LHC signals for Singlet Neutrinos from a Natural Warped Seesaw (I)

Abstract

Recently, it was shown in arXiv:1512.06742 that a straightforward implementation of the type I seesaw mechanism in a warped extra dimensional framework is in reality a {\em natural} realization of "inverse" seesaw, i.e., the Standard Model (SM) neutrino mass is dominantly generated by exchange of pseudo-Dirac {\em TeV}-mass SM singlet neutrinos. By the AdS/CFT correspondence, this scenario is {\em dual} to these singlet particles being composites of some new strong dynamics, along with the SM Higgs boson, with the rest of the SM particles being mostly elementary. We study signals from production of these heavy neutrinos at the Large Hadron Collider (LHC). We focus on the scenario where the strong sector has a global $SU(2{)}_{\mathrm{L}}\times SU(2{)}_{\mathrm{R}}\times U(1{)}_{\mathrm{X}}$ symmetry; such a left-right (LR) structure being motivated by consistency with the electroweak (EW) precision tests. The singlet neutrinos are charged under $SU(2{)}_{\mathrm{R}}\times U(1{)}_{\mathrm{X}}$ symmetry, thus can be produced from $W_R^{\pm }$ exchange, as in four-dimensional (4D) LR symmetric models. However, the direct coupling of light quarks to $W_R^{\pm }$ is negligible, due to $W_R^{\pm }$ also being composite; nonetheless, a sizable coupling can be induced by mixings among the various types of $W^{\pm }$ bosons. Furthermore, $W_R^{\pm }$ decays dominantly into the singlet and {\em composite} partner of charged lepton. This heavy charged lepton, in turn, decays into SM lepton, {\em plus} $Z$/Higgs, thus the latter can be used for extra identification of the signal. For a benchmark scenario with $W_R^{\pm }$ of mass 2 TeV and singlet neutrino of mass 750 GeV, we find that, in both the di-lepton + di-jet + Higgs and tri-lepton + Higgs channels, significant evidence can be seen at the LHC14 for an integrated luminosity of 300/fb and that even discovery is possible with slightly more luminosity.

45 pages

References in corpus (16)

• PYTHIA 6.4 Physics and Manual
• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• A custodial symmetry for Zbb
• The Flavor of the Composite Pseudo-Goldstone Higgs
• Effects of new leptons in Electroweak Precision Data
• Non-unitarity of the leptonic mixing matrix: Present bounds and future sensitivities
• Delta F=2 Observables and Fine-Tuning in a Warped Extra Dimension with Custodial Protection
• LHC Signals for Warped Electroweak Neutral Gauge Bosons
• Direct Bounds on Electroweak Scale Pseudo-Dirac Neutrinos from $\sqrt{s}=8$ TeV LHC Data
• On Partial Compositeness and the CP asymmetry in charm decays
• Electroweak scale seesaw and heavy Dirac neutrino signals at LHC
• Natural Neutrino Masses and Mixings from Warped Geometry
• LHC Signals for Warped Electroweak Charged Gauge Bosons
• Search for new resonances decaying to a $W$ or $Z$ boson and a Higgs boson in the ${\ell }^{+}{\ell }^{-}b\bar{b}$, $\ell \nu b\bar{b}$, and $\nu \bar{\nu }b\bar{b}$ channels with $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• Extra dimensions and Seesaw Neutrinos at the International Linear Collider
• LHC Signals for Singlet Neutrinos from a Natural Warped Seesaw (II)

Cited by in corpus (5)

• On the behaviour of composite resonances breaking lepton flavour universality
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• LHC Signals for Singlet Neutrinos from a Natural Warped Seesaw (II)
• Inverse see-saw neutrino masses in the Littlest Higgs model with T-parity
• Conformal Leptogenesis in Composite Higgs Models