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 three and apparently only three generations of quarks and leptons in nature falling into a hierarchical mass and mixing pattern, 10 suggests also, among other things, a scalar boson U, with mass around 17 MeV and small couplings to quarks and leptons, 11 which might explain 9 the [Formula: see text] anomaly reported in experiment. 12 The U arises in FSM initially as a state in the predicted “hidden sector” with mass around 17[Formula: see text]MeV, which mixes with the standard model (SM) Higgs [Formula: see text], acquiring thereby a coupling to quarks and leptons and a mass just below 17[Formula: see text]MeV. The initial purpose of this 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 [Formula: see text] lies within a narrow range just below the unmixed mass. As a result from this, one has an estimate [Formula: see text]–17[Formula: see text]MeV for the mass of U, and from some further considerations the estimate [Formula: see text][Formula: see text]eV for its width, both of which may be useful for an eventual search for it in experiment. 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 even the bulk, of the dark matter in the universe.