Probing R-parity violating models of neutrino mass at the Fermilab Tevatron via top squark decays -: art. no. 015009

We have estimated the limiting branching ratio of the R-parity violating (RPV) decay of the lighter top squark, t(1)-->l(+)d (l=e or mu and d is a down-type quark of any flavor), as a function of the top squark mass (m(t1)) for an observable signal in the di-lepton plus di-jet channel at the Tevatron Run-II experiment with 2 fb(-1) luminosity. Our simulations indicate that the lepton number violating nature of the underlying decay dynamics can be confirmed via the reconstruction of m(t1). The above decay is interesting in the context of RPV models of neutrino mass where the RPV couplings (lambda(i3j)(')) driving the above decay are constrained to be small (less than or similar to10(-3)-10(-4)) by the measured values of the neutrino oscillation parameters. If t(1) is the next lightest super particle-a theoretically well motivated scenario-then the RPV decay can compete with the R-parity conserving (RPC) modes which also have naturally suppressed widths. The model independent limiting branching ratio can delineate the parameter space in specific supersymmetric models, where the RPV decay is observable and predicts the minimum magnitude of the RPV coupling that will be sensitive to Run-II data. We have found it to be in the ballpark value required by models of neutrino mass, for a wide range of m(t1). A comprehensive future strategy for linking top squark decays with models of neutrino mass is sketched.