Branching ratio for a light Higgs boson to decay intoμ+μpairs

Abstract
We evaluate the effects of final-state interactions on the decay of a light Higgs boson to two pions. Although the formalism is completely general and can be applied to any strong-interaction decay mode of the Higgs boson, we are particularly interested in the regime where the Higgs-boson mass mh satisfies the constraint 2mπ<mh<2mK. In this case the dominant decay modes of the Higgs boson are to μ+ μ and two pions. Final-state interactions tend to enhance the two-pion mode and thus suppress the branching ratio to two muons. Since the two-muon mode is the cleanest signature for identifying the Higgs boson, it is important to obtain a good determination of this branching ratio. We find B(h→μ+ μ) 102101.