Measurement of the CP-violation parameter of B⁰ mixing and decay with pp̅ → μμX data

Authors

V. M. Abazov, Joint Institute for Nuclear Research, Dubna, Russia
Kenneth A. Bloom, University of Nebraska-LincolnFollow
Gregory R. Snow, University of Nebraska-LincolnFollow
D0 Collaboration

Date of this Version

11-8-2006

Comments

Published by American Physical Society. Phys. Rev. D 74, 092001 (2005). http://prd.aps.org. Copyright © 2006 American Physical Society. Permission to use.

Abstract

We measure the dimuon charge asymmetry A in pp̅ collisions at a center of mass energy √s =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 B⁰ ↔ B̅ mixing and decay, we extract the CP-violation parameter of B⁰ mixing and decay: [ℜ(∊_B⁰)]/[1+∣∊_B⁰∣² = (A_B⁰)/4 = -0.0023 ± 0.0011 (stat) ± 0.0008(syst). A_B⁰ is the dimuon charge asymmetry from decays of B⁰B̅⁰ pairs. The general case, with CP violation in both B⁰ and B⁰_s systems, is also considered. Finally we obtain the forward-backward asymmetry that quantifies the tendency of μ⁺ to go in the proton direction and μ^- to go in the antiproton direction. The results are consistent with the standard model and constrain new physics.