  I argue that LHC may shed light on the nature of neutrino mass through the
probe of the seesaw mechanism. The smoking gun signature is lepton number
violation through the production of same sign lepton pairs, a collider analogy
of the neutrinoless double beta decay. I discuss this in the context of L-R
symmetric theories, which led originally to neutrino mass and the seesaw
mechanism. A W_R gauge boson with a mass in a few TeV region could easily
dominate neutrinoless double beta decay, and its discovery at LHC would have
spectacular signatures of parity restoration and lepton number violation.
Moreover, LHC can measure the masses of the right-handed neutrinos and the
right-handed leptonic mixing matrix, which could in turn be used to predict the
rates for neutrinoless double decay and lepton flavor violating violating
processes. The LR scale at the LHC energies offers great hope of observing
these low energy processes in the present and upcoming experiments.
