{"title":"Multiplicity-dependent jet modification from di-hadron correlations in pp collisions at $\\sqrt{s} = 13$ TeV","authors":"ALICE Collaboration","doi":"arxiv-2409.04501","DOIUrl":null,"url":null,"abstract":"Short-range correlations between charged particles are studied via\ntwo-particle angular correlations in pp collisions at $\\sqrt{s}=13$ TeV. The\ncorrelation functions are measured as a function of the relative azimuthal\nangle $\\Delta\\varphi$ and the pseudorapidity separation $\\Delta\\eta$ for pairs\nof primary charged particles within the pseudorapidity interval $|\\eta| < 0.9$\nand the transverse-momentum range $1 < p_{\\rm T} < 8$ GeV/$c$. Near-side\n($|\\Delta\\varphi|<1.3$) peak widths are extracted from a generalised Gaussian\nfitted over the correlations in full pseudorapidity separation\n($|\\Delta\\eta|<1.8$), while the per-trigger associated near-side yields are\nextracted for the short-range correlations ($|\\Delta\\eta|<1.3$). Both are\nevaluated as a function of charged-particle multiplicity obtained by two\ndifferent event activity estimators. The width of the near-side peak decreases\nwith increasing multiplicity, and this trend is reproduced qualitatively by the\nMonte Carlo event generators PYTHIA 8, AMPT, and EPOS. However, the models\noverestimate the width in the low transverse-momentum region ($p_{\\rm T} < 3$\nGeV/$c$). The per-trigger associated near-side yield increases with increasing\nmultiplicity. Although this trend is also captured qualitatively by the\nconsidered event generators, the yield is mostly overestimated by the models in\nthe considered kinematic range. The measurement of the shape and yield of the\nshort-range correlation peak can help us understand the interplay between jet\nfragmentation and event activity, quantify the narrowing trend of the near-side\npeak as a function of transverse momentum and multiplicity selections in pp\ncollisions, and search for final-state jet modification in small collision\nsystems. \\","PeriodicalId":501206,"journal":{"name":"arXiv - PHYS - Nuclear Experiment","volume":"51 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"arXiv - PHYS - Nuclear Experiment","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/arxiv-2409.04501","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Short-range correlations between charged particles are studied via
two-particle angular correlations in pp collisions at $\sqrt{s}=13$ TeV. The
correlation functions are measured as a function of the relative azimuthal
angle $\Delta\varphi$ and the pseudorapidity separation $\Delta\eta$ for pairs
of primary charged particles within the pseudorapidity interval $|\eta| < 0.9$
and the transverse-momentum range $1 < p_{\rm T} < 8$ GeV/$c$. Near-side
($|\Delta\varphi|<1.3$) peak widths are extracted from a generalised Gaussian
fitted over the correlations in full pseudorapidity separation
($|\Delta\eta|<1.8$), while the per-trigger associated near-side yields are
extracted for the short-range correlations ($|\Delta\eta|<1.3$). Both are
evaluated as a function of charged-particle multiplicity obtained by two
different event activity estimators. The width of the near-side peak decreases
with increasing multiplicity, and this trend is reproduced qualitatively by the
Monte Carlo event generators PYTHIA 8, AMPT, and EPOS. However, the models
overestimate the width in the low transverse-momentum region ($p_{\rm T} < 3$
GeV/$c$). The per-trigger associated near-side yield increases with increasing
multiplicity. Although this trend is also captured qualitatively by the
considered event generators, the yield is mostly overestimated by the models in
the considered kinematic range. The measurement of the shape and yield of the
short-range correlation peak can help us understand the interplay between jet
fragmentation and event activity, quantify the narrowing trend of the near-side
peak as a function of transverse momentum and multiplicity selections in pp
collisions, and search for final-state jet modification in small collision
systems. \