Dominant two-loop electroweak corrections to the hadroproduction of a pseudoscalar Higgs boson and its photonic decay

TL;DR

This paper calculates the main two-loop electroweak corrections to the decay widths and production cross sections of a pseudoscalar Higgs boson in the two-Higgs-doublet model, relevant for collider experiments.

Contribution

It provides the first detailed computation of dominant two-loop electroweak corrections for a pseudoscalar Higgs in the 2HDM, including handling of gamma_5 in dimensional regularization.

Findings

Corrections are negative, amounting to several percent.

They counteract or partially offset QCD enhancements.

Results apply to hadronic and photon collider production processes.

Abstract

We present the dominant two-loop electroweak corrections to the partial decay widths to gluon jets and prompt photons of the neutral CP-odd Higgs boson A^0, with mass M_{A^0} < 2 M_W, in the two-Higgs-doublet model for low to intermediate values of the ratio tan(beta) = v_2/v_1 of the vacuum expectation values. They apply as they stand to the production cross sections in hadronic and two-photon collisions, at the Tevatron, the LHC, and a future photon collider. The appearance of three gamma_5 matrices in closed fermion loops requires special care in the dimensional regularization of ultraviolet divergences. The corrections are negative and amount to several percent, so that they fully compensate or partly screen the enhancement due to QCD corrections.