benedikt, Michael; Chanel, M; Garoby, R; Giovannozzi, Massimo; Hancock, S; Martini, M; Métral, Elias; Métral, G; Schindl, Karlheinz; Vallet, J L

    2001-01-01

    The LHC pre-injector complex, comprising Linac 2, the PS Booster (PSB) and the PS, has undergone a major upgrade in order to meet the very stringent requirements of the LHC. Whereas bunches with the nominal spacing and transverse beam brightness were already available from the PS in 1999 [1], their length proved to be outside tolerance due to a debunching procedure plagued by microwave instabilities. An alternative scenario was then proposed, based on a series of bunch-splitting steps in the PS. The entire process has recently been implemented successfully, and beams whose longitudinal characteristics are safely inside LHC specifications are now routinely available. Variants of the method also enable bunch trains with gaps of different lengths to be generated. These are of interest for the study and possible cure of electron cloud effects in both the SPS and LHC. The paper summarizes the beam dynamics issues that had to be addressed to produce beams with all the requisite qualities for the LHC.

  15. High Luminosity LHC: challenges and plans

    Science.gov (United States)

    Arduini, G.; Barranco, J.; Bertarelli, A.; Biancacci, N.; Bruce, R.; Brüning, O.; Buffat, X.; Cai, Y.; Carver, L. R.; Fartoukh, S.; Giovannozzi, M.; Iadarola, G.; Li, K.; Lechner, A.; Medina Medrano, L.; Métral, E.; Nosochkov, Y.; Papaphilippou, Y.; Pellegrini, D.; Pieloni, T.; Qiang, J.; Redaelli, S.; Romano, A.; Rossi, L.; Rumolo, G.; Salvant, B.; Schenk, M.; Tambasco, C.; Tomás, R.; Valishev, S.; Van der Veken, F. F.

    2016-12-01

    The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will undergo a major upgrade in the 2020s. This will increase its rate of collisions by a factor of five beyond the original design value and the integrated luminosity by a factor ten. The new configuration, known as High Luminosity LHC (HL-LHC), will rely on a number of key innovations that push accelerator technology beyond its present limits. Among these are cutting-edge 11-12 T superconducting magnets, including Nb3Sn-based magnets never used in accelerators before, compact superconducting cavities for longitudinal beam rotation, new technology and physical processes for beam collimation. The dynamics of the HL-LHC beams will be also particularly challenging and this aspect is the main focus of this paper.

  16. Particles are back in the LHC

    CERN Multimedia

    CERN Bulletin

    2016-01-01

    The LHC has introduced beam for the first time since the year-end technical stop began in December 2015.   CERN Management and LHC operators applaud as the first beam circulates in the LHC, on Friday 25 March.   On Friday, the LHC opened its doors to allow particles to travel around the ring for the first time since the year-end technical stop (YETS) began in December 2015. At 10:30 a.m., a first bunch was circulating and by midday the beam was circulating in both directions. Progress over the weekend has been good and low intensity beam has already been taken to 6.5 TeV and through the squeeze. Last week, the LHC underwent the final phase of preparation before beam -known as the machine checkout. During this phase all the systems of the LHC are put through their paces without beam. A key part of the process is driving the magnetic circuits, radiofrequency accelerating cavities, collimators, transverse dampers etc. repeatedly through the nominal LHC cycle. A fu...

  17. The first LHC sector is fully interconnected

    CERN Multimedia

    2006-01-01

    Sector 7-8 is the first sector of the LHC to become fully operational. All the magnets, cryogenic line, vacuum chambers and services are interconnected. The cool down of this sector can soon commence. LHC project leader Lyn Evans, the teams from CERN's AT/MCS, AT/VAC and AT/MEL groups, and the members of the IEG consortium celebrate the completion of the first LHC sector. The 10th of November was a red letter day for the LHC accelerator teams, marking the completion of the first sector of the machine. The magnets of sector 7-8, together with the cryogenic line, the vacuum chambers and the distribution feedboxes (DFBs) are now all completely interconnected. Sector 7-8 has thus been closed and is the first LHC sector to become operational. The interconnection work required several thousand electrical, cryogenic and insulating connections to be made on the 210 interfaces between the magnets in the arc, the 30 interfaces between the special magnets and the interfaces with the cryogenic line. 'This represent...

  18. Snapshots to shed light on LHC performance

    CERN Multimedia

    2006-01-01

    With the impressive size and unprecedented power of the LHC, it is all too easy to overlook the smaller devices that have the difficult task of monitoring the new accelerator. You don't have to stand too far back from the big picture to see examples of clever technology inside the LHC. One of the undulators installed in the LHC tunnel can be seen on the right of the photo. From right to left, back row: Lucio Rossi (group leader, MCS), Davide Tommasini (conceptual design, MCS), Thierry Tenaglia (integration design,TS-MME), Remo Maccaferri (project leader, MCS) and Hans Kummer (MCS/ME); front row: Gilles Trachez (MCS-ME) and Bruno Meunier (FSU-AT12). In contrast to the usual articles about the LHC's big number statistics, examples of clever problem-solving found in beam monitoring machinery show that smaller things can be beautiful too. The design of the LHC accelerator brought new challenges for monitoring the shape of the particle beam, known as the beam profile. The size of the beam shrinks as higher energi...

  19. LHC Highlights, from dream to reality

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    The idea of the Large Hadron Collider (LHC) was born in the early 1980s. Although LEP (CERN’s previous large accelerator) was still under construction at that time, scientists were already starting to think about re-using the 27-kilometre ring for an even more powerful machine. Turning this ambitious scientific plan into reality proved to be an immensely complex task. Civil engineering work, state-of-the-art technologies, a new approach to data storage and analysis: many people worked hard for many years to accomplish all this.   Here are some of the highlights: 1984. A symposium organized in Lausanne, Switzerland, is the official starting point for the LHC. LHC prototype of the two beam pipes (1992). 1989. The first embryonic collaborations begin. 1992. A meeting in Evian, France, marks the beginning of the LHC experiments. 1994. The CERN Council approves the construction of the LHC accelerator. 1995. Japan becomes an Observer of CERN and announces a financial contribution to ...

  20. Academic Training: The LHC machine /experiment interface

    CERN Multimedia

    Françoise Benz

    2005-01-01

    2004-2005 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 18, 19, 20, 21 & 22 April from 11.00 to 12.00 hrs - Main Auditorium, bldg. 500 The LHC machine /experiment interface S. TAPPROGGE, Univ. of Mainz, D, R. ASSMANN, CERN-AB E. TSESMELIS and D. MACINA, CERN-TS This series of lectures will cover some of the major issues at the boundary between the LHC machine and the experiments: 1) The physics motivation and expectations of the experiments regarding the machine operation. This will include an overview of the LHC physics programme (in pp and PbPb collisions), of the experimental signatures (from high pT objects to leading nucleons) and of the expected trigger rates as well as the data sets needed for specific measurements. Furthermore, issues related to various modes of operation of the machine (e.g. bunch spacings of 25 ns. vs. 75 ns.) and special requirements of the detectors for their commissioning will be described. 2) The LHC machine aspects: introduction of the main LHC parameters and disc...

  1. Academic Training - LHC luminosity upgrade: detector challenges

    CERN Multimedia

    Françoise Benz

    2006-01-01

    ACADEMIC TRAINING LECTURE SERIES 13, 14, 15, March, from 11:00 to 12:00 - 16 March from 10:00 to 12:00 Main Auditorium, bldg. 500 on 14, 15 March, Council Room on 13, 16 March LHC luminosity upgrade: detector challenges A. De Roeck / CERN-PH, D. Bortoletto / Purdue Univ. USA, R. Wigmans / Texas, Tech Univ. USA, W. Riegler / CERN-PH, W. Smith / Wisconsin Univ. USA The upgrade of the LHC machine towards higher luminosity (1035 cm-2s-1) has been studied over the last few years. These studies have investigated scenarios to achieve the increase in peak luminosity by an order of magnitude, as well as the physics potential of such an upgrade and the impact of a machine upgrade on the LHC DETECTORS. This series of lectures will cover the following topics: Physics motivation and machine scenarios for an order of magnitude increase in the LHC peak luminosity (lecture 1) Detector challenges including overview of ideas for R&D programs by the LHC experiments: tracking and calorimetry, other new detector ...

  2. LHC Report: The machine under maintenance

    CERN Multimedia

    Katy Foraz for the LHC Team

    2012-01-01

    The LHC Christmas break started on 12 December. Since then, teams have been working hard to complete all the maintenance work planned to ensure the reliable operation of the LHC in 2012.   Installation of shielding at Point 1. The maintenance work is being carried out on key infrastructure such as the cooling, ventilation, electricity and safety systems. Maintenance work is being carried out not just in the LHC but also across the whole accelerator complex, which makes planning the work even more complicated. At the time of going to print, 50% of the cryogenics system maintenance has been finished, which, according to the schedule, will allow the LHC teams to start cooling down the first sectors next week to have the entire machine cold by the end of February. A lot of activity is going on in order to mitigate the effects of radiation on equipment installed in the LHC tunnel and underground areas during 2012 operation. To this end, teams have installed additional shielding at Point 1 (see ph...

  3. Prototype HL-LHC magnet undergoes testing

    CERN Multimedia

    Corinne Pralavorio

    2016-01-01

    A preliminary short prototype of the quadrupole magnets for the High-Luminosity LHC has passed its first tests.   The first short prototype of the quadrupole magnet for the High Luminosity LHC. (Photo: G. Ambrosio (US-LARP and Fermilab), P. Ferracin and E. Todesco (CERN TE-MSC)) Momentum is gathering behind the High-Luminosity LHC (HL-LHC) project. In laboratories on either side of the Atlantic, a host of tests are being carried out on the various magnet models. In mid-March, a short prototype of the quadrupole magnet underwent its first testing phase at the Fermilab laboratory in the United States. This magnet is a pre-prototype of the quadrupole magnets that will be installed near to the ATLAS and CMS detectors to squeeze the beams before collisions. Six quadrupole magnets will be installed on each side of each experiment, giving a total of 24 magnets, and will replace the LHC's triplet magnets. Made of superconducting niobium-tin, the magnets will be more powerful than their p...

  4. LHC Power Converters: A Precision Game

    CERN Multimedia

    2001-01-01

    The LHC test-bed, String 2, is close to commissioning and one important element to get a first chance to prove what it can do is the power converter system. In String 2 there are 16 converters, in the full LHC there will be almost 1800. This article takes a look at what is so special about the power converters for the LHC. The 13 000 Amps power converters with the watercooled cables going to the String 2 feedboxes. The LHC's superconducting magnets will be the pinnacle of high technology. But to work, they'll need the help of high-precision power converters to supply them with extremely stable DC current. Perfection will be the name of the game, with an accuracy of just 1-2 parts per million (ppm) required. LEP, for the sake of comparison, could live with 10-20 ppm. The LHC's power converters will be very different from those of LEP or the SPS since the new accelerator's magnets are mostly superconducting. That means that they require much higher currents at a lower voltage since superconductors have no re...

  5. The LHC Project Status and Prospects

    CERN Document Server

    Faugeras, Paul E

    2001-01-01

    The Large Hadron Collider (LHC), CERN's future major facility for high-energy physics, has entered into the construction and preparation for installation phases. After recalling briefly the main machine design choices and challenges, one will review the progress of civil works for the machine and experimental areas and the status of the main LHC components, which are presently series-built and for some of them procured in kind through world-wide collaborations. Report will also be given on the full-scale prototype of an elementary LHC lattice cell, called String 2, which is being commissioned and used for optimising the installation and testing procedures of the LHC. The size and duration of the LHC Project, its intrinsic complexity and the large number of world-wide collaborations involved require rather elaborate project management tools, which will be shortly described. Finally, following the extended running of the LEP and the delay for emptying of the machine tunnel, a new planning for project completion...

  6. $A^t_{FB}$ Meets LHC

    Energy Technology Data Exchange (ETDEWEB)

    Hewett, JoAnne L.; /SLAC; Shelton, Jessie; /Yale U.; Spannowsky, Michael; /Oregon U.; Tait, Tim M.P.; /UC, Irvine; Takeuchi, Michihisa; /Heidelberg U.

    2012-02-14

    The recent Tevatron measurement of the forward-backward asymmetry of the top quark shows an intriguing discrepancy with Standard Model expectations, particularly at large t{bar t} invariant masses. Measurements of this quantity are subtle at the LHC, due to its pp initial state, however, one can define a forward-central-charge asymmetry which captures the physics. We study the capability of the LHC to measure this asymmetry and find that within the SM a measurement at the 5{sigma} level is possible with roughly 60 fb{sup -1} at {radical}s = 14 TeV. If nature realizes a model which enhances the asymmetry (as is necessary to explain the Tevatron measurements), a significant difference from zero can be observed much earlier, perhaps even during early LHC running at {radical}s = 7 TeV. We further explore the capabilities of the 7 TeV LHC to discover resonances or contact interactions which modify the t{bar t} invariant mass distribution using recent boosted top tagging techniques. We find that TeV-scale color octet resonances can be discovered, even with small coupling strengths and that contact interactions can be probed at scales exceeding 6 TeV. Overall, the LHC has good potential to clarify the situation with regards to the Tevatron forward-backward measurement.

  7. High Luminosity LHC: Challenges and plans

    International Nuclear Information System (INIS)

    Arduini, G.; Barranco, J.; Bertarelli, A.; Biancacci, N.; Bruce, R.

    2016-01-01

    The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will undergo a major upgrade in the 2020s. This will increase its rate of collisions by a factor of five beyond the original design value and the integrated luminosity by a factor ten. The new configuration, known as High Luminosity LHC (HL-LHC), will rely on a number of key innovations that push accelerator technology beyond its present limits. Among these are cutting-edge 11–12 T superconducting magnets, including Nb 3 Sn-based magnets never used in accelerators before, compact superconducting cavities for longitudinal beam rotation, new technology and physical processes for beam collimation. As a result, the dynamics of the HL-LHC beams will be also particularly challenging and this aspect is the main focus of this paper.

  8. Press Conference: LHC Restart, Season 2

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    PRESS BRIEFING ON THE LARGE HADRON COLLIDER (LHC) RE-START, SEASON 2 AT CERN, GLOBE OF SCIENCE AND INNOVATION Where :   http://cern.ch/directions   at the Globe of Science and Innovation When : Thursday, 12 March from 2.30 to 3.30pm - Open seating as from 2.15pm Speakers : CERN’s Director General, Rolf Heuer and Director of Accelerators, Frédérick Bordry, and representatives of the LHC experiments Webcast : https://webcast.web.cern.ch/webcast/ Dear Journalists, CERN is pleased to invite you to the above press briefing which will take place on Thursday 12 March, in the Globe of Science and Innovation, 1st floor, from 2.30 to 3.30pm. The Large Hadron Collider (LHC) is ready to start up for its second three-year run. The 27km LHC is the largest and most powerful particle accelerator in the world operating at a temperature of -217 degrees Centigrade and powered to a current of 11,000 amps. Run 2 of the LHC follows a two-year technical s...

  9. LHC@home is ready to support HiLumi LHC: take part!

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    Recently relaunched, the LHC@home volunteer computing project is now ready to support the HiLumi LHC project, the design phase of the planned upgrade of the LHC that will increase its luminosity by a factor of 5 to 10 beyond its original design value. HiLumi will need massive simulations to test the beam dynamics. Whether you are at home or at work, you can help experts design the future LHC by connecting your computer to LHC@home. Go for it!   LHC@home is aimed at involving the public in real science. If you have a computer that is connected to the Internet, you can join the large team of volunteers who are already supporting its two main projects: Test4Theory, which runs computer simulations of high-energy particle collisions, and SixTrack, which is aimed at optimizing the LHC performance by performing beam dynamics simulations. In both cases, the software is designed to run only when your computer is idle and causes no disruption to your normal activities. To the simulations run by the Six...

  10. Flexibility of LHC Optics for Forward Proton Measurements

    CERN Document Server

    Cieśla, Krzysztof

    2016-01-01

    The geometric acceptance of the ATLAS Forward Proton detectors is studied. The elements of the LHC magnetic lattice that are most important for the acceptance are identified. The effects of possible changes of the LHC optics are studied.

  11. Issues in the design of the LHC

    CERN Document Server

    Evans, Lyndon R; CERN. Geneva

    1995-01-01

    The lectures aim is to give an overall view of the project rather than a detailed specialized analysis.The main issues are reviewed in the first lecture. After a brief overall description of the machine as foreseen at the present stage of the dessign,the various problems that the design team has to face and the proposed solutions are detailed.The beam dynamics and beam optics problems are briefly discussed. The superconducting magnet technology is presented together with the first models and prototypes results. Some indications are given on the possible strategy for their manufacture.The required performance of the cryogenics system is given,the utilization of the LEP cryogenics plant in the LHC cryogenics system is explained. The implantation of the LHC equipment in underground caverns and in surface buildings is reviewed. Finally some indications are given on the running in of LHC.

  12. An Improved Cllimation System for the LHC

    CERN Document Server

    Assmann, R W; Bertarelli, A; Braun, H; Brugger, M; Brüning, Oliver Sim; Bruno, L; Calatroni, S; Chiaveri, Enrico; Dehning, Bernd; Ferrari, A; Goddard, B; Holzer, E B; Jeanneret, J B; Jiménez, M; Kain, V; Lamont, M; Mayer, M; Métral, Elias; Perret, R; Redaelli, S; Risselada, Thys; Robert-Démolaize, G; Sösler, S; Ruggiero, F; Schmidt, R; Schulte, Daniel; Sievers, P; Vlachoudis, V; Vos, L; Vossenberg, Eugène B; Wenninger, J; Ajguirei, I L; Baishev, I S; Kurochkin, I; Tsutsui, H; Kaltchev, D I

    2004-01-01

    The handling of the high-intensity LHC beams in a super-conducting environment requires a high-robustness collimation system with unprecedented cleaning efficiency. For gap closures down to 2.2 mm no beam instabilities must be induced from the collimator impedance. A difficult trade-off between collimator robustness, cleaning efficiency and collimator impedance is encountered. The conflicting LHC requirements are resolved with a phased approach, relying on low Z collimators for maximum robustness and hybrid metallic collimators for maximum performance. Efficiency is further enhanced with an additional cleaning close to the insertion triplets. The machine layouts have been adapted to the new requirements. The LHC collimation hardware is presently under design and has entered into the prototyping and early testing phase. Plans for collimator tests with beam are presented.

  13. View of the LHC tunnel with worker.

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    The 616th dipole out of 1232, on its way to its final position in the tunnel of the LHC. Technicians and engineers continue to work day and night carefully installing 20 magnets a week. Each of the dipoles weighs 34 tonnes and is 15 m long. Once they have been lowered down the specially constructed shaft on the Meyrin site, they begin a slow progression to their final destinations in the LHC tunnel, taking about 10 hours to arrive at Point 6, the furthest point on the LHC ring. Upon arrival, each of the dipoles is aligned and interconnected to the magnets that are already installed.Bigger files available (39Mpx)

  14. LIGHT and LUMINOSITY, from Einstein to LHC

    CERN Multimedia

    CERN. Geneva; Prof. ROSSI, Lucio

    2015-01-01

    After an introduction on the concept of light in physics, this talk will focus on CERN’s High Luminosity LHC project, aiming at extending the discovery potential of CERN’s flagship accelerator by increasing its “luminosity” (ie the number of particles that can be squeezed inside the accelerator to maximize the number of collisions). To achieve this objective, many new technologies are being developed at CERN and many collaborating institutes worldwide, especially in the field of superconductivity. Lucio Rossi, the main speaker, is the head of the HL-LHC project, based at CERN. Giorgio Apollinari, Director for the LHC Accelerator Research Program (LARP) will speak through a videoconference from Fermilab (USA). The event is webcast live and will be followed by Fermilab and other institutes in the USA.

  15. Critical services in the LHC computing

    International Nuclear Information System (INIS)

    Sciaba, A

    2010-01-01

    The LHC experiments (ALICE, ATLAS, CMS and LHCb) rely for the data acquisition, processing, distribution, analysis and simulation on complex computing systems, running using a variety of services, provided by the experiments, the Worldwide LHC Computing Grid and the different computing centres. These services range from the most basic (network, batch systems, file systems) to the mass storage services or the Grid information system, up to the different workload management systems, data catalogues and data transfer tools, often internally developed in the collaborations. In this contribution we review the status of the services most critical to the experiments by quantitatively measuring their readiness with respect to the start of the LHC operations. Shortcomings are identified and common recommendations are offered.

  16. New EU project supports LHC theorists

    CERN Multimedia

    Katarina Anthony

    2011-01-01

    LHCPhenonet, a new EU-funded research network aimed at improving the theoretical predictions that guide the LHC experiments, has begun its 4-year run as a Marie Curie Initial Training Network. CERN joins the network as an associate partner, along with almost 30 multinational institutions and computing companies.   Theorists from around the world gathered in Valencia to attend LHCPhenonet's kick-off meeting. LHCPhenonet will create research opportunities for young, talented European theorists, providing funding for both doctoral and post-doctoral positions across the various participating institutions – including the University of Durham, DESY, and the Istituto Nazionale di Fisica Nucleare (INFN). LHCPhenoNet aims to improve the Quantum Field Theory calculations that set the parameters of the LHC experiments, focusing on the LHC phenomenology that gave it its name. The 4.5 million euro project is funded by the EU's 7th Research Framework Programme and will be coordinated through the Span...

  17. Big advance towards the LHC upgrade

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    The LHC is currently the world’s most powerful accelerator. With its technical achievements it has already set world records. However, big science looks very far ahead in time and is already preparing already for the LHC’s magnet upgrade, which should involve a 10-fold increase of the collision rates toward the end of the next decade. The new magnet technology involves the use of an advanced superconducting material that has just started to show its potential.   The first Long Quadrupole Shell (LQS01) model during assembly at Fermilab. The first important step in the qualification of the new technology for use in the LHC was achieved at the beginning of December when the US LHC Accelerator Research Program (LARP) – a consortium of Brookhaven National Laboratory, Fermilab, Lawrence Berkeley National Laboratory and the SLAC National Accelerator Laboratory founded by US Department Of Energy (DOE) in 2003 – successfully tested the first long focussing magnet th...

  18. Heavy ion physics at the LHC

    International Nuclear Information System (INIS)

    Vogt, R.

    2004-01-01

    The ion-ion center of mass energies at the LHC will exceed that at RHIC by nearly a factor of 30, providing exciting opportunities for addressing unique physics issues in a completely new energy domain. Some highlights of this new physics domain are presented here. We briefly describe how these collisions will provide new insights into the high density, low momentum gluon content of the nucleus expected to dominate the dynamics of the early state of the system. We then discuss how the dense initial state of the nucleus affects the lifetime and temperature of the produced system. Finally, we explain how the high energy domain of the LHC allows abundant production of ''rare'' processes, hard probes calculable in perturbative quantum chromodynamics, QCD. At the LHC, high momentum jets and b(bar b) bound states, the Υ family, will be produced with high statistics for the first time in heavy ion collisions

  19. LHC Results on Charmonium in Heavy Ions

    CERN Document Server

    Hong, Byungsik

    2012-01-01

    In heavy-ion collisions at high energies, the quantum chromodynamics (QCD) predicts the production of the deconfined quark-gluon plasma (QGP) state. Quarkonia ($c\\bar{c}$ or $b\\bar{b}$ bound states) are a useful means to probe QGP and to investigate the behavior of QCD under the high parton-density environment. Up to now, the large hadron collider (LHC) at CERN provided two runs for PbPb collisions at $\\sqrt{s_{NN}}$ = 2.76 TeV in the years 2010 and 2011. The ALICE, ATLAS, and CMS experiments at LHC have analyzed the yields and spectra of the $J/\\psi$ and $\\Upsilon$ families. In this article, we review particularly the recent charmonium results in PbPb collisions at LHC from the 2010 run.

  20. Quench Performance of the LHC Insertion Magnets

    CERN Document Server

    Lasheras, N C; Siemko, A; Ostojic, R; Kirby, G

    2009-01-01

    After final installation in the LHC tunnel, the MQM and MQY quadrupole magnets of the LHC insertions are now being commissioned to their nominal currents. These two types of magnets operate at 1.9 K and 4.5 K and with nominal currents ranging from 3600 A to 5390 A. From the very first acceptance tests of the bare magnets coming from the manufacturers, they have been powered using different cycles, in different configurations, at different temperatures and in different tests facilities. In this paper we present the global results of these powering tests. We aim at separating common from individual features of these groups of magnets. Temperature dependence of the training, temperature margin, and ultimate current can be extracted from these tests. As these magnets are used to match the optics and the dispersion in the machine, the projected ultimate current at which they can be operated is critical in view of operation of LHC.

  1. Demineralised water cooling in the LHC accelerator

    CERN Document Server

    Peón-Hernández, G

    2002-01-01

    In spite of the LHC accelerator being a cryogenic machine, it remains nevertheless a not negligible heat load to be removed by conventional water-cooling. About 24MW will be taken away by demineralised water cooled directly by primary water from the LHC cooling towers placed at the even points. This paper describes the demineralised water network in the LHC tunnel including pipe diameters, lengths, water speed, estimated friction factor, head losses and available supply and return pressures for each point. It lists all water cooled equipment, highlights the water cooled cables as the most demanding equipment followed by the radio frequency racks and cavities, and by the power converters. Their main cooling requirements and their positions in the tunnel are also presented.

  2. The LHC machine-experiment interface

    CERN Multimedia

    CERN. Geneva; Tsesmelis, Emmanuel; Brüning, Oliver Sim

    2002-01-01

    This series of three lectures will provide an overview of issues arising at the interface between the LHC machine and the experiments, which are required for guiding the interaction between the collider and the experiments when operation of the LHC commences. A basic description of the LHC Collider and its operating parameters, such as its energy, currents, bunch structure and luminosity, as well as variations on these parameters, will be given. Furthermore, the optics foreseen for the experimental insertions, the sources and intensities of beam losses and the running-in scenarios for the various phases of operation will be discussed. A second module will cover the specific requirements and expectations of each experiment in terms of the layout of experimental areas, the matters related to radiation monitoring and shielding, the design of the beam pipe and the vacuum system, alignment issues and the measurement of the total cross-section and absolute luminosity by the experiments. Finally an analysis of infor...

  3. Remote Inspection, Measurement and Handling for LHC

    CERN Document Server

    Kershaw, K; Coin, A; Delsaux, F; Feniet, T; Grenard, J L; Valbuena, R

    2007-01-01

    Personnel access to the LHC tunnel will be restricted to varying extents during the life of the machine due to radiation, cryogenic and pressure hazards. The ability to carry out visual inspection, measurement and handling activities remotely during periods when the LHC tunnel is potentially hazardous offers advantages in terms of safety, accelerator down time, and costs. The first applications identified were remote measurement of radiation levels at the start of shut-down, remote geometrical survey measurements in the collimation regions, and remote visual inspection during pressure testing and initial machine cool-down. In addition, for remote handling operations, it will be necessary to be able to transmit several real-time video images from the tunnel to the control room. The paper describes the design, development and use of a remotely controlled vehicle to demonstrate the feasibility of meeting the above requirements in the LHC tunnel. Design choices are explained along with operating experience to-dat...

  4. Configuration of the Beam Loss Monitors for the LHC arcs

    CERN Document Server

    Arauzo-Garcia, A

    2000-01-01

    A revised configuration for a beam loss detection system is given for the arcs of the LHC. The last modifications of the LHC arc layout have been taken into account, LHC optics version 6.2. A set of 6 Loss Detectors will be placed outside the cryostat around each short straight section. Quench alarm thresholds are estimated for each detector in all possible LHC arc layout configurations. Threshold values are proposed for top and injection energy beam loss.

  5. Optics Measurements and Correction Challenges for the HL-LHC

    CERN Document Server

    Carlier, Felix Simon; Fartoukh, Stephane; Fol, Elena; Gamba, Davide; Garcia-Tabares Valdivieso, Ana; Giovannozzi, Massimo; Hofer, Michael; Langner, Andy Sven; Maclean, Ewen Hamish; Malina, Lukas; Medina Medrano, Luis Eduardo; Persson, Tobias Hakan Bjorn; Skowronski, Piotr Krzysztof; Tomas Garcia, Rogelio; Van Der Veken, Frederik; Wegscheider, Andreas

    2017-01-01

    Optics control in the HL-LHC will be challenged by a very small β* of 15 cm in the two main experiments. HL-LHC physics fills will keep a constant luminosity during several hours via β* leveling. This will require the commissioning of a large number of optical configurations, further challenging the efficiency of the optics measurements and correction tools. We report on the achieved level of optics control in the LHC with simulations and extrapolations for the HL-LHC.

  6. STATISTICAL CHALLENGES FOR SEARCHES FOR NEW PHYSICS AT THE LHC.

    Energy Technology Data Exchange (ETDEWEB)

    CRANMER, K.

    2005-09-12

    Because the emphasis of the LHC is on 5{sigma} discoveries and the LHC environment induces high systematic errors, many of the common statistical procedures used in High Energy Physics are not adequate. I review the basic ingredients of LHC searches, the sources of systematics, and the performance of several methods. Finally, I indicate the methods that seem most promising for the LHC and areas that are in need of further study.

  7. Top Physics at CMS/LHC

    Directory of Open Access Journals (Sweden)

    Daskalakis Georgios

    2017-01-01

    Full Text Available Recent results on the inclusive and differential production cross sections of top-quark pair and single top-quark processes are presented, obtained using data from proton-proton collisions collected with the CMS detector at the LHC. The large centre-of-mass energies available at LHC allow for the copious production of top-quark pairs in association with other final state particles at high transverse momentum. Measurements of such processes as well as of the top-quark mass and other properties will be discussed. The results are compared with the most up-to-date standard model theory predictions.

  8. Supersymmetry and the LHC (Lectures CANCELLED)

    CERN Multimedia

    CERN. Geneva

    2006-01-01

    I will first give a pedagogical motivation for, and introduction to, supersymmetric extensions of the Standard Model. The biggest obstacle that prevents theorists from making clear-cut predictions for the production of superparticles at the LHC is our lack of knowledge of how supersymmetry is broken. I will review the most promising SUSY breaking mechanisms that have been suggested so far, and outline the resulting signatures for LHC experiments. Finally, I will try to make contact with other areas of particle physics and cosmology, where supersymmetry also might play a role.

  9. Optimizing Chromatic Coupling Measurement in the LHC

    CERN Document Server

    Persson, Tobias

    2016-01-01

    Optimizing chromatic coupling measurement in the LHC Chromatic coupling introduces a dependency of transverse coupling with energy. LHC is equipped with skew sextupoles to compensate the possible adverse effects of chromatic coupling. In 2012 a beam-based correction was calculated and applied successfully for the fist time. However, the method used to reconstruct the chromatic coupling was dependent on stable tunes and equal chromaticities between the horizontal and vertical planes. In this article an improved method to calculate the chromatic coupling without these constraints is presented.

  10. LHC II system sensitivity to magnetic fluids

    CERN Document Server

    Cotae, Vlad

    2005-01-01

    Experiments have been designed to reveal the influences of ferrofluid treatment and static magnetic field exposure on the photosynthetic system II, where the light harvesting complex (LHC II) controls the ratio chlorophyll a/ chlorophyll b (revealing, indirectly, the photosynthesis rate). Spectrophotometric measurement of chlorophyll content revealed different influences for relatively low ferrofluid concentrations (10-30 mul/l) in comparison to higher concentrations (70-100 mul/l). The overlapped effect of the static magnetic field shaped better the stimulatory ferrofluid action on LHC II system in young poppy plantlets.

  11. Manufacturing and QA of adaptors for LHC

    International Nuclear Information System (INIS)

    Madhu Murthy, V.; Dwivedi, J.; Goswami, S.G.; Soni, H.C.; Mainaud Durand, H.; Quesnel, J.P.; )

    2006-01-01

    The LHC low beta quadrupoles, have very tight alignment tolerances and are located in areas with strong radiation field. They require remote re-alignment, by motorized jacks, based on the feedback of alignment sensors of each magnet. Jacks designed to support arc cryomagnets of LHC are modified and motorized with the help of adaptors. Two types of adapters, for vertical and transverse axes of the jacks, were developed and supplied through collaboration between RRCAT, DAE, India and CERN, Geneva. This paper describes their functional requirements, manufacture and quality assurance (QA). (author)

  12. A full acceptance detector at the LHC

    International Nuclear Information System (INIS)

    Avati, V.; Eggert, K.; Taylor, C.

    1999-01-01

    The FELIX collaboration has proposed the construction of a full acceptance detector for the LHC, to be located at Intersection Region 4, and to be commissioned concurrently with the LHC. The primary mission of FELIX is QCD: to provide comprehensive and definitive observations of a very broad range of strong-interaction processes. This paper reviews the detector concept and performance characteristics, the physics menu, and plans for integration of FELIX into the collider lattice and physical environment. The current status of the FELIX Letter of Intent is discussed

  13. Stability of the LHC transfer lines

    CERN Document Server

    Kain, V; Bartmann, W; Bracco, C; Goddard, B; Meddahi, M; Uythoven, J; Wenninger, J

    2011-01-01

    The LHC is filled from the SPS through two 3 km transfer lines. The injected beam parameters need to be well under control for luminosity performance, machine protection and operational efficiency. Small fractions of beam loss on the transfer line collimation system create showers which can trigger the sensitive LHC beam loss monitor system nearby and cause a beam abort during filling. The stability of the transfer line trajectory through the collimators is particularly critical in this respect. This paper will report on the transfer line trajectory stability during the proton run in 2011, correlations with injection losses, correction frequency and the most likely sources for the observed oscillations.

  14. QCD are we ready for the LHC?

    CERN Multimedia

    CERN. Geneva

    2006-01-01

    The LHC energy regime poses a serious challenge to our capability of predicting QCD reactions to the level of accuracy necessary for a successful programme of searches for physics beyond the Standard Model. In these lectures, I'll introduce basic concepts in QCD, and present techniques based on perturbation theory, such as fixed-order and resummed computations, and Monte Carlo simulations. I'll discuss applications of these techniques to hadron-hadron processes, concentrating on recent trends in perturbative QCD aimed at improving our understanding of LHC phenomenology.

  15. Composite Higgs under LHC Experimental Scrutiny

    Directory of Open Access Journals (Sweden)

    Mühlleitner M.

    2012-06-01

    Full Text Available The LHC has been built to understand the dynamics at the origin of the breaking of the electroweak symmetry. Weakly coupled models with a fundamental Higgs boson have focused most of the attention of the experimental searches. We will discuss here how to reinterpret these searches in the context of strongly coupled models where the Higgs boson emerges as a composite particle. In particular, we use LHC data to constrain the compositeness scale. We also briefly review the prospects to observe other bosonic and fermionic resonances of the strong sector.

  16. The last stage of LHC construction

    International Nuclear Information System (INIS)

    Serin, L.

    2006-01-01

    A few months ago the setting of the LHC (large hadron collider) machine began in the Lep's tunnel at CERN. The LHC is composed of 1200 dipole magnets that are progressively installed in the 27 km long underground circular facility, 2 universal experiments ATLAS and CMS, huge by the size of their respective detector: 40 x 20 x 20 m as well as by their number of participants: 1500 people for each one are being built in gigantic carves. All the efforts are concentrated to make every component of the machine fully installed by summer 2007 in order to get the first collisions before 2008

  17. Charged-particle multiplicity at LHC energies

    CERN Multimedia

    CERN. Geneva

    2010-01-01

    The talk presents the measurement of the pseudorapidity density and the multiplicity distribution with ALICE at the achieved LHC energies of 0.9 and 2.36 TeV.An overview about multiplicity measurements prior to LHC is given and the related theoretical concepts are briefly discussed.The analysis procedure is presented and the systematic uncertainties are detailed. The applied acceptance corrections and the treatment of diffraction are discussed.The results are compared with model predictions. The validity of KNO scaling in restricted phase space regions is revisited. 

  18. The LHC detectors and the first CMS data

    CERN Document Server

    Green, Dan

    2015-01-01

    This chapter describes the subsystems of a generic LHC detector and explains how the values of the detector parameters were selected. The design of the LHC detectors follows from the requirement of confronting electroweak symmetry breaking in a decisive fashion. The LHC accelerator also meets those requirements.

  19. 6. workshop on electronics for LHC experiments. Proceedings

    International Nuclear Information System (INIS)

    2000-01-01

    The purpose of the workshop was to review the electronics for LHC experiments and to identify areas and encourage common efforts for the development of electronics within and between the different LHC experiments and to promote collaboration in the engineering and physics communities involved in the LHC activities. (orig.)

  20. 6. workshop on electronics for LHC experiments. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-10-25

    The purpose of the workshop was to review the electronics for LHC experiments and to identify areas and encourage common efforts for the development of electronics within and between the different LHC experiments and to promote collaboration in the engineering and physics communities involved in the LHC activities. (orig.)

  1. Robert Aymar seals the last interconnect in the LHC

    CERN Multimedia

    Maximilien Brice

    2007-01-01

    The LHC completes the circle. On 7 November, in a brief ceremony in the LHC tunnel, CERN Director General Robert Aymar (Photo 1) sealed the last interconnect between the main magnets of the Large Hadron Collider (LHC). Jean-Philippe Tock, leader of the Interconnections team, tightens the last bolt (Photos 4-8).

  2. Proposal to negotiate a collaboration agreement for the design, testing and prototyping of superconducting elements for the High Luminosity LHC (HL-LHC) project and for the production of spare quadrupole magnets for LHC

    CERN Document Server

    2016-01-01

    Proposal to negotiate a collaboration agreement for the design, testing and prototyping of superconducting elements for the High Luminosity LHC (HL-LHC) project and for the production of spare quadrupole magnets for LHC

  3. After spectacular start, the LHC injures itself

    CERN Document Server

    Cho, Adrian

    2008-01-01

    When physicists first sent particles racing through the world's biggest atom smasher on 10 September, the gargantuan machine purred like a kitten. But only 9 days later, the LHC proved it can also be a temperamental tiger, damaging itself so severely that it will be out of action until next spring. (1 page)

  4. View of an open LHC interconnection

    CERN Multimedia

    Maximilien Brice

    2005-01-01

    Two LHC magnets are seen before they are connected together. The blue cylinders contain the magnetic yoke and coil of the dipole magnets together with the liquid helium system required to cool the magnet so that it becomes superconducting. Eventually this connection will be welded together so that the beams are contained within the beam pipes.

  5. signal of NMSSM at the LHC

    Indian Academy of Sciences (India)

    Jacky Kumar

    2017-10-05

    Oct 5, 2017 ... γγ + l + /ET signal of NMSSM at the LHC ... mechanism of diphoton mode of A1 and its detection possibility in the final-state. (γγ + l + ... example, it is known for quite sometime that light .... (A) and singlet (S) weak eigenstates.

  6. Behind the scenes at the LHC inauguration

    CERN Document Server

    2008-01-01

    On 21 October the LHC inauguration ceremony will take place and people from all over CERN have been busy preparing. With delegations from 38 countries attending, including ministers and heads of state, the Bulletin has gone behind the scenes to see what it takes to put together an event of this scale.

  7. Beam-Beam Interaction Studies at LHC

    CERN Document Server

    Schaumann, Michaela; Alemany Fernandez, R

    2011-01-01

    The beam-beam force is one of the most important limiting factors in the performance of a collider, mainly in the delivered luminosity. Therefore, it is essential to measure the effects in LHC. Moreover, adequate understanding of LHC beam-beam interaction is of crucial importance in the design phases of the LHC luminosity upgrade. Due to the complexity of this topic the work presented in this thesis concentrates on the beam-beam tune shift and orbit effects. The study of the Linear Coherent Beam-Beam Parameter at the LHC has been determined with head-on collisions with small number of bunches at injection energy (450 GeV). For high bunch intensities the beam-beam force is strong enough to expect orbit effects if the two beams do not collide head-on but with a crossing angle or with a given offset. As a consequence the closed orbit changes. The closed orbit of an unperturbed machine with respect to a machine where the beam-beam force becomes more and more important has been studied and the results are as well ...

  8. The LHC enters a new phase

    CERN Document Server

    CERN Bulletin

    2010-01-01

    After achieving the world record energy of 1.18 TeV per proton beam last November, the LHC is now preparing for higher energy and luminosity.   The teams are working in the tunnel to improve the electrical reliability of the magnet protection system.   Before the 2009 running period began, all the necessary preparations to run the LHC at the collision energy of 1.18 TeV per beam had been carried out. The goal of the technical stop, which will end mid-February, is to prepare the machine for running at 3.5 TeV per beam. In order to achieve that, a current as high as 6 kAmps will have to flow into the LHC magnets. The main work is taking place on the new quench protection system (nQPS) where teams are improving the electrical reliability of the connection between the Instrumentation Feedthrough Systems (IFS) on the magnets and the nQPS equipment. There are around 500 of these connectors for each of the eight sectors in the LHC that need to be repaired. These operations are necessary to en...

  9. W′ and Z′ searches at the LHC

    DEFF Research Database (Denmark)

    Accomando, E.; Becciolini, D.; Belyaev, A.

    Searches for extra heavy W′ and Z′-bosons in the leptonic Drell-Yan channel at the Large Hadron Collider (LHC) are favoured by present and future data. We focus on a common approximation used in theoretical and experimental analyses: neglecting interference between the new gauge bosons W′± (Z...

  10. Probing the scotogenic FIMP at the LHC

    DEFF Research Database (Denmark)

    Hessler, Andre G.; Ibarra, Alejandro; Molinaro, Emiliano

    2017-01-01

    We analyse the signatures at the Large Hadron Collider (LHC) of the scotogenic model, when the lightest Z2-odd particle is a singlet fermion and a feebly interacting massive particle (FIMP). We further assume that the singlet fermion constitutes the dark matter and that it is produced in the early...

  11. Cryogenic Silicon Microstrip Detector Modules for LHC

    CERN Document Server

    Perea-Solano, B

    2004-01-01

    CERN is presently constructing the LHC, which will produce collisions of 7 TeV protons in 4 interaction points at a design luminosity of 1034 cm-2 s-1. The radiation dose resulting from the operation at high luminosity will cause a serious deterioration of the silicon tracker performance. The state-of-art silicon microstrip detectors can tolerate a fluence of about 3 1014 cm-2 of hadrons or charged leptons. This is insufficient, however, for long-term operation in the central parts of the LHC trackers, in particular after the possible luminosity upgrade of the LHC. By operating the detectors at cryogenic temperatures the radiation hardness can be improved by a factor 10. This work proposes a cryogenic microstrip detector module concept which has the features required for the microstrip trackers of the upgraded LHC experiments at CERN. The module can hold an edgeless sensor, being a good candidate for improved luminosity and total cross-section measurements in the ATLAS, CMS and TOTEM experiments. The design o...

  12. Magnet failure could delay the LHC

    CERN Multimedia

    2007-01-01

    "Bosses at the CERN particle-physics laboratory in Geneva will decide later this month if the Large Hadron Collider (LHC) can start up in November as planned after one of its superconducting magnets failed preliminary tests at the end of March." (1 page)

  13. LHC Dipoles: The countdown has begun

    CERN Document Server

    2002-01-01

    One of the LHC dipole magnets has just achieved a record magnetic field of 9 Tesla in one go without quenching. The challenge now is to increase the production rate to 35 magnets a month by 2004. As a new information panel in Building 30 shows, the countdown has begun.

  14. LHC opening delayed, operating schedule extended

    CERN Multimedia

    2009-01-01

    "The Large Hadron Collider (LHC) will reportedly reopen in October rather than this summer [...]. The $ 6.5 billion particle accelerator has 1'232 superconducting dipole magnets out of a total of more than 1'700 large magnets" (0.5 page)

  15. Prospects for Higgs searches at the LHC

    International Nuclear Information System (INIS)

    Dissertori, G.

    2006-01-01

    In this talk I will summarize the current simulation studies by the LHC experiments regarding the searches for Higgs bosons, both in the context of the Standard Model as well as its supersymmetric extension. Some emphasis will be given to the early discovery reach, as well as to recent studies regarding background estimations and systematic uncertainties. (author)

  16. Installation of the LHC transfer lines begins

    CERN Multimedia

    Patrice Loïez

    2003-01-01

    The first of 700 magnets has been installed in one of the two transfer tunnels built to transfer the SPS beam into the LHC. The start of this first installation phase of the LHC transfer lines provides the opportunity to launch a new and highly original modular system for transporting and installing all kinds of magnets in very narrow tunnels. The system is based on very compact bogies, up to four of which can be coupled together to form a convoy. The wheels are fitted with individual motors enabling them to swivel through an angle of 90° and the convoy to move laterally. In this way the magnet is delivered directly to its installation point, but beneath the beamline. It is then raised into its final position in the beamline using air cushions, which form an integrated part of the transport system.Photos 01, 02: Pictured with the newly installed magnet and transport system in the transfer line tunnel are LHC project leader Lyn Evans (second left, white helmet); Volker Mertens, responsible for the LHC injecti...

  17. Installation of the LHC transfer lines begins

    CERN Multimedia

    2003-01-01

    On 19 February, the very first magnet was installed in one of the two tunnels that will house the transfer lines leading to the LHC. This magnet, recycled from a previous facility, was transported and positioned using a novel system designed for conveying large objects through narrow tunnels.

  18. High Luminosity LHC Studies with ATLAS

    CERN Document Server

    Duncan, Anna Kathryn; The ATLAS collaboration

    2017-01-01

    The High-Luminosity LHC aims to provide a total integrated luminosity of 3000fb$^{-1}$ from proton-proton collisions at $\\sqrt{s}$ = 14 TeV over the course of $\\sim$ 10 years, reaching instantaneous luminosities of up to L = 7.5 $\\times$ 1034cm$^{-2}s$^{-1}$, corresponding to an average of 200 inelastic p-p collisions per bunch crossing ($\\mu$ = 200). Fast simulation studies have been carried out to evaluate the prospects of various benchmark physics analyses to be performed using the upgraded ATLAS detector with the full HL-LHC dataset. The performance of the upgrade has been estimated in full simulation studies, assuming expected HL-LHC conditions. This talk will focus on the results of physics prospects studies for benchmark analyses involving in particular boosted hadronic objects (e.g. ttbar resonances, HH resonances), and on results of Jet/EtMiss studies of jet performance and pileup mitigation techniques that will be critical in HL-LHC analyses.

  19. US-LHC Magnet Database and conventions

    CERN Document Server

    Wei, J; Jain, A; Peggs, S; Pilat, F; Bottura, L; Sabbi, G L; MacKay, W W

    1999-01-01

    The US-LHC Magnet Database is designed for production-magnet quality assurance, field and alignment error impact analysis, cryostat assembly assistance, and ring installation assistance. The database consists of tables designed to store magnet field and alignment measurements data and quench data. This information will also be essential for future machine operations including local IR corrections. (7 refs).

  20. Model of an LHC superconducting quadrupole magnet

    CERN Multimedia

    Laurent Guiraud

    2000-01-01

    Model of a superconducting quadrupole magnet for the LHC project. These magnets are used to focus the beam by squeezing it into a smaller cross-section, a similar effect to a lens focusing light. However, each magnet only focuses the beam in one direction so alternating magnet arrangements are required to produce a fully focused beam.

  1. Status of the LHCf apparatus at LHC

    CERN Document Server

    Bonechi, L; Bongi, M; Castellini, G; D’Alessandro, R; Faus, A; Fukui, K; Haguenauer, M; Itow, Y; Kasahara, K; Macina, D; Mase, T; Masuda, K; Matsubara, Y; Menjo, H; Mizuishi, M; Muraki, Y; Papini, P; Perrot, A L; Ricciarini, S; Sako, T; Shimizu, Y; Taki, K; Tamura, T; Torii, S; Tricomi, A; Turner, W C; Velasco, J; Viciani, A; Yoshida, K

    2009-01-01

    The LHCf experiment at the LHC accelerator is ready for data taking. Both the LHCf detectors have been successfully tested and installed in their running configuration. The status of the apparatus, control software and some results of the last beam test at the SPS accelerator are presented in this work.

  2. CVD diamond pixel detectors for LHC experiments

    CERN Document Server

    Wedenig, R; Bauer, C; Berdermann, E; Bergonzo, P; Bogani, F; Borchi, E; Brambilla, A; Bruzzi, Mara; Colledani, C; Conway, J; Dabrowski, W; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Fizzotti, F; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Grigoriev, E; Hallewell, G D; Hall-Wilton, R; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Kagan, H; Kania, D R; Kaplon, J; Karl, C; Kass, R; Knöpfle, K T; Krammer, Manfred; Lo Giudice, A; Lü, R; Manfredi, P F; Manfredotti, C; Marshall, R D; Meier, D; Mishina, M; Oh, A; Pan, L S; Palmieri, V G; Pernicka, Manfred; Peitz, A; Pirollo, S; Polesello, P; Pretzl, Klaus P; Procario, M; Re, V; Riester, J L; Roe, S; Roff, D G; Rudge, A; Runólfsson, O; Russ, J; Schnetzer, S R; Sciortino, S; Speziali, V; Stelzer, H; Stone, R; Suter, B; Tapper, R J; Tesarek, R J; Trawick, M L; Trischuk, W; Vittone, E; Wagner, A; Walsh, A M; Weilhammer, Peter; White, C; Zeuner, W; Ziock, H J; Zöller, M

    1999-01-01

    This paper reviews the development of CVD diamond pixel detectors. The preparation of the diamond pixel sensors for bump-bonding to the pixel readout electronics for the LHC and the results from beam tests carried out at CERN are described. (9 refs).

  3. CVD diamond pixel detectors for LHC experiments

    Energy Technology Data Exchange (ETDEWEB)

    Wedenig, R.; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Karl, C.; Kass, R.; Knoepfle, K.T.; Krammer, M.; Logiudice, A.; Lu, R.; Manfredi, P.F.; Manfredotti, C.; Marshall, R.D.; Meier, D.; Mishina, M.; Oh, A.; Pan, L.S.; Palmieri, V.G.; Pernicka, M.; Peitz, A.; Pirollo, S.; Polesello, P.; Pretzl, K.; Procario, M.; Re, V.; Riester, J.L.; Roe, S.; Roff, D.; Rudge, A.; Runolfsson, O.; Russ, J.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trawick, M.; Trischuk, W.; Vittone, E.; Wagner, A.; Walsh, A.M.; Weilhammer, P.; White, C.; Zeuner, W.; Ziock, H.; Zoeller, M.; Blanquart, L.; Breugnion, P.; Charles, E.; Ciocio, A.; Clemens, J.C.; Dao, K.; Einsweiler, K.; Fasching, D.; Fischer, P.; Joshi, A.; Keil, M.; Klasen, V.; Kleinfelder, S.; Laugier, D.; Meuser, S.; Milgrome, O.; Mouthuy, T.; Richardson, J.; Sinervo, P.; Treis, J.; Wermes, N

    1999-08-01

    This paper reviews the development of CVD diamond pixel detectors. The preparation of the diamond pixel sensors for bump-bonding to the pixel readout electronics for the LHC and the results from beam tests carried out at CERN are described.

  4. CVD diamond pixel detectors for LHC experiments

    International Nuclear Information System (INIS)

    Wedenig, R.; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Karl, C.; Kass, R.; Knoepfle, K.T.; Krammer, M.; Logiudice, A.; Lu, R.; Manfredi, P.F.; Manfredotti, C.; Marshall, R.D.; Meier, D.; Mishina, M.; Oh, A.; Pan, L.S.; Palmieri, V.G.; Pernicka, M.; Peitz, A.; Pirollo, S.; Polesello, P.; Pretzl, K.; Procario, M.; Re, V.; Riester, J.L.; Roe, S.; Roff, D.; Rudge, A.; Runolfsson, O.; Russ, J.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trawick, M.; Trischuk, W.; Vittone, E.; Wagner, A.; Walsh, A.M.; Weilhammer, P.; White, C.; Zeuner, W.; Ziock, H.; Zoeller, M.; Blanquart, L.; Breugnion, P.; Charles, E.; Ciocio, A.; Clemens, J.C.; Dao, K.; Einsweiler, K.; Fasching, D.; Fischer, P.; Joshi, A.; Keil, M.; Klasen, V.; Kleinfelder, S.; Laugier, D.; Meuser, S.; Milgrome, O.; Mouthuy, T.; Richardson, J.; Sinervo, P.; Treis, J.; Wermes, N.

    1999-01-01

    This paper reviews the development of CVD diamond pixel detectors. The preparation of the diamond pixel sensors for bump-bonding to the pixel readout electronics for the LHC and the results from beam tests carried out at CERN are described

  5. LHC Report: Full data production mode

    CERN Multimedia

    Mike Lamont for the LHC Team

    2012-01-01

    The LHC is accumulating as much data as possible for the experiments before the summer conferences. Performance is impressive, with 1380 bunches of around 1.5x1011 protons per bunch giving a peak luminosity of 6.8 x1033 cm-2s-1 and with integrated rates topping 20 pb-1 an hour at the start of fill.  As of today (13 June), the LHC has delivered more collisions in 2012 than it did in the whole of 2011. Not only that, the collisions have been at the higher energy of 4 TeV. In 2011, the LHC delivered an integrated luminosity of around 5.6 fb-1 to both ATLAS and CMS. Now, just a few months after the machine began its 2012 run, these integrated luminosity levels have been past. Follow the LHC performance and statistics on the dedicated page. The step-up in particle collision rates compared with 2011 is due to further reduction in the beam sizes at the interaction point, in conjunction with the use of tight collimator settings, the increase in energy to 4 TeV and the continued excellent beam quality from...

  6. LHC experiences close encounters with UFOs

    CERN Multimedia

    Mike Lamont for the LHC Team

    2011-01-01

    On 29 May, yet another record was set as 1092 bunches per beam were injected into the LHC, hitting a peak luminosity of 1.26x1033 cm-2 s-1. While running at 3.5 TeV each beam now packs a total energy of over 70 MJ – equivalent to a TGV travelling at a 70 kph.   Operators in the LHC Control Centre happily show off their display screens after succesfully injecting 1092 bunches injected into the machine for the first time.  As the total beam intensity has been pushed up, the LHC has encountered a number of related problems, such as the so-called UFOs (Unidentified Falling Objects). These are thought to be dust particles falling through the beam, causing localized beam loss. The losses can push nearby beam loss monitors over the threshold and dump the beam. This is more of an annoyance than a danger for the LHC, but UFOs do reduce the operational efficiency of the machine. Despite this, the luminosity delivered to the experiments has steadily increased. On three occasions there ha...

  7. U.S. Involvement in the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Green, Dan

    2016-12-30

    The demise of the SSC in the U.S. created an upheaval in the U.S. High energy physics (HEP) community. The subsequent redirection of HEP efforts to the CERN Large Hadron Collider (LHC) can perhaps be seen as informing on possible future paths for worldwide collaboration on future HEP megaprojects

  8. US-LHC Magnet Database and Conventions

    International Nuclear Information System (INIS)

    Wei, J.; McChesney, D.; Jain, A.; Peggs, S.; Pilat, F.; Bottura, L.; Sabbi, G.

    1999-01-01

    The US-LHC Magnet Database is designed for production-magnet quality assurance, field and alignment error impact analysis, cryostat assembly assistance, and ring installation assistance. The database consists of tables designed to store magnet field and alignment measurements data and quench data. This information will also be essential for future machine operations including local IR corrections

  9. A Review of the LHC Beam Instrumentation

    CERN Document Server

    Fischer, Cl

    1998-01-01

    This is a review of the diagnostics presently considered for LHC running in and operation. The purpose of each instrument is given and, except for the pick-ups of the Beam Position Monitoring system w hich have their position already reserved, the optimal location and an estimate of the required length along the vacuum chamber are given.

  10. LHC Injectors Upgrade (LIU) Project at CERN

    CERN Document Server

    Shaposhnikova, Elena; Damerau, Heiko; Funken, Anne; Gilardoni, Simone; Goddard, Brennan; Hanke, Klaus; Kobzeva, Lelyzaveta; Lombardi, Alessandra; Manglunki, Django; Mataguez, Simon; Meddahi, Malika; Mikulec, Bettina; Rumolo, Giovanni; Scrivens, Richard; Vretenar, Maurizio

    2016-01-01

    A massive improvement program of the LHC injector chain is presently being conducted under the LIU project. For the proton chain, this includes the replacement of Linac2 with Linac4 as well as all necessary upgrades to the Proton Synchrotron Booster (PSB), the Proton Synchrotron (PS) and Super Proton Synchrotron (SPS), aimed at producing beams with the challenging High Luminosity LHC (HL-LHC) parameters. Regarding the heavy ions, plans to improve the performance of Linac3 and the Low Energy Ion Ring (LEIR) are also pursued under the general LIU program. The full LHC injection chain returned to operation after Long Shutdown 1, with extended beam studies taking place in Run 2. A general project Cost and Schedule Review also took place in March 2015, and several dedicated LIU project reviews were held to address issues awaiting pending decisions. In view of these developments, 2014 and 2015 have been key years to define a number of important aspects of the final LIU path. This paper will describe the reviewed LI...

  11. Lepton number violation searches at the LHC

    CERN Document Server

    Salvucci, Antonio; The ATLAS collaboration

    2017-01-01

    Lepton number is conserved in the Standard Model, therefore, any evidence for its violation would indicate the existence of new physics. This talk presents a review of the latest searches performed at the LHC concerning Lepton Number Violation (LNV) processes in the context of Left-Right Symmetric theory and Seesaw mechanism.

  12. Searches for Dark Matter at the LHC

    CERN Document Server

    Butler, John; The ATLAS collaboration

    2018-01-01

    The existance of a new form of matter, Dark Matter, has been established by a large body of astrophysical measurements. The particle nature of Dark Matter is one of the most intriguing and important open issues in physics today. A review of searches for Dark Matter by the LHC experiments is presented

  13. Azimuthal anisotropy of jet quenching at LHC

    Indian Academy of Sciences (India)

    Abstract. We analyze the azimuthal anisotropy of jet spectra due to energy loss of hard partons in quark–gluon plasma, created initially in nuclear overlap zone in collisions with non-zero impact parameter. The calculations are performed for semi-central Pb–Pb collisions at LHC energy.

  14. The ALICE experiment at the CERN LHC

    NARCIS (Netherlands)

    Aamodt, K.; de Haas, A.P.; Grebenyuk, O.|info:eu-repo/dai/nl/304848883; Ivan, C.G.|info:eu-repo/dai/nl/304847747; Kamermans, R.|info:eu-repo/dai/nl/073698733; Mischke, A.|info:eu-repo/dai/nl/325781435; Nooren, G.J.L.|info:eu-repo/dai/nl/07051349X; Oskamp, C.J.; Peitzmann, T.|info:eu-repo/dai/nl/304833959; Simili, E.; van den Brink, A.; van Eijndhoven, N.J.A.M.|info:eu-repo/dai/nl/072823674; Yuting, B.

    2008-01-01

    ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy

  15. Beleaguered LHC gears up for restart

    CERN Multimedia

    Cartwright, Jon

    2009-01-01

    "The Large Hadron Collider (LHC) is finally set to restart in mid-November following last year's accident. Initially it will collide protons at an energy of only 3.5 TeV per beam, and staff at Cern will have to wait until late next year before trying to run the collider at its maximum energy" (0.75 page)

  16. LHC Availability 2017: Standard Proton Physics

    CERN Document Server

    Todd, Benjamin; Apollonio, Andrea; Walsh, David John; CERN. Geneva. ATS Department

    2017-01-01

    This document summarises the LHC machine availability for the period from restart to the end of standard proton physics in 2017. This covers the whole standard proton physics production period. This note has been produced and ratified by the Availability Working Group which has complied fault information for the period in question using the Accelerator Fault Tracker.

  17. Production of Excited Neutrinos at the LHC

    CERN Document Server

    Belyaev, A; Mehdiyev, R

    2005-01-01

    We study the potential of the CERN LHC in the search for the single production of excited neutrino through gauge interactions. Subsequent decays of excited neutrino via gauge interactions are examined. The mass range accessible with the ATLAS detector is obtained.

  18. Big meeting puts the case for LHC

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    It was a workshop on a scale to match the ultimate goal. When some 500 physicists met in Aachen, Germany, in October to put the research case for the proposed Large Hadron Collider (LHC) at CERN, the turnout was among the biggest attendances of the year

  19. Precision transport of LHC superconducting magnet

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    These photos show tests of the first convoy with a prototype short straight section (SSS) quadrupole in the LHC tunnel. There is little free space in the tunnel as the SSS convoy passes alongside a dipole vacuum vessel. These convoys feature infrared guidance, which offsets the minimal clearance in the tunnel and limits vibration, both of which could damage the fragile magnets.

  20. String 2, test facility for the LHC

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    String 2 is the long chain seen to the right, representing one complete cell of bending dipoles, focusing quadrupoles and corrector magnets. On 17 June 2002 the test string reached the nominal running current of 11 860 A and magnetic field of 8.335 T for the LHC.

  1. Particles are back in the LHC!

    CERN Multimedia

    2009-01-01

    Last weekend (23-25 October) particles once again entered the LHC after the one-year interruption following the incident of September 2008. Particles travelled through one sector clockwise and one anticlockwise. ALICE and LHCb, the two experiments sitting along the portion of the beam lines in question, were able to observe the first effects of real beams in the machine.

  2. Electron cloud buildup studies for the LHC

    CERN Document Server

    AUTHOR|(CDS)2160803; Boine-Frankenheim, Oliver

    Electron clouds can develop in accelerators operating with positively charged particles. The con- sequences of e-cloud related effects are very important for the operation of the Large Hadron Collider (LHC) at CERN, and for the design of future accelerators including the LHC luminosity upgrade (HL-LHC). High electron densities are generated by an interaction between the beam and the confining chamber. Primary electrons, that can be generated through various mecha- nisms, are accelerated by the beam and impinge on the chamber walls, thereby extracting more electrons from the material. Furthermore they also deposit their kinetic energy in the process, which has to be compensated by the cooling system. Especially in cryogenic environments, as it is the case for a large part of the LHC, high heat loads can pose a serious problem. In order to improve the understanding of the electron cloud, simulation studies are performed with the code PyECLOUD, developed at CERN. The work of the first half of the project is desc...

  3. Plans for the upgrade of the LHC injectors

    CERN Document Server

    Garoby, R; Goddard, B; Hanke, K; Meddahi, M; Vretenar, M

    2011-01-01

    The LHC injectors upgrade (LIU) project has been launched at the end of 2010 to prepare the CERN accelerator complex for reliably providing beam with the challenging characteristics required by the high luminosity LHC until at least 2030. Based on the work already started on Linac4, PS Booster, PS and SPS, the LIU project coordinates studies and implementation, and interfaces with the high luminosity LHC (HL-LHC) project which looks after the upgrade of the LHC itself, expected by the end of the present decade. The anticipated beam characteristics are described, as well as the status of the studies and the solutions envisaged for improving the injector performances.

  4. Strongly coupled models at the LHC

    International Nuclear Information System (INIS)

    Vries, Maikel de

    2014-10-01

    In this thesis strongly coupled models where the Higgs boson is composite are discussed. These models provide an explanation for the origin of electroweak symmetry breaking including a solution for the hierarchy problem. Strongly coupled models provide an alternative to the weakly coupled supersymmetric extensions of the Standard Model and lead to different and interesting phenomenology at the Large Hadron Collider (LHC). This thesis discusses two particular strongly coupled models, a composite Higgs model with partial compositeness and the Littlest Higgs model with T-parity - a composite model with collective symmetry breaking. The phenomenology relevant for the LHC is covered and the applicability of effective operators for these types of strongly coupled models is explored. First, a composite Higgs model with partial compositeness is discussed. In this model right-handed light quarks could be significantly composite, yet compatible with experimental searches at the LHC and precision tests on Standard Model couplings. In these scenarios, which are motivated by flavour physics, large cross sections for the production of new resonances coupling to light quarks are expected. Experimental signatures of right-handed compositeness at the LHC are studied, and constraints on the parameter space of these models are derived using recent results by ATLAS and CMS. Furthermore, dedicated searches for multi-jet signals at the LHC are proposed which could significantly improve the sensitivity to signatures of right-handed compositeness. The Littlest Higgs model with T-parity, providing an attractive solution to the fine-tuning problem, is discussed next. This solution is only natural if its intrinsic symmetry breaking scale f is relatively close to the electroweak scale. The constraints from the latest results of the 8 TeV run at the LHC are examined. The model's parameter space is being excluded based on a combination of electroweak precision observables, Higgs precision

  5. Open Access to the LHC takes on a new meaning

    CERN Multimedia

    2008-01-01

    Complete scientific documentation on the LHC machine and detectors is now freely available on the Web. The ATLAS collaboration, shown here, contributed to the 1,600-page scientific documentation of the LHC, along with staff from the other five detectors and the LHC machine.Now that the LHC tunnel and the experimental caverns are shut down for public visits, "Open Access to the LHC" has taken on an entirely new meaning. Last Thursday, 14 August, seven major articles were published electronically in a special issue of the Journal of Instrumentation (JINST). Together they form the complete scientific documentation on the design and construction of the LHC machine and the six detectors (ALICE, ATLAS, CMS, LHCb, LHCf and TOTEM), and thus on the entire LHC project, well before start-up on 10 September. For many years to come, these papers will serve as key references for the stream of scientific results that will begin to emerge from the ...

  6. Academic Training: A walk through the LHC injector chain

    CERN Multimedia

    Françoise Benz

    2005-01-01

    2004-2005 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 21, 22, 23 March from 11.00 to 12.00 hrs - Main Auditorium, bldg. 500 A walk through the LHC injector chain M. BENEDIKT, P. COLLIER, K. SCHINDL /CERN-AB Proton linac, PS Booster, PS, SPS and the two transfer channels from SPS to LHC are used for LHC proton injection. The lectures will review the features of these faithful machines and underline the modifications required for the LHC era. Moreover, an overview of the LHC lead ion injector scheme from the ion source through ion linac, LEIR, PS and SPS right to the LHC entry will be given. The particular behaviour of heavy ions in the LHC will be sketched and the repercussions on the injectors will be discussed. ENSEIGNEMENT ACADEMIQUE ACADEMIC TRAINING Françoise Benz 73127 academic.training@cern.ch

  7. Gravitinos and hidden supersymmetry at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Bobrovskyi, Sergei

    2012-08-15

    We investigate phenomenological consequences of locally supersymmetric extensions of the Standard Model consistent with primordial nucleosynthesis, leptogenesis and dark matter constraints. An unequivocal prediction of local supersymmetry is the existence of the gravitino, the spin-3/2 superpartner of the graviton. Due to its extremely weak couplings, decays involving the gravitino in the initial or the final state may cause problems in the early universe. One class of models solving the gravitino problem makes the gravitino either the heaviest or the lightest supersymmetric particle (LSP), while predicting a higgsino-like neutralino as the LSP or the next-to-lightest superparticle (NLSP), respectively. In both cases the LHC phenomenology is determined by the higgsino states. The mass degeneracy between the charged and neutral states, together with very heavy colored states, prevent an early discovery at the LHC, especially if one demands a lightest Higgs mass compatible with the recent LHC signal excess. Another class of models, in which the gravitino is also a dark matter candidate, introduces a small violation of R-parity to render the cosmology consistent. In this case, the phenomenology at the LHC is determined by the R-parity violating decays of the NLSP which can be a bino-like or a higgsino-like neutralino or a stau. Using a novel approach to describing bilinear R-parity violation, we compute decay rates of the gravitino and the possible NLSP. Due to a connection between the gravitino and neutralino decay widths, we can predict the neutralino NLSP decay length at the LHC directly from the recent Fermi-LAT results for decaying dark matter searches. The decays of the NLSP in the detectors distort the missing transverse energy (MET) signature, which complicates the searches relying on it, while creating a new secondary vertex signature. We conclude that for gluino and squark masses accessible at the LHC, searches based on secondary vertices can probe values of

  8. Gravitinos and hidden supersymmetry at the LHC

    International Nuclear Information System (INIS)

    Bobrovskyi, Sergei

    2012-08-01

    We investigate phenomenological consequences of locally supersymmetric extensions of the Standard Model consistent with primordial nucleosynthesis, leptogenesis and dark matter constraints. An unequivocal prediction of local supersymmetry is the existence of the gravitino, the spin-3/2 superpartner of the graviton. Due to its extremely weak couplings, decays involving the gravitino in the initial or the final state may cause problems in the early universe. One class of models solving the gravitino problem makes the gravitino either the heaviest or the lightest supersymmetric particle (LSP), while predicting a higgsino-like neutralino as the LSP or the next-to-lightest superparticle (NLSP), respectively. In both cases the LHC phenomenology is determined by the higgsino states. The mass degeneracy between the charged and neutral states, together with very heavy colored states, prevent an early discovery at the LHC, especially if one demands a lightest Higgs mass compatible with the recent LHC signal excess. Another class of models, in which the gravitino is also a dark matter candidate, introduces a small violation of R-parity to render the cosmology consistent. In this case, the phenomenology at the LHC is determined by the R-parity violating decays of the NLSP which can be a bino-like or a higgsino-like neutralino or a stau. Using a novel approach to describing bilinear R-parity violation, we compute decay rates of the gravitino and the possible NLSP. Due to a connection between the gravitino and neutralino decay widths, we can predict the neutralino NLSP decay length at the LHC directly from the recent Fermi-LAT results for decaying dark matter searches. The decays of the NLSP in the detectors distort the missing transverse energy (MET) signature, which complicates the searches relying on it, while creating a new secondary vertex signature. We conclude that for gluino and squark masses accessible at the LHC, searches based on secondary vertices can probe values of

  9. The ALICE experiment at the CERN LHC

    Energy Technology Data Exchange (ETDEWEB)

    Aamodt, K [Department of Physics, University of Oslo, Oslo (Norway); Abrahantes Quintana, A [Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear (CEADEN), Madrid/Havana, Spain (Cuba); Achenbach, R [Kirchhoff-Institut fuer Physik, Ruprecht-Karls-Universitaet Heidelberg, Heidelberg, Germany BMBF (Germany); Acounis, S [SUBATECH, Ecole des Mines de Nantes, Universite de Nantes, CNRS/IN2P3, Nantes (France); Adamova, D [Academy of Sciences of the Czech Republic, Nuclear Physics Institute, Rez/Prague (Czech Republic); Adler, C [Physikalisches Institut, Ruprecht-Karls-Universitaet Heidelberg, Heidelberg, Germany BMBF (Germany); Aggarwal, M [Physics Department, Panjab University, Chandigarh (India); Agnese, F [IPHC, Universite Louis Pasteur, CNRS/IN2P3, Strasbourg (France); Rinella, G Aglieri [CERN, European Organization for Nuclear Reasearch, Geneva (Switzerland); Ahammed, Z [Variable Energy Cyclotron Centre, Kolkata (India); Ahmad, A; Ahmad, N; Ahmad, S [Department of Physics Aligarh Muslim University, Aligarh (India); Akindinov, A [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Akishin, P [JINR, Joint Institute for Nuclear Research, Dubna, (Russian Federation); Aleksandrov, D [Russian Research Center Kurchatov Institute, Moscow (Russian Federation); Alessandro, B; Alfarone, G [Sezione INFN, Torino (Italy); Alfaro, R [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Mexico City (Mexico); Alici, A [Dipartimento di Fisica dell' Universita and Sezione INFN, Bologna (Italy)], E-mail: Hans-Ake.Gustafsson@hep.lu.se (and others)

    2008-08-15

    ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries. Its overall dimensions are 16 x 16 x 26 m{sup 3} with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010

  10. Elementary Particle Interactions with CMS at LHC

    International Nuclear Information System (INIS)

    Spanier, Stefan

    2016-01-01

    The High Energy Particle Physics group of the University of Tennessee participates in the search for new particles and forces in proton-proton collisions at the LHC with the Compact Muon Solenoid experiment. Since the discovery of the Higgs boson in 2012, the search has intensified to find new generations of particles beyond the standard model using the higher collision energies and ever increasing luminosity, either directly or via deviations from standard model predictions such as the Higgs boson decays. As part of this effort, the UTK group has expanded the search for new particles in four-muon final states, and in final states with jets, has successfully helped and continues to help to implement and operate an instrument for improved measurements of the luminosity needed for all data analyses, and has continued to conduct research of new technologies for charged particle tracking at a high-luminosity LHC.

  11. Mechanical Behaviour of the LHC Cryodipoles

    CERN Document Server

    Buenaventura, A; Skoczen, Blazej

    2000-01-01

    The LHC cryodipoles are slender and heavy objects more than 15-m long. The major components of the cryodipole assembly are the 28-tonne cold mass, supported on its three Glass-Fibre-Reinforced-Epoxy support posts and the 4-tonne vacuum vessel. The performance of the LHC depends very much upon the accurate positioning of the dipoles and the beam tubes, in particular to maximise the useful beam apertures. The cryodipoles will be conditioned and measured in surface assembly buildings, then handled and transported to their positions in the tunnel and, finally, aligned. This paper presents the static and dynamic studies of the cryodipole in different configurations. The tests and analyses carried out have led to a thorough understanding of the mechanical behaviour of the cryodipoles. From the static analysis, an hyperstatic supporting system is proposed in order to minimise the systematic deflections and the effects due to changing temperature conditions in the tunnel. The dynamic analysis has shown that the cryod...

  12. Black hole chromosphere at the CERN LHC

    International Nuclear Information System (INIS)

    Anchordoqui, Luis; Goldberg, Haim

    2003-01-01

    If the scale of quantum gravity is near a TeV, black holes will be copiously produced at the CERN LHC. In this work we study the main properties of the light descendants of these black holes. We show that the emitted partons are closely spaced outside the horizon, and hence they do not fragment into hadrons in vacuum but more likely into a kind of quark-gluon plasma. Consequently, the thermal emission occurs far from the horizon, at a temperature characteristic of the QCD scale. We analyze the energy spectrum of the particles emerging from the 'chromosphere', and find that the hard hadronic jets are almost entirely suppressed. They are replaced by an isotropic distribution of soft photons and hadrons, with hundreds of particles in the GeV range. This provides a new distinctive signature for black hole events at LHC

  13. The LHC Beam Pipe Waveguide Mode Reflectometer

    CERN Document Server

    Kroyer, T; Caspers, Friedhelm; Sulek, Z; Williams, L R

    2007-01-01

    The waveguide-mode reflectometer for obstacle detection in the LHC beam pipe has been intensively used for more than 18 months. The â€ワAssembly” version is based on the synthetic pulse method using a modern vector network analyzer. It has mode selective excitation couplers for the first TE and TM mode and uses a specially developed waveguide mode dispersion compensation algorithm with external software. In addition there is a similar â€ワIn Situ” version of the reflectometer which uses permanently installed microwave couplers at the end of each of the nearly 3 km long LHC arcs. During installation a considerable number of unexpected objects have been found in the beam pipes and subsequently removed. Operational statistics and lessons learned are presented and the overall performance is discussed.

  14. Quasi-stable neutralinos at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Bobrovskyi, S.; Buchmueller, W.; Hajer, J.; Schmidt, J.

    2011-07-15

    We study supersymmetric extensions of the Standard Model with small R-parity and lepton number violating couplings which are naturally consistent with primordial nucleosynthesis, thermal leptogenesis and gravitino dark matter. We consider supergravity models where the gravitino is the lightest superparticle followed by a bino-like next-to-lightest superparticle (NLSP). Extending previous work we investigate in detail the sensitivity of LHC experiments to the R-parity breaking parameter {xi} for various gluino and squark masses. We perform a simulation of signal and background events for the generic detector DELPHES for which we implement the finite NLSP decay length. We find that for gluino and squark masses accessible at the LHC, values of {xi} can be probed which are one to two orders of magnitude smaller than the present upper bound obtained from astrophysics and cosmology. (orig.)

  15. Observability of inert scalars at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Hashemi, Majid [Shiraz University, Physics Department, College of Sciences, Shiraz (Iran, Islamic Republic of); Najjari, Saereh [University of Warsaw, Faculty of Physics, Warsaw (Poland)

    2017-09-15

    In this work we investigate the observability of inert doublet model scalars at the LHC operating at the center of mass energy of 14 TeV. The signal production process is pp → AH{sup ±} → ZHW{sup ±}H leading to two different final states of l{sup +}l{sup -}HjjH and l{sup +}l{sup -}Hl{sup ±}νH based on the hadronic and leptonic decay channels of the W boson. All the relevant background processes are considered and an event selection is designed to distinguish the signal from the large Standard Model background. We found that signals of the selected search channels are well observable at the LHC with an integrated luminosity of 300 fb{sup -1}. (orig.)

  16. Pulling the trigger on LHC electronics

    CERN Document Server

    CERN. Geneva

    2001-01-01

    The conditions at CERN's Large Hadron Collider pose severe challenges for the designers and builders of front-end, trigger and data acquisition electronics. A recent workshop reviewed the encouraging progress so far and discussed what remains to be done. The LHC experiments have addressed level one trigger systems with a variety of high-speed hardware. The CMS Calorimeter Level One Regional Trigger uses 160 MHz logic boards plugged into the front and back of a custom backplane, which provides point-to-point links between the cards. Much of the processing in this system is performed by five types of 160 MHz digital applications-specific integrated circuits designed using Vitesse submicron high-integration gallium arsenide gate array technology. The LHC experiments make extensive use of field programmable gate arrays (FPGAs). These offer programmable reconfigurable logic, which has the flexibility that trigger designers need to be able to alter algorithms so that they can follow the physics and detector perform...

  17. CERN LHC Technical Infrastructure Monitoring (TIM)

    CERN Document Server

    Epting, U; Martini, R; Sollander, P; Bartolomé, R; Vercoutter, B; Morodo-Testa, M C

    1999-01-01

    The CERN Large Hadron Collider (LHC) will start to deliver particles to its experiments in the year 2005. However, all the primary services such as electricity, cooling, ventilation, safety systems and others such as vacuum and cryogenics will be commissioned gradually between 2001 and 2005. This technical infrastructure will be controlled using industrial control systems, which have either already been purchased from specialized companies or are currently being put together for tender. This paper discusses the overall architecture and interfaces that will be used by the CERN Technical Control Room (TCR) to monitor the technical services at CERN and those of the LHC and its experiments. The issue of coherently integrating existing and future control systems over a period of five years with constantly evolving technology is addressed. The paper also summarizes the functionality of all the tools needed by the control room such as alarm reporting, data logging systems, man machine interfaces and the console mana...

  18. Simplified Models for LHC New Physics Searches

    CERN Document Server

    Alves, Daniele; Arora, Sanjay; Bai, Yang; Baumgart, Matthew; Berger, Joshua; Buckley, Matthew; Butler, Bart; Chang, Spencer; Cheng, Hsin-Chia; Cheung, Clifford; Chivukula, R.Sekhar; Cho, Won Sang; Cotta, Randy; D'Alfonso, Mariarosaria; El Hedri, Sonia; Essig, Rouven; Evans, Jared A.; Fitzpatrick, Liam; Fox, Patrick; Franceschini, Roberto; Freitas, Ayres; Gainer, James S.; Gershtein, Yuri; Gray, Richard; Gregoire, Thomas; Gripaios, Ben; Gunion, Jack; Han, Tao; Haas, Andy; Hansson, Per; Hewett, JoAnne; Hits, Dmitry; Hubisz, Jay; Izaguirre, Eder; Kaplan, Jared; Katz, Emanuel; Kilic, Can; Kim, Hyung-Do; Kitano, Ryuichiro; Koay, Sue Ann; Ko, Pyungwon; Krohn, David; Kuflik, Eric; Lewis, Ian; Lisanti, Mariangela; Liu, Tao; Liu, Zhen; Lu, Ran; Luty, Markus; Meade, Patrick; Morrissey, David; Mrenna, Stephen; Nojiri, Mihoko; Okui, Takemichi; Padhi, Sanjay; Papucci, Michele; Park, Michael; Park, Myeonghun; Perelstein, Maxim; Peskin, Michael; Phalen, Daniel; Rehermann, Keith; Rentala, Vikram; Roy, Tuhin; Ruderman, Joshua T.; Sanz, Veronica; Schmaltz, Martin; Schnetzer, Stephen; Schuster, Philip; Schwaller, Pedro; Schwartz, Matthew D.; Schwartzman, Ariel; Shao, Jing; Shelton, Jessie; Shih, David; Shu, Jing; Silverstein, Daniel; Simmons, Elizabeth; Somalwar, Sunil; Spannowsky, Michael; Spethmann, Christian; Strassler, Matthew; Su, Shufang; Tait, Tim; Thomas, Brooks; Thomas, Scott; Toro, Natalia; Volansky, Tomer; Wacker, Jay; Waltenberger, Wolfgang; Yavin, Itay; Yu, Felix; Zhao, Yue; Zurek, Kathryn

    2012-01-01

    This document proposes a collection of simplified models relevant to the design of new-physics searches at the LHC and the characterization of their results. Both ATLAS and CMS have already presented some results in terms of simplified models, and we encourage them to continue and expand this effort, which supplements both signature-based results and benchmark model interpretations. A simplified model is defined by an effective Lagrangian describing the interactions of a small number of new particles. Simplified models can equally well be described by a small number of masses and cross-sections. These parameters are directly related to collider physics observables, making simplified models a particularly effective framework for evaluating searches and a useful starting point for characterizing positive signals of new physics. This document serves as an official summary of the results from the "Topologies for Early LHC Searches" workshop, held at SLAC in September of 2010, the purpose of which was to develop a...

  19. The ATLAS Tile Calorimeter Performance at LHC

    CERN Document Server

    Molander, S; The ATLAS collaboration

    2013-01-01

    The Tile Calorimeter (TileCal) is the central section of the hadronic calorimeter of the ATLAS experiment at LHC. The TileCal pays a major role in detecting hadrons, jets, hadronic decays of tau leptons and measuring the missing transverse energy. Due to the very good signal to noise ratio it assists the muon spectrometer in the identification and reconstruction of muons, which are also a tool for the in situ energy scale validation. The results presented here stem from the data collection in dedicated calibration runs, in cosmic rays data-taking and in LHC collisions along 3 years of operation. The uniformity, stability and precision of the energy scale, the time measurement capabilities and the robustness of the performance against pile-up are exposed through the usage of hadronic and muon final states and confirm the design expectations.

  20. CMS tracker towards the HL-LHC

    CERN Document Server

    Alunni Solestizi, Luisa

    2015-01-01

    In sight of the incoming new LHC era (High Luminosity - LHC), characterized by a jump forward in the precision boundary and in the event rate, all the CMS sub-detector are developing and studying innovative strategies of trigger, pattern recognition, event timing and so on. A crucial aspect will be the online event selection: a totally new paradigm is needed, given the huge amount of events. In this picture the most granular and innermost sub-detector, the tracker, will play a decisive role. The phase-2 tracker will be involved in the L1 Trigger and, taking advantage of both the Associative Memories and the FPGA, it can ensure a trigger decision in proper time and with satisfactory performances.

  1. Supersymmetry, Dark Matter and the LHC

    International Nuclear Information System (INIS)

    Tata, Xerxes

    2010-01-01

    The conceptually simplest scenario for dark matter (DM) is that it is a stable thermal relic from standard Big Bang cosmology, in many SUSY models the lightest neutralino. The relic density determination selects special regions in SUSY model parameter space with concomitant implications for collider physics, dark matter searches and low energy measurements. By studying various one-parameter extensions of the much-studied mSUGRA model (where we relax the untested universality assumptions) constructed to be in accord with the measured relic density, we show that these implications are in general model-dependent, so that LHC and DM measurements will provide clues to how sparticles acquire their masses. We point out some relatively robust implications for LHC and DM searches and conclude with an outlook for the future.

  2. Yukawa Bound States and Their LHC Phenomenology

    Directory of Open Access Journals (Sweden)

    Enkhbat Tsedenbaljir

    2013-01-01

    Full Text Available We present the current status on the possible bound states of extra generation quarks. These include phenomenology and search strategy at the LHC. If chiral fourth-generation quarks do exist their strong Yukawa couplings, implied by current experimental lower bound on their masses, may lead to formation of bound states. Due to nearly degenerate 4G masses suggested by Precision Electroweak Test one can employ “heavy isospin” symmetry to classify possible spectrum. Among these states, the color-octet isosinglet vector ω 8 is the easiest to be produced at the LHC. The discovery potential and corresponding decay channels are covered in this paper. With possible light Higgs at ~125 GeV two-Higgs doublet version is briefly discussed.

  3. Jet physics at the LHC with ALICE

    International Nuclear Information System (INIS)

    Morsch, A.

    2005-01-01

    In central Pb-Pb collisions at the LHC, jet rates are expected to be high at energies at which ALICE can reconstruct jets over the background of the underlying event. This will open the possibility to quantify the effect of partonic energy loss through medium induced gluon radiation, jet quenching, by detailed measurement of the modification of the longitudinal and transverse structure of identified jets. In order to obtain probes sensitive to the properties of the QCD medium, it is mandatory to measure the high-p T parton fragments together with the low-p T particles from the radiated gluons. Hence, the excellent charged particle tracking capabilities of ALICE combined with the proposed electromagnetic calorimeter for ALICE, EMCAL, represent an ideal tool for jet quenching studies at the LHC. (orig.)

  4. Exotic highly ionising particles at the LHC

    CERN Document Server

    De Roeck, A; Mermod, P; Milstead, D; Sloan, T

    2012-01-01

    The experiments at the Large Hadron Collider (LHC) are able to discover or set limits on the production of exotic particles with TeV-scale masses possessing values of electric and/or magnetic charge such that they appear as highly ionising particles (HIPs). In this paper the sensitivity of the LHC experiments to HIP production is discussed in detail. It is shown that a number of different detection methods are required to investigate as fully as possible the charge-mass range. These include direct detection as the HIPs pass through detectors and, in the case of magnetically charged objects, the so-called induction method with which monopoles which stop in accelerator and detector material could be observed. The benefit of using complementary approaches to HIP detection is discussed.

  5. Dipoles for High-Energy LHC

    CERN Document Server

    Todesco, E; De Rijk, G; Rossi, L

    2014-01-01

    For the High Energy LHC, a study of a 33 TeV center of mass collider in the LHC tunnel, main dipoles of 20 T operational field are needed. In this paper we first review the conceptual design based on block coil proposed in the Malta workshop, addressing the issues related to coil fabrication and assembly. We then propose successive simplifications of this design, associating a cost estimate of the conductor. We then analyse a block layout for a 15 T magnet. Finally, we consider two layouts based on the D20 and HD2 short models built by LBL. A first analysis of the aspects related to protection of these challenging magnets is given.

  6. First LHC Shutdown: Coordination and Schedule Issues

    CERN Document Server

    Coupard, J; Grillot, S

    2010-01-01

    The first LHC shutdown started in fall 2008, just after the incident on the 19th of September 2008. In addition to the typical work of a shutdown, a large number of interventions, related to the “consolidation after the incident” were performed in the LHC loop. Moreover the amount of work increased during the shutdown, following the recommendations and conclusions of the different working groups in charge of the safety of the personnel and of the machine. This paper will give an overview of the work performed, the organization of the coordination, emphasizing the new safety risks (electrical and cryogenic), and how the interventions were implemented in order to ensure both the safety of personnel and a minimized time window.

  7. Lecture 7: Worldwide LHC Computing Grid Overview

    CERN Multimedia

    CERN. Geneva

    2013-01-01

    This presentation will introduce in an informal, but technically correct way the challenges that are linked to the needs of massively distributed computing architectures in the context of the LHC offline computing. The topics include technological and organizational aspects touching many aspects of LHC computing, from data access, to maintenance of large databases and huge collections of files, to the organization of computing farms and monitoring. Fabrizio Furano holds a Ph.D in Computer Science and has worked in the field of Computing for High Energy Physics for many years. Some of his preferred topics include application architectures, system design and project management, with focus on performance and scalability of data access. Fabrizio has experience in a wide variety of environments, from private companies to academic research in particular in object oriented methodologies, mainly using C++. He has also teaching experience at university level in Software Engineering and C++ Programming.

  8. La Physique au LHC - Partie I

    CERN Multimedia

    CERN. Geneva

    2004-01-01

    Le LHC devrait permettre l'observation du boson de Higgs et pouvoir lever le voile sur l'un des scénarios de nouvelle physique présentés dans la cours précédent. Ce cours détaillera les perspectives de physique au LHC (découvertes possibles et mesures de précision) ainsi que les méthodes et difficultés expérimentales. L'accent sera mis sur les problèmes liés à la brisure de la symétrie electrofaible. Les possibilités de développement futur à plus haute luminosité et/ou énergie seront également discutées.

  9. Installation of the LHC transfer lines begins

    CERN Multimedia

    Patrice Loïez

    2003-01-01

    The first of 700 magnets has been installed in one of the two transfer tunnels built to transfer the SPS beam into the LHC. The start of this first installation phase of the LHC transfer lines provides the opportunity to launch a new and highly original modular system for transporting and installing all kinds of magnets in very narrow tunnels. The system is based on very compact bogies, up to four of which can be coupled together to form a convoy. The wheels are fitted with individual motors enabling them to swivel through an angle of 90° and the convoy to move laterally. In this way the magnet is delivered directly to its installation point, but beneath the beamline. It is then raised into its final position in the beamline using air cushions, which form an integrated part of the transport system. Here we see the transport vehicle alongside the magnet supports. Visible in the background is the first magnet in place.

  10. LHC Survey Laser Tracker Controls Renovation

    CERN Document Server

    Charrondière, C

    2011-01-01

    The LHC survey laser tracker control system is based on an industrial software package (Axyz) from Leica Geosystems™ that has an interface to Visual Basic™, which we used to automate the geometric measurements for the LHC magnets. With the new version of the Leica software, this Visual Basic™ interface is no longerb available and we had to redesign the interface software to adapt to a PC-DMIS server that replaced the Axyz software. As this package is no longer supported, we have taken the decision to recode the automation application in LabVIEW. This presentation describes the existing equipment, interface and application showing the reasons for our decisions to move to PC-DMIS and LabVIEW. A comparison between the new and legacy system is made

  11. ATLAS Distributed Computing in LHC Run2

    CERN Document Server

    Campana, Simone; The ATLAS collaboration

    2015-01-01

    The ATLAS Distributed Computing infrastructure has evolved after the first period of LHC data taking in order to cope with the challenges of the upcoming LHC Run2. An increased data rate and computing demands of the Monte-Carlo simulation, as well as new approaches to ATLAS analysis, dictated a more dynamic workload management system (ProdSys2) and data management system (Rucio), overcoming the boundaries imposed by the design of the old computing model. In particular, the commissioning of new central computing system components was the core part of the migration toward the flexible computing model. The flexible computing utilization exploring the opportunistic resources such as HPC, cloud, and volunteer computing is embedded in the new computing model, the data access mechanisms have been enhanced with the remote access, and the network topology and performance is deeply integrated into the core of the system. Moreover a new data management strategy, based on defined lifetime for each dataset, has been defin...

  12. Top quark production at the LHC

    CERN Document Server

    Ferreira da Silva, Pedro

    2016-01-01

    Twenty years past its discovery, the top quark continues attracting great interest as experiments keep unveiling its properties. An overview of the latest measurements in the domain of top quark production, performed by the ATLAS and CMS experiments at the CERN LHC, is given. The latest measurements of top quark production rates via strong and electroweak processes are reported and compared to different perturbative QCD predictions. Fundamental properties, such as the mass or the couplings of the top quark, as well as re-interpretations seeking for beyond the standard model contributions in the top quark sector, are extracted from these measurements. In each case an attempt to highlight the first results and main prospects for the on-going Run 2 of the LHC is made.

  13. Slice through an LHC focusing magnet

    CERN Multimedia

    Slice through an LHC superconducting quadrupole (focusing) magnet. The slice includes a cut through the magnet wiring (niobium titanium), the beampipe and the steel magnet yokes. Particle beams in the Large Hadron Collider (LHC) have the same energy as a high-speed train, squeezed ready for collision into a space narrower than a human hair. Huge forces are needed to control them. Dipole magnets (2 poles) are used to bend the paths of the protons around the 27 km ring. Quadrupole magnets (4 poles) focus the proton beams and squeeze them so that more particles collide when the beams’ paths cross. Bringing beams into collision requires a precision comparable to making two knitting needles collide, launched from either side of the Atlantic Ocean.

  14. The heavy quark search at the LHC

    International Nuclear Information System (INIS)

    Holdom, Bob

    2007-01-01

    We explore further the discovery potential for heavy quarks at the LHC, with emphasis on the t' and b' of a sequential fourth family associated with electroweak symmetry breaking. We consider QCD multijets, t t-bar + jets, W + jets and single t backgrounds using event generation based on improved matrix elements and low sensitivity to the modeling of initial state radiation. We exploit a jet mass technique for the identification of hadronically decaying W's and t's, to be used in the reconstruction of the t' or b' mass. This along with other aspects of event selection can reduce backgrounds to very manageable levels. It even allows a search for both t' and b' in the absence of b-tagging, of interest for the early running of the LHC. A heavy quark mass of order 600 GeV is motivated by the connection to electroweak symmetry breaking, but our analysis is relevant for any new heavy quarks with weak decay modes

  15. Scientific Opportunity: the Tevatron and the LHC

    CERN Multimedia

    2010-01-01

    The press makes much of the competition between CERN’s LHC and Fermilab’s Tevatron in the search for the Higgs boson. This competitive aspect is real, and probably adds spice to the scientific exploration, but for us such reporting often feels like spilling the entire pepper shaker over a fine meal. The media’s emphasis on competition obscures the more important substance of our long-standing collaboration in scientific discovery.   Our laboratories and our communities have worked together for decades. Europeans have contributed greatly to the Tevatron’s many successes, including the discovery of the top quark, the discovery of fast oscillations in the decay of strange B mesons and the many searches for new phenomena. Americans have contributed to many programs at CERN, notably the extraordinary precision measurements of LEP, and more recently construction of the LHC accelerator and detectors. Fermilab scientists played a vital role throughout 2009 in...

  16. Installation Strategy for the LHC Main Dipoles

    CERN Multimedia

    Fartoukh, Stephane David

    2004-01-01

    All positions in the LHC machine are not equivalent in terms of beam requirements on the geometry and the field quality of the main dipoles. In the presence of slightly or strongly out-of tolerance magnets, a well-defined installation strategy will therefore contribute to preserve or even optimize the performance of the machine. Based on the present status of the production, we have anticipated a list of potential issues (geometry, transfer function, field direction and random b3) which, combined by order of priority, have been taken into account to define a simple but efficient installation algorithm for the LHC main dipoles. Its output is a prescription for installing the available dipoles in sequence while reducing to an absolute minimum the number of holes required by geometry or FQ issues.

  17. LHC survey laser tracker controls renovation

    International Nuclear Information System (INIS)

    Charrondiere, C.; Nybo, M.

    2012-01-01

    The LHC survey laser tracker control system is based on an industrial software package (Axyz) from Leica Geosystems (TM) that has an interface to Visual Basic (TM), which we used to automate the geometric measurements for the LHC magnets. With the new version of the Leica software, this Visual Basic (TM) interface is no longer available and we had to redesign the interface software to adapt to a PC-DMIS server that replaced the Axyz software. As this package is no longer supported, we have taken the decision to re-code the automation application in LabVIEW. This presentation describes the existing equipment, interface and application showing the reasons for our decisions to move to PC-DMIS and LabVIEW. A comparison between the new and the existing system is made. (authors)

  18. QCD-instantons at LHC. Theoretical aspects

    International Nuclear Information System (INIS)

    Petermann, M.

    2007-06-01

    Instantons are nonperturbative, topologically nontrivial field configurations, which occur in every nonabelian gauge theory. They can be understood as tunneling processes between topologically distinct vacua. Although being a basic theoretical aspect of the Standard Model, a direct experimental verification of instanton processes is still lacking. In this thesis the general discovery potential for QCD-instantons at the LHC is studied in detail by means of instanton perturbation theory. In this context the close correspondence between the leading instanton induced processes at HERA and at LHC becomes important. Essential aspects and differences to deep inelastic scattering can already be revealed by studying the simplest process. Based on these results inclusive cross sections are calculated including the emission of final state gluons. Compared to deep inelastic scattering, a large enhancement of the cross section is found. (orig.)

  19. The LHC and its electrotechnical challenges

    International Nuclear Information System (INIS)

    Bordry, F.

    2010-01-01

    After a brief presentation of the CERN, the European organization for nuclear research, this article presents the LHC, the Large Hadron Collider, the largest and most powerful particle accelerator in the world. The project somehow started in 1984 and relies on several technological challenges which are herein described: superconducting magnets (their characteristics and cryogenic operation), operation security with particularly high energies stored in magnets and beams, LHC electricity supply (electric circuits with high time constant, a required precision and reproducibility of the magnetic field during all the operation phases, importance of power converters). Then the author evokes the starting procedures, some serious damages which occurred, and the restart of the operation period with spectacular results in terms of beam energy. Future experiments and expected results are also evoked

  20. Overview of LHC Beam Loss Measurements

    CERN Document Server

    Dehning, B; Effinger, E; Emery, J; Fadakis, E; Holzer, E B; Jackson, S; Kruk, G; Kurfuerst, C; Marsili, A; Misiowiec, M; Nebot Del Busto, E; Nordt, A; Priebe, A; Roderick, C; Sapinski, M; Zamantzas, C; Grishin, V; Griesmayer, E

    2011-01-01

    The LHC beam loss monitoring system provides measurements with an update rate of 1 Hz and high time resolution data by event triggering. These informations are used for the initiation of beam aborts, fixed displays and the off line analysis. The analysis of fast and localized loss events resulted in the determination of its rate, duration, peak amplitudes, its scaling with intensity, number of bunches and beam energy. The calibration of the secondary shower beam loss signal in respect to the needed beam energy deposition to quench the magnet coil is addressed at 450GeV and 3.5T eV . The adjustment of collimators is checked my measuring the loss pattern and its variation in the collimation regions of the LHC. Loss pattern changes during a fill allow the observation of non typical fill parameters.