Impact of bosonic decays on the search for (tau)over-bar(2) and (nu)over-bar(tau)

We perform a detailed study of the decays of the heavier tau slepton (<(tau )over tilde>(2)) and tau-sneutrino (<(nu)over tilde>(r)) in the Minimal Sup ersymmetric Standard Model (MSSM). We show that the decays into Higgs or ga uge bosons, i.e. <(tau)over tilde>(-)(2) --> <(tau)over tilde>(-)(1) + (h(0 ), H-0, A(0) or Z(0)), <(tau)over tilde>(-)(2) --> <(nu)over tilde>(tau) (H - or W-), and <(nu)over tilde>(tau) --> <(tau)over tilde>(-)(1) + (H+ or W), can be very important due to the sizable tau Yukawa coupling and large m ixing parameters of <(tau)over tilde>. Compared to the decays into fermions , such as <(tau)over tilde>(-)(2) --> tau(-) + <(chi)over tilde>(0)(i) and <(tau)over tilde>(-)(2) --> nu(tau) + <(chi)over tilde>(-)(j), these bosoni c decay modes can have significantly different decay distributions. This co uld have an important influence on the search for <(tau)over tilde>(2) and <(nu)over tilde>(tau) and the determination of the MSSM parameters at futur e colliders. (C) 1999 Published by Elsevier Science B.V. All rights reserve d.