1 / 32

ATLAS first run scenarios for B physics

ATLAS first run scenarios for B physics. Paula Eerola, Lund University On behalf of the ATLAS collaboration Beauty 2006, Oxford, 25-29 September 2006. This talk includes:. Introduction A summary of the LHC start-up scenario

zofia
Download Presentation

ATLAS first run scenarios for B physics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ATLAS first run scenarios for B physics Paula Eerola, Lund University On behalf of the ATLAS collaboration Beauty 2006, Oxford, 25-29 September 2006

  2. This talk includes: • Introduction • A summary of the LHC start-up scenario • B-production in the LHC commissioning run (450 GeV + 450 GeV) until the end of 2007. • The first physics run at 14 TeV • Role of B-physics and Heavy Quarkonia events in understanding the detector, trigger and online/offline software with 100 pb-1. • Strategies for B-physics with 100 pb-1 - 1 fb-1 Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  3. Introduction • ATLAS is a general-purpose experiment, with an emphasis on high-pT physics beyond the Standard Model. • ATLAS has also capabilities for a rich B-physics programme, thanks to precise vertexing and tracking, high-resolution calorimetry, good muon identification, and a dedicated and flexible B-physics trigger scheme. • ATLAS has a well-defined B-physics programme for all stages of the LHC operation, from the commissioning run all the way up to the highest luminosity running. Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  4. CP violation sin(2b) +FNP Measurement of Bs properties D ms, DGs, Gs, the weak phase fs Bc mesons Bc mass, t, QCD/EW interplay Lb polarization measurements Asymmetry parameter ab, Pb, life-time measurements Rare decays Precise measurements of the branching ratios and asymmetries ATLAS B-physics goals: precision measurements and new physics • CP-violation parameters • B-hadron parameters: masses, lifetimes, widths, oscillation parameters, couplings, b-production, etc. • Search for New Physics effects: very rare decay modes, forbidden decays/couplings, etc. Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  5. News from the LHC machine Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  6. New LHC machine schedule • P. Jenni ATLAS Overview Week July 2006 • A new LHC schedule and turn-on strategy was presented to the CERN SPC and Council June 2006. The main features of the new schedule are: • The beam pipe closure date will be end of August 2007. • LHC commissioning run with collisions at the injection energy (√s =900 GeV), scheduled November 2007. Luminosity typically L = 1029cm-2s-1. • During the commissioning run at 900 GeV the LHC will be a static machine, no ramp, no squeeze, to debug the machine and the detectors. • Then there will be a shut-down (typically 3 months) during which the remaining machine sectors will be commissioned without beam to full energy (√s = 14 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: goal several fb-1 by the end of 2008. Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  7. b b The commissioning run • The run in 2007 will primarily be a detector and computing commissioning run, much more than a physics run. • A few weeks of stable running conditions at the injection energy. • b cross section dominates at both √s = 900 GeV and 14 TeV. • At √s = 900 GeV the b fraction of total inelastic events is ~10 x smaller than at 14 TeV. Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  8. Triggers for the commissioning running • √s = 0.9 TeV, L = 1029cm-2s-1, sinel=40 mb <=> 4 kHz interaction rate • Commissioning the detector, the trigger, the offline reconstruction and analysis chains • Data taking with loose level-1 (LVL1) single muon triggers (pT>5 GeV) or minimum bias triggers • The High Level Trigger (HLT) in pass-through mode for testing • See J. Kirk’s talk on ATLAS triggers Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  9. b b b Rates and statistics √s=900 GeV, L=1029cm-2s-1 *) 1 full day is 8.64 * 104 s, 30% machine and data taking efficiency assumed Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  10. √s=900 GeV, L=1029cm-2s-1 h  m5 X bb  m5 X bb  m5m3 X pp   (m5m3) X pp  J/y (m5m3) X bb  J/y (m5m3)X Number of events in ATLAS after all cuts 30% machine and data taking efficiency assumed. Reconstruction and trigger efficiencies included. Number of days of data taking Event statistics with B and Quarkonium muonic decays Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  11. W  e Z  ee bb  m5m3X pp + bb  J/Y(m5m3)X √s=900 GeV, L=1029cm-2s-1 Event statistics for the commissioning run 30% data taking efficiency included. Efficiency of trigger and analysis cuts included. Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  12. Heavy flavours b and c will be a source of ~4.7k single muons and ~370 di-muons given 30 days of beam (30% machine and data taking efficiency). Soft LVL1 single-muon trigger can be used to select those events. High-level trigger in pass-through mode. The dimuon sample includes about 90 J/y(m5m3) and 130  (m5m3) – can serve for first tests of mass reconstruction. Any heavy flavour physics? Low statistics will not allow separating direct and indirect J/y sources. S/B a factor of 10 worse than at the nominal LHC c.m. energy. Muons from hadron decays dominate the trigger rate due to worse S/B and softer spectrum. The ratio of J/y and  - events may be the best bet. Conclusions for the commissioning run Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  13. The first physics run: B-physics strategies - Serve as a tool for understanding the trigger and the detector: calibration, alignment, material, magnetic field, event reconstruction.- Physics: cross-section measurements at new energy - QCD tests and optimization of B-trigger strategies.- Control B-channels will be used to verify if we measure correctly well known B-physics quantities (with increasing integrated luminosity  real measurements).- Control B-channels will also be used to prepare for high-precision B-measurements and searches for rare decays: tagging calibration, production asymmetries, background channels specific for rare decays. Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  14. Trigger priorities for the first physics running • √s = 14 TeV, L = 1032-33cm-2s-1 • Many customers for the data • Data for commissioning the detector, the trigger, the offline reconstruction and analysis chains • Data samples high-pT physics studies • Data samples for B-physics studies • Scope depends on luminosity and available HLT resources • Data samples for “minimum-bias” physics studies • Needed also for tuning Monte Carlo generators used in other physics studies Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  15. EM RoI e+ e- Trigger menus for B-physics • The ATLAS B-physics programme is based on LVL1 muon triggers • Inclusive low-pT single-muon triggers at low luminosity • Low-pT dimuon triggers at higher luminosities • Search for specific final states (exclusive or semi-exclusive) in HLT • Refine muon selection, then reconstruct tracks from B decays in the inner detector (ID) • Tracks in ID: track search in the full ID or in regions given by LVL1 Regions of Interests (RoIs), depending on the HLT processor capacity and luminosity • See J. Kirk Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  16. b b b B cross-section at LHC • All LHC experiments plan to measure B-cross section in proton-proton collisions. • Measurements will cover different phase space – will be complementary. • Partial phase-space overlaps: LHCb, ATLAS, CMS, ALICE - opportunity for cross-checks. • Methods of measurement for low- and medium-pT events in ATLAS • b  m6 X ; • b → m6m3 X; • Exclusive channels B+→J/y K+, B0→ J/y K0* • b- correlations: B→J/y X +b m Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006 Df=f J/y - fm

  17. b b c Statistics for cross-section and correlation measurements Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  18. b b B-physics with 100 pb-1: J/y and  Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  19. B physics with 100 pb-1: exclusive B decays Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  20. Lifetime “reconstruction” with control channels The reconstructed masses and lifetimes of the well-known control channels are sensitive tests of those detector features which have a strong impact on B-physics measurements. Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  21. B physics with 100 pb-1: sensitivity to rare exclusive B decays Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  22. B0s→ µ+µ- with 100 pb-1, 10 fb-1 and 30 fb-1 Discovery channel B0s→ µ+µ- Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  23. Commissioning run at 900 GeV, very low luminosity Commissioning of the detector, the trigger, the offline reconstruction and the analysis chains. In 30 days ~4.7k single muons and ~370 di-muons from b and c: first tests of trigger and offline muon reconstruction. 90 J/y and 130 : first tests of mass reconstruction. First physics run at 14 TeV, 100 pb-1 – 1 fb-1 Measurements of B masses and lifetimes: a sensitive test of understanding the detector – alignment, material, magnetic field, event reconstruction etc. Cross-section measurements at new energy: QCD tests and also optimization of B-trigger strategies. J/Y and  measurements. Control B-channel measurements to prepare for further B physics – precision measurements and new physics measurements. With 100 pb-1 ATLAS can achieve a sensitivity of 6.4×10-8 in the discovery channelBr(B0s→ µ+µ- ), which is at the level of current Tevatron results. Conclusions Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  24. Thank you! Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  25. BACKUP SLIDES Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  26. b b b Cross sections in ATLAS for muonic channels *) Dimuon pT cuts for muon reconstruction and identification are: (6, 3) GeV at 14 TeV and (5, 3) GeV for 900 GeV. For both muons |h|<2.5. Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  27. single-muon all h b c b all b h di-muon J/y c Sources of low-pT single and double muons LVL1 muon trigger rates @ 14 TeV and 1033cm-2s-1 • The figure shows sources of low-pT muons at 14 TeV. • Muons from hadron decays in flight (“h” in the figure) have a softer spectrum than muons from b. • At 900 GeV their relative contribution is larger – b fraction of total inelastic cross section ~ 10 smaller than at 14 TeV. Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  28. Cross sections for several dominant channels: in LHC (yellow) and in ATLAS volume (rest). *) m6(5) - muon pT cuts for 14TeV (900 GeV) Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  29. 900 GeV 1029cm-2s-1 rates, statistics Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  30. Event statistics with B and Quarkonium muonic decays √s=900 GeV, L=1029cm-2s-1 bb  m5 X bb  m5m3 X pp   (m5m3) X pp+bb  J/y (m5m3) X 40% machine and data taking efficiency assumed. No reconstruction efficiencies included. Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  31. W  e Z  ee √s=900 GeV, L=1029cm-2s-1 30% data taking efficiency included. Efficiency of all analysis cuts included. Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

  32. Detector configuration during the first physics run • B-layer OK. • ID complete, only TRT C-wheels staged • HLT configuration: full 45kHz LVL1 capacity. Paula Eerola, Lund University Beauty 2006, Oxford, 25-29 September 2006

More Related