Probing the heavy neutrinos of inverse seesaw model at the LHeC

We consider the production of a heavy neutrino and its possible signals at the Large Hadron-electron Collider (LHeC) in the context of an inverse-seesaw model for neutrino mass generation. The inverse seesaw model extends the Standard Model (SM) particle content by adding two neutral singlet fermions for each lepton generation. It is a well-motivated model in the context of generating nonzero neutrino masses and mixings. The proposed future LHeC machine presents us with a particularly interesting possibility to probe such extensions of the SM with new leptons due to the presence of an electron beam in the initial state. We show that the LHeC will be able to probe an inverse scenario with much better efficacy compared to the LHC with very nominal integrated luminosities as well as exploit the advantage of having the electron beam polarized to enhance the heavy neutrino production rates.

Figure 1

Feynman diagram for the various final states derived from $Nj$ production channel.

Figure 2

Feynman diagram for the various final states derived from $Nj{W}^{-}$ production channel.

Figure 3

Feynman diagram for the various final states derived from $e^{-}j{W}^{-}$ production channel.

Figure 4

Production cross section of $Nj$, $Nj{W}^{-}$ and $e^{-}j{W}^{-}$ at LHeC with and without 80% left-polarized electron beam along with that of the most dominant production mode of the heavy neutrinos at the LHC, $\ell N$, with varying heavy neutrino masses. The blue solid and dotted lines represent the variation of production cross section in $Nj$ channel with and without the left-polarized electron beam. Likewise, the brown and the green lines represent the $Nj{W}^{-}$ and $e^{-}j{W}^{-}$ production channels, respectively. The black (dashed) line corresponds to the $\ell N$ production cross section at the LHC at 14 TeV center of mass energy.

Figure 5

Transverse momentum of the $e^{-}$ originating from decaying $N_e$ for $m_N=150$ and 400 GeV obtained from the $Nj$ production channel.