Heavy Neutrinos in displaced vertex searches at the LHC and HL-LHC

TL;DR

This paper evaluates the potential of displaced vertex searches at the LHC and HL-LHC for detecting heavy neutrinos, proposing new detection methods and demonstrating significant improvements over existing constraints.

Contribution

It introduces a novel search method using muon chambers and provides sensitivity estimates that surpass current bounds by several orders of magnitude.

Findings

Displaced vertex searches can improve constraints on heavy neutrino mixing by over four orders of magnitude.

A new muon chamber-based search enhances detection capabilities outside the tracker.

Sensitivity estimates are based on benchmark models with exclusive mixing to Standard Model generations.

Abstract

We study the sensitivity of displaced vertex searches for heavy neutrinos produced in W boson decays in the LHC detectors ATLAS, CMS and LHCb. We also propose a new search that uses the muon chambers to detect muons from heavy neutrino decays outside the tracker. The sensitivity estimates are based on benchmark models in which the heavy neutrinos mix exclusively with one of the three Standard Model generations. In the most sensitive mass regime the displaced vertex searches can improve existing constraints on the mixing with the first two Standard Model generations by more than four orders of magnitude and by three orders of magnitude for the mixing with the third generation.