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 $b\\to s \\mu^+\\mu^-$, 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 $NN\\to Z Z $ and $NN\\to Z H_0(\\to Z Z )$ 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.