Measurement of CP violation observables and parameters for the decays B±→DK*±

Abstract

We study the decay B − → D K * − using a sample of 379 × 10 6 Υ ( 4 S ) → B ¯¯¯ B events collected with the BABAR detector at the PEP-II B factory. We perform a Gronau-London-Wyler analysis where the D meson decays into either a C P -even ( C P + ) eigenstate ( K + K − , π + π − ), C P -odd ( C P − ) eigenstate ( K 0 S π 0 , K 0 S ϕ , K 0 S ω ) or a non- C P state ( K − π + ). We also analyze D meson decays into K + π − from a Cabibbo-favored ¯¯¯ D 0 decay or doubly suppressed D 0 decay [Atwood-Dunietz-Soni (ADS) analysis]. We measure observables that are sensitive to the Cabibbo-Kobayashi-Maskawa angle γ : the partial-rate charge asymmetries A C P ± , the ratios R C P ± of the B -decay branching fractions in C P ± and non- C P decay, the ratio R ADS of the charge-averaged branching fractions, and the charge asymmetry A ADS of the ADS decays: A C P + = 0.09 ± 0.13 ± 0.06 , A C P − = − 0.23 ± 0.21 ± 0.07 , R C P + = 2.17 ± 0.35 ± 0.09 , R C P − = 1.03 ± 0.27 ± 0.13 , R ADS = 0.066 ± 0.031 ± 0.010 , and A ADS = − 0.34 ± 0.43 ± 0.16 , where the first uncertainty is statistical and the second is systematic. Combining all the measurements and using a frequentist approach yields the magnitude of the ratio between the Cabibbo-suppressed and favored amplitudes, r B = 0.31 with a one (two) sigma confidence level interval of [0.24, 0.38] ([0.17, 0.43]). The value r B = 0 is excluded at the 3.3 sigma level. A similar analysis excludes values of γ in the intervals [0, 7]°, [55, 111]°, and [175, 180]° ([85, 99]°) at the one (two) sigma confidence level.