1. Status and Expected Performance of the LHCb Experiment Pascal PERRET Laboratoire de Physique Corpusculaire Clermont-Ferrand Université Blaise Pascal – CNRS/IN2P3 France On behalf of the LHCb Collaboration 6 th International Conference on Hyperons, Charm and Beauty Hadrons Chicago 3 rd July 2004

2. 2 P. Perret 3 rd July 2004 Beach 2004 OUTLINE n Introduction: Physics motivation n LHC n The LHCb experiment wStatus of the experiment wTrigger n Physics prospects  Measurement of angle  n Summary and conclusions n Introduction: Physics motivation n LHC n The LHCb experiment wStatus of the experiment wTrigger n Physics prospects  Measurement of angle  n Summary and conclusions

3. 3 P. Perret 3 rd July 2004 Beach 2004 SM predicts large CP violating asymmetries for B mesons, in many (often rare!) decays  LHCb: dedicated b physics precision experiment of 2 nd generation to study CP violation and rare b-decays n Much higher statistics n Access to all b-hadron species: B d, B u, B s, B c, Λ b, … n Overconstrain the unitarity triangles (consistency checks) n Search for New Physics beyond the SM Physics motivation of LHCb Unitarity Triangles B d 0     B d 0    B S 0  D S  B d 0  J/  K S 0 B S 0  J/  BdBd BsBs New particles may show up in loop diagrams, overconstrain will allow to disentangle SM components from the new-physics ones NP? b d d b t t High statistics is mandatory    V ud V ub V td V tb V cd V cb ** * B d 0  DK *0 B S 0  D S K B d 0  D*     V tb V ub V td V ud V ts V us * *  *

4. 4 P. Perret 3 rd July 2004 Beach 2004 Advantage of LHC LHC startup in spring 2007 n pp collisions at √s = 14 TeV, f=40 MHz, multiple pp interactions/bx n Clear objective is to get to 10 33 cm -2 s -1 during 2007 operation n Increase luminosity to 10 34 cm -2 s -1 in the next few years n  total ~ 100 mb,  visible ~ 65 mb,  bb ~ 500 µb,  bb /  visible = 0.8% n Forward production of bb, correlatedLHCb n Single arm spectrometer  12 mrad <θ< 300 mrad (1,9< η <4,9) n LHCb = 2 x10 32 cm -2 s -1 (tunable: controlled beam focus at LHCb IP) n Efficient trigger and clean events 100  b 230  b  ~10 12 bb events per year (10 7 s) with nominal LHCb luminosity at LHC start-up _

5. 5 P. Perret 3 rd July 2004 Beach 2004 LHC Geneva CERN

6. 6 P. Perret 3 rd July 2004 Beach 2004 LHC TI8 - MBIT TI8 - MBIBV QRL Dipoles > 300/1200 delivered Transfer line installed (2.6 km) 1 st beam October Short Straight Sections

7. 7 P. Perret 3 rd July 2004 Beach 2004 LHCb Requirements n Efficient trigger for many B decay topologies  Leptonic final state → Muon system, ECAL + Preshower  Hadronic final state → HCAL  High pt-particles with large impact parameter → VELO,TT n Efficient particle identification  π/K separation (1<p<100GeV) → RICH n Good decay time resolution → VELO n Good mass resolution → Tracker and Magnet Bd K*Bd K* B d  J/   HIGH STATISTICS

8. 8 P. Perret 3 rd July 2004 Beach 2004 LHCb detector VertexLocator TrackingStations RICH II HCAL MuonStations RICH I SPD/PSECAL Magnet TriggerTracker 20 m Forward spectrometer (running in pp collider mode) Construction well progressing

9. 9 P. Perret 3 rd July 2004 Beach 2004 LHCb status: Vertex Locator  21 stations, retractable during injection  sensitive area starts at only 8 mm from beam axis  r/φ sensors (single sided, 45º r-sectors)  pitch ranges from 35 μm to 102 μm  200 μm thin silicon  180k readout channels Vertex AND Tracking detector VELO mechanics 2 halves in a “Roman-pot” PV resolution: ~8μm (x,y) and ~44μm (z) IP precision: ~40μm 1m sensors

10. 10 P. Perret 3 rd July 2004 Beach 2004 LHCb status: Tracking system Tracking system and dipole magnet to measure angles and momenta:  Magnetic field regularly reversed to reduce experimental systematics n dp/p ~ 0.37 %, n mass resolution ~ 14 MeV (for B s  D s K) n tracking efficiency ~ 94% (for p>10 GeV)

11. 11 P. Perret 3 rd July 2004 Beach 2004 Magnet  Warm Al conductor  4 Tm integrated field  Weight = 1500 tons  4.2 MW n Assembly of yoke completed n Moving magnet into final position (July 04) n Field map measurements (2004- 2005)

12. 12 P. Perret 3 rd July 2004 Beach 2004 Tracking chambers (TT, IT, OT) Trigger Tracker Level-1 trigger K S, low-p tracks Inner Tracker Outer Tracker  3 stations with 4 double layers  5mm straw tubes  50k readout ch.  3 stations with 4 layers each  198 μm readout pitch  130k readout ch.  1.3% of sensitive area → 20% of all tracks  2*2 layers  410 μm silicon  198 μm r/o pitch  144k readout ch. beam pipe 320 µm thick sensors 410 µm thick sensors TT IT OT T1 to T3 ~1.4x1.2 m 2 ~6x5 m 2 ~1.2x.4 m 2

13. 13 P. Perret 3 rd July 2004 Beach 2004 Tracking chambers (TT, IT, OT) Outer Tracker  3 stations with 4 double layers  5mm straw tubes  50k readout ch. Production started OT

14. 14 P. Perret 3 rd July 2004 Beach 2004 RICH  Provide > 3 σ π–K separation for 3 < p < 80 GeV Two RICH detectors for charged hadron identification Bs K+K-Bs K+K- p=84% ε=79% p=13% Aerogel and C 4 F 10 CF 4 RICH-1: 25-300 mrad RICH-2: 15-120 mrad ε(K → K)=88%; ε(π → K)=3%

15. 15 P. Perret 3 rd July 2004 Beach 2004 RICH RICH2 super structure ready Photon detector: Hybrid Photodiodes (1024 pixels- LHCb development) ordered RICH 1 : 168 HPD RICH2 : 262 HPD Exit/entrance windows ready 80 mm

16. 16 P. Perret 3 rd July 2004 Beach 2004 Calorimeter: SPD,PS,ECAL,HCAL  e h  Identification: electrons, hadrons and neutrals ( γ, π 0 ) Readout every 25 ns (L0 trigger) SPD,PS (2.5X 0 ), ECAL(25X 0 ): 5962 channels (Pb/scintillator) HCAL(5.6 λ ): 1468 channels (Iron/scintillator)  σ m ( π 0  γγ ) ~ 10 MeV/c 2 2 resolved clusters  (2 merged clusters: ~ 15 MeV/c 2 )  ECAL:  E/E =8.3%/  E  1.5%  HCAL:  E/E =75%/  E  10%  (e  e) = 95%,  (  e) = 0.7% Conversion

17. 17 P. Perret 3 rd July 2004 Beach 2004 SPD - PS n PS/SPD modules: ~ 25% completed n Assembly SuperModules: start September 200 64APMT

18. 18 P. Perret 3 rd July 2004 Beach 2004 ECAL - HCAL n HCAL modules: ~ 60% completed Installation start December n ECAL modules: 100% completed Installation start November (shashlyk type)

19. 19 P. Perret 3 rd July 2004 Beach 2004 Muon System  µ id. efficiency ~ 94% for pion misidentification rate <~1%   1380 MWPC chambers  Chambers in M2-M5: 4 layers in M1: 2 layers  x and y projectivity to Interaction Point  435 m 2  26 k readout channels  hadron absorber thickness of 20 Muon identification, also used in first level of trigger

20. 20 P. Perret 3 rd July 2004 Beach 2004 Muon System Foam Panel Production Automated wiring machine Final chamber assembly  Production started  5 sites  ~5% ready

21. 21 P. Perret 3 rd July 2004 Beach 2004 Trigger  bb ~ 500  b, < 1% of inelastic cross-section n Use multi-level trigger to select interesting events:  high p T electrons, muons or hadrons  vertex structure and p T of tracks full reconstruction ~ 200 Hz to tape   30–60% efficiency HCAL trigger dominates MUON trigger dominates ECAL trigger dominates L0 L1 HLT µ: p T >1.1 GeV e: E T >2.8 GeV  E T >2.6 GeV h: E T >3.6 GeV

22. 22 P. Perret 3 rd July 2004 Beach 2004 1 MHz 40 kHz 200 Hz output Level-1: Impact parameter p T ~ 20% HLT: Final state Reconstruction Calorimeter Muon Pile-up Vertex Trigger Tracker Level-0 objects Full detector Information Level-0: p T of , e, h,   µs 1 ms 1 800 CPU L0 = synchronized hardware trigger commercial hardware flexible (L1 ↔ HLT) scalable → easy upgrade Trigger 40 MHz asynchronous SW trigger

23. 23 P. Perret 3 rd July 2004 Beach 2004 Simulation MC Pythia 6.2 tuned on CDF and UA5 data, QQ, GEANT3 Multiple pp interactions and spill-over effects included Complete description of material from TDRs Individual detector responses tuned on test beam results Complete pattern recognition in reconstruction: without using MC true information 2003: 67M events produced 10M inclusive bb events (4 mn of data taking!) Used for expected physics performance quoted here 2004: 180M events simulation and analysis in a distributed way (Grid) Started in May (already ~50M events produced), 3000 jobs/day Pythia, EvtGen, GEANT4 TT T1 T2 T3 VELOMagnet RICH1

24. 24 P. Perret 3 rd July 2004 Beach 2004 Efficiencies, event yields and B bb /S ratios Nominal year = 10 12 bb pairs produced (10 7 s at L=2  10 32 cm  2 s  1 with  bb =500  b) Yields include factor 2 from CP-conjugated decays Branching ratios from PDG or SM predictions

25. 25 P. Perret 3 rd July 2004 Beach 2004 n The ‘gold plated’ channel at B-factories n Precision measurement of this parameter is very important     from B 0  J/  K s =0 in SM =sin 2  In one year with 240k events:  sin  0.02 Comparing with other channels may indicate NP in penguin diagrams Background-subtracted B   J/  (  )K S CP asymmetry after one year  =37%  tag =45%  eff ≈3% B/S=0.8 n LHC(b) will bring a lot of statistics to this channel, which can be used to look into higher order effects, and fit A dir Similar sensitivity ATLAS/CMS

26. 26 P. Perret 3 rd July 2004 Beach 2004  m s  m s from B s  D s - (KK  )  + n If NP is present … Expected unmixed B s  D s    sample in one year of data taking (fast MC) n Fully reconstructed decay: wExcellent momentum resolution, decay length resolution ~200 µm wProper time resolution ~40fs  =30%  tag =55%  eff ≈9% B/S=0.3 In one year with 80k events: can observe >5  oscillation signal if  m s < 68 ps  1 well beyond SM prediction (14.8-26 ps  1 ) Once a B s –B s oscillation signal is seen, the frequency is precisely determined:  (  ms ) ~ 0.01 ps -1 ATLAS/CMS:  m s < 30 ps  1

27. 27 P. Perret 3 rd July 2004 Beach 2004     from B s  J/  n Is not CP eigenstate (VV decay). Angular analysis needed to separate CP-even and CP-odd contributions (from transversity angle distribution): needs fit to angular distributions of decay final states as a function of proper-time (good proper- time resolution is essential) In one year with 120k events:  sin  0.06  s  s  0.02  sin    0.06,  s  s  0.02 In SM expected asymmetry  sin 2   very small ~ 0.04  sensitive probe for new physics Reconstruct J/      or e  e ,  K  K  B s counterpart of the golden mode B 0  J/  K S n measures the phase of B s mixing

28. 28 P. Perret 3 rd July 2004 Beach 2004   from B      and B s  K  K  n In both decays large b  d(s) penguin contributions to b  u n Measure time-dependent CP asymmetries in B      and B s  K  K  decays: A CP (t)=A dir cos(  m t) + A mix sin(  m t) n Exploit U-spin flavour symmetry for P/T ratio [Fleischer]  f Use measure of  from B 0  J/  and  from B 0  J/  K s n 4 measurements (CP asymmetries) and 3 unknowns ( , d and )  can solve for  Good  /K identification B      In one year :  deg    deg U-spin symmetry assumed; sensitive to new physics in penguins BsKKBsKK 37 k B bb /S=0.3 26 k B bb /S<0.7

29. 29 P. Perret 3 rd July 2004 Beach 2004 A3A3 √2 A 2   from B   D  K *  and B   D  K *  n B   D CP K *  : interference between 2 tree diagrams n Application of Gronau-Wyler method [Dunietz]: In one year :  deg    deg n Measure 6 decay rates (following three + CP-conjugates) A 1 = A 1 √2 A 2 A3A3 22  yield/yr B/S B   D 0 (K   + ) K *  (K +   )0.5k<1.8 B   D 0 (K +   ) K *  (K +   )3.4k<0.3 B   D CP (KK) K *  (K +   )0.6k<1.4  =65 o,  =0 n No proper time measurement or tagging required n assumes D CP = (D  + D  )/  2 sensitive to new phase in D CP state

30. 30 P. Perret 3 rd July 2004 Beach 2004   from B s  D s  K + n Interference between 2 tree diagrams (again) via B s mixing Measure  -2  from time-dependent rates: B s  D s  K  (b  c) and B s  D s  K  (b  u) (+ CP conjugates) Use 2  from B s  J/  n Mistag extracted from B s  D s    sample 5.4 k B/S<1 B s  D s π is background for D s K Branching ratio ~ 12  higher In one year :  deg    deg No theoretical uncertainty; insensitive to new physics in B mixing The two B s -B s asymmetries after 5 years of data

31. 31 P. Perret 3 rd July 2004 Beach 2004 B s  D s K 1. B s  D s K B  , B s  KK 2. B  , B s  KK B  DK* 3. B  DK*  not affected by new physics  affected by possible new physics in penguin new physics in penguin  affected by possible new physics in D-D mixing ,  Determine the CKM parameters A, ,  independent of new physics Extract the contribution of new physics to the oscillations and penguins  New physics in angle  measurement ? Interest in over-constraining the CKM UT

32. 32 P. Perret 3 rd July 2004 Beach 2004 Other physics at LHCb n New physics in b  s penguin processes  B 0  K * , B 0   K S,B s   KK,  … B s 0  J/  B s 0  J/ ,, … Direct CP violation: B  u  K *   n Rare decays  B s     ,B 0 d  K *0     (cf talk from S. Viret) n B c physics wLifetime, mass, branching fractions   measurements from B c  D D s difficult! n b baryons n …

33. 33 P. Perret 3 rd July 2004 Beach 2004 Conclusion n LHCb is dedicated to the study of b physics wa devoted trigger wexcellent vertex and momentum resolution wexcellent particle identification  Access to all b-hadron species: B u, B d, B s, B c,  b … n LHCb detector will be ready for data taking in 2007 at LHC start-up wConstruction of the experiment is progressing well winstallation of detectors starts this year  m s Already in year one, LHCb will have competitive measurements on  m s and other parameters LHCb offers an excellent opportunity to spot New Physics signals beyond the Standard Model very soon at LHC

34. 34 P. Perret 3 rd July 2004 Beach 2004 Are Penguins New Physics Guards?