Heavy neutrinos and lepton number violation in ℓp colliders

Abstract

We discuss the prospects of studying lepton number violating processes in order to identify Majorana neutrinos from low scale seesaw mechanisms at lepton-proton colliders. In particular, we consider the scenarios of colliding electrons with LHC energy protons and, motivated by the efforts towards the construction of a muon collider, the prospects of muon-proton collisions. We find that present constraints on the mixing of the Majorana neutrinos still allow for a detectable signal at these kind of facilities given the smallness of the Standard Model background. We discuss possible cuts in order to further increase the signal over background ratio and the prospects of reconstructing the neutrino mass from the kinematics of the final state particles.

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

“…[108] soon after the commissioning of HERA. Recently, right-handed neutrino searches at e − p colliders were investigated in the context of seesaw models [109][110][111], effective field theories [112], and in left-right symmetric [113,114] theories.…”

“…An unambiguous signal for lepton-number-violating processes is given by the final states + α jjj (where lepton number is violated by two units) for which there is no SM background. The lepton-number-violating final state with α = e is studied by [109][110][111][112][113][114] for the LHeC, which are however suppressed by the (approximate) protective symmetry.…”

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].…”

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].…”