TY - JOUR A2 - Petrov, Alexey AU - Dedes, Athanasios AU - Suxho, Kristaq PY - 2013 DA - 2013/06/18 TI - Anatomy of the Higgs Boson Decay into Two Photons in the Unitary Gauge SP - 631841 VL - 2013 AB - We review and clarify computational issues about the W-gauge boson one-loop contribution to the Hγγ decay amplitude, in the unitary gauge and in the Standard Model. We find that highly divergent integrals depend upon the choice of shifting momenta with arbitrary vectors. One particular combination of these arbitrary vectors reduces the superficial divergency down to a logarithmic one. The remaining ambiguity is then fixed by exploiting gauge invariance and the Goldstone Boson Equivalence Theorem. Our method is strictly realised in four dimensions. The result for the amplitude agrees with the “famous” one obtained using dimensional regularisation (DR) in the limit d4, where d is the number of spatial dimensions in Euclidean space. At the exact equality d=4, a three-sphere surface term appears that renders the Ward Identities and the equivalence theorem inconsistent. We also examined a recently proposed four-dimensional regularisation scheme and found agreement with the DR outcome. SN - 1687-7357 UR - https://doi.org/10.1155/2013/631841 DO - 10.1155/2013/631841 JF - Advances in High Energy Physics PB - Hindawi Publishing Corporation KW - ER -