Neutrino masses and proton decay in SO(10)

We consider the constraints on SO(10) unified models coming from the lower limits on proton lifetime and on the scale of B−L symmetry break-ing within the framework of the seesaw model for neutrino masses. By upgrading a triangular relationship for the inverse of νL Majorana masses to the experimental situation with non maximal θ23 and non vanishing θ13, we get for the sum of νL masses the upper limit 0.16 eV