skip to main content


This content will become publicly available on May 1, 2025

Title: Measurement of inclusive charged-particle jet production in pp and p-Pb collisions at $$ \sqrt{s_{\textrm{NN}}} $$ = 5.02 TeV
A<sc>bstract</sc>

Measurements of inclusive charged-particle jet production in pp and p-Pb collisions at center-of-mass energy per nucleon-nucleon collision$$ \sqrt{s_{\textrm{NN}}} $$sNN= 5.02 TeV and the corresponding nuclear modification factor$$ {R}_{\textrm{pPb}}^{\textrm{ch}\ \textrm{jet}} $$RpPbchjetare presented, using data collected with the ALICE detector at the LHC. Jets are reconstructed in the central rapidity region |ηjet|<0.5 from charged particles using the anti-kTalgorithm with resolution parametersR= 0.2, 0.3, and 0.4. ThepT-differential inclusive production cross section of charged-particle jets, as well as the corresponding cross section ratios, are reported for pp and p-Pb collisions in the transverse momentum range 10<$$ {p}_{\textrm{T},\textrm{jet}}^{\textrm{ch}} $$pT,jetch<140 GeV/cand 10<$$ {p}_{\textrm{T},\textrm{jet}}^{\textrm{ch}} $$pT,jetch<160 GeV/c, respectively, together with the nuclear modification factor$$ {R}_{\textrm{pPb}}^{\textrm{ch}\ \textrm{jet}} $$RpPbchjetin the range 10<$$ {p}_{\textrm{T},\textrm{jet}}^{\textrm{ch}} $$pT,jetch<140 GeV/c. The analysis extends thepTrange of the previously-reported charged-particle jet measurements by the ALICE Collaboration. The nuclear modification factor is found to be consistent with one and independent of the jet resolution parameter with the improved precision of this study, indicating that the possible influence of cold nuclear matter effects on the production cross section of charged-particle jets in p-Pb collisions at$$ \sqrt{s_{\textrm{NN}}} $$sNN= 5.02 TeV is smaller than the current precision. The obtained results are in agreement with other minimum bias jet measurements available for RHIC and LHC energies, and are well reproduced by the NLO perturbative QCD Powhegcalculations with parton shower provided by Pythia8 as well as by Jetscapesimulations.

 
more » « less
Award ID(s):
2208883
NSF-PAR ID:
10514234
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more » ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; « less
Corporate Creator(s):
Publisher / Repository:
ink.springer.com
Date Published:
Journal Name:
Journal of High Energy Physics
Volume:
2024
Issue:
5
ISSN:
1029-8479
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. A<sc>bstract</sc>

    Measurements of charged-particle production in pp, p–Pb, and Pb–Pb collisions in the toward, away, and transverse regions with the ALICE detector are discussed. These regions are defined event-by-event relative to the azimuthal direction of the charged trigger particle, which is the reconstructed particle with the largest transverse momentum$$ \left({p}_{\textrm{T}}^{\textrm{trig}}\right) $$pTtrigin the range 8<$$ {p}_{\textrm{T}}^{\textrm{trig}} $$pTtrig<15 GeV/c. The toward and away regions contain the primary and recoil jets, respectively; both regions are accompanied by the underlying event (UE). In contrast, the transverse region perpendicular to the direction of the trigger particle is dominated by the so-called UE dynamics, and includes also contributions from initial- and final-state radiation. The relative transverse activity classifier,$$ {R}_{\textrm{T}}={N}_{\textrm{ch}}^{\textrm{T}}/\left\langle {N}_{\textrm{ch}}^{\textrm{T}}\right\rangle $$RT=NchT/NchT, is used to group events according to their UE activity, where$$ {N}_{\textrm{ch}}^{\textrm{T}} $$NchTis the charged-particle multiplicity per event in the transverse region and$$ \left\langle {N}_{\textrm{ch}}^{\textrm{T}}\right\rangle $$NchTis the mean value over the whole analysed sample. The energy dependence of theRTdistributions in pp collisions at$$ \sqrt{s} $$s= 2.76, 5.02, 7, and 13 TeV is reported, exploring the Koba-Nielsen-Olesen (KNO) scaling properties of the multiplicity distributions. The first measurements of charged-particlepTspectra as a function ofRTin the three azimuthal regions in pp, p–Pb, and Pb–Pb collisions at$$ \sqrt{s_{\textrm{NN}}} $$sNN= 5.02 TeV are also reported. Data are compared with predictions obtained from the event generators PYTHIA 8 and EPOS LHC. This set of measurements is expected to contribute to the understanding of the origin of collective-like effects in small collision systems (pp and p–Pb).

     
    more » « less
  2. A<sc>bstract</sc>

    The collective behavior of$$ {\textrm{K}}_{\textrm{S}}^0 $$KS0and$$ \Lambda /\overline{\Lambda} $$Λ/Λ¯strange hadrons is studied by measuring the elliptic azimuthal anisotropy (v2) using the scalar-product and multiparticle correlation methods. Proton-lead (pPb) collisions at a nucleon-nucleon center-of-mass energy$$ \sqrt{s_{\textrm{NN}}} $$sNN= 8.16 TeV and lead-lead (PbPb) collisions at$$ \sqrt{s_{\textrm{NN}}} $$sNN= 5.02 TeV collected by the CMS experiment at the LHC are investigated. Nonflow effects in the pPb collisions are studied by using a subevent cumulant analysis and by excluding events where a jet with transverse momentum greater than 20 GeV is present. The strange hadronv2values extracted in pPb collisions via the four- and six-particle correlation method are found to be nearly identical, suggesting the collective behavior. Comparisons of the pPb and PbPb results for both strange hadrons and charged particles illustrate how event-by-event flow fluctuations depend on the system size.

     
    more » « less
  3. A<sc>bstract</sc>

    Results on the transverse spherocity dependence of light-flavor particle production (π, K, p,ϕ, K*0,$$ {\textrm{K}}_{\textrm{S}}^0 $$KS0, Λ, Ξ) at midrapidity in high-multiplicity pp collisions at$$ \sqrt{s} $$s= 13 TeV were obtained with the ALICE apparatus. The transverse spherocity estimator$$ \left({S}_{\textrm{O}}^{p_{\textrm{T}}=1}\right) $$SOpT=1categorizes events by their azimuthal topology. Utilizing narrow selections on$$ {S}_{\textrm{O}}^{p_{\textrm{T}}=1} $$SOpT=1, it is possible to contrast particle production in collisions dominated by many soft initial interactions with that observed in collisions dominated by one or more hard scatterings. Results are reported for two multiplicity estimators covering different pseudorapidity regions. The$$ {S}_{\textrm{O}}^{p_{\textrm{T}}=1} $$SOpT=1estimator is found to effectively constrain the hardness of the events when the midrapidity (|η| < 0.8) estimator is used.

    The production rates of strange particles are found to be slightly higher for soft isotropic topologies, and severely suppressed in hard jet-like topologies. These effects are more pronounced for hadrons with larger mass and strangeness content, and observed when the topological selection is done within a narrow multiplicity interval. This demonstrates that an important aspect of the universal scaling of strangeness enhancement with final-state multiplicity is that high-multiplicity collisions are dominated by soft, isotropic processes. On the contrary, strangeness production in events with jet-like processes is significantly reduced.

    The results presented in this article are compared with several QCD-inspired Monte Carlo event generators. Models that incorporate a two-component phenomenology, either through mechanisms accounting for string density, or thermal production, are able to describe the observed strangeness enhancement as a function of$$ {S}_{\textrm{O}}^{p_{\textrm{T}}=1} $$SOpT=1.

     
    more » « less
  4. A<sc>bstract</sc>

    This article reports measurements of the angle between differently defined jet axes in pp collisions at$$ \sqrt{s} $$s= 5.02 TeV carried out by the ALICE Collaboration. Charged particles at midrapidity are clustered into jets with resolution parametersR= 0.2 and 0.4. The jet axis, before and after Soft Drop grooming, is compared to the jet axis from the Winner-Takes-All (WTA) recombination scheme. The angle between these axes, ∆Raxis, probes a wide phase space of the jet formation and evolution, ranging from the initial high-momentum-transfer scattering to the hadronization process. The ∆Raxisobservable is presented for 20<$$ {p}_{\textrm{T}}^{\textrm{ch}\ \textrm{jet}} $$pTchjet<100 GeV/c, and compared to predictions from the PYTHIA 8 and Herwig 7 event generators. The distributions can also be calculated analytically with a leading hadronization correction related to the non-perturbative component of the Collins-Soper-Sterman (CSS) evolution kernel. Comparisons to analytical predictions at next-to-leading-logarithmic accuracy with leading hadronization correction implemented from experimental extractions of the CSS kernel in Drell-Yan measurements are presented. The analytical predictions describe the measured data within 20% in the perturbative regime, with surprising agreement in the non-perturbative regime as well. These results are compatible with the universality of the CSS kernel in the context of jet substructure.

     
    more » « less
  5. Abstract

    The azimuthal ($$\Delta \varphi $$Δφ) correlation distributions between heavy-flavor decay electrons and associated charged particles are measured in pp and p–Pb collisions at$$\sqrt{s_{\mathrm{{NN}}}} = 5.02$$sNN=5.02TeV. Results are reported for electrons with transverse momentum$$44<pT<16$$\textrm{GeV}/c$$GeV/c and pseudorapidity$$|\eta |<0.6$$|η|<0.6. The associated charged particles are selected with transverse momentum$$11<pT<7$$\textrm{GeV}/c$$GeV/c, and relative pseudorapidity separation with the leading electron$$|\Delta \eta | < 1$$|Δη|<1. The correlation measurements are performed to study and characterize the fragmentation and hadronization of heavy quarks. The correlation structures are fitted with a constant and two von Mises functions to obtain the baseline and the near- and away-side peaks, respectively. The results from p–Pb collisions are compared with those from pp collisions to study the effects of cold nuclear matter. In the measured trigger electron and associated particle kinematic regions, the two collision systems give consistent results. The$$\Delta \varphi $$Δφdistribution and the peak observables in pp and p–Pb collisions are compared with calculations from various Monte Carlo event generators.

     
    more » « less