B+ → K+ν(ν)over-bar excess and DM semi-annihilation

초록

In 2023, the Belle II Collaboration announced the observation of the B+ -> K+nu(nu) over bar decay channel for the first time. This decay channel provides a clean signal with high precision in theoretical calculations. However, we encounter a 2.8 sigma deviation from the Standard Model prediction. To resolve this excess, we study a scalar dark matter model with local discrete Z(3) symmetry. Assuming dark U(1)(X) equivalent to U(1)(L mu-L tau) symmetry, this U(1)(L mu-L tau) symmetry is spontaneously broken into local discrete Z(3) by nonzero vacuum expectation value of dark Higgs boson. Considering a dark Higgs mass is 2 GeV, we can explain the recent Br(B+ -> K+nu(nu) over bar) excess reported from the Belle II Collaboration and relic abundance at the same time.

키워드