HIGGS STUDIES IN POLARIZED GAMMA-GAMMA COLLISIONS

The study of an intermediate mass Higgs boson via the process gamma ga mma-->H--><b(b)over bar> from an initially polarized J(z)=0 state has been advocated as an important feasible goal of a future photon linear collider. The crucial argument was the m(b)(2)/s suppression of the b ackground process gamma gamma(J(z)=0)--><b(b)over bar>. We critically review the contribution of the radiative background processes (in whic h the m(b)(2)/s suppression is absent) to the quasi-two-jet-like event s with at least one, but preferably two, tagged energetic b jets. With in a complete study of the radiative processes, we find that a sizable background contribution can come from the helicity-violating gamma ga mma(J(z)=0)--><b(b)over bar> process accompanied by soft gluon emissio n. These latter radiative corrections contain a new type of double log arithmic (DL) terms. We clarify the physical nature of these novel DL corrections. Despite the fact that the one-loop DL terms are comparabl e or even larger than the Born term, fortunately we find that the calc ulation of the cross section in the two-loop approximation is sufficie nt for a reliable evaluation of the background to the Higgs signal.