A possible search for Majorana neutrinos at future lepton colliders

Abstract

We discuss the process ${\ell }^{+}{\ell }^{-}\to N{W}^{\pm }{\ell }^{\mp }$, where $N$ is a heavy Majorana neutrino and $\ell =e,\mu$. Large cross sections are expected for these processes at high center-of-mass energies, which can be reached at future lepton-lepton colliders. The Monte Carlo simulation of the studied processes is produced within the framework of the seesaw type-I model, where the Majorana neutrinos (or heavy neutral leptons, HNL), are introduced in the standard leptonic sector. Recently the possibility to search for the direct HNL production was studied in the ${\ell }^{+}{\ell }^{-}\to N{\nu }_{\ell }$ process with the subsequent decay $N\to W^{\pm }{\ell }^{\mp }$. In this paper we investigate an alternative process ${\ell }^{+}{\ell }^{-}\to N{W}^{\pm }{\ell }^{\mp }\to W^{\pm }{W}^{\pm }{\ell }^{\mp }{\ell }^{\mp }$ with the lepton number violation by two units. The similar processes appear in collisions with the same-sign beams, $e^{-}{e}^{-}\to N{W}^{-}{e}^{-}\to W^{-}{W}^{-}{e}^{+}{e}^{-}$ or ${\mu }^{+}{\mu }^{+}\to N{W}^{+}{\mu }^{+}\to W^{+}{W}^{+}{\mu }^{+}{\mu }^{-}$. The cross sections of the processes under consideration are enhanced by the soft photon exchange in the $t$-channel. We calculate the cross sections for the signals and potential Standard Model backgrounds for the $e^{+}{e}^{-}$ beam collisions at the 1 TeV center-of-mass energy and the ${\mu }^{+}{\mu }^{-}$ collisions at 3 TeV and 10 TeV. Due to the diagrams with soft $t$-channel photons and respective interference the promptly emitted leptons are produced in the direction close to the corresponding beam. These leptons will be lost in the beam pipe or badly measured by forward detectors. However, the signal events can be well separated from backgrounds using the rest of the event containing the $WW\ell$ particles. Finally, the expected upper limits on the mixing parameters $|V_{\ell N}{|}^2$ as a function of M($N$) are calculated.

arXiv comment8 pages, 5 figures, 3 tables, published in JETP Letters

References in corpus (22)

• PYTHIA 6.4 Physics and Manual
• PYTHIA 6.2 Physics and Manual
• DELPHES 3, A modular framework for fast simulation of a generic collider experiment
• FeynRules 2.0 - A complete toolbox for tree-level phenomenology
• MadGraph 5 : Going Beyond
• Oscillating neutrinos and mu --> e, gamma
• WHIZARD: Simulating Multi-Particle Processes at LHC and ILC
• Neutrino-less Double Beta Decay and Particle Physics
• Neutrinos and Collider Physics
• TeV Scale See-Saw Mechanisms of Neutrino Mass Generation, the Majorana Nature of the Heavy Singlet Neutrinos and $\betabeta$-Decay
• Heavy neutrino signals at large hadron colliders
• LanHEP - a package for the automatic generation of Feynman rules in field theory. Version 3.0
• Prospects of Heavy Neutrino Searches at Future Lepton Colliders
• Mixing of Active and Sterile Neutrinos
• An allowed window for heavy neutral leptons below the kaon mass
• Single Top Production in $e^{+}{e}^{-}$, $e^{-}{e}^{-}$, $\gamma e$ and $\gamma \gamma$ Collisions
• Probing the Weinberg Operator at Colliders
• Optimal search reach for heavy neutral leptons at a muon collider
• Heavy neutrinos at future linear e${}^{+}$e${}^{-}$ colliders
• Seesaw mechanism at electron-electron colliders
• Search for heavy Majorana neutrinos at electron-proton colliders
• Dirac and Majorana heavy neutrinos at LEP II

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