Multiplicity and event-scale dependent flow and jet fragmentation in pp collisions at $\sqrt{s}$ = 13 TeV and in p$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV

Abstract

Long- and short-range correlations for pairs of charged particles are studied via two-particle angular correlations in pp collisions at $\sqrt{s}=13$ TeV and p$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV. The correlation functions are measured as a function of relative azimuthal angle $\Delta \phi$ and pseudorapidity separation $\Delta \eta$ for pairs of primary charged particles within the pseudorapidity interval $|\eta |<0.9$ and the transverse-momentum interval $1<p_{\mathrm{T}}<4$ GeV/$c$. Flow coefficients are extracted for the long-range correlations ($1.6<|\Delta \eta |<1.8$) in various high-multiplicity event classes using the low-multiplicity template fit method. The method is used to subtract the enhanced yield of away-side jet fragments in high-multiplicity events. These results show decreasing flow signals toward lower multiplicity events. Furthermore, the flow coefficients for events with hard probes, such as jets or leading particles, do not exhibit any significant changes compared to those obtained from high-multiplicity events without any specific event selection criteria. The results are compared with hydrodynamic-model calculations, and it is found that a better understanding of the initial conditions is necessary to describe the results, particularly for low-multiplicity events.

31 pages, 7 captioned figures, 2 tables, authors from page 25, published version, figures at http://alice-publications.web.cern.ch/node/9602

References in corpus (10)

• Viscosity Information from Relativistic Nuclear Collisions: How Perfect is the Fluid Observed at RHIC?
• Tuning PYTHIA 8.1: the Monash 2013 Tune
• Elliptic and triangular flow in event-by-event (3+1)D viscous hydrodynamics
• Alternative ansatz to wounded nucleon and binary collision scaling in high-energy nuclear collisions
• Event-by-event gluon multiplicity, energy density and eccentricities at RHIC and LHC
• Event-by-event hydrodynamics and elliptic flow from fluctuating initial state
• Imprints of fluctuating proton shapes on flow in proton-lead collisions at the LHC
• Evidence for BFKL and saturation dynamics from di-hadron spectra at the LHC
• Transverse nucleon structure and diagnostics of hard parton-parton processes at LHC
• Importance of initial and final state effects for azimuthal correlations in p+Pb collisions

Cited by in corpus (6)

• The Dynamics of Particle-Particle Correlations and the Ridge Effect in Proton-Proton Collisions
• Emergence of long-range angular correlations in low-multiplicity proton-proton collisions
• How Gubser flow ends in a holographic conformal theory
• Superfluids in expanding backgrounds and attractor times
• Investigating strangeness enhancement in jet and medium via $\varphi$(1020) production in p$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV
• Finite $V_{2\Delta }$ puzzle in low-multiplicity pp collisions from ultra-long-range azimuthal correlations in the string-shoving model