Impact on the decay rate of $B_s\to \mu^+\mu^-$ from the dispersive two-photon transition

Research paper by Dao-Neng Gao

Indexed on: 12 Jan '20Published on: 31 May '19Published in: arXiv - High Energy Physics - Phenomenology


We study the long-distance contribution to $B_s\to\mu^+\mu^-$ decay, which is generated by the two-photon intermediate state via $B_s\to\gamma^*\gamma^*\to\mu^+\mu^-$ transition. It is found that the dispersive two-photon amplitude can interfere with the dominant short-distance amplitude, which will give rise to a new uncertainty in the branching ratio of $B_s\to\mu^+\mu^-$ decay. This novel effect has not been investigated before, and may be of the same order of magnitude as some uncertainties of ${\cal B}(B_s\to\mu^+\mu^-)$ analyzed in the past literature. Future precise studies of the double radiative $B_s\to\gamma\gamma$ decay could help to reduce this uncertainty.