: The production of ϒ(2S) and ϒ(3S) mesons in lead-lead (Pb-Pb) and proton-proton (pp) collisions is studied in their dimuon decay channel using the CMS detector at the LHC. The ϒ(3S) meson is observed for the first time in Pb-Pb collisions, with a significance above 5 standard deviations. The ratios of yields measured in Pb-Pb and pp collisions are reported for both the ϒ(2S) and ϒ(3S) mesons, as functions of transverse momentum and Pb-Pb collision centrality. These ratios, when appropriately scaled, are significantly less than unity, indicating a suppression of ϒ yields in Pb-Pb collisions. This suppression increases from peripheral to central Pb-Pb collisions. Furthermore, the suppression is stronger for ϒ(3S) mesons compared to ϒ(2S) mesons, extending the pattern of sequential suppression of quarkonium states in nuclear collisions previously seen for the J/ψ, ψ(2S), ϒ(1S), and ϒ(2S) mesons.
Observation of the Y(3S) Meson and Suppression of the Y States in Pb-Pb Collisions at sqrt(sNN) = 5.02 TeV
Cappati, A.;Meridiani, P.;Amapane, N.;Argiro, S.;Bellan, R.;Bellora, A.;Costa, M.;Covarelli, R.;Grippo, M.;Kiani, B.;Mecca, A.;Migliore, E.;Monteil, E.;Obertino, M. M.;Pacher, L.;Shchelina, K.;Siviero, F.;Sola, V.;Solano, A.;Soldi, D.;Tornago, M.;Vagnerini, A.;Rumerio, P.;Ravera, F.;Salvatico, R.;
2024-01-01
Abstract
: The production of ϒ(2S) and ϒ(3S) mesons in lead-lead (Pb-Pb) and proton-proton (pp) collisions is studied in their dimuon decay channel using the CMS detector at the LHC. The ϒ(3S) meson is observed for the first time in Pb-Pb collisions, with a significance above 5 standard deviations. The ratios of yields measured in Pb-Pb and pp collisions are reported for both the ϒ(2S) and ϒ(3S) mesons, as functions of transverse momentum and Pb-Pb collision centrality. These ratios, when appropriately scaled, are significantly less than unity, indicating a suppression of ϒ yields in Pb-Pb collisions. This suppression increases from peripheral to central Pb-Pb collisions. Furthermore, the suppression is stronger for ϒ(3S) mesons compared to ϒ(2S) mesons, extending the pattern of sequential suppression of quarkonium states in nuclear collisions previously seen for the J/ψ, ψ(2S), ϒ(1S), and ϒ(2S) mesons.File | Dimensione | Formato | |
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PhysRevLett.133.022302.pdf
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