02-07-2010: Colloquium Guennadi Borissov

29 - 06 - 2010

Friday 2 July 2010, 11:00h, at Nikhef in H331

Speaker: Guennadi Borissov (D0)

Title: Evidence for an anomalous like-sign dimuon charge asymmetry


We measure the charge asymmetry (A) of like-sign dimuon events in 6.1 inverse fb of p-pbar collisions recorded with the D0 detector at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider.  From A, we extract the like-sign dimuon charge asymmetry in semileptonic b-hadron decays: Asupb_(sl)  = −0.00957 pm 0.00251 (stat) pm 0.00146 (syst). This result differs by 3.2 standard deviations from the standard model prediction Asupb_(sl) (SM) =  âˆ’2.3 (+0.5) (-0.6) times 10sup(-4) and provides the first evidence of anomalous CP-violation in the mixing of neutral B mesons.