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

Majorana neutrinos production at LHeC in an effective approach

We investigate the possibility of detecting Majorana neutrinos at the Large Hadron-electron Collider (LHeC), an electron-proton collision mode at CERN. We study the $l_j^{+} + 3 jets$ ($l_j\equiv e ,μ,τ$) final states which are, due to leptonic number violation, a clear signature for intermediate Majorana neutrino contributions. Such signals are not possible if the heavy neutrinos have Dirac nature. The interactions between Majorana neutrinos and the Standard Model (SM) particles are obtained from an effective lagrangian approach. We present our results for the total cross section as a functio…

Seesaw Type I and III at the LHeC

We study the potential of testing the seesaw type I and III models at the LHeC, an e-p collision mode at the CERN collider. The e-p collision mode provides an excellent place to study lepton number violating process e^- p \to N j + X \to l^+ W^- j + X with W^- into hadron jets. Here N is a heavy Majorana neutrino and j is a hard hadron jet. With the electron energy E_e = 140 GeV and proton energy E_p = 7 TeV, we find that the cross section for the heavy neutrino N production can be as large as a few fb for the mass scale as high as 1 TeV, higher than what can be achieved by the p-p collision m…

Left-Right Symmetry and Lepton Number Violation at the Large Hadron Electron Collider

We show that the proposed Large Hadron electron Collider (LHeC) will provide an opportunity to search for left-right symmetry and establish lepton number violation, complementing current and planned searches based on LHC data and neutrinoless double beta decay. We consider several plausible configurations for the LHeC -- including different electron energies and polarizations, as well as distinct values for the charge misidentification rate. Within left-right symmetric theories we determine the values of right-handed neutrino and gauge boson masses that could be tested at the LHeC after one, f…

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

We study the possibility of future $e^{+}e^{-}$ colliders to disentangle different new physics contributions to the production of heavy sterile Majorana neutrinos in the lepton number violating channel $e^{+}e^{-}\rightarrow l^{+} l^{+}+ 4 jets$, with $l=e, μ, τ$. This is done investigating the final anti-tau polarization trails and initial beam polarization dependence of the signal on effective operators with distinct Dirac-Lorentz structure contributing to the Majorana neutrino production and decay, which parameterize new physics from a higher energy scale. We find both analyses could well d…

在质子-电子对撞机上的 $τ$ 末态中寻找重马约拉纳中微子

Search for heavy Majorana neutrinos in the $τ$ final state at proton-electron colliders

本文提出在未来质子-电子对撞机利用轻子数破坏过程 $p e^- \to τ^+ jjj$ 寻找重马约拉纳中微子，通过多变量分析排除背景并重建质量，预测了其在 10-3000 GeV 质量范围内的发现灵敏度，发现其优于 EWPD 和 DELPHI 的现有约束。

Search for heavy Majorana neutrinos at electron-proton colliders

We develop the search strategy for a heavy Majorana neutrino via the lepton number violation signal process $p\, e^- \to μ^+ jjj$ at future electron-proton colliders. The signal and dominant standard model background events are generated with the fast detector simulation. We apply the pre-selection criteria and perform the multi-variate analysis based on machine-learning to reject the background. Distributions of representative kinematic observables are presented for both signal and background processes and effects on final limits are compared by inputting two different set of observables when…