Study of psi(3770) decaying to baryon anti-baryon pairs

摘要

To study the decays of psi (3770) going to baryon anti-baryon pairs (B (B) over bar), all available experiments of measuring the cross sections of e(+)e(-) -> B (B) over bar at center-of-mass energy ranging from 3.0 GeV to 3.9 GeV are combined. To relate the baryon octets, a model based on the SU(3) flavor symmetry is used and the SU(3) breaking effects are also considered. Assuming the electric and magnetic form factors are equal (vertical bar G(E)vertical bar = vertical bar G(M)vertical bar), a global fit including the interference between the QED process and the resonant process is performed. The branching fraction of psi(3770) -> B (B) over bar is determined to be (2.4 +/- 0.8 +/- 0.3) x 10(-5), (1.7 +/- 0.6 +/- 0.1) x 10(-5), (4.5 +/- 0.9 +/- 0.1) x 10(-5), (4.5 +/- 0.9 +/- 0.1) x 10(-5), (2.0 +/- 0.7 +/- 0.1) x 10(-5), and (2.0 +/- 0.7 +/- 0.1) x 10(-5) for B = p, Lambda, Sigma(+), Sigma(0), Xi(-) and Xi(0), respectively, where the first uncertainty is from the global fit and the second uncertainty is the systematic uncertainty due to the assumption vertical bar G(E)vertical bar = vertical bar G(M)vertical bar. They are at least one order of magnitude larger than a simple scaling of the branching fraction of J/psi/psi (3686) -> B (B) over bar. (C) 2016 The Author. Published by Elsevier B.V.