Observation of the Charged-Particle Multiplicity Dependence of <math display="inline"><mrow><msub><mrow><mi>σ</mi></mrow><mrow><mi>ψ</mi><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo></mrow></msub><mo>/</mo><msub><mrow><mi>σ</mi></mrow><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></msub></mrow></math> in <math display="inline"><mi>p</mi></math>-Pb Collisions at 8.16 TeV

Jain, Sandhya;Bein, Samuel;Benecke, Anna;Bethani, Agni;CMS;et.al.
(2025) Physical Review Letters — Vol. 135 (2025)

Files

document.pdf
  • Open Access
  • Adobe PDF
  • 1.09 MB
Download

Details

Authors
Show more
Abstract
Bound states of charm and anticharm quarks, known as charmonia, have a rich spectroscopic structure that can be used to probe the dynamics of hadron production in high-energy hadron collisions. Here, the cross section ratio of excited <math display="inline"><mo stretchy="false">(</mo><mrow><mi>ψ</mi><mo stretchy="false">(</mo><mrow><mn>2</mn><mi>S</mi></mrow><mo stretchy="false">)</mo></mrow><mo stretchy="false">)</mo></math> and ground state <math display="inline"><mo stretchy="false">(</mo><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow><mo stretchy="false">)</mo></math> vector mesons is measured as a function of the charged-particle multiplicity in proton-lead (<math display="inline"><mrow><mi>p</mi><mi>Pb</mi></mrow></math>) collisions at a center-of-mass (CM) energy per nucleon pair of 8.16 TeV. The data corresponding to an integrated luminosity of <math display="inline"><mn>175</mn><mtext> </mtext><mtext> </mtext><msup><mi>nb</mi><mrow><mo>-</mo><mn>1</mn></mrow></msup></math> were collected using the CMS detector. The ratio is measured separately for prompt and nonprompt charmonia in the transverse momentum range <math display="inline"><mn>6.5</mn><mo>&lt;</mo><msub><mi>p</mi><mi mathvariant="normal">T</mi></msub><mo>&lt;</mo><mn>30</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math> and in four rapidity ranges spanning <math display="inline"><mo>-</mo><mn>2.865</mn><mo>&lt;</mo><msub><mi>y</mi><mi>CM</mi></msub><mo>&lt;</mo><mn>1.935</mn></math>. For the first time, a statistically significant multiplicity dependence of the prompt cross section ratio is observed in proton-nucleus collisions. There is no clear rapidity dependence in the ratio. The prompt measurements are compared with a theoretical model which includes interactions with nearby particles during the evolution of the system. These results provide additional constraints on hadronization models of heavy quarks in nuclear collisions.
Affiliations

Citations

  • APA
  • Chicago
  • FWB

Jain, S., Bein, S., Benecke, A., Bethani, A., Bruno, G., Caputo, C., de Favereau de Jeneret, J., Delaere, C., Donertas, I. S., Giammanco, A., Guzel, A. O., Jain, S., Lemaitre, V., Lidrych, J., Mastrapasqua, P., Tran, T. T., Turkcapar, S., CMS, & et al. (2025). Observation of the Charged-Particle Multiplicity Dependence of <math display=“inline”><mrow><msub><mrow><mi>σ</mi></mrow><mrow><mi>ψ</mi><mo stretchy=“false”>(</mo><mn>2</mn><mi>S</mi><mo stretchy=“false”>)</mo></mrow></msub><mo>/</mo><msub><mrow><mi>σ</mi></mrow><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></msub></mrow></math> in <math display=“inline”><mi>p</mi></math>-Pb Collisions at 8.16 TeV. Physical Review Letters, 135. https://doi.org/10.1103/c9wp-5tq3 (Original work published 2025)