Neutrinos, neutralinos, and light neutral Higgs bosons in supersymmetric flipped SU(5)

Abstract

It is shown that the flipped SU(5) model recently proposed by Antoniadis et al. necessarily contains a light scalar N, a light pseudoscalar A, and a light higgsino N . We argue that m N and m N lie in the range of a few GeV to a few tens of GeV whereas m A is estimated to be below 1 GeV. The interactions of these particles with ordinary matter occur only via superheavy particle exchanges making their direct detection via laboratory experiments essentially impossible. The photino, or more generally the lightest supersymmetric particle of conventional SUSY models, might decay into N+γ with a lifetime of order 10 3 years. Some cosmological implications of the existence of these light particles are pointed out.