Leptophilic dark matter in gauged $L_{\mu }-L_{\tau }$ extension of MSSM

Abstract

Positron excess upto energies $\sim$350 GeV has been observed by AMS-02 result and it is consistent with the positron excess observed by PAMELA upto 100 GeV. There is no observed excess of anti-protons over the expected CR background. We propose a leptophilic dark matter with an $U(1{)}_{L_{\mu }-L_{\tau }}$ gauge extension of MSSM. The dark matter is an admixture of the $L_{\mu }-L_{\tau }$ gaugino and fermionic partners of the extra $SU(2)$ singlet Higgs boson, which break the $L_{\mu }-L_{\tau }$ symmetry. We construct the SM$\otimes U(1{)}_{L_{\mu }-L_{\tau }}$ SUSY model which provides the correct relic density of dark matter and is consistent with constrain on $Z^{\prime }$ from LHC. The large dark matter annihilation cross-section into ${\mu }^{+}{\mu }^{-}$ and ${\tau }^{+}{\tau }^{-}$, needed to explain PAMELA and AMS-02 is achieved by Breit-Wigner resonance.

Comments: 16 pages, 3 figures, ref. updated, version accepted for publication in PRD