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Large Hadron Collider & ATLAS, CMS Experiments

Large Hadron Collider & ATLAS, CMS Experiments. Bing Zhou The University of Michigan CCAST Worshop @Tsinghua University Nov. 6-11, 2006. Outline. Introduction – from SSC to LHC LHC Status and Start up Plan 3) Status of the LHC detectors: ATLAS & CMS

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Large Hadron Collider & ATLAS, CMS Experiments

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  1. Large Hadron Collider&ATLAS, CMS Experiments Bing Zhou The University of Michigan CCAST Worshop @Tsinghua University Nov. 6-11, 2006

  2. Outline Introduction – from SSC to LHC LHC Status and Start up Plan 3) Status of the LHC detectors: ATLAS & CMS -- detector design and construction -- installation and commissioning 4) Physics Potential of the LHC Experiments -- Physics study tools -- Discovery potentials 5) Grid Computing for LHC experiments

  3. Introduction Why need TeV energy ? • Traditionally, particle physics have focused on the inner space frontier, pursuing the questions of the construction of matter and the fundamental forces at the smallest scale accessible. l ~ h/p  smaller distance ~ higher energy • Today, we also pressing the questions from universe – dark matter and dark energy. The understanding of the micro- world and our tools are invaluable in investigating universe at large, and the cosmic phenomena effect microphysics  high energy physics.

  4. What is Universe Made of ? Standard Model Higgs Boson etc. Intriguingly, dark matter points to the same place where the standard model starts to break down … Dark matter particles mass and interactions

  5. The Energy Scale 1018 GeV Quantum Gravity ? • Particle Physics today explores a very wide range of energies • Of particular interest are the highest energies, corresponding to the smallest distances and most massive elementary particles. • The TeV scale contains the mystery of Electroweak symmetry breaking. • Hope a more unified force to describe nature. Unification of Forces? Right-handed neutrinos? LHC Tevatron Higgs? 100 GeV Generation of mass 1 GeV QCD Confines 1 MeV Nuclear process 1 eV Atomic process

  6. LHC-Energy: 14 Trillions of Electron-Volts • The Large Hadron Collider (LHC) at CERN will accelerate each of two counter-rotating beams of protons to 7 TeV per proton.

  7. The Universe is a Mysterious Place!The Early Universe IS high energy physics • We only ‘understand About 5% of matter & Energy content of the Universe. • Particle physics, as the science of matter, energy, space and time Must help to explain the early universe and dark world of universe. Dark matter & dark energy are among among the top questions in physical science today

  8. But (like capitalism!) it contains the seeds of its own destruction The Revolution is Coming! • The standard model makes precise and accurate predictions • It provides an understanding of what protons, neutrons, atoms, stars, you and me are made of • Its spectacular success in describing phenomena at energy scales below 1 TeV is based on • At least one unobserved ingredient • the Higgs Boson • Whose mass is unstable in quantum mechanics • requires additional new forces or particles to fix • It is common conviction that SM is fundamentally incomplete and flawed (a long list of fundamental questions on SM). • The way forward is through experiments at particle accelerators

  9. From SSC to LHC “Without new observations we cannot advance our understanding in particle physics .” “We need a Super-Conducting Super Collider to explore new physics in TeV energy scale.” --- 1984 C. Quigg at el. wrote a review paper on TeV physics, which performed many fundamental calculations and defined the major parameters of the next generation hadron Collider (SSC): Center-of-mass energy: 40 TeV (20 TeV per beam) Luminosity: 1033 cm-2 s-1

  10. From SSC to LHC 1987 – 1990 Design SSC detectors and form collaborations -- SCD (Approved by SSC Program Advisory Committee) -- L* (S.S. C. Ting) (Approved by PAC) -- EMPACT -- Taxas -- GEM (Barish & Willis) detector design in 1990 followed L* design principle : precision Gamma, Electron and Muon 1993: US Congress killed SSC project 1992 – 1994: Design LHC detectors and form collaborations

  11. Main Detector proposals (Express of Interest) Mar.1992 Large Hadron Collider in LEP tunnel • L3+1L3P (S. Ting) • EAGLE (Jenni) • ASCOT (Norton) • CMS (M. Negra, J. C. Lattin) 1994: LoI: ATLAS & CMS ATLAS SSC Accelerator & Detecor R&D results  LHC Initial LHC parameter in 14 years ago

  12. The Large Hadron Collider at CERNCM = 14 GeV, Lumi = 1034 cm-2 s-1 • 27 km Tunnel in Switzerland & France CMS TOTEM pp, general purpose; HI pp, general purpose; HI Atlas First Beams: Fall 2007 Physics Runs: from Spring 2008 ALICE : HI LHCb: B-physics

  13. LHC Construction Team: CERN, US, Japan

  14. Global Requirements on The Machine • Highest energy proton collisions for ATLAS and CMS • Nominal luminosity 1034 cm-2 s-1 in points 1 and 5 • Highest energy proton collisions for LHCb • Nominal luminosity ~ 5 1032 cm-2 s-1 in point 8 • Proton collisions @ various energies for ALICE • Nominal luminosity ~ 1030 cm-2 s-1 in point 2 • Ion collisions @ various energies for ALICE • Nominal luminosity ~ 1027 cm-2 s-1 in point 2 • ATLAS and CMS will also take data • Proton collisions @ various energies for TOTEM Proton luminosity running Dedicated Dedicated

  15. Proton luminosity running HSM -> 4 l (MHiggs = 140-155 GeV and 190-450 GeV) can be discovered with ~ 5 fb-1 Some supersymmetry can be discovered at more modest luminosities ~ 1 fb-1 ATLAS and CMS • Minimize event pileup early on • Go to 25ns as soon as possible • Will make use of any beam for detector commissioning LHCb • Tune IP8 to optimize luminosity (1m <  *>50m) • Go to 25ns as soon as possible (optimized for ~ 1 events/crossing) • Dipole polarity change ~ every fill (!) ALICE • Will use proton beams (intrinsic interest and reference data) • Tune IP2 to optimize luminosity (0.5m <  *>50m) • Magnet polarities change ( + - 0 ) a few times per year (106 seconds @ <L> of 1033 cm-2 s-1 = 1 fb-1)

  16. LHC High Luminosity Run

  17. 2808 is a lot of bunches per beam • Filling scheme requires 12 SPS cycles per beam • Each with 2,3 or 4 batches of 72 bunches • Crossing angle needed • Emittance conservation with 1011 protons per bunch through • Injecting • Ramping • Squeezing to 0.55m

  18. 362MJ is a lot of beam energy to handle

  19. Each Proton bunch is like a bullet!

  20. News from the LHC machine

  21. LHC Scheduleas presented to CERN Council on 23 June 2006 • Last magnet installed : March 2007 Machine and experiments closed : 31 August 2007 • First collisions (s = 900 GeV, L~1029 cm-2 s-1) : November 2007 Commissioning run at injection energy until end 2007, then shutdown (3-4 months) • First collisions at s=14 TeV (followed by first physics run): Spring 2008 Goal : deliver integrated luminosity of few fb-1 by end 2008 The main features of the new schedule are: - The beam pipe closure date will be end of August 2007 (instead of end of June 2007) - After that there will still be a few weeks of controlled access to the cavern - This is followed by an LHC commissioning run with collisions at the injection energy (450 + 450 GeV), until the end of 2007 - Then there will be a shut-down (typically 3 months) during which the remaining machine sectors will be commissioned without beam to full energy (7 TeV) - After that the LHC will be brought into operation for the first physics run at 14 TeV, with the aim to integrate substantial luminosity by the end of 2008

  22. Milestones for the machine (Presented by CERN to SPC and Council) LHC commissioning - Sectors 7-8 and 8-1 will be fully commissioned up to 7 TeV in 2006-2007. If we continue to commission the other sectors up to 7 TeV, we will not get circulating beam in 2007. - The other sectors will be commissioned up to the field needed for de-Gaussing. - Initial operation will be at 900 GeV (CM) with a static machine (no ramp, no squeeze) to debug machine and detectors. - Full commissioning up to 7 TeV will be done in the winter 2008 shutdown

  23. Sector test with beam Aim to send beam • Out of SPS TT40  • Down TI8 • Inject into LHC R8 • Through insertion R8 • Through LHCb • Through IP8 • Through insertion L8 • Through arc 8-7 • To dump at Q6 R7

  24. Apr. 2005 First magnets were installed in the LHC tunnel. Oct. 2005 July 2006 Half-way point(616th) for the 1232 dipole magnets “The longest journey: the LHC dipoles arrive on time” (CERN Courier, Oct. 2006)

  25. Number of quenches to reach nominal field for dipoles on second thermal cycle

  26. CERN management’s conclusion We now have enough information to produce a consolidated plan for commissioning. Three quarters of the machine has been liberated for magnet installation and interconnect work is proceeding in 2 octants in parallel. Magnet installation is now steady at 25/wk . Installation will finish March 2007. The machine will be closed in August 2007. Every effort is being made to establish colliding beams before the end of 2007 at reduced energy. The full commissioning up to 7 TeV will be done during the 2008 winter shutdown ready for a Physics run at full energy in spring 2008. (Presented last week by J Engelen at the Cracow Physics at LHC conference)

  27. 2008 up to 1-2 fb-1 end 2008, up to 10fb-1 end 2009 ? 2008-2009  2010 O(100) fb-1 Note: dates and integrated luminosities are MY interpretation (F. Gianotti)

  28. Stage I Commissioning • Start as simple as possible • No squeeze • * = 18m in 1 & 5 • * = 10m in 2 & 8 • Avoid parasitic beam-beam • No crossing angle • D1L to D1R ~ 116m • Minimum bunch spacing 232m, ~ 0.8μs • 43 bunches per beam convenient for the injectors, spacing 2.025μs • Switch off all unused equipment • Under these relatively clean, safe conditions • Injection of beam from SPS is always safe • Stored beam energy comparable to other facilities • Commission the nominal cycle • Establish reproducible operation • Commission machine protection systems • Beam measurement campaign • Make a few single beam runs at top energy • First high energy collisions • Increase performance • Bring on crossing angle • Luminosity may well go down (remember SPS collider and LEP) • Recover as much as possible without parasitic beam-beam

  29. Stage I physics run • Start as simple as possible • Change 1 parameter (kb N *1 , 5) at a time • All values for • 7TeV • 10m * in point 2 (luminosity looks fine) Protons/beam ≾ 1013 (LEP beam currents) Stored energy/beam ≾ 10MJ (SPS fixed target beam)

  30. Stage II physics run • Relaxed crossing angle (250 rad) • Start un-squeezed • Then go to where we were in stage I • All values for • nominal emittance • 7TeV • 10m * in points 2 and 8 Protons/beam ≈ few 1013 Stored energy/beam ≤ 100MJ

  31. Stage III physics run • Nominal crossing angle (285 rad) • Start un-squeezed • Then go to where we were in stage II • All values for • nominal emittance • 7TeV • 10m * in points 2 and 8 Protons/beam ≈ 1014 Stored energy/beam ≥ 100MJ

  32. Breakdown of a normal year 7-8 ~ 140-160 days for physics per year Not forgetting ion and TOTEM operation Leaves ~ 100-120 days for proton luminosity running ? Efficiency for physics 50% ? ~ 1200 h or ~ 4 106 s of proton luminosity running / year

  33. List of Questions on SM

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