Trilepton signature of minimal supergravity at the upgraded Fermilab Tevatron

The prospects for detecting trilepton events $(l=e$ or $\mu )$ from chargino-neutralino $\left({\chi }_1^{\pm }{\chi }_2^0\right)$ associated production are investigated for the upgraded Fermilab Tevatron Collider in the context of the minimal supergravity model (MSUGRA). In some regions of parameter space, ${\chi }_1^{\pm }$ and ${\chi }_2^0$ decay dominantly into final states with $\tau$ leptons and the contributions from $\tau$-leptonic decays enhance the trilepton signal substantially when soft cuts on lepton transverse momenta are used. Additional sources of the MSUGRA trilepton signal and dominant irreducible backgrounds are discussed. The dilepton ${(l}^{+}{l}^{-})$ invariant mass distribution near the end point is considered as a test of MSUGRA mass relations. Discovery contours for $p\overline{p}\to 3l+X$ at 2 TeV with an integrated luminosity of 2–30 ${\mathrm{fb}}^{-1}$ are presented in the MSUGRA parameter space of ${(m}_0{,m}_{1/2})$ for several choices of $\tan \beta .$