Nucleon two-body decays in SU(5)

Proton and neutron decay to meson and antilepton is studied in SU(5) as a function of the momentum of the antiquark produced; two different Higgs structures are considered. Branching ratios which are independent of the motion of the antiquark are displayed, as well as branching ratios which probe the antiquark's motion. The partial-rate predictions for Cabibbo-suppressed modes of the two different Higgs structures are compared. Tables of reduced partial rates are presented and their connection to the absolute partial rates is displayed. We expect the dominant part of the nucleon's width to result from two-body decay (including $\eta$, $\rho$, and $\omega$ production). We find that it varies by a factor of 3 depending upon how the motion of the antiquark at production is treated. Momentum suppression due to "spectator" recoil and muon phase space is also incorporated, and tables of absolute partial rates and proton and neutron lifetime are included.