CP asymmetries at D0

TL;DR

This paper reports measurements of CP asymmetries in B meson decays, constraining the CP violating phase in the B_s system and measuring direct CP violation in B+ decays using data from the D0 detector at Fermilab.

Contribution

It provides new experimental constraints on the CP violating phase in the B_s system and measures direct CP asymmetry in B+ decays, using data from the D0 detector.

Findings

CP violating phase φ_s = -0.70^{+0.47}_{-0.39}

Direct CP asymmetry A_CP(B+ → J/ψ K+) = +0.0067 ± 0.0074(stat) ± 0.0026(syst)

Data sample of 1.1 fb^{-1} and 1.6 fb^{-1} from Fermilab Tevatron

Abstract

Using two independent measurements of the semileptonic CP asymmetry in the $B_s$ system, we constrain the CP violating phase of the $B_s$ system to be $\phi_s = -0.70^{+0.47}_{-0.39}$. The data sample corresponds to an integrated luminosity of 1.1 fb$^{-1}$ accumulated with D0 detector at the Fermilab Tevatron collider. We also measure the direct CP violating asymmetry in the decay $B^+ \to J/\psi K^+$ to be $A_{CP}(B^+ \to J/\psi K^+) = +0.0067 \pm 0.0074$(stat)$\pm0.0026$(syst). The data corresponds to an integrated luminosity of 1.6 fb$^{-1}$.