Abstract
We report the STAR measurements of dielectron () production at midrapidity () in collisions at . The measurements are evaluated in different invariant mass regions with a focus on 0.30–0.76 (-like), 0.76–0.80 (-like), and 0.98–1.05 (-like) . The spectrum in the -like and -like regions can be well described by the hadronic cocktail simulation. In the -like region, however, the vacuum spectral function cannot describe the shape of the dielectron excess. In this range, an enhancement of is determined with respect to the hadronic cocktail simulation that excludes the meson. The excess yield in the -like region increases with the number of collision participants faster than the and yields. Theoretical models with broadened contributions through interactions with constituents in the hot QCD medium provide a consistent description of the dilepton mass spectra for the measurement presented here and the earlier data at the Super Proton Synchrotron energies.
- Received 31 December 2013
- Publisher error corrected 14 July 2014
DOI:https://doi.org/10.1103/PhysRevLett.113.022301
© 2014 American Physical Society
Corrections
14 July 2014