Electroweak loops as a probe of new physics in toverline{t} production at the LHC

Till Martini,Markus Schulze

doi:10.1007/jhep04(2020)017

Abstract

We calculate the \U0001d4aa(α) weak corrections to top quark pair production at the LHC and include anomalous electroweak interactions from dimension-six operators. The loop calculation and renormalization are consistently done within the Standard Model Effective Field Theory. Sensitivity to the involved operators is exposed through the virtual corrections, which receive enhancement from electroweak Sudakov logarithms. We investigate the prospects of using this feature for probing New Physics at the LHC that so far has only been studied in final states with on-shell sensitivity such as toverline{t} + Z or t → bW. We find that the large toverline{t} production rate and the excellent perturbative control allow compensating the loop suppression and yield remarkably strong constraints that are competitive with those from toverline{t} + Z.

Highlights

JHEP04(2020)017 mass was indicated accurately by LEP precision fits arising from electroweak loops [40]
We investigate the prospects of using this feature for probing New Physics at the LHC that so far has only been studied in final states with on-shell sensitivity such as tt+ Z or t → bW
The resulting constraints on New Physics are substantial, but the above analyses have their limitations: 1) The associated production processes tt + X suffer from relatively small cross sections because of coupling suppression, a high production threshold and penalties from branching fractions; 2) Sensitivity in top quark decay dynamics is often diminished by cancellations between the squared matrix element in the numerator and the total width in the denominator

Summary

Introduction

JHEP04(2020) mass was indicated accurately by LEP precision fits arising from electroweak loops [40]. It is essential to explore alternative avenues such as sensitivity to New Physics from electroweak loop corrections Let us substantiate this reasoning by presenting a first estimate of such prospects. The QCD production dynamics are known to very high perturbative order (NNLO+NNLL QCD [1, 25,26,27, 31]) This should allow for a precise extraction of the electroweak effects which have been found to be comparable or even exceeding the current QCD uncertainties in some phase space regions

Objectives

Results

Conclusion