Anomalous couplings in single Higgs production throughγγ collisions

Abstract

We show that single Higgs production inγγ collisions through laser backscattering provides the best way to look for New Physics (NP) effects inducing anomalous Higgs couplings. Our analysis is based on the fourdim=6 operators\({\mathcal{O}}_{UB} , {\mathcal{O}}_{UW, } \bar {\mathcal{O}}_{UB} \), and\(\bar {\mathcal{O}}_{UW} \) which describe New Physics effects in this sector. Using the Higgs production rate we establish observability limits for the couplings of the aforementioned operators at a level of 10−3, which means establishing lower bounds on the scale of NP of the order 30 to 200 TeV. Higgs branching ratios, especially the ratio Γ(H→γγ)/Γ(H→γZ), are shown to provide powerful ways to disentangle the effects of the various operators.