Study of J/psi -> eta phi pi(+)pi(-) at BESIII

Abstract

Based on a sample of 2.25×108J/? events taken with the BESIII detector at the BEPCII collider, we present the results of a study of the decay J/?????+?-. The Y(2175) resonance is observed in the invariant mass spectrum of ?f0(980) with a statistical significance of greater than 10?. The corresponding mass and width are determined to be M=2200±6(stat)±5(syst) MeV/c2 and ?=104±15(stat)±15(syst) MeV, respectively, and the product branching fraction is measured to be B(J/???Y(2175),Y(2175)??f0(980),f0(980)??+?-)=(1.20±0.14(stat)±0.37(syst))×10-4. The results are consistent within errors with those of previous experiments. We also measure the branching fraction of J/???f1(1285) with f1(1285)???+?- and set upper limits on the branching fractions for J/????(1405)/?X(1835)/?X(1870) with ?(1405)/X(1835)/X(1870)???+?- at the 90% confidence level. © 2015 American Physical Society.