Abstract
We report on measurements of sequential suppression in collisions at with the STAR detector at the Relativistic Heavy Ion Collider (RHIC) through both the dielectron and dimuon decay channels. In the 0%–60% centrality class, the nuclear modification factors (), which quantify the level of yield suppression in heavy-ion collisions compared to collisions, for and are and , respectively, while the upper limit of the is 0.17 at a 95% confidence level. This provides experimental evidence that the is significantly more suppressed than the at RHIC. The level of suppression for is comparable to that observed at the much higher collision energy at the Large Hadron Collider. These results point to the creation of a medium at RHIC whose temperature is sufficiently high to strongly suppress excited states.
- Received 14 July 2022
- Revised 30 November 2022
- Accepted 26 January 2023
DOI:https://doi.org/10.1103/PhysRevLett.130.112301
© 2023 American Physical Society