TESLA: potentials of yy and e(+)e(-) options in stoponium searches

In some supersymmetric extensions of the Standard Model fairly light superp artner of t-quark is predicted, which may form bound states (stoponiums) un der certain conditions. We estimate potentials of TESLA linear collider in search for stoponium, considering the basic electron-positron option and th e gamma gamma option (Photon Linear Collider-PLC). It is found that PLC could be the best machine for discovery and study of t hese new narrow strong resonances. It can produce thousands stoponiums per 100 fb(-1) integrated gamma gamma luminosity in the high energy peak. In th e case of scenarios, when stoponium decays mainly into two gluons the signa l/background ratio is about 1/4. In addition, the decay channel S --> hh in to two lightest Higgs bosons could be seen with high significance. Thus, se veral weeks run is sufficient for the discovery of stoponium, if its mass i s approximately known (for example, from observation of direct stops produc tion at LHC). Then, in MSSM scenarios with dominant S --> hh decay PLC show s excellent possibilities to discover bound state of stops, practically imm ediately after beginning of operating. Thus, PLC has good possibilities to study strong interaction of top quark superpartners in nonperturbative regi me. The e(+)e(-) option also has some prospects to observe stoponium but only i n the case of scenarios with dominant decay into two lightest Higgs bosons, with tens of events per 100 fb-1. Interesting possibility appears in the c ase when the resonance is seated on 0.1% width luminosity peak-one could re solve the stoponium exited states. (C) 2001 Elsevier Science B.V. All right s reserved.