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Binosi, D., Chang, L., Ding, M. H., Gao, F., Papavassiliou, J., & Roberts, C. D. (2019). Distribution amplitudes of heavy-light mesons. Phys. Lett. B, 790, 257–262.
Abstract: A symmetry-preserving approach to the continuum bound-state problem in quantum field theory is used to calculate the masses, leptonic decay constants and light-front distribution amplitudes of empirically accessible heavy-light mesons. The inverse moment of the B-meson distribution is particularly important in treatments of exclusive B-decays using effective field theory and the factorisation formalism; and its value is therefore computed: lambda(B) = (zeta = 2GeV) = 0.54(3) GeV. As an example and in anticipation of precision measurements at new-generation B-factories, the branching fraction for the rare B -> gamma (E-gamma)l nu(l) radiative decay is also calculated, retaining 1/m(B)(2), and 1/E-gamma(2) corrections to the differential decay width, with the result Gamma(B -> gamma l nu l) /Gamma(B) = 0.47 (15) on E-gamma > 1.5 GeV.
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Bordes, J., Chan, H. M., & Tsou, S. T. (2023). Search for new physics in semileptonic decays of K and B as implied by the g-2 anomaly in FSM. Int. J. Mod. Phys. A, 38, 2350177–24pp.
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 g – 2 anomaly reported in experiment.(12) 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 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 m(U) lies within a narrow range just below the unmixed mass. As a result from this, one has an estimate m(U) similar to 15-17 MeV for the mass of U, and from some further considerations the estimate Gamma(U) similar to 0.02 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.
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