Measurement of exclusive J / ψ and ψ ( 2 S ) production at √ s = 13 TeV

SCIPOST PHYSICS. 2025. Vol. 18. Article 071.

Aaij R., Abdelmotteleb A. S., Abellan Beteta C., Abudinén F., Ackernley T., Ratnikov F., Hushchyn M., Bocharnikov V., Boldyrev A., Ryzhikov A.

Measurements are presented of the cross-section for the central exclusive production of J/ψ→μ+μ− and ψ(2S)→μ+μ− processes in proton-proton collisions at √s=13 TeV with 2016–2018 data. They are performed by requiring both muons to be in the LHCb acceptance (with pseudorapidity 2<ημ±<4.5) and mesons in the rapidity range 2.0<y<4.5. The integrated cross-section results areσJ/ψ→μ+μ−(2.0<yJ/ψ<4.5,2.0<ημ±<4.5)=400±2±5±12 pb,σψ(2S)→μ+μ−(2.0<yψ(2S)<4.5,2.0<ημ±<4.5)=9.40±0.15±0.13±0.27 pb,where the uncertainties are statistical, systematic and due to the luminosity determination. In addition, a measurement of the ratio of ψ(2S) and J/ψ cross-sections, at an average photon-proton centre-of-mass energy of 1 TeV, is performed, givingσψ(2S)σJ/ψ=0.1763±0.0029±0.0008±0.0039,where the first uncertainty is statistical, the second systematic and the third due to the knowledge of the involved branching fractions. For the first time, the dependence of the J/ψ and ψ(2S) cross-sections on the total transverse momentum transfer is determined in pp collisions and is found consistent with the behaviour observed in electron-proton collisions.

Keywords: физика частиц, Experimental Particle Physics

Publication based on the results of: Development of theoretical foundations and methods of generative artificial intelligence and their application to heterogeneous domain area (2025)