Measurement of the Absolute Branching Fraction of Xi(1530)^{-} to (Xi pi)^{-} and Updated Measurement of the Branching Fraction of psi(3686) to anti-Xi^{+} Xi(1530)^{-} + c.c

TL;DR

This paper reports the first measurement of the absolute branching fractions of Xi(1530)^{-} decays to Xi^{0} pi^{-} and Xi^{-} pi^{0}, and updates the branching fraction of psi(3686) to anti-Xi^{+} Xi(1530)^{-} + c.c., using a large data sample from BESIII.

Contribution

It provides the first measurement of the combined branching fraction of Xi(1530)^{-} decays and an updated measurement of psi(3686) decay to anti-Xi^{+} Xi(1530)^{-} + c.c.

Findings

B(Xi(1530)^{-} to Xi^{0} pi^{-}) = (61.4 ± 4.5 ± 4.6)%

B(Xi(1530)^{-} to Xi^{-} pi^{0}) = (29.7 ± 2.2 ± 2.2)%

B(psi(3686) to anti-Xi^{+} Xi(1530)^{-} + c.c.) = (8.67 ± 0.52 ± 0.58 ± 0.57)×10^{-6}

Abstract

Based on (2712.4+-14.3)*10^{6} psi(3686) events collected with the BESIII detector, the decays Xi(1530)^{-} to Xi^{0} pi^{-} and Xi(1530)^{-} to Xi^{-} pi^{0} are investigated jointly via the process psi(3686) to anti-Xi^{+} Xi(1530)^{-} + c.c. Under the assumption of isospin symmetry, the two decay modes are treated as fully correlated, and we report the first measurement of their absolute branching fractions. The results are B(Xi(1530)^{-} to Xi^{0} pi^{-})=(61.4+-4.5+-4.6)% and B(Xi(1530)^{-} to Xi^{-} pi^{0}) =(29.7+-2.2+-2.2)%. The combined branching fraction of the two decays is B(Xi(1530)^{-} to (Xi pi)^{-})=(91.1+-6.7+-6.8)%, with uncertainties accounting for the correlations between the two modes. Here, the first uncertainties are statistical, while the second are systematic. Additionally, we update the branching fraction of the decay psi(3686) to anti-Xi^{+} Xi(1530)^{-} + c.c. The updated measurement is B(psi(3686) to anti-Xi^{+} Xi(1530)^{-} + c.c.)=(8.67+-0.52+-0.58+-0.57)*10^{-6}, where the first uncertainty is statistical, the second is systematic related to event selection and the fit model, and the third is associated with the interference effect.