LHCb Experiment: Probing B-Meson Decay & CP Violations

1. -K separation CF4 C4F10 C4F10 + CF4 Aerogel • LHC is the most intense source of B mesons (Bd, Bu, Bs, Bc) with sbb = 500 mb • Luminosity <L>LHCb = 2 x1032 cm-2 s-1 • 1012 bb / 107 s • Range of channels available in LHCb: ~1m • sensitive to CKM angle  •  ~ 20 - 50in 1 year • depends on |P/T| and strong phase  • Backgrounds also have • Rate asymmetries measure angle g-2dg • Expect 2400 eventsin 1 year of data taking • s(g-2dg) = 60 .. 140 LHC-b Experiment RICH1 RICH2 Bd ->  + Physics aims: • LHCb is a 2nd generation experiment that will determine CP violations in a variety of decays of Bd and Bs mesons to test consistency of Unitarity Triangles. • It will follow on from Babar, BELLE that have already established CP violationsforBd mesons(in the decay Bd -> J/Y K) and will constrain unitarity triangles to unprecedented accuracy. Rutherford Appleton Laboratory Vertex Locator (VELO) • UK Contributions to LHCb vital for LHCb physics: • RICH detectors • Vertex Locator (VELO) Unitarity Triangles Particle Identificationwith RICH detectors Number of silicon sensors: 100 Area of silicon: 0.32m2Number of channels: 204,800 VELO Expected physics results: Tree T Penguin P Parameter Channels Evts/year (1 year) LHCb feature 2(+) Bd 4900 |P/T| = 0 2-5 PID, hadron trigger Bdr ~1300 3-6 PID, hadron trigger 2+ Bd  D* 340000 > 11 PID, hadron trigger  BdJ/Ks 37000 0.6 -2 Bs DsK 2400 6-14 PID, hadron trigger, t  Bd  DK* 400 10 PID, hadron trigger  Bs  J/yf 44000 0.6 t Bs oscillations xs Bs  Ds 120000 up to 75 hadron trigger, t Rare Decays BR Bs   <210-9 t Bd  K*mm 22400 PID RICH2 RICH1 Bs -> DsK