Measurement of CP Observables for the Decays B+/- --> D0_CP K*+/-

TL;DR

This study measures CP observables in B+/- decays to D0 and K*+/- using a large dataset, providing insights into the CKM angle gamma with specific asymmetry and ratio measurements.

Contribution

It presents the first measurement of four CP-sensitive observables in B+/- decays to D0 and K*+/- with a large dataset, improving constraints on the CKM angle gamma.

Findings

Measured charge asymmetries A_CP+/- with uncertainties.

Determined ratios R_CP+/- of branching fractions.

Provided results consistent with Standard Model expectations.

Abstract

Using a sample of 232 million Upsilon(4S) --> B Bbar events collected with the BABAR detector at the PEP-II B Factory in 1999-2004, we study B- --> D0 K*(892)- decays where K*- --> KS pi- and D0 --> K-pi+, K-pi+pi0, K-pi+pi+pi- (non-CP final states); K+K-, pi+pi- (CP+ eigenstates); KSpi0, KSphi and KSomega (CP- eigenstates). We measure four observables that are sensitive to the angle gamma of the CKM unitarity triangle; the partial-rate charge asymmetries A_CP+/- and the ratios of the B-decay branching fraction in CP+/- and non-CP decays R_CP+/-: A_CP+ = -0.08 +/- 0.19 (stat.) +/- 0.08 (syst.) A_CP- = -0.26 +/- 0.40 (stat.) +/- 0.12 (syst.) R_CP+ = 1.96 +/- 0.40 (stat.) +/- 0.11 (syst.) R_CP- = 0.65 +/- 0.26 (stat.) +/- 0.08 (syst.)