Fully-Automated Precision Predictions for Heavy Neutrino Production Mechanisms at Hadron Colliders

Abstract

Motivated by TeV-scale neutrino mass models, we propose a systematic treatment of heavy neutrino $(N)$ production at hadron colliders. Our simple and efficient modeling of the vector boson fusion (VBF) $W^{\pm }\gamma \to N{\ell }^{\pm }$ and $N{\ell }^{\pm }+nj$ signal definitions resolve collinear and soft divergences that have plagued past studies, and is applicable to other color-singlet processes, e.g., associated Higgs $(W^{\pm }h)$, sparticle $({\tilde{\ell }}^{\pm }\widetilde{{\nu }_{\ell }})$, and charged Higgs $(h^{\pm \pm }{h}^{\mp })$ production. We present, for the first time, a comparison of all leading $N$ production modes, including both gluon fusion (GF) $gg\to Z^{\ast }/h^{\ast }\to N\stackrel{(-)}{{\nu }_{\ell }}$ and VBF. We obtain fully differential results up to next-to-leading order (NLO) in QCD accuracy using a Monte Carlo tool chain linking FeynRules, N{\small LO}CT, and MadGraph5\_aMC@NLO. Associated model files are publicly available. At the 14 TeV LHC, the leading order GF rate is small and comparable to the NLO $N{\ell }^{\pm }+1j$ rate; at a future 100 TeV Very Large Hadron Collider, GF dominates for $m_N=300-1500$ GeV, beyond which VBF takes lead.

Comments: Updated to match published version; no change in results. 8 pages, 3 figures. Model files available from http://feynrules.irmp.ucl.ac.be/wiki/HeavyN