Radiative processes [τ→μγ, μ→eγ and (g-2)μ] as probes of the extended supersymmetric standard model in SO(10) -: art. no. 035004

The extended supersymmetric standard model (ESSM), motivated on several grounds, introduces two vectorlike families (16+(16) over bar) of SO(10) with masses of the order of one TeV. It is noted that the successful predictions of prior work on fermion masses and mixings, based on the MSSM embedded in SO(10), can be retained rather simply within the ESSM extension. These include an understanding of the smallness of V(cb)approximate to0.04 and the largeness of the nu(mu)-nu(tau) oscillation angle, sin(2)2theta(nu mu nu tau)(osc)approximate to1. We analyze the new contributions arising through the exchange of the vectorlike families of the ESSM to radiative processes including tau-->mugamma, mu-->egamma, b-->sgamma, the EDM of the muon and the muon (g-2). We show that the ESSM makes significant contributions especially to the decays tau-->mugamma and mu-->egamma and simultaneously to muon (g-2). For a large and plausible range of relevant parameters, we obtain a(mu)(ESSM)approximate to+(10-40)x10(-10), with a correlated prediction that tau-->mugamma should be discovered with an improvement in its current limit by a factor of 3-20. The implications for mu-->egamma are very similar. The muon EDM is within reach of the next generation experiments. Thus, the ESSM, with heavy leptons being lighter than about 1 TeV (say), can be probed effectively by radiative processes before a direct search for these vectorlike leptons and quarks is feasible at the CERN LHC.