Analysis of the resonant components in ¯¯¯B0s→J/ψπ+π−

Abstract

The decay ¯¯¯ B 0 s → J / ψ π + π − can be exploited to study C P violation. A detailed understanding of its structure is imperative in order to optimize its usefulness. An analysis of this three-body final state is performed using a 1.0 fb − 1 sample of data produced in 7 TeV p p collisions at the LHC and collected by the LHCb experiment. A modified Dalitz plot analysis of the final state is performed using both the invariant mass spectra and the decay angular distributions. The π + π − system is shown to be dominantly in an S -wave state, and the C P -odd fraction in this ¯¯¯ B 0 s decay is shown to be greater than 0.977 at 95% confidence level. In addition, we report the first measurement of the J / ψ π + π − branching fraction relative to J / ψ ϕ of ( 19.79 ± 0.47 ± 0.52 ) % .