Search for the weak decays J/? ? D(?)- s e+?e + c.c

Abstract

Using a sample of 2.25 × 108 J/? events collected with the BESIII detector at the BEPCII collider, we search for the J/? semileptonic weak decay J/? ? D-s e+?e+ c.c. with a much higher sensitivity than previous searches. We also perform the first search for J/? ? D?-s e+?e + c.c. No significant excess of a signal above background is observed in either channel. At the 90% confidence level, the upper limits are determined to be B(J/? ? D-s e+?e + c.c. )< 1.3 × 10-6 and B(J=? ? D?-s e+?e + c.c. ) < 1.8 × 10-6, respectively. Both are consistent with Standard Model predictions. © 2014 American Physical Society.