QCD Corrections to Heavy Quark Pair Production in Polarized $\gamma\gamma$ Collisions and the Intermediate Mass Higgs Signal

Abstract

Perturbative QCD one-loop corrections to the cross sections of the $b\bar b$ $(c\bar c)$ quark pair production in polarized photon-photon collisions, as well as cross sections of the radiative processes photon-photon ->$b\bar b g$,$c\bar c g$ leading to two- and three-jet final states are calculated. It is shown that the signal from the intermediate mass Higgs boson is observable and precise measurements of the Higgs boson two-photon width are possible at a photon-photon collider, although the statistical significance is substantially reduced with respect to the tree level calculations. We demonstrate that virtual corrections are of the same order or larger than the Born contribution in the $J_z=0$ channel at high energy for small values of the cutoff $y_{cut}$, separating two-jet from three-jet topologies. The nature of these large corrections is elucidated. For $b\bar b$ pair production at $\sqrt{s_{\gamma\gamma}}\sim 100$~GeV and for small values of $y_{cut}\leq 0.04$ the higher order resummation of double logarithmic terms ${\cal O}\left(\alpha_s m_b^2/s\ln^2(s/m_b^2)\right)$ is needed.