Bc, B**, and L b Properties at the Tevatron

Bc, B**, and Lb Properties at the Tevatron S.Towers for the D0 and CDF collaborations S.Towers, SUNY-SB

High b-production rate (bb)100b at 2 TeV (cf(bb)1nb at B-factories) • All B species produced! (B,B0,Bs,Bc,b,…) • BUT: must deal with 103larger background! • RunII thus required major upgrades in detectors, electronics and triggers… Tevatron Main Injector and Recycler S.Towers, SUNY-SB

CDF Detector in Run II Inherited from Run I: • Central Calorimeter (||<1) • Solenoid (1.4T) Partially New: • Muon system (extended to ||~1.5) New: • Tracking System • - 3D Silicon Tracker (up to ||~2) • - faster Drift Chamber • Time-of-Flight (particle ID) • Trigger system (new trigger on displaced tracks) S.Towers, SUNY-SB

DZero Detector SMT H-disks SMT F-disks SMT barrels • Muon system with coverage |η|<2 and good shielding • Trackers • Silicon Tracker: |η|<3 • Fiber Tracker: |η|<2 • Magnetic field 2T S.Towers, SUNY-SB

Results are based on smaller datasets S.Towers, SUNY-SB

Long-standing discrepancy in Λb and b-baryon lifetimes compared to theory • (from Operator Product Expansion (OPE), Heavy Quark Effective Theory (HQET) and lattice gauge predictions) S.Towers, SUNY-SB

States including J/+- easy to trigger on <L>~1 mm Very similar topology to BdJ/Ks S.Towers, SUNY-SB

t(Lb)=1.25±0.26±0.10 ps (cf WA 1.229±0.080 ps) S.Towers, SUNY-SB

250 pb-1 +0.217 t(Lb)=1.221 ±0.028 ps (cf WA 1.229±0.080 ps) -0.179 S.Towers, SUNY-SB

70 pb-1 5620±1.6±1.2 MeV (cf WA 5624±9 MeV) S.Towers, SUNY-SB

Charmless Lbgpp and LbgpK decays CKM suppressed and/or (QCD,EW) Data selected with two-displaced-track trigger 767 observed, 772±13 expected BR(Lbghh)<22E-6 (90% CL) cf SM BR(Lbghh)~1 to 2 E-6 S.Towers, SUNY-SB

20.4 signal +6.2 - 5.5 +0.18 t 0.46 0.03 ps - 0.16 Bc meson • Last of ground state mesons to be definitively observed! • Theory: Lifetime 0.3-0.5 ps • Theory: Mass 6.4 GeV ±0.3 • Only previous evidence CDF RunI result mass 6.4±0.39±0.13 GeV S.Towers, SUNY-SB

Bc Meson Take advantage of easy-to-trigger-on trilepton final state: Start with 210 pb-1 of data Select 231 J/ymX candidates Background estimated with J/y+track data control sample, separated into prompt and non-prompt (aka “heavy flavour”) components m- m+ n m+ Bc+ PV S.Towers, SUNY-SB

Mass: 5.95 ±0.34 GeV +0.14 -0.13 Lifetime: 0.448 ±0.121 ps +0.123 -0.096 Do combined likelihood fit to invariant mass and pseudo-proper time distribution: Mass log likelihood Lifetime log likelihood #signal: 95±12±11 S.Towers, SUNY-SB

Background-only fit: D2log(likelihood) is 60 for 5 degrees of freedom S.Towers, SUNY-SB

Other properties: Bc b c b c Forms weakly decaying charmed hadron Probability m within f ±90 degrees of Bc candidate = 5±2% Probability m within f ±90 degrees of background = 1% S.Towers, SUNY-SB

B spectroscopy – B** First observation of separated L=1states Only Bd,Bu,Bs and B* considered established by PDG. Masses and widths of L=1 B1 and B2* predicted by various models. Measurement of B1 and B2* masses can help shed light on quark interactions in bound states and aid development of non-perturbative QCD

Summary t(Lb)=1.25±0.26±0.10 ps 2003 65 pb-1 t(Lb)=1.221 ±0.028 ps 2004 250 pb-1 Mass Lb 5620±1.6±1.2 MeV 2003 70 pb-1 BR(Lbghh)<22E-6 (90% CL) 2004 193 pb-1 +0.217 -0.179 +0.14 Bc mass: 5.95 ±0.34 GeV 2004 210 pb-1 -0.13 +0.123 Bc lifetime: 0.448 ±0.121 ps 2004 210 pb-1 -0.096 S.Towers, SUNY-SB

Bc, B**, and L b Properties at the Tevatron