Search for the weak decay ?'›K±?± and precise measurement of the branching fraction B(J/?›??')

Abstract

We present the first search for the rare decay of ?' into K±?± in J/?›??', using a sample of 1.3×109 J/? events collected with the BESIII detector. No significant signal is observed, and the upper limit at the 90\% confidence level for the ratio B(?'›K±?±)B(?'›??+?-) is determined to be 1.3×10-4. In addition, we report the measurement of the branching fraction of J/?›??' to be (5.10±0.03(stat.)±0.32(syst.))×10-4, which agrees with previous results from BESII.