TeV Scale Seesaw and a flavorful Z' at the LHC

TL;DR

This paper explores how a TeV-scale Z' gauge boson, arising from an anomaly-free U(1)_{nu} symmetry, can be produced and distinguished at the LHC, providing insights into neutrino masses and flavor structure.

Contribution

It introduces a model with a flavorful Z' gauge boson linked to neutrino mass generation, and analyzes its discovery potential and flavor discrimination at the LHC.

Findings

LHC can discover Z' up to 4.5 TeV with 100 fb^{-1}

Distinguishing dielectron and dimuon channels requires high luminosity

Forward-backward asymmetry helps differentiate lepton channels

Abstract

Small neutrino masses and their large mixing angles can be generated at the TeV scale by augmenting the Standard Model with an additional generation dependent, anomaly-free U(1)_{nu} symmetry, in the presence of three right-handed neutrinos. The Z' gauge boson associated with the breaking of the U(1)_{nu} symmetry can be produced at the LHC. The flavorful nature of the Z' can be established by measuring its non-universal couplings to the charged leptons as determined by the lepton's U(1)_{nu} charges, which also govern the neutrino flavor structure. While the LHC has the potential of discovering the Z' up to M_{Z'} = 4.5 TeV with 100 fb^(-1) data at the center of mass energy sqrt{s} = 14 TeV, to establish the flavorful nature of the Z' requires much higher integrated luminosity. For our bench mark parameters that are consistent with neutrino oscillation data, at sqrt{s} = 14 TeV, a 5 sigma distinction between the dielectron and dimuon channels for M_{Z'} = 3 TeV requires 500 fb^(-1) of data. We find that the forward backward asymmetry distributions can also be useful in distinguishing the dielectron and dimuon channels in the low invariant mass and transverse momentum regions.