PRODUCTION AND DECAY OF SCALAR TOP SQUARKONIUM BOUND-STATES

In this paper we discuss possible signatures for the production of sca lar t1t1 (top squarkonium) bound states sigma(t1) at hadron colliders , where t1 is the lighter scalar top eigenstate. We first study the de cay of sigma(t1); explicit expressions are given for all potentially i mportant decay modes. If t1 has unsuppressed two-body decays, they wil l always overwhelm the annihilation decays of sigma(t1). Among the lat ter, we find that usually either the gg or hh final state dominates, d epending on the size of the off-diagonal entry of the top squark mass matrix; h is the lighter neutral scalar Higgs boson of the minimal sup ersymmetric model. If m(sigma)t) happens to be close to the mass of on e of the neutral scalar Higgs bosons, QQBAR final states dominate (Q = b or t). W+ W- and ZZ final states are subdominant. We argue that sig ma(t1) --> gammagamma decays offer the best signal for top squarkonium production at hadron colliders. The Fermilab Tevatron should be able to close the light top squark window left open by CERN LEP searches, b ut its mass reach is limited to m(sigma)t) less-than-or-equal-to 90 Ge V. In contrast, at the CERN LHC one should ultimately be able to probe the region m(sigma(t)) less-than-or-equal-to 700 GeV, if the hh parti al width is not too large. We also comment on the feasibility of searc hing for sigma(t1) production at hadron colliders in the ZZ, Zgamma, a nd tau+tau+tau-tau- final states, and briefly mention sigma(t1) produc tion at gammagamma colliders.