Towards a measurement of the two-photon decay width of the Higgs boson at a Photon Collider

A study of the measurement of the two photon decay width times the branching ratio of a Higgs boson with the mass of 120 GeV in photon - photon collisions is presented, assuming a gamma-gamma integrated luminosity of 80 fb^-1 in the high energy part of the spectrum. The analysis is based on the reconstruction of the Higgs events produced in the gamma gamma --> H process, followed by the decay of the Higgs into a bbbar pair. A statistical error of the measurement of the two-photon width times the branching ratio of the Higgs boson decaying into b-quarks is found to be 2.1% for one year of data taking.