Observable proton decay in flipped SU(5)

We explore proton decay in a class of realistic supersymmetric flipped $SU(5)$ models supplemented by $U(1)_R$ symmetry which plays an essential role implementing hybrid inflation. Two distinct neutrino mass models, based on inverse seesaw and type I seesaw, are identified, with the latter arising from breaking nonrenormalizable superpotential terms. Depending model appropriate set intermediate scale color triplets Higgs superfields play key channels that include $p \rightarrow (e^{+},\mu^+)\, \pi^0$, ( e^+,\mu^{+})\, K^0 $, \overline{\nu}\, \pi^{+}$, K^+ $. identify regions parameter space yield lifetime estimates testable at Hyper-Kamiokande other next generation experiments. discuss how gauge coupling unification presence particles is realized, $Z_4$ utilized to show such scales can arise $SU(5)$. Finally, we compare our predictions for previous work