Multilepton study for search for new flavors and the Higgs boson

Multilepton events in high-energy hadron collisions are studied as a means to probe new particles in heavy-flavor associative production and $Z^0{H}^0$ bremsstrahlung production. We concentrate attention on trileptons. Some newly proposed transverse-momentum variables $T$, $T_{\perp }$, $H_{\perp }$ and the dilepton invariant mass $M\left(\mathrm{ll}\right)\mathrm{}$ provide useful signatures for the search for new particles.