Dark matter contribution to b → sμ+μ− anomaly in local U(1)Lμ−Lτ model

We propose a local U(1)Lμ−Lτ model to explain b→sμ+μ− anomaly observed at the LHCb and Belle experiments. The model also has a natural dark matter candidate N. We introduce SU(2)L-doublet colored scalar q˜ to mediate b→s transition at one-loop level. The U(1)Lμ−Lτ gauge symmetry is broken spontaneously by the scalar S. All the new particles are charged under U(1)Lμ−Lτ. We can obtain C9μ,NP∼−1 to solve the b→sμ+μ− anomaly and can explain the correct dark matter relic density of the universe, ΩDMh2≈0.12, simultaneously, while evading constraints from electroweak precision tests, neutrino trident experiments and other quark flavor-changing loop processes such as b→sγ and Bs−B‾s mixing. Our model can be tested by searching for Z′ and new colored scalar at the LHC and B→K⁎νν‾ process at Belle-II.