Measurement of $\psi$(2S) production as a function of charged-particle pseudorapidity density in pp collisions at $\sqrt{s}$ = 13 TeV and p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 8.16 TeV with ALICE at the LHC

Abstract

Production of inclusive charmonia in pp collisions at center-of-mass energy of $\sqrt{s}$ = 13 TeV and p-Pb collisions at center-of-mass energy per nucleon pair of $\sqrt{s_{\mathrm{NN}}}$ = 8.16 TeV is studied as a function of charged-particle pseudorapidity density with ALICE. Ground and excited charmonium states (J/$\psi$, $\psi$(2S)) are measured from their dimuon decays in the interval of rapidity in the center-of-mass frame $2.5<y_{\mathrm{cms}}<4.0$ for pp collisions, and $2.03<y_{\mathrm{cms}}<3.53$ and $-4.46<y_{\mathrm{cms}}<-2.96$ for p-Pb collisions. The charged-particle pseudorapidity density is measured around midrapidity ($|\eta |<1.0$). In pp collisions, the measured charged-particle multiplicity extends to about six times the average value, while in p-Pb collisions at forward (backward) rapidity a multiplicity corresponding to about three (four) times the average is reached. The $\psi$(2S) yield increases with the charged-particle pseudorapidity density. The ratio of $\psi$(2S) over J/$\psi$ yield does not show a significant multiplicity dependence in either colliding system, suggesting a similar behavior of J/$\psi$ and $\psi$(2S) yields with respect to charged-particle pseudorapidity density. Results for the $\psi$(2S) yield and its ratio with respect to J/$\psi$ agree with available model calculations.

25 pages, 6 captioned figures, 2 tables, authors from page 20, published version, figures at http://alice-publications.web.cern.ch/node/7849

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Cited by in corpus (3)

• Shedding Light on Hadronization by Quarkonium Energy Correlator
• Observation of the charged-particle multiplicity dependence of ${\sigma }_{\psi (2S)}/{\sigma }_{\text{J}/\psi }$ in pPb collisions at 8.16 TeV
• Measurement of inclusive J/$\psi$ pair production cross section in pp collisions at $\sqrt{s}=13$ TeV