Constraining the top quark effective field theory using the top quark pair production in association with a jet at future lepton colliders

Reza Jafari,Parvin Eslami,Mojtaba Mohammadi Najafabadi,Hamzeh Khanpour

doi:10.1016/j.physletb.2020.135469

Abstract

Our main aim in this paper is to constrain the effective field theory describing the top quark couplings through the e−e+→tt¯ + jet process. The analysis is carried out considering two different center-of-mass energies of 500 and 3000 GeV including a realistic simulation of the detector response and the main sources of background processes. The expected limits at 95% CL are derived on the new physics couplings such as tt¯γ, tt¯Z, and tt¯g for each benchmark scenario using the dileptonic tt¯ final state. We show that the 95% CL limits on dimensionless Wilson coefficients c¯i considered in this analysis could be probed down to 10−4.

Highlights

Since the Higgs boson observation [1,2] at the Large Hadron Collider (LHC) by the ATLAS and CMS Collaborations, the primary focus of high energy particle physics is to probe its properties in details [3,4,5]
In order to investigate how far these sensitivities are changed with including uncertainties, we present the contours at 95% CL by considering 10% uncertainty on the cross sections of the background processes and a total 10% uncertainty on the efficiency of signal
We perform a study to probe the sensitivity of future lepton colliders to the top quark effective couplings at the center-of-mass energies of 500 and 3000 GeV

Summary

Introduction

Since the Higgs boson observation [1,2] at the Large Hadron Collider (LHC) by the ATLAS and CMS Collaborations, the primary focus of high energy particle physics is to probe its properties in details [3,4,5]. In the case that the possible new degrees of freedom are not light enough to be directly produced at a collider, they could affect the SM observables indirectly through virtual effects In such conditions, a powerful tool to parametrise any potential deviations from the SM predictions in a model-independent way is the standard model effective field theory (SMEFT). From the phenomenological point of view, there is a large volume of published works to study the SMEFT in particular in the top quark and Higgs boson sectors from the LHC, from electron-positron colliders, and from future proposed high-energy lepton-hadron and hadron-hadron colliders [25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63]

Objectives

Results

Conclusion