A framework for Higgs characterisation

160

176

Abstract:We treat the Standard Model as the low-energy limit of an effective field theory that incorporates higher-dimensional operators to capture the effects of decoupled new physics. We consider the constraints imposed on the coefficients of dimension-6 operators by electroweak precision tests (EWPTs), applying a framework for the effects of dimension-6 operators on electroweak precision tests that is more general than the standard S, T formalism, and use measurements of Higgs couplings and the kinematics of associated Higgs production at the Tevatron and LHC, as well as triple-gauge couplings at the LHC. We highlight the complementarity between EWPTs, Tevatron and LHC measurements in obtaining model-independent limits on the effective Standard Model after LHC Run 1. We illustrate the combined constraints with the example of the two-Higgs doublet model.

Section: Tgc Constraints On Dimension-6 Operator Coefficientsmentioning

confidence: 99%

The effective Standard Model after LHC Run I

Ellis

Sanz

You

2015

160

176

“…[86][87][88][89][90][91]). This is highly relevant since in this way indirect BSM effects can be directly tested in the experimental analyses.…”

Section: Jhep03(2017)115mentioning

confidence: 99%

Modeling BSM effects on the Higgs transverse-momentum spectrum in an EFT approach

Grazzini

Ilnicka

Spira

et al. 2017

Abstract:We consider the transverse-momentum distribution of a Higgs boson produced through gluon fusion in hadron collisions. At small transverse momenta, the large logarithmic terms are resummed up to next-to-leading-logarithmic (NLL) accuracy. The resummed computation is consistently matched to the next-to-leading-order (NLO) result valid at large transverse momenta. The ensuing Standard Model prediction is supplemented by possible new-physics effects parametrised through three dimension-six operators related to the modification of the top and bottom Yukawa couplings, and to the inclusion of a point-like Higgs-gluon coupling, respectively. We present resummed transverse-momentum spectra including the effect of these operators at NLL+NLO accuracy and study their impact on the shape of the distribution. We find that such modifications, while affecting the total rate within the current uncertainties, can lead to significant distortions of the spectrum. The proper parametrization of such effects becomes increasingly important for experimental analyses in Run II of the LHC.

“…only use data in phase space regions which are not sensitive to the ultraviolet completions, for example requiring p T < 100 GeV for the tagging jets in weak boson fusion [124][125][126][127][128] or an upper bound on p V T in V H production. The obvious disadvantage of this approach is that we lose experimental information and produce worse bounds, as we will see.…”

Section: Kinematic Distributionsmentioning

confidence: 99%

The Higgs legacy of the LHC Run I

Corbett

Éboli

Gonçalves

et al. 2015

127

158

Based on Run I data we present a comprehensive analysis of Higgs couplings. For the first time this SFitter analysis includes independent tests of the Higgs-gluon and top Yukawa couplings, Higgs decays to invisible particles, and off-shell Higgs measurements. The observed Higgs boson is fully consistent with the Standard Model, both in terms of coupling modifications and effective field theory. Based only on Higgs total rates the results using both approaches are essentially equivalent, with the exception of strong correlations in the parameter space induced by effective operators. These correlations can be controlled through additional experimental input, namely kinematic distributions. Including kinematic distributions the typical Run I reach for weakly interacting new physics now reaches 300 to 500 GeV.