Neutral currents and n1B + n2L conservation

We look for possible forms of deviations from the SU(2)sub(L) x U(1) of neutral current parameters when there exists one globally conserved quantum number (n1B + n2L) in a grand unified model, and obtain several relations between these parameters. It is shown that precision experiments on these parameters will hint at a globally conserved number even before an accurate measurement of the proton decay. (orig.)