Gauged B-xiL origin of R parity and its implications

Gauged B - L is a popular candidate for the origin of the conservation of R parity, i.e. R = (-)(3B+L+2j), in supersymmetry, but it fails to forbid the effective dimension-five terms arising from the superfield combinations Q Q Q L, u(c)u(c)d(c)e(c), and u(c)d(c)d(c)N(c), which allow the proton to decay. Changing it to B - x(i)L, where x(e) + x(mu) + x(tau) = 3 (with x(i) not equal 1) for the three families, would forbid these terms while still serving as a gauge origin of R parity. We show how this is achieved in two minimal models with realistic neutrino mass matrices, and discuss their phenomenological implications. (c) 2010 Elsevier B.V. All rights reserved.