%0 Chart or Table
%A ALICE Collaboration
%T Multiplicity dependence of charged-particle intra-jet properties in pp collisions at √s = 13 TeV
%M GSI-2025-00146
%D 2024
%Z Journal Article GSI record: GSI-2025-00145
%X 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<sub>T</sub> algorithm with jet resolution parameters R = 0.2, 0.3, and 0.4 for the transverse momentum (p<sub>T</sub>) 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<sub>T</sub> in qualitative agreement with previous measurements at lower energies. The distributions of jet fragmentation function variables z<sup>ch</sup> and ξ<sup>ch</sup> are measured for different jet-p<sub>T</sub> intervals. Jet-p<sub>T</sub> independent fragmentation of leading jets is observed for wider jets except at high- and low-z<sup>ch</sup> values. The observed "hump-backed plateau" structure in the ξ<sup>ch</sup> distribution indicates suppression of low-p<sub>T</sub> particles. In high-multiplicity events, an enhancement of the fragmentation probability of low-z<sup>ch</sup> particles accompanied by a suppression of  high-z<sup>ch</sup> particles is observed compared to minimum-bias events. This behavior becomes more prominent for low-p<sub>T</sub> 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<sub>T</sub>. These measurements provide important constraints to models of jet fragmentation.                            
%F PUB:(DE-HGF)32
%9 Dataset
%R 10.17182/HEPDATA.153919
%U https://repository.gsi.de/record/355060