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Extending the Standard Model: an upper bound for a neutrino mass from the rare decay K+ -> Pi+ neutrino antineutrino

B. Machet
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Abstract

The standard model seeming at a loss to account for the present experimental average rate for the rare decay K+ -> Pi+ neutrino antineutrino, I tackle the question with the extension of the Glashow-Salam-Weinberg model to an SU(2)left x U(1) gauge theory of J=0 mesons proposed by the author in [Phys. Lett. B 385 (1996) 198], in which, in addition, the neutrinos are given Dirac masses from Yukawa couplings to the Higgs boson. The latter triggers a new contribution to this decay through flavor changing neutral currents that arise in the quartic term of the symmetry breaking potential; it becomes sizeable for a neutrino mass in the $MeV$ range; the experimental upper limit for the decay rate translates into an upper bound of 5.5 MeV for the mass of the neutrino, three times lower than present direct bounds.

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B. Machet. 2000-04-17. Extending the Standard Model: an upper bound for a neutrino mass from the rare decay K+ -> Pi+ neutrino antineutrino. https://doi.org/10.1142/s021773230000058x

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