Heavy neutral leptons and top quarks in effective field theory

TL;DR

This paper explores the production and detection of heavy neutral leptons at the LHC using effective field theory, focusing on operators involving top quarks and assessing detector sensitivities for various scenarios.

Contribution

It provides a detailed analysis of HNL phenomenology at the LHC within an EFT framework, emphasizing operators with top quarks and detector sensitivity estimates.

Findings

ATLAS can probe new physics scales up to 12 TeV.

MATHUSLA and ANUBIS can probe up to 4.5 TeV.

Different detectors cover complementary HNL mass ranges.

Abstract

We study the phenomenology of heavy neutral leptons (HNLs) at the LHC in effective field theory, concentrating on $d=6$ operators with top quarks. Depending on the operator choice and HNL mass, the HNLs will be produced either from proton-proton collisions in association with a single top, or via non-standard decays of top quarks. For long-lived HNLs we estimate the sensitivity reach of different detectors to various operators with top quarks and the HNLs for the high-luminosity phase of the LHC. For certain operators, ATLAS and some far detectors (MATHUSLA and ANUBIS) will be able to probe the associated new-physics scale as large as 12 TeV and 4.5 TeV, respectively, covering complementary HNL-mass ranges.