Moscow International School of Physics 2026

Measurement of associated charmonia production at CMS

Feb 26, 2026, 4:54 PM

12m

HSE Study Center “Voronovo”

Talk (10+2 min) Young Scientist Forum Young Scientist Forum

Speaker

Shiyang Chen (Tsinghua University, Beijing, China)

Description

Associated multiple charmonia production in high energy proton collision has great significance for the research in QCD and the mechanism of charmonium production. In this study, data collected at CMS Run 2 in 2018 is utilized in measuring the integrated and differential cross-section and the fraction of DPS in $J/\psi-\psi(2S)$ associated production. Acceptance and efficiency corrections are applied to the selected experimental data based on MC samples. A 4-dimensional fit is carried out to exclude combinatorial and non-prompt backgrounds. The total cross-section is acquired in the fiducial volume $|y|<2.0$, $10\text{GeV/c}7.5\mathrm{GeV/c^2}$ and systematic uncertainties are evaluated. The differential cross-sections are measured as functions of $M_{inv}^{J/\psi-\psi(2S)}$, $|\Delta y|$, $|\Delta\phi|$, $p_T^{J/\psi-\psi(2S)}$ and $|y^{J/\psi-\psi(2S)}|$. The fraction of DPS in the production is attained by a template fit to the differential cross-section.
This research measured, for the first time, the cross-section of $J/\psi-\psi(2S)$ associated production at $13\text{TeV}$ in central phase space, serving as a complement to the forward phase space. The results is expected to promote research in NRQCD and the mechanism of charmonium production.

Presentation materials

Measurement of associated charmonia production at CMS_v3.pdf