A light dimuon resonance in B decays?

Abstract

The observed deviations from the Standard Model in several b → sµµ processes can be explained in terms of a new vector boson produced on-shell in B meson decays. A mass of 2.5 − 3 GeV and a total width of 10 − 20% allow to hide the associated dimuon bump in the poorly known charmonium region, and the large invisible decay width can be interpreted in terms of Dark Matter. This proposal predicts a contribution to the muon anomalous magnetic moment, that could explain the long-standing tension with the Standard Model. It also predicts sizeable invisible B decays and a peculiar q 2 -dependence of the lepton flavor universality ratios RK and RK * , that could be tested at the LHCb and Belle-II. This proceeding is based on [1], and slightly extends it with comments about Dark Matter.

Towards excluding a light $Z^\prime$ explanation of $b\to s\ell^+\ell^-$

“…Because all these solutions, except the Z one, involve charged particles they must be realized at the electroweak scale, or even significantly above, due to the constraints from direct searches. However, a Z boson can be light and, in fact, such solutions to the b → s + − anomalies have been proposed and studied in the literature [108][109][110][111][112][113][114][115]. Importantly, this is the only NP model addressing the b → s + − anomalies which predicts R(K ( * ) ) > 0 in the high q 2 bins, i.e.…”