2008/07/07 by Joachim Brod, Frank Fugel, Bernd A. Kniehl
Mathematics · Physics and Astronomy · #Combinatorics #Cosmology and Gravitation Theories #Electroweak interaction #Gauge boson #Gauge theory #Higgs boson #Loop (graph theory) #Mathematics #Particle physics #Particle physics theoretical and experimental studies #Physics #Quantum Chromodynamics and Particle Interactions #Technicolor #hep-ph
paper · pdf · doi:10.1016/j.nuclphysb.2008.08.021
published as Nucl.Phys.B807:188-209,2009 · 27 pages, 11 figures
arxiv created 2008/07/07 · openalex publication_date 2008/08/24 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Using the asymptotic-expansion technique, we compute the dominant two-loop electroweak corrections, of O(GF mt2), to production and decay via a pair of photons or gluons of the CP-odd Higgs boson A0 in a two-Higgs-doublet model with low- to intermediate values of the Higgs-boson masses and ratio tan(beta)=v2/v1 of the vacuum expectation values. We also study the influence of a sequential heavy-fermion generation. The appearance of three gamma5 matrices in closed fermion loops requires special care in the dimensional regularisation of ultraviolet divergences. The finite renormalisation constant for the pseudoscalar current effectively restoring the anticommutativity of the gamma5 matrix, familiar from perturbative quantum chromodynamics, is found not to receive a correction in this order. We also revisit the dominant two-loop electroweak correction to the H -> gamma gamma decay width in the standard model with a fourth fermion generation.