Measurement of J/psi -> Xi(1530+)(-) (Xi)over-bar(+) and evidence for the radiative decay Xi(153)(-) -> gamma Xi(-)

Abstract

The SU(3)-flavor violating decay J/psi -> Xi(1530)(-) (Xi) over bar (+) + c.c. is studied using (1310.6 +/- 7.0) x 10(6) J/psi events collected with the BESIII detector at BEPCII, and the branching fraction is measured to be B(J/psi -> Xi(1530)(-) (Xi) over bar (+) + c.c.) = (3.17 +/- 0.02(stat) +/- 0.08(syst)) x 10(-4). This result is consistent with previous measurements with an order of magnitude improved precision. The angular parameter for this decay is measured for the first time and is found to be alpha = -0.21 +/- 0.04(stat) +/- 0.06(syst). In addition, we report evidence for the radiative decay Xi(1530)(-) -> gamma Xi(-) with a significance of 3.9 sigma, including the systematic uncertainties. The 90% confidence level upper limit on the branching fraction is determined to be B(Xi(1530)(-) -> gamma Xi(-)) <= 3.7%.