ϒ production in U + U collisions at sNN =193 GeV measured with the STAR experiment

Abstract

© 2016 American Physical Society. We present a measurement of the inclusive production of ϒ mesons in U+U collisions at sNN=193 GeV at midrapidity (|y|<1). Previous studies in central Au+Au collisions at sNN=200 GeV show a suppression of ϒ(1S+2S+3S) production relative to expectations from the ϒ yield in p+p collisions scaled by the number of binary nucleon-nucleon collisions (Ncoll), with an indication that the ϒ(1S) state is also suppressed. The present measurement extends the number of participant nucleons in the collision (Npart) by 20% compared to Au+Au collisions, and allows us to study a system with higher energy density. We observe a suppression in both the ϒ(1S+2S+3S) and ϒ(1S) yields in central U+U data, which consolidates and extends the previously observed suppression trend in Au+Au collisions.