Measurement of exclusive J/psi and psi(2S) production at โˆšs=13 TeV

This paper reports the first measurement of the transverse momentum (๐‘T) spectra of primary charged pions, kaons, (anti)protons, and unidentified particles as a function of the charged-particle flattenicity in pp collisions at โˆš๐‘  =13 TeV. Flattenicity is a novel event shape observable that is measur...

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Main Authors: Aaij, Roel (Author) , Bachmann, Sebastian (Author) , Carus, Leon (Author) , Celani, Sara (Author) , Caspary, Rowina (Author) , Cocha Toapaxi, Carlos (Author) , De Cian, Michel (Author) , Dittmann, Lucas (Author)
Corporate Author: LHCb Collaboration (Author)
Format: Article (Journal)
Language:English
Published: 26 February 2025
In: SciPost physics
Year: 2025, Volume: 18, Issue: 1, Pages: 1-33
ISSN:2542-4653
DOI:10.1103/PhysRevD.111.012010
Online Access:Verlag, kostenfrei, Volltext: https://doi.org/10.1103/PhysRevD.111.012010
Verlag, kostenfrei, Volltext: https://link.aps.org/doi/10.1103/PhysRevD.111.012010
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Author Notes:LHCB collaboration*
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Summary:This paper reports the first measurement of the transverse momentum (๐‘T) spectra of primary charged pions, kaons, (anti)protons, and unidentified particles as a function of the charged-particle flattenicity in pp collisions at โˆš๐‘  =13 TeV. Flattenicity is a novel event shape observable that is measured in the pseudorapidity intervals covered by the V0 detector, 2.8 <๐œ‚ <5.1 and โˆ’3.7 <๐œ‚ <โˆ’1.7. According to QCD-inspired phenomenological models, it shows sensitivity to multiparton interactions and is less affected by biases toward larger ๐‘T due to local multiplicity fluctuations in the V0 acceptance than multiplicity. The analysis is performed in minimum-bias (MB) as well as in high-multiplicity events up to ๐‘T=20 GeV/โข๐‘. The event selection requires at least one charged particle produced in the pseudorapidity interval |๐œ‚| <1. The measured ๐‘T distributions, average ๐‘T, kaon-to-pion and proton-to-pion particle ratios, presented in this paper, are compared to model calculations using pythia 8 based on color strings and EPOS LHC. The modification of the ๐‘T-spectral shapes in low-flattenicity events that have large event activity with respect to those measured in MB events develops a pronounced peak at intermediate ๐‘T (2 <๐‘T <8 GeV/๐‘), and approaches the vicinity of unity at higher ๐‘T. The results are qualitatively described by pythia, and they show different behavior than those measured as a function of charged-particle multiplicity based on the V0M estimator.
Item Description:Gesehen am 04.12.2025
LHCB coolaboration: Roel Aaij,
Physical Description:Online Resource
ISSN:2542-4653
DOI:10.1103/PhysRevD.111.012010