Bounds on the CP Asymmetry in Like-Sign Dileptons from $B^{0}\bar{B}^{0}$ Meson Decays

TL;DR

This paper reports a measurement of charge asymmetry in like-sign dilepton events from B meson decays, providing bounds on CP violation parameters with improved precision using data from the CLEO detector.

Contribution

The study presents the first combined measurement of the CP impurity parameter epsilon_B, refining bounds on CP asymmetry in B meson mixing.

Findings

Measured charge asymmetry a_ll = +0.013 +/- 0.050 +/- 0.005

Combined result for Re(epsilon_B)/(1+|epsilon_B|^2) = +0.0035 +/- 0.0103 +/- 0.0015

Set bounds on CP violation in B^0 - B^0-bar mixing.

Abstract

We have measured the charge asymmetry in like-sign dilepton yields from B^0 B^0-bar meson decays using the CLEO detector at the Cornell Electron Storage Ring. We find a_ll = [N(l+l+) - N(l-l-)]/[N(l+l+) + N[l-l-)] = +0.013 +/- 0.050 +/- 0.005 . We combine this result with a previous, independent measurement and obtain Re(epsilon_B)/(1+|epsilon_B|^2) = +0.0035 +/- 0.0103 +/- 0.0015 (uncertainties are statistical and systematic, respectively) for the CP impurity parameter, epsilon_B.