LHC: PAST, PRESENT AND FUTURE

Transcription

1 LHC: PAST, PRESENT AND FUTURE ATLAS CMS AERES visit to IRFU Samira Hassani 7 JANUARY 2014 CEA 10 AVRIL 2012 PAGE 1

2 LHC IS Physics Calibration Reconstruction Simulation R&D Computing Commissioning Magnets Installation Construction LHC CEA 7 January 2014 PAGE 2

3 THE CONTEXT OF LHC IN IRFU Early and strong support to LHC in the IRFU community (since Lausanne workshop 1984) Contributions to the conception, design and technological choices of LHC experiments Continuous efforts, strong involvement and extreme dedication by the IRFU teams in: 20 years of detector and physics simulations 15 years of detector construction and test beams 8 years of world-wide computing data challenges 3 years of detectors commissioning 2 years of data taking with wealth of physics results Participation to the physics coordination of the ATLAS and CMS experiments: data preparation coordinator, computing coordinator, performance convenors, physics convenors, analysis review chairs, publications committee, CEA 7 January 2014 PAGE 3

4 ATLAS MUON SPECTROMETER Conception Toroidal magnet Muon chamber alignment system Barrel: 1300 beams 50 µ over 3000m 2 Magnetic field Hall probes positioning & Reconstruction Muon Reconstruction Software Muon Performance Muon efficiency measured with Zµµ CEA 7 January 2014 PAGE 4

5 ATLAS ELECTROMAGNETIC CALORIMETERS Conception Construction Installation Stability of EM calorimeter response vs time (and pile-up) <0.1% Electron efficiency measured with Zee CEA 7 January 2014 PAGE 5

6 CMS Electromagnetic calorimeter Conception Construction/Installation Many contributions : - Crystal R&D - APD R&D - Electronics - Trigger + CMS solenoïd (SACM) Laser Monitoring System Calibration@IRFU - Laser monitoring - Zee - π 0 Stability of EM calorimeter response vs time (and pile-up) <0.1% Impact on Zee 07/01/2014 CEA 7 January 2014 PAGE 6

7 ANALYSIS STRATEGY AT IRFU The Physics analysis strategy is coherently built on : Key issues in Particle Physics detector expertise 1) Higgs searches data prepartion effort 2) Electroweak Precision analyses know-how from Tevatron legacy 3) Beyond Standard Model collaboration with the theorists CEA 7 January 2014 PAGE 7

8 DISCOVERY OF A HIGGS-LIKE PARTICLE July Revolution (1830) July Revolution (2012) CEA 7 January 2014 PAGE 8

9 CONTRIBUTIONS TO CMS HIGGS RESULTS H γγ H γγ :Spin-parity H ττ 3.2σ (4.2σ exp.) First introduction and development of the VBF and VH productions search Spin/parity analysis Leading role in the Fermiophobic Higgs boson search The observation is well compatible with SM Higgs expectations 0 + Contribution to µτ h most sensitive channel Trigger strategy and background estimation Evidence for Hττ signal: 3.4 (3.6) σ obs GeV CEA 7 January 2014 PAGE 9

10 CONTRIBUTIONS TO ATLAS HIGGS RESULTS HZZ*4 leptons Spin-parity 6.6σ (4.4σ exp.) Muon and electron performance expertise Data driven estimate of Z+jets and ttbar background First introduction and development of Final State Radiation study (ATLAS Thesis Award 2012) Use Variables sensitive to decay angles(matrix Element Likelihood Analysis) Data favour J P =0 +. All alternative hypotheses disfavoured at >97.8% CL CEA 7 January 2014 PAGE 10

11 TOP QUARK PROPERTIES AT THE LHC Mass Development of 3D method (leptons+jets): Fit simultaneously top mass, JES and b-jes ATLAS(prelim)3D result CMS (prelim) combination LHC combination Tevatron combination ±1.54GeV ±0.99GeV ±0.94GeV ±0.87GeV Charge asymmetry Measurement lead by Tevatron s colleagues joining ATLAS Consistent with SM predictions CEA 7 January 2014 PAGE 11

12 CHALLENGES FOR MEASURING W MASS AT LHC LHC ultimate goal M W 5 MeV (underway with 2011 data in ATLAS, expect M W MeV) Tevatron precision: 15 MeV P T (l) is the main measurement probe due to Pile-up (stat. sensitivity : 1 MeV) Lepton energy scales measured at < 10-4 (IRFU/SPP responsible for electron/photon calibration) Theory uncertainties are controlled using P T (Z) measurement (measurement performed at IRFU/SPP) CEA 7 January 2014 PAGE 12

13 DIBOSON STUDIES CONSTRAINTS ON THE EWK LAGRANGIAN Accurate measurement of total and fiducial cross-sections and differential distributions for Wγ, Zγ, WW, WZ, and ZZ production to test underlying theory Probe «New Physics» due to Triple Gauge Coupling (TGC) No deviations from SM, LHC limits on TGC already close or equal to LEP limits CEA 7 January 2014 PAGE 13

14 SOME OF BEYOND STANDARD MODEL SEARCHES Dark Matter search in the mono photon channel Extra-dimensions searches in the mono photon channel bb /T 5/3 T 5/3 WtWt Technicolor ω T Zγ Z µµ CEA 7 January 2014 PAGE 14

15 SHORT-TERM & LONG-TERM OUTLOOK In depth studies of the found Higgs boson : improved measurements of mass, spin, signal strengths and couplings (Final legacy results from the full dataset in 2014) Elucidate the detailed nature of the new boson : 2015 and beyond ( s > 13 TeV) search for rare decay modes and make increasingly precise measurements of the couplings, self-interaction, is it alone? is it elementary or composite? how much does it contribute to restoring unitarity in VBF? Direct search for New Physics: Invisible particles (dark matter candidate) Z Supersymmetry Top composite Extra-dimensions CEA 7 January 2014 PAGE 15

16 SHORT-TERM & LONG-TERM OUTLOOK In depth studies of the found Higgs boson : improved measurements of mass, spin, signal strengths and couplings (Final legacy results from the full dataset in 2014) Elucidate the detailed nature of the new boson : 2015 and beyond ( s > 13 TeV) search for rare decay modes and make increasingly precise measurements of the couplings, self-interaction, is it alone? is it elementary or composite? how much does it contribute to restoring unitarity in VBF? Direct search for New Physics: Invisible particles (dark matter candidate), Z, Indirect search for New Physics through more precise SM measurements : Top physics : study rare decays and measure couplings Diboson physics : search for anomalous TGC s Study of New Physics via vector boson fusion Detector upgrades : maintain or improve on the present performance as the instantaneous luminosity increases A particular challenge is to refine the hardware (level-1) and software(high level) triggers to maintain sensitivity with pileup CEA 7 January 2014 PAGE 16

17 ATLAS UPGRADES (PHASE 1) New Small Wheel impact : Micromegas for precision Tracking and L1 trigger Small strip Thin Gas Chambers for L1 trigger Calorimetric trigger Rate/3 Improved granularity available to L1 calorimeter trigger more precise isolation variables at level 1 Example L1 electron trigger rate with improved selections CEA 7 January 2014 PAGE 17

18 CONCLUSIONS 7/8 TeV 30 fb x Hz/cm 2 50ns PU20 First phase of LHC running successfully concluded LHC Phase 1 13/14 TeV 300 fb -1 LS LS Strong implication of the IRFU s community in the LHC physics program 1.6 x Hz/cm 2 25ns PU40 30 fb -1 / year We seem to have discovered a particle sans precedent The discovery of Higgs boson is just the start of a major programme at the LHC. Two complementary approaches: 2.5 x Hz/cm 2 25ns PU70 70 fb -1 / year HL-LHC? Phase 2 14 TeV 3000 fb -1 LS Precision measurements (not only of the new boson) Searches for new particles and phenomena 5 x Hz/cm 2 25ns PU fb -1 / year