R-parity violation, sneutrino mixing phenomena, and CP violation in p(p)over-bar ->(nu)over-tilde -> l(+)l(-)+X - art. no. 055012

The sneutrino resonance reactions p(p)over-bar-->(nu)over-tilde + X-->l(+)l (-) + X, for l = e, mu, tau, in the MSSM without R-parity an considered. We perform a cross-section analysis and show that present limits on some prod ucts of Wp Couplings in the sneutrino sector can he significantly improved in future upgraded Fermilab Tevatron runs. Furthermore, we introduce CP-vio lating and CP-conserving tau-spin asymmetries which are generated already a t the tree level in the reaction p(p)over-bar-->(nu)over-tilde + X-->tau(+) tau(-) + X if then is (nu)over-tilde(mu)-(nu)over-tilde(mu) mixing and that vanish in the SM. We find, for example, that for muon-sneutrino masses in the range 150 GeV less than or equal to m((nu))over-tilde>mu) less than or similar to 450 GeV, these spin asymmetries reach similar to 20-30% and simi lar to 10% for mass splitting between the muon-sneutrino CP-odd and CP-even states at the level of Delta m similar to Gamma and Delta m similar to Gam ma/4, respectively, where Gamma is the (nu)over-tilde(mu) width. Both the C P-violating and the CP-conserving spin asymmetries should be detectable in future Tevatron runs even for a heavy sneutrino with a mass less than or si milar to 500 GeV. If detected, such asymmetries-being proportional to the m ass splitting between the CP-even and CP-odd sneutrino states-may serve as a strong indication for the existence of the sneutrino mixing phenomenon. [ S0556-2821(99)04103-X].