Overview of LHCb

1. Brazil Poland Ukraine France UK Switzerland Germany PRC Romania Russia Italy Netherlands Spain Overview of LHCb XXXXth Rencontres de Moriond QCD AND HIGH ENERGY HADRONIC INTERACTIONS Spectroscopy On behalf of the LHCb Experiment Overview of LHCb

2. Overview of LHCb Contents : - Physics Motivations - LHC environment - LHCb expected performance Overview of LHCb

3. b b B0s New particles B0s s s Physics Motivations CKM fit (ICHEP 2004) - BABAR, BELLE, Tevatron and kaon experiments have testedand will test CKM pictureof CP violation (no clear hint of NP for the moment) - NP could still be hidden in box and loop diagrams Overview of LHCb

4. Physics Motivations LHCb will study all types of B mesons ! B0d system B0s system B0 ->rr,pp,rp (s(a)~100) B0s ->J/yf,ff B0 ->J/y Ks, J/yp0,fKs (s(b)~0.70) B0s ->DsK, KK B0 ->DK*, D*(s(g)~100-200) (Expected sensitivities of B factories in 2007) Overview of LHCb

5. PYTHIA LHC environment • LHC : pp collisions at s = 14 TeV (40 MHz) • bb pairs are mostly produced at small angles wrt beam pipe --> forward spectrometer • L= 2.1033 - 1034 cm-2s-1 • to avoid high number of interaction / bunch crossings : L = 2 .1032cm-2s-1 for LHCb • --> simpler events and less radiation damage for the detectors • sinelastic 80 mb and sbb 0.5 mb • --> need an efficient trigger • but Nbb(1 year in 4p) = 1012 • with B+ / B0d / B0s / b-baryon • (4 : 4 : 1 : 1 ) Overview of LHCb

6. HCAL trigger dominates MUON trigger dominates ECAL trigger dominates Trigger • multi-level trigger : • - Level 0 (40 MHz --> 1 MHz): • reject complicated events • high pTe, g, p0,m, or hadrons • - Level 1 (1 MHz --> 40 KHz): • large IP and pT tracks • - HLT (40 KHz --> 200 Hz): • access to complete events • ~ offline selection • + 1.8 KHz to get systematics from data • high dimuon mass --> tracking • inclusive b (bm) --> trigger + data mining • D* --> PID Overview of LHCb

7. magnet LHCb detector requirements K- few mm B0s K+ p p Primary vertex • Efficient particle identification : • - p/K separation (1-->100 GeV) --> RICH (for B0(s) -->hh, flavour tagging, …) • - electron and muon ID --> CALO + MUON (for B0(s) -->J/y X, flavour tagging, …) • Good decay time resolution (~ 40 fs): • - vertex detector (for B0s -->Dsp, B0s -->J/y f, ...) • The best mass resolution and efficient tracking : • - tracker and magnet Overview of LHCb

8. LHCb experiment Single arm forward spectrometer 250/300 mrad v / h Acceptance 10 mrad pp collision side view Overview of LHCb

9. Vertex Locator Vertex and tracking detector : - silicon discs - 8 mm from beam axis - 21 stations (retractable) Interaction region stations PV position resolution : ~ 8 mm (x,y) and ~44 mm (z) IP precision : ~ 40 mm Vacuumvessel 1 m Overview of LHCb

10. Expected unmixed BsDssample in one year of LHCb data taking Bs oscillation frequency Dms • LEP + SLD -> ms> 14.4 ps-1 • Important physics subject of CDF+D0 • Needed for the observation of CP asymmetries with Bs decays • Use BsDs (~80k evts/yearexpected) • If ms= 20 ps1 (ms) = 0.011 ps1 • Can observe 5 oscillation signal ifms < 68 ps1(well beyond SM prediction) Propertime resolution : Overview of LHCb

11. RICH B0s -->KK B0s -->KK 2 RICHs and 3 Cherenkov radiators to cover the full momentum range good p/K separation for 2<p<100 GeV Overview of LHCb

12. Calorimeter System With Bremsstrahlung recovery SPD/PS (2X0) ECAL (25X0) : lead/scintillator HCAL (5.7l) : iron/scintillator Readout every 25 ns (L0 trigger) Identification : electrons, hadrons and p0 ECAL : sE/E ~ 10% / E  1% HCAL : sE/E ~ 80% / E  10% e e e ~ 94% andep  e ~ 0.7% for tracks in ECAL acceptance (~ 60 MeV/c²) Overview of LHCb

13. Muon System ( ~ 10 MeV/c²) 5 stations with 1380 MWPCs Projective geometry Each station subdivided into four regions em m ~ 93 % ep  m ~ 1.0 % for tracks in Muon detector acceptance Overview of LHCb

14. Many Physics Topics at LHCb • - Measurement of a angle • B -> rp (12k evts/year) s(a) < 100 (1 year) • - Measurement of b angle • B -> J/yKs (240k evts/year) s(b) ~ 0.70 (1 year) • - Measurement of g angle • with Bs->DsK, B->pp and Bs->KK, B->DK* decay • - Measurement of Bs mixing angle c • with Bs->J/yf decay • - New physics in b -> s penguin process • B -> K*g , B -> fKs , Bs -> ff, fg • D physics • Mixing, CPV • - Rare decays • Bs -> mm, B -> K* mm • - Bc physics, b baryons • lifetimes, masses, branching ratios I will give more details hereafter Overview of LHCb

15. Propertime resolution st= 38 fs B0s Mixing Phase (c) - needed for some g measurements - use Bs->J/yf (~120k evts/year expected) Angular analysis to separate CP even and CP odd s(sin 2c)~0.06 and s(DGs/Gs)~0.02 (with Dms = 20 ps-1) Overview of LHCb

16. gaffected by possible new physics in D-D mixing Measurements of angle g : possible scenario 2. B->pp, Bs->KK (s(g)4-60) 3. B->DK* (s(g)7-80) 1. Bs->DsK (s(g)14-150) gnot affected by new physics in loop diagrams gaffected by possible new physics in penguin Determine the CKM parameters A, r, h independent of new physics Extract the contribution of new physics to the oscillations and penguins Overview of LHCb

17. Conclusion • LHC offers great opportunity for B physics • LHCb is dedicated to b Physics with • Efficient trigger for b physics • Excellent vertex and momentum resolution • Excellent particle identification • Access to all b-hadron species • Promising potential for studying New Physics • Construction of the experiment is on the way… Overview of LHCb

18. Overview of LHCb

19. Back Up Slides Overview of LHCb

20. CKM fit (ICHEP 2004) Adding  and measurements Adding  measurements Overview of LHCb

21. RICH PID performance Overview of LHCb

22. u c K+ D-s W+ s s W- b c b u D-s B0s K+ B0s s s u c D+s K- W+ s s W- b u b c B0s B0s K- D+s s s Bs -> DsK diagrams Overview of LHCb

23. u p+(K+) d (s) W b u B0d(s) p-(K-) d(s) b d(s) W u p+(K+) t c u B0d(s) g u p-(K-) d(s) B0d(s) -> hh diagrams Overview of LHCb

24. D0 W u B0d u s b b s c K*0 d D0 W c B0d K*0 d B0d-> DK* diagrams Overview of LHCb