$\Upsilon$ production in p-Pb and Pb-Pb collisions with ALICE at the LHC

Abstract

ALICE (A Large Ion Collider Experiment) is devoted to the study of heavy-ion collisions at LHC energies. In such collisions a deconfined state of nuclear matter, the Quark-Gluon Plasma (QGP), is formed. Due to their early production, quarkonium states are good probes to study the QGP evolution. Such states are affected by suppression mechanisms which lead to reduced yields with respect to pp and p-Pb collisions, while regeneration phenomena might lead to an enhancement of their production. The latter effects are expected to be negligible at LHC for bottomonium states. The recent ALICE results on $\Upsilon$ production in Pb-Pb collisions at $\sqrt{s_{\rm NN}}=5.02\;\rm{T}e\rm{V}$ will be presented and compared with previous measurements at $\sqrt{s_{\rm NN}}=2.76\;\rm{T}e\rm{V}$. A comparison with theoretical calculations will be performed as well. Results obtained in p-Pb collisions at $\sqrt{s_{\rm NN}}=5.02\;\rm{T}e\rm{V}$ will also be discussed.