Topic
Electroweak interaction
About: Electroweak interaction is a research topic. Over the lifetime, 16333 publications have been published within this topic receiving 468927 citations. The topic is also known as: electroweak force.
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TL;DR: In this article, the authors studied the evolution of axion-like particle couplings from the new-physics scale to energies at and below the scale of electroweak symmetry breaking.
Abstract: Axions and axion-like particles (ALPs) are well-motivated low-energy relics of high-energy extensions of the Standard Model, which interact with the known particles through higher-dimensional operators suppressed by the mass scale Λ of the new-physics sector. Starting from the most general dimension-5 interactions, we discuss in detail the evolution of the ALP couplings from the new-physics scale to energies at and below the scale of electroweak symmetry breaking. We derive the relevant anomalous dimensions at two-loop order in gauge couplings and one-loop order in Yukawa interactions, carefully considering the treatment of a redundant operator involving an ALP coupling to the Higgs current. We account for one-loop (and partially two-loop) matching contributions at the weak scale, including in particular flavor-changing effects. The relations between different equivalent forms of the effective Lagrangian are discussed in detail. We also construct the effective chiral Lagrangian for an ALP interacting with photons and light pseudoscalar mesons, pointing out important differences with the corresponding Lagrangian for the QCD axion.
117 citations
TL;DR: In this paper, the authors investigated isosinglet neutrino production and decays within different models and concluded that these may discover the existence of singlets neutrinos and substantially improve and extend present limits on their mass and coupling strength.
116 citations
TL;DR: In this article, the branching ratio in the low-q 2 region, BRll, was shown to change by about +1% and −4%, respectively, due to accidental cancellations.
Abstract: We complete the next-to-next-to-leading order QCD calculation of the branching ratio for ¯ B → Xsl + l including recent results for the three-loop anomalous dimension matrix and two-loop matrix elements. These new contributions modify the branching ratio in the low-q 2 region, BRll, by about +1% and −4%, respectively. We furthermore discuss the appropriate normalization of the electromagnetic coupling α and calculate the dominant higher order electroweak effects, showing that, due to accidental cancellations, they change BRll by only −1.5% if α(� ) is normalized at � = O(mb), while they shift it by about −8.5% if one uses a high scale normalization � = O(MW). The position of the zero of the forwardbackward asymmetry, q 2 0 , is changed by around +2%. After introducing a few additional improvements in order to reduce the theoretical error, we perform a comprehensive study of the uncertainty. We obtain BRll(1GeV 2 ≤ q 2 ≤ 6GeV 2 ) = (1.57 ± 0.16) × 10 6 and q 2 0 = (3.76 ±0.33)GeV 2 and note that the part of the uncertainty due to the b-quark mass
116 citations
TL;DR: In this article, the authors investigate the main experimental signatures of these possibilities, related to the production of Kaluza-Klein excitations of gluons and electroweak gauge bosons.
116 citations
TL;DR: In this paper, the effects of new physics at the electroweak scale were studied using LHC data and the effective Lagrangian expansion (ELG) framework, and the results showed that the triple gauge vertices lead to a significant improvement in the entire set of operators describing Higgs couplings.
Abstract: The effective Lagrangian expansion provides a framework to study effects of new physics at the electroweak scale. To make full use of LHC data in constraining higher-dimensional operators we need to include both the Higgs and the electroweak gauge sector in our study. We first present an analysis of the relevant di-boson production LHC results to update constraints on triple gauge boson couplings. Our bounds are several times stronger than those obtained from LEP data. Next, we show how in combination with Higgs measurements the triple gauge vertices lead to a significant improvement in the entire set of operators, including operators describing Higgs couplings.
116 citations