Angular and polarization trails from effective interactions of Majorana neutrinos at the LHeC

Abstract

We study the possibility of the LHeC facility to disentangle different new physics contributions to the production of heavy sterile Majorana neutrinos in the lepton number violating channel e − p → l. This is done investigating the angular and polarization trails of effective operators with distinct Dirac-Lorentz structure contributing to the Majorana neutrino production, which parameterize new physics from a higher energy scale. We study an asymmetry in the angular distribution of the final anti-lepton and the initial electron polarization effect on the number of signal events produced by the vectorial and scalar effective interactions, finding both analyses could well separate their contributions.

Final taus and initial state polarization signatures from effective interactions of Majorana neutrinos at future $$e^{+}e^{-}$$ e + e -

“…The vectorial operators give a greater contribution to the unpolarized cross section by nearly one order of magnitude. This behavior was previously found for other effective N interaction signals studied in the past [25,27].…”

“…Dimension 7 effective N operators are studied in [18,19]. The collider phenomenology of the dimension 6 effective Lagrangian used in this paper has been studied by our group and others in [13,[20][21][22][23][24][25][26][27]. Recently, the predictions of the effective interactions in leptonic decays of pseudoscalar mesons have been investigated in [28].…”

“…In [27] we studied the potential of final lepton angular asymmetries and initial electron polarization observables to disentangle the possible contributions of effective operators with different Dirac-Lorentz structure to the LNV e − p → l + +3jets process. Now we aim to take advantage of the clean environment in electron-positron colliders and exploit initial state polarization observables to distinguish the contributions from scalar and vectorial effective interactions.…”

Searching for the light Higgsinos in the MSSM at future e−p colliders

“…The total cross sections are 330. A left-handed polarization of electron beam may in principle enhance the signal production rate but the background will be enlarged at the same time [42,43]. The polarization of electron beam does not significantly improve the result so we focus on the un-polarized cases.…”

Majorana neutrinos with effective interactions in B decays

“…One can think of an alternative treatment and consider the Majorana neutrino interactions as originating in new physics described by an unknown underlying renormalizable theory valid at a higher energy (UV) scale and parametrized at low energies by a model independent effective Lagrangian. In this approach, we consider that the sterile N interacts with the SM particles by higher dimension effective operators, taking these interactions to be dominant in comparison with the mixing with light neutrinos through the Yukawa couplings, which we neglect [12][13][14][15][16][17][18][19]. We depart from the usual viewpoint in which the mixing with the standard neutrinos is assumed to govern the N production and decay mechanisms.…”