Low-$p_{T}$ $\mu^{+}\mu^{-}$ pair production in Au+Au collisions at $\sqrt{s_{_{\rm NN}}}$ = 200 GeV at STAR

Recently, significant enhancements of $e^{+}e^{-}$ pair at very low transverse momentum ($p_{T}$) were observed by the STAR collaboration in peripheral Au+Au collisions. The excess can be explained by photon-photon interactions induced by the extremely strong electromagnetic field produced by the fast-moving heavy ions. The photon interaction was usually studied in ultra-peripheral collisions without any nuclear overlaps. However, the photon interaction in peripheral collisions may provide a novel probe of QGP because the very-low-$p_{T}$ dileptons are produced in the early stage of the collisions and there could be QGP produced in the nuclear overlapping region in peripheral collisions. In such collisions, the photon-photon interactions could be further used to probe the possible existence of strong magnetic fields trapped in a conducting QGP medium. Measurements with $\mu^{+}\mu^{-}$ pairs provide a complementary channel to investigate these phenomena. In 2014 and 2016, the STAR experiment at RHIC recorded large samples of Au+Au collisions at $\sqrt{s}$ = 200 GeV. In this talk, we will present invariant mass and yield distributions for $\mu^{+}\mu^{-}$ pair production at $p_{T} < 0.15$ GeV/$c$.The $p_{T}^{2}$ distribution of the excess yields will also be shown.