Study of CP violation in neutral B(s) meson going to J/psi phi decays at D0.

摘要

In a universe dominated by matter, the source of CP violation may explain one of the greatest mysteries in particle physics: what happened to the antimatter? The Standard Model successfully describes CP violation in the B+ and B0d systems, yet insufficiently accounts for the observed matter-antimatter asymmetry. The Standard Model predicts a small value of CP violation in the B0s meson system, which has only recently been experimentally tested. A measurement of large, anomalous CP violation in the B0s system would be a clear indication of new physics sources beyond the Standard Model. This dissertation describes a study of CP violation in approximately 2000 B0s → J/psi&phis; decays reconstructed in a 2.8 fb--1 data sample collected by the DO Run II detector at Fermi National Accelerator Laboratory in Batavia, Illinois. This data was provided by pp¯ collisions at s = 1.96 TeV delivered by the Tevatron accelerator between April 2002 and August 2007. Flavor-tagged B0s → J/psi(mu+mu-- )&phis;(K+K --) decays and an angular analysis are used to study the time evolution of the final state angular distributions. From this analysis, we measure the width difference between the heavy and light mass eigenstates, BLs and BHs , to be DeltaGammas = 0.19 +/- 0.07 and the CP-violating phase &phis;s = -0.57+.24-.30 .