Measurement of the CP-violating parameter of B0 mixing and decay in the ppbar -> mu mu X data

GUSTAVO OTERO Y GARZON, THE DZERO COLLABORATION

PHYSICAL REVIEW D - PARTICLE AND FILDS

Año: 2006 p. 920011 - 920016

0556-2821

We measure the dimuon charge asymmetry A in ppbar collisions at a center of mass energy of 1960 GeV. The data was recorded with the D0 detector and corresponds to an integrated luminosity of approximately 1.0 fb-1. Assuming that the asymmetry A is due to asymmetric B0B0 bar mixing and decay, we extract the CP-violation parameter of B0 mixing and decay AB0 / 4 = 0.0023 ± 0.0011(stat) ± 0.0008(syst), AB0  is the dimuon charge asymmetry from decays of B0B0 bar pairs. The general case, with CP violation in both B0 and Bs0 systems, is also considered. Finally we obtain the forward-backward asymmetry that quantifies the tendency of m+ to go in the proton direction and m- to go in the antiproton direction. The results are consistent with the standard model and constrain new physics.