In this contribution we report $e^{ +}e^{ -}$ spectra with various invariant mass and p$_{ T}$ differentials in Au$+$Au collisions at $\sqrt{ s_{ NN}}$=200 GeV and U$+$U collisions at $\sqrt{ s_{ NN}}$=193 GeV. The structure of the t ($t\approx p^2_{ \mathrm{ T}}$) distributions of these mass regions will be shown and compared with the same distributions in ultra-peripheral collisions. Additionally, this contribution discusses first measurements of $\mu^{ +}\mu^{ -}$ invariant mass spectra from STAR's recently installed Muon Telescope Detector (MTD) in p$+$p and Au$+$Au collisions at $\sqrt{ s_{ NN}}$ = 200 GeV.
Categories: nucl-ex