Prospects for and Implications of Measuring the Higgs to Photon-Photon Branching Ratio at the Next Linear $e^{+}{e}^{-}$ Collider

Abstract

We evaluate the prospects for measuring $BR(h\to \gamma \gamma )$ for a Standard-Model-like Higgs boson at the Next Linear $e^{+}{e}^{-}$ Collider in the $e^{+}{e}^{-}\to Z^{\ast }\to Zh$ and $e^{+}{e}^{-}\to {\nu }_e\text{anti}{\nu }_{e}h$ production modes. Relative merits of different machine energy/luminosity strategies and different electromagnetic calorimeter designs are evaluated. We emphasize the importance of measuring $BR(h\to \gamma \gamma )$ in order to obtain the total width of a light Higgs boson and thereby the $b\text{anti}b$ partial width that will be critical in discriminating between the SM Higgs and the Higgs bosons of an extended model.

Comments: 11 pages, full postscript file also available via anonymous ftp at ftp://ucdhep.ucdavis.edu/gunion/htogamgam.ps. Revisions are substantial; in particular, the $WW$-fusion Higgs production mode is now considered in addition to the $Zh$ Higgs production mode