Collaboration, D0 and Abazov, V. and Bertram, Iain and Williams, Mark and Borissov, Guennadi and Ratoff, Peter and Fox, Harald (2008) Study of direct CP violation in $B^{\pm} \to J/ψK^{\pm}(π^{\pm})$ decays. Physical review letters, 100 (21): 211802. ISSN 1079-7114
Abstract
We present a search for direct CP violation in $B^{\pm} \to J/\psi K^{\pm}(\pi^{\pm})$ decays. The event sample is selected from 2.8 fb$^{-1}$ of $p\bar{p}$ collisions recorded by D0 experiment in Run II of the Fermilab Tevatron Collider. The charge asymmetry $A_{CP}(B^+ \to J/\psi K^+) = +0.0075 \pm 0.0061$(stat.)$\pm 0.0027$(syst.) is obtained using a sample of approximately 40 thousand $B^{\pm} \to J/\psi K^{\pm}$ decays. The achieved precision is of the same level as the expected deviation predicted by some extensions of the standard model. We also measured the charge asymmetry $A_{CP}(B^+ \to J/\psi \pi^+) = -0.09 \pm 0.08$(stat.)$\pm 0.03$(syst.).