Multiplicity dependence of charged-particle intra-jet properties in pp collisions at s = 13 TeV.

Autor: Acharya, S., Adamová, D., Rinella, G. Aglieri, Aglietta, L., Agnello, M., Agrawal, N., Ahammed, Z., Ahmad, S., Ahn, S. U., Ahuja, I., Akindinov, A., Al-Turany, M., Aleksandrov, D., Alessandro, B., Alfanda, H. M., Molina, R. Alfaro, Ali, B., Alici, A., Alizadehvandchali, N., Alkin, A.
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Zdroj: European Physical Journal C -- Particles & Fields; Oct2024, Vol. 84 Issue 10, p1-26, 26p
Abstrakt: The first measurement of the multiplicity dependence of intra-jet properties of leading charged-particle jets in proton–proton (pp) collisions is reported. The mean charged-particle multiplicity and jet fragmentation distributions are measured in minimum-bias and high-multiplicity pp collisions at center-of-mass energy s = 13 TeV using the ALICE detector. Jets are reconstructed from charged particles produced in the midrapidity region ( | η | < 0.9 ) using the sequential recombination anti- k T algorithm with jet resolution parameters R = 0.2, 0.3, and 0.4 for the transverse momentum ( p T ) interval 5–110 GeV/c. The high-multiplicity events are selected by the forward V0 scintillator detectors. The mean charged-particle multiplicity inside the leading jet cone rises monotonically with increasing jet p T in qualitative agreement with previous measurements at lower energies. The distributions of jet fragmentation function variables z ch and ξ ch are measured for different jet- p T intervals. Jet- p T independent fragmentation of leading jets is observed for wider jets except at high- and low- z ch values. The observed "hump-backed plateau" structure in the ξ ch distribution indicates suppression of low- p T particles. In high-multiplicity events, an enhancement of the fragmentation probability of low- z ch particles accompanied by a suppression of high- z ch particles is observed compared to minimum-bias events. This behavior becomes more prominent for low- p T jets with larger jet radius. The results are compared with predictions of QCD-inspired event generators, PYTHIA 8 with Monash 2013 tune and EPOS LHC. It is found that PYTHIA 8 qualitatively reproduces the jet modification in high-multiplicity events except at high jet p T . These measurements provide important constraints to models of jet fragmentation. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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