Proton decay: is it fast enough?

Abstract

A comprehensive Bethe-Salpeter model for qq̅ and qqq systems under harmonic confinement, which has provided an impressive set of agreements in respect of (i) qq̅, qqq mass spectra, (ii) electromagnetic properties of mesons and baryons, the photon charge radius and (iii) strong couplings of hadrons, all with two basic parameters (universal spring constant W̅ = 0.15 GeV and quark mass m_q = 0.28 GeV), is employed for the calculation of proton decay rates (inclusive and exclusive). Keeping the GUT parameters fixed at the "standard" values listed, e.g. in Langacker's review, the decay rates for the inclusive and exclusive modes are: = Γ(p → e⁺ qq̅) = 0.540, Γ(p → e⁺π⁰ = 0.1824, in 10^-33 yr^-1 units. These values (which are mutually consistent) are smaller by about a factor of 100, than several contemporary calculations, but do not yet seem to be ruled out by the available data.