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 ± γ → N ℓ ± and N ℓ ± + 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 ± h), sparticle (l ±ν ℓ ), and charged Higgs (h ±± h ∓ ) production. We present, for the first time, a comparison of all leading N production modes, including both gluon fusion (GF)ν ℓ 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, NLOCT, 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 ℓ ± + 1j rate; at a future 100 TeV Very Large Hadron Collider, GF dominates for mN = 300 − 1500 GeV, beyond which VBF takes lead.

Not-that-heavy Majorana neutrino signals at the LHC

“…The inquiry into the Majorana nature of neutrinos has led to dedicated searches for evidence of LNV at hadron colliders in the very well known same-sign dilepton (ss-dilepton) channel pp → l + i l + j + 2 jets (see [7][8][9][10][11][12][13][14][15][16] and references therein) recently including new production mechanisms [17][18][19], and the chances to discover heavy Majorana neutrinos in e + e − , e − P , e − γ and γγ colliders have been studied [20][21][22][23][24][25][26][27][28][29][30]. Searches for heavy Majorana neutrinos in the ss-dilepton channel are currently being performed at the LHC [31][32][33][34][35].…”

Sterile neutrino searches at future e−e+, pp and e−p colliders

“…Furthermore, also the heavy neutrino production via the Higgs boson becomes increasingly relevant for large M , and has been shown to dominate over Drell-Yan at √ s = 100 TeV for M > 1.5 TeV, see refs. [71,72]. Nevertheless, we will focus on the leading order signatures via Z s and W s in the following.…”

Effective Majorana neutrino decay

“…The possibilities of discovering heavy Majorana neutrinos have been and are still extensively investigated, for example involving production and decay in e + e − and e − P colliders [10][11][12][13][14][15][16][17], in e − γ and γ γ colliders [18][19][20], in hadron colliders via lepton number violating dilepton signals [9,[21][22][23][24][25][26][27][28][29][30], and recently including new production mechanisms [31][32][33]. Some searches are currently being performed in the LHC [34][35][36][37].…”