Torsion limits from tt¯ production at the LHC

F M L De Almeida,M A B Do Vale,A A Nepomuceno,F R De Andrade

doi:10.1103/physrevd.97.075036

F M L De Almeida, M A B Do Vale + Show 2 more

Open Access

https://doi.org/10.1103/physrevd.97.075036

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Abstract

Torsion models constitute a well known class of extended quantum gravity models. In this work, one investigates the phenomenological consequences of a torsion field interacting with top quarks at the LHC. A torsion field could appear as a new heavy state characterized by its mass and couplings to fermions. This new state would form a resonance decaying into a top anti-top pair. The latest ATLAS $t\bar t$ production results from LHC 13 TeV data are used to set limits on torsion parameters. The integrated luminosity needed to observe torsion resonance at the next LHC upgrades are also evaluated, considering different values for the torsion mass and its couplings to Standard Model fermions. Finally, prospects for torsion exclusion at the future LHC phases II and III are obtained using fast detector simulations.

Highlights

Since the start of the LHC era, its experiments have performed an impressive set of measurements in different energy regimes that has strengthened our confidence in the Standard Model (SM)
The ATLAS experiment has searched for heavy particles decaying into tt at center-of-mass energy of 13 TeV with a data sample corresponding to an integrated luminosity of 3.2 fb−1 [19]
Exclusion limits on torsion mass and couplings based on ATLAS tt results from LHC 13 TeV data are derived

Summary

INTRODUCTION

Since the start of the LHC era, its experiments have performed an impressive set of measurements in different energy regimes that has strengthened our confidence in the Standard Model (SM). It is generally accepted that a consistent quantum gravity theory does not exist In this scenario, the most realistic candidate to a universal theory would be the string theory, which induces gravitational interactions in the low energy limit. The coupling between torsion and fermions can be, in principle, nonuniversal This possibility is explored in this paper. The ATLAS experiment has put limits on torsion mass and couplings using 7 TeV data in the dilepton channel [11]. Limits on torsion from this channel, using LHC published data, are derived here for the first time.

THE TORSION INTERACTIONS

MONTE CARLO AND DETECTOR SIMULATION

OBSERVED EXCLUSION LIMITS

DISCOVERY POTENTIAL AND LIMITS AT RUNS II AND III

Findings

CONCLUSIONS