Evidence for an Anomalous Like-Sign Dimuon Charge Asymmetry

D0 COLLABORATION, ..., R.PIEGAIA,

PHYSICAL REVIEW LETTERS

AMER PHYSICAL SOC

Año: 2010 vol. 105 p. 81801 - 81811

0031-9007

We measure the charge asymmetry A≡(N++-N--)/(N+++N--) of like-sign dimuon events in 6.1  fb-1 of pp̅ collisions recorded with the D0 detector at a center-of-mass energy √s=1.96  TeV at the Fermilab Tevatron collider. From A we extract the like-sign dimuon charge asymmetry in semileptonic b-hadron decays: Aslb=-0.009 57±0.002 51(stat)±0.001 46(sys). It differs by 3.2 standard deviations from the standard model prediction Aslb(SM)=(-2.3-0.6+0.5)×10-4, and provides first evidence of anomalous CP violation in the mixing of neutral B mesons.