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

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 $Z'$ 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.