Effective Field Theory in quest to parametrise Higgs properties: the transverse momentum spectrum case

Massimiliano Grazzini,Michael Spira,Agnieszka Ilnicka,Marius Wiesemann

doi:10.1088/1742-6596/873/1/012050

Abstract

After the Higgs boson discovery, LHC turned into the precision machine to explore its properties. In case new resonances will not be found, the only access to New Physics would be via measuring small deviations from the SM predictions. A consistent approach which can be useful in both above cases is a bottom-up Effective Field Theory, with dimension six operators build of Standard Model fields. We present how this approach would work in case of the transverse momentum spectrum of the Higgs particle. In our calculation we augmented the Standard Model with three additional operators: modifications of the top and bottom Yukawa couplings, and a point-like Higgs coupling to gluons. 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. We also discuss the effect of the chromomagnetic operator on the Higgs production cross section at LO.For more details see our paper [1].

Highlights

Introduction to "Symmetry": The second quest Richard ArnowittThis content was downloaded from IP address 129.132.109.47 on 18/01/2018 at 15:40Fifth Symposium on Prospects in the Physics of Discrete Symmetries IOP Conf
Looking at the low-pT interval (0 GeV≤ pT ≤ 400 GeV) in Fig. 2 (a) we can directly deduce that modifications of the bottom Yukawa coupling through cb dominantly affect the low-pT shape of the distribution
SMEFT offers a formalism for the parametrisation of high-scale beyond the SM (BSM) effects, which can be used for this purpose

Summary

Introduction

The scalar resonance discovered by ATLAS and CMS at the LHC in 2012 [2, 3] closely resembles the Higgs boson postulated in the Standard Model (SM). Many theories beyond the SM (BSM) addressing the above issues have been developed, which manifest different patterns in the scalar sector and in the Higgs boson properties. As no strict argument exists for the discovery of new physics at the TeV scale, it is possible that new physics effects are accessible only by measuring small deviations from SM predictions. A consistent way to parametrise these deviations is offered by the Effective Field Theory (EFT), in which the unknown high-scale fields are integrated out leaving an infinite ladder of higher-dimensional operators (dim> 4), with a well-defined hierarchy. A matching to the EFT allows for the translation of the Wilson coefficients into bounds on the physical parameters of new physics models. We develop a strategy to determine such bounds by using the transverse-momentum (pT ) spectrum of the Higgs boson

Transverse-momentum spectrum

Results

Conclusions