Key points are not available for this paper at this time.
The J/ ^+^-^+^- decay has been observed with a statistical significance in excess of five standard deviations. The analysis is based on an event sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the CMS experiment in 2018 and corresponding to an integrated luminosity of 33. 6 fb^-1. Normalizing to the J/ ^+^- decay mode leads to a branching fraction 10. 1 ^+3. 3-₂. ₇ (stat) 0. 4 (syst) 10^-7, a value that is consistent with the standard model prediction.
Hayrapetyan et al. (Sun,) studied this question.