ANOMALOUS COUPLINGS IN SINGLE HIGGS PRODUCTION THROUGH GAMMA-GAMMA COLLISIONS

We show that single Higgs production in gamma gamma collisions through laser backscattering provides the best way to look for New Physics (N P) effects inducing anomalous Higgs couplings. Our analysis is based o n the four dim = 6 operators O-UB, O-UW, <(O)over bar(UB)> and <(O)ove r bar(UW)>, which describe New Physics effects in this sector. Using t he Higgs production rate we establish observability limits for the cou plings of the aforementioned operators at a level of 10(-3), which mea ns establishing lower bounds on the scale of NP of the order 30 to 200 TeV. Higgs branching ratios, especially the ratio Gamma(H --> gamma g amma)/Gamma(H --> gamma Z), are shown to provide powerful ways to dise ntangle the effects of the various operators.