Studies of the Decay B+- -> D_CP K+-

TL;DR

This study measures branching ratios and asymmetries in B+- decays to D_CP K+-, providing insights into CP violation and decay dynamics using data from the Belle detector at KEKB.

Contribution

First measurement of branching ratios and partial rate asymmetries for B+- -> D_CP K+- decays with CP eigenstates of D0, using a large data sample at Belle.

Findings

Branching ratio ratios for B- -> D_1 K- and B- -> D_2 K- decays measured.

Partial rate asymmetries for B+- -> D_CP K+- decays determined.

Results contribute to understanding CP violation in B meson decays.

Abstract

We report studies of the decay B+- -> D_CP K+-, where D_CP denotes neutral D mesons that decay to CP eigenstates. The analysis is based on a 29.1/fb data sample of collected at the \Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e+ e- storage ring. Ratios of branching fractions of Cabibbo-suppressed to Cabibbo-favored processes involving D_CP are determined to be B(B- -> D_1 K-)/B(B- -> D_1 pi-)=0.125 +- 0.036 +- 0.010 and B(B- -> D_2 K-)/B(B- -> D_2 pi-)=0.119 +- 0.028 +- 0.006, where indices 1 and 2 represent the CP=+1 and CP=-1 eigenstates of the D0 - anti D0 system, respectively. We also extract the partial rate asymmetries for B+- -> D_CP K+-, finding A_1 = 0.29 +- 0.26 +- 0.05 and A_2 = -0.22 +- 0.24 +- 0.04.