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Event-shape and multiplicity dependence of freeze-out radii in pp collisions at root s=7 TeV
- 1.0510215 - ÚJF 2020 RIV US eng J - Journal Article
Acharya, S. - Adamová, Dagmar - Bielčík, J. - Bielčíková, Jana - Broz, M. - Contreras, J. G. - Křížková Gajdošová, K. - Horák, D. - Křížek, Filip - Kučera, Vít - Kushpil, Svetlana - Lavička, R. - Mareš, Jiří A. - Petráček, V. - Šumbera, Michal - Závada, Petr … Total 1016 authors
Event-shape and multiplicity dependence of freeze-out radii in pp collisions at root s=7 TeV.
Journal of High Energy Physics. Roč. 2019, č. 9 (2019), č. článku 108. ISSN 1029-8479. E-ISSN 1029-8479
R&D Projects: GA MŠMT(CZ) LTT17018
Research Infrastructure: CERN-CZ - 90058
Institutional support: RVO:68378271 ; RVO:61389005
Keywords : ALICE collaboration * heavy ion experiments * particle correlations and fluctuations
OECD category: Nuclear physics; Particles and field physics (FZU-D)
Impact factor: 5.875, year: 2019
Method of publishing: Open access
https://doi.org/10.1007/JHEP09(2019)108
Two-particle correlations in high-energy collision experiments enable the extraction of particle source radii by using the Bose-Einstein enhancement of pion production at low relative momentum q proportional to 1/R. It was previously observed that in pp collisions at root s = 7 TeV the average pair transverse momentum k(T) range of such analyses is limited due to large background correlations which were attributed to mini-jet phenomena. To investigate this further, an event-shape dependent analysis of Bose-Einstein correlations for pion pairs is performed in this work. By categorizing the events by their transverse sphericity S-T into spherical (S-T > 0.7) and jet-like (S-T < 0.3) events a method was developed that allows for the determination of source radii for much larger values of k(T) for the first time. Spherical events demonstrate little or no background correlations while jet-like events are dominated by them. This observation agrees with the hypothesis of a mini-jet origin of the non-femtoscopic background correlations and gives new insight into the physics interpretation of the k(T) dependence of the radii. The emission source size in spherical events shows a substantially diminished k(T) dependence, while jet-like events show indications of a negative trend with respect to k(T) in the highest multiplicity events. Regarding the emission source shape, the correlation functions for both event sphericity classes show good agreement with an exponential shape, rather than a Gaussian one.
Permanent Link: http://hdl.handle.net/11104/0300744
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Number of the records: 1