Two-loop large Higgs mass correction to the ϱ-parameter

Abstract

The two-loop correction to the o-parameter in lhe limit of the large l-tiggs mass is calculated. Numerically it is found that the two-loop contribution is equal in magnitude, but of opposite sign to the one-kw, p correction if the tliggs mass is about 137 times the vector boson mass. The calculation suggest a breakdown of perturbation theory if the tliggs mass is larger than 3 TeV. There is no direct correspondence between our results and the poles at n = 3 of the simple non-linear o-model at the two-loop level. * For an unknown reason these terms were misrepresented in ref. [5].

Superpartner spectrum of minimal gaugino-gauge mediation

“…where the dilogarithm is defined by Li 2 (x) = − 1 0 dt t log(1 − xt), and an analytical expression for h can be found in [14]. We refer the reader to ref.…”

Two-loop tensor integrals in quantum field theory

“…We obtain [36] and has also been applied to one-loop diagrams in [37]. Well-known packages for diagram handling are listed in [38].…”

Three-loop electroweak correction to the rho parameter in the large Higgs mass limit

“…Since the Higgs self-coupling grows like m 2 H higher loop effects can play a role and cancel against the one-loop leading log(m H ) effects. At the two-loop level such radiative corrections have been calculated, also allowing for anomalous Higgs-boson self-couplings [7,8]. Inclusion of these two-loop corrections does not make it possible to fit the data with a heavy Higgs boson.…”

“…Here, one might expect to find corrections of order m 2L H , since the W and Z self-energies contain terms of this order, but it turns out that such terms are screened in low energy observables such as the ρ-parameter [2]. The leading one-loop terms in ∆ρ depend logarithmically on m H [13], and the leading two-loop correction is proportional to m 2 H [7,14]. In this paper, we present the leading three-loop correction ∆ρ (3) , which is of order m 4 H .…”

“…Two and three-loop vertices and boxes can only contribute to the leading order term of ∆ρ (3) if they contain one-loop subgraphs of order m 2 H or two-loop subgraphs of order m 4 H . However, it is possible to choose a renormalization scheme in which all terms of order m 2 H (m 4 H ) in the relevant one-loop (two-loop) subgraphs are absorbed into the renormalization factors [7,15]. In such a scheme, vertices and boxes do not contribute to ∆ρ at the leading order in m H , and one is left with just the corrections coming from the transversal W and Z self-energies,…”