Gauged U(1)_{L_mu -L_tau } scotogenic model in light of R_{K^{(*)}} anomaly and AMS-02 positron excess

Abstract

We study the gauged U(1)_{L_mu -L_tau } scotogenic model with emphasis on latest measurement of LHCb R_{K^{(*)}} anomaly and AMS-02 positron excess. In this model, neutrino masses are induced at one-loop level with Z_2-odd particles, i.e., right-handed neutrinos N_ell (ell =e,mu ,tau ) and inert scalar doublet eta inside the loop. Meanwhile, the gauged U(1)_{L_mu -L_tau } symmetry is broken spontaneously by the scalar singlet S, resulting to the massive gauge boson Z'. Provided certain couplings to quarks induced by heavy vector-like quarks, the gauge boson Z' would contribute to the transition brightarrow s mu ^+mu ^-, hence explain the R_{K^{(*)}} anomaly. As for the Majorana fermion DM N, the gauge boson Z' and the singlet Higgs H_0 will generate various annihilation channels, among which the NNrightarrow Z'Z' and NNrightarrow Z'H_0(rightarrow Z'Z') channel could be used to interpret the AMS-02 positron excess. We give a comprehensive analysis on model parameter space with consider various current constraints. The combined analysis shows that the R_{K^{(*)}} anomaly and AMS-02 positron excess can be explained simultaneously.