Search for new physics in semileptonic decays of K and B as implied by the g-2 anomaly in FSM

Abstract

The framed standard model (FSM), constructed to explain, with some success, why there should be 3 and apparently only 3 generations of quarks and leptons in nature falling into a hierarchical mass and mixing pattern, suggests also, among other things, a scalar boson U, with mass around 17 MeV and small couplings to quarks and leptons, which might explain the g-2 anomaly reported in experiment. The U arises in FSM initially as a state in the predicted `hidden sector' with mass around 17 MeV, which mixes with the standard model (SM) Higgs $h_W$, acquiring thereby a coupling to quarks and leptons and a mass just below 17 MeV. The initial purpose of the present paper is to check whether this proposal is compatible with experiment on semileptonic decays of Ks and Bs where the U can also appear. The answer to this we find is affirmative, in that the contribution of U to new physics as calculated in the FSM remains within the experimental bounds, but only if $m_U$ lies within a narrow range just below the unmixed mass. As a result from this, one has an estimate $m_U \sim 15 - 17$ MeV for the mass of $U$, and from some further considerations the estimate $Γ_U \sim 0.02$ eV for its width, both of which may be useful for an eventual search for it in experiment. And, if found, it will be, for the FSM, not just the discovery of a predicted new particle, but the opening of a window into a whole ``hidden sector" containing at least some, perhaps ven the bulk, of the dark matter in the universe.