Analysis of the resonant components in (B)over-bar(s)(0) -> J/psi pi(+)pi(-)

The decay (B) over bar (0)(s) -> J/psi pi(+)pi(-) can be exploited to study CP 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 pp 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 pi(+)pi(-) system is shown to be dominantly in an S-wave state, and the CP-odd fraction in this (B) over bar (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/psi pi(+)pi(-) branching fraction relative to J/psi phi of (19.79 +/- 0.47 +/- 0.52)%.