Measurement of the B+/B0 production ratio in e+e- collisions at the γ(4S) resonance using B → J/ψ(ll)K decays at Belle

Abstract

We measure the ratio of branching fractions for the gamma(4S) decays to B+/B- and B-0(B) over barB(0) using B+ -> J/psi(ll)K+ and B-0 -> J/psi(ll)K-0 samples, where J/psi(ll) stands for J/psi -> l(+)l(-) (l = e or mu), with 711 fb(-1) of data collected at the gamma(4S) resonance with the Belle detector. We find the decay rate ratio of gamma(4S) -> B-0(B) over barB(0) over gamma(4S) -> B-0(B) over barB(0) to be 1.065 +/- 0.012 +/- 0.019 +/- 0.047, which is the most precise measurement to date.

The first and second uncertainties are statistical and systematic, respectively, and the third uncertainty is due to the assumption of isospin symmetry in B -> J/psi(ll)K.

Keywords

• Measurement
• the B+/B0 production
• ratio
• in e+e- collisions
• γ4S
• resonance
• using B → J/ψllK decays
• Belle