This is the FeynRules model file for the generic $U(1)_X$ model. Contains three massive Majorana neutrinos and a scalar. All the SM particles and new scalar are charged under the new gauge $U(1)_X$. After solving the anomaly cancelation equations we can write the $U(1)_X$ charges of the chaged fermions in the model as a linear combination of the $U(1)_Y$ and $U(1)_{\rm B-L}$. We express these charges in terms of the $U(1)_X$ charges of the $SU(2)$ doublet Higgs ($x_H$) and SM singlet scalar ($x_{\Phi}$), respectively.  To cancel the anomalies we introduced three generation of Right Handed Neutrinos (RHN) whose Majorana mass terms are generated after the $U(1)_X$ breaking. These RHNs mixed with light neutrinos to generate the tiny neutrino mass through the seesaw mechanisim (Type-I). In this scenario, there is a neutral gauge boson $Z'$ whose mass will be generated after the $U(1)_X$ symmetry breakin through the vev of new scalar ($v_\Phi$). This $Z'$ can show a variety of phenomenological aspects, which can be probed at the LHC and future colliders. 


RHNs: heavy neutrino masses and the light-heavy neutrino mixing parameters are defined in the model file as $M_{N_i}$ and $V_{\ell N_i}$, respectively.


$Z'$: Note that, for $x_{H}=0$ and $x_{\Phi}=1$ this model reduces to the B-L scenario. For for $x_{H}=-2$ and $x_{\Phi}=1$ the model reduces to the $U(1)_R$ scenario.

References: 

(1) A. Das, P. S. B. Dev, Y. Hosotani and S. Mandal, ``Probing the minimal $U(1)_X$ model at future electron-positron colliders via the fermion pair-production channel,'' [arXiv:2104.10902 [hep-ph]].

(2) C. W. Chiang, G. Cottin, A. Das and S. Mandal, ``Displaced heavy neutrinos from $Z′$ decays at the LHC,'' [arXiv:1908.09838 [hep-ph]].

(3) A. Das, N. Okada and D. Raut, ``Enhanced pair production of heavy Majorana neutrinos at the LHC,'' [arXiv:1710.03377 [hep-ph]].

(4) A. Das, S. Jana, S. Mandal and S. Nandi, ``Probing right handed neutrinos at the LHeC and lepton colliders using fat jet signatures,'' [arXiv:1811.04291 [hep-ph]]