Production of Heavy neutrino in next-to-leading order QCD at the LHC and beyond

TL;DR

This paper calculates next-to-leading order QCD corrections for heavy neutrino production at colliders, analyzing their potential detection signatures and setting bounds on neutrino mixing angles at current and future high-energy colliders.

Contribution

It provides the first detailed NLO QCD correction analysis for heavy neutrino production at colliders, including scale variation and kinematic distributions for different neutrino types.

Findings

NLO QCD corrections significantly affect production cross-sections.

Projected bounds on neutrino mixing angles at 14 TeV LHC and 100 TeV collider.

Distinct signatures for Majorana and pseudo-Dirac neutrinos in collider experiments.

Abstract

Majorana and pseudo-Dirac heavy neutrinos are introduced into the type-I and inverse seesaw models, respectively, in explaining the naturally small neutrino mass. TeV scale heavy neutrinos can also be accommodated to have a sizable mixing with the Standard Model light neutrinos, through which they can be produced and detected at the high energy colliders. In this paper we consider the Next-to-Leading Order QCD corrections to the heavy neutrino production, and study the scale variation in cross-sections as well as the kinematic distributions with different final states at $14$ TeV LHC and also in the context of $100$ TeV hadron collider. The repertoire of the Majorana neutrino is realized through the characteristic signature of the same-sign dilepton pair, whereas, due to a small lepton number violation, the pseudo-Dirac heavy neutrino can manifest the trileptons associated with missing energy in the final state. Using the $\sqrt{s}=8$ TeV, $20.3$ fb$^{-1}$ and $19.7$ fb$^{-1}$ data at the ATLAS and CMS respectively, we obtain prospective scale dependent upper bounds of the light-heavy neutrino mixing angles for the Majorana heavy neutrinos at the $14$ TeV LHC and $100$ TeV collider. Further exploiting a recent study on the anomalous multilepton search by CMS at $\sqrt{s}=8$ TeV with $19.5$ fb$^{-1}$ data, we also obtain the prospective scale dependent upper bounds on the mixing angles for the pseudo-Dirac neutrinos. We thus project a scale dependent prospective reach using the NLO processes at the $14$ TeV LHC.