Study of flavor tagging with semi-exclusive reconstruction of b [right arrow] D(sigma)X decays

Abstract

The BaBar experiment measures CP violation in the B meson system by analyzing the decays of B⁰B̄⁰ pairs in which one of the mesons decays into a CP eigenstate. By measuring the decay time distribution separately for B⁰ and B̄⁰ decays the CP violating asymmetry and sin 2[beta] can be measured. In order to measure the decay time distribution for the B⁰ and B̄⁰ decays, it is necessary to identify the flavor, or tag, of the second B meson. The flavor of the B meson is identified by an algorithm which analyzes physical processes which carry flavor information from its decay. Analyzing new physical processes could potentially improve the efficiency of the tagging algorithm. I tested the effect of adding subtaggers which estimated the flavor of the tag B based on the flavor or the charge of its D⁰ or Ds daughters. However due to the low yields and high backgrounds of reconstructed D⁰ and Ds candidates, these subtaggers were not effective at making a net contribution to the tagging process.