Constraints on vector-like models from natural conservation of strangeness in neutral currents

Abstract

In a vector-like model with natural conservation of strangeness, the neutral current of the d-quark is pure vector, which can in principle be tested directly. With Cabibbo universality this leads to a non-trivial lower bound on the ratio of antineutrino to neutrino total inelastic cross sections for neutral currents. On an isoscalar target, this bound is larger than or equal to 5 7 when the weak isospin of the d-quark is negative.