Speaker
Description
Because of the different binding energies, bottomonium mesons are particularly useful probes to understand the thermal properties of quark-gluon plasma. Previously, CMS observed the sequential suppression of $\Upsilon$(1S), $\Upsilon$(2S), and $\Upsilon$(3S) in heavy ion (AA) collisions, which was widely accepted as evidence for the QGP formation. However, the $\Upsilon$(3S) yield was excessively low, thus allowing us to report only statistical upper limits. In this talk, we present a detailed study of the measurement of excited bottomonium states with improved analysis technique and high-statistics data that enables us to observe the $\Upsilon$(3S) meson in AA for the first time. The results are discussed together with the previous measurements in pPb collisions, which finally provides a full scan of all $\Upsilon$(nS) states over the whole phase space.
