Higgs production in two-photon process and transition form factor

The Higgs production in the two-photon fusion process is investigated where one of the photons is off-shell while the other one is on-shell. This process is realized in either electron–positron collision or electron–photon collision where the scattered electron or positron is detected (single tagging) and described by the transition form factor. We calculate the contributions to the transition form factor of the Higgs boson coming from top-quark loops and W  -boson loops. We then study the Q2Q2 dependence of each contribution to the total transition form factor and also of the differential cross section for the Higgs production.