Multiplicity dependence of light-flavor hadron production in pp collisions at root s=7 TeV

The ALICE Collaboration, S. Acharya, E. J. Brücken, B. Chang, T. E. Hilden, D. J. Kim, V. Litichevskyi, M. M. Mieskolainen, R. Orava, J. E. Parkkila, J. Rak, S. S. Räsänen, S. Saarinen, M. Slupecki, T. W. Snellman, W. H. Trzaska, M. Vargyas, J. Viinikainen

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Comprehensive results on the production of unidentified charged particles, pi(+/-), K-+/-, K-s(0), K*(892)(0), p, (p) over bar, phi(1020), Lambda, (Lambda) over bar, Xi(-) , (Xi) over bar (+), Omega(-), and (Omega) over bar (+) hadrons in proton-proton (pp) collisions at root s = 7 TeV at midrapidity (vertical bar y vertical bar < 0.5) as a function of charged-particle multiplicity density are presented. In order to avoid autocorrelation biases, the actual transverse momentum (p(T)) spectra of the particles under study and the event activity are measured in different rapidity windows. In the highest multiplicity class, the charged-particle density reaches about 3.5 times the value measured in inelastic collisions. While the yield of protons normalized to pions remains approximately constant as a function of multiplicity, the corresponding ratios of strange hadrons to pions show a significant enhancement that increases with increasing strangeness content. Furthermore, all identified particleto-pion ratios are shown to depend solely on charged-particle multiplicity density, regardless of system type and collision energy. The evolution of the spectral shapes with multiplicity and hadron mass shows patterns that are similar to those observed in p-Pb and Pb-Pb collisions at Large Hadron Collider energies. The obtained p(T), distributions and yields are compared to expectations from QCD-based pp event generators as well as to predictions from thermal and hydrodynamic models. These comparisons indicate that traces of a collective, equilibrated system are already present in high-multiplicity pp collisions.
Original languageEnglish
Article number024906
JournalPhysical Review C
Volume99
Issue number2
Number of pages30
ISSN2469-9985
DOIs
Publication statusPublished - 8 Feb 2019
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 114 Physical sciences
  • PB-PB COLLISIONS
  • TRANSVERSE-MOMENTUM
  • FREEZE-OUT
  • STATISTICAL HADRONIZATION
  • PARTICLE
  • RESONANCES
  • PHYSICS
  • PROTON
  • PIONS
  • MODEL

Cite this

The ALICE Collaboration, Acharya, S., Brücken, E. J., Chang, B., Hilden, T. E., Kim, D. J., ... Viinikainen, J. (2019). Multiplicity dependence of light-flavor hadron production in pp collisions at root s=7 TeV. Physical Review C, 99(2), [024906]. https://doi.org/10.1103/PhysRevC.99.024906
The ALICE Collaboration ; Acharya, S. ; Brücken, E. J. ; Chang, B. ; Hilden, T. E. ; Kim, D. J. ; Litichevskyi, V. ; Mieskolainen, M. M. ; Orava, R. ; Parkkila, J. E. ; Rak, J. ; Räsänen, S. S. ; Saarinen, S. ; Slupecki, M. ; Snellman, T. W. ; Trzaska, W. H. ; Vargyas, M. ; Viinikainen, J. / Multiplicity dependence of light-flavor hadron production in pp collisions at root s=7 TeV. In: Physical Review C. 2019 ; Vol. 99, No. 2.
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title = "Multiplicity dependence of light-flavor hadron production in pp collisions at root s=7 TeV",
abstract = "Comprehensive results on the production of unidentified charged particles, pi(+/-), K-+/-, K-s(0), K*(892)(0), p, (p) over bar, phi(1020), Lambda, (Lambda) over bar, Xi(-) , (Xi) over bar (+), Omega(-), and (Omega) over bar (+) hadrons in proton-proton (pp) collisions at root s = 7 TeV at midrapidity (vertical bar y vertical bar < 0.5) as a function of charged-particle multiplicity density are presented. In order to avoid autocorrelation biases, the actual transverse momentum (p(T)) spectra of the particles under study and the event activity are measured in different rapidity windows. In the highest multiplicity class, the charged-particle density reaches about 3.5 times the value measured in inelastic collisions. While the yield of protons normalized to pions remains approximately constant as a function of multiplicity, the corresponding ratios of strange hadrons to pions show a significant enhancement that increases with increasing strangeness content. Furthermore, all identified particleto-pion ratios are shown to depend solely on charged-particle multiplicity density, regardless of system type and collision energy. The evolution of the spectral shapes with multiplicity and hadron mass shows patterns that are similar to those observed in p-Pb and Pb-Pb collisions at Large Hadron Collider energies. The obtained p(T), distributions and yields are compared to expectations from QCD-based pp event generators as well as to predictions from thermal and hydrodynamic models. These comparisons indicate that traces of a collective, equilibrated system are already present in high-multiplicity pp collisions.",
keywords = "114 Physical sciences, PB-PB COLLISIONS, TRANSVERSE-MOMENTUM, FREEZE-OUT, STATISTICAL HADRONIZATION, PARTICLE, RESONANCES, PHYSICS, PROTON, PIONS, MODEL",
author = "{The ALICE Collaboration} and S. Acharya and Br{\"u}cken, {E. J.} and B. Chang and Hilden, {T. E.} and Kim, {D. J.} and V. Litichevskyi and Mieskolainen, {M. M.} and R. Orava and Parkkila, {J. E.} and J. Rak and R{\"a}s{\"a}nen, {S. S.} and S. Saarinen and M. Slupecki and Snellman, {T. W.} and Trzaska, {W. H.} and M. Vargyas and J. Viinikainen",
year = "2019",
month = "2",
day = "8",
doi = "10.1103/PhysRevC.99.024906",
language = "English",
volume = "99",
journal = "Physical Review C",
issn = "2469-9985",
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The ALICE Collaboration, Acharya, S, Brücken, EJ, Chang, B, Hilden, TE, Kim, DJ, Litichevskyi, V, Mieskolainen, MM, Orava, R, Parkkila, JE, Rak, J, Räsänen, SS, Saarinen, S, Slupecki, M, Snellman, TW, Trzaska, WH, Vargyas, M & Viinikainen, J 2019, 'Multiplicity dependence of light-flavor hadron production in pp collisions at root s=7 TeV', Physical Review C, vol. 99, no. 2, 024906. https://doi.org/10.1103/PhysRevC.99.024906

Multiplicity dependence of light-flavor hadron production in pp collisions at root s=7 TeV. / The ALICE Collaboration; Acharya, S.; Brücken, E. J.; Chang, B.; Hilden, T. E.; Kim, D. J.; Litichevskyi, V.; Mieskolainen, M. M.; Orava, R.; Parkkila, J. E.; Rak, J.; Räsänen, S. S.; Saarinen, S.; Slupecki, M.; Snellman, T. W.; Trzaska, W. H.; Vargyas, M.; Viinikainen, J.

In: Physical Review C, Vol. 99, No. 2, 024906, 08.02.2019.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Multiplicity dependence of light-flavor hadron production in pp collisions at root s=7 TeV

AU - The ALICE Collaboration

AU - Acharya, S.

AU - Brücken, E. J.

AU - Chang, B.

AU - Hilden, T. E.

AU - Kim, D. J.

AU - Litichevskyi, V.

AU - Mieskolainen, M. M.

AU - Orava, R.

AU - Parkkila, J. E.

AU - Rak, J.

AU - Räsänen, S. S.

AU - Saarinen, S.

AU - Slupecki, M.

AU - Snellman, T. W.

AU - Trzaska, W. H.

AU - Vargyas, M.

AU - Viinikainen, J.

PY - 2019/2/8

Y1 - 2019/2/8

N2 - Comprehensive results on the production of unidentified charged particles, pi(+/-), K-+/-, K-s(0), K*(892)(0), p, (p) over bar, phi(1020), Lambda, (Lambda) over bar, Xi(-) , (Xi) over bar (+), Omega(-), and (Omega) over bar (+) hadrons in proton-proton (pp) collisions at root s = 7 TeV at midrapidity (vertical bar y vertical bar < 0.5) as a function of charged-particle multiplicity density are presented. In order to avoid autocorrelation biases, the actual transverse momentum (p(T)) spectra of the particles under study and the event activity are measured in different rapidity windows. In the highest multiplicity class, the charged-particle density reaches about 3.5 times the value measured in inelastic collisions. While the yield of protons normalized to pions remains approximately constant as a function of multiplicity, the corresponding ratios of strange hadrons to pions show a significant enhancement that increases with increasing strangeness content. Furthermore, all identified particleto-pion ratios are shown to depend solely on charged-particle multiplicity density, regardless of system type and collision energy. The evolution of the spectral shapes with multiplicity and hadron mass shows patterns that are similar to those observed in p-Pb and Pb-Pb collisions at Large Hadron Collider energies. The obtained p(T), distributions and yields are compared to expectations from QCD-based pp event generators as well as to predictions from thermal and hydrodynamic models. These comparisons indicate that traces of a collective, equilibrated system are already present in high-multiplicity pp collisions.

AB - Comprehensive results on the production of unidentified charged particles, pi(+/-), K-+/-, K-s(0), K*(892)(0), p, (p) over bar, phi(1020), Lambda, (Lambda) over bar, Xi(-) , (Xi) over bar (+), Omega(-), and (Omega) over bar (+) hadrons in proton-proton (pp) collisions at root s = 7 TeV at midrapidity (vertical bar y vertical bar < 0.5) as a function of charged-particle multiplicity density are presented. In order to avoid autocorrelation biases, the actual transverse momentum (p(T)) spectra of the particles under study and the event activity are measured in different rapidity windows. In the highest multiplicity class, the charged-particle density reaches about 3.5 times the value measured in inelastic collisions. While the yield of protons normalized to pions remains approximately constant as a function of multiplicity, the corresponding ratios of strange hadrons to pions show a significant enhancement that increases with increasing strangeness content. Furthermore, all identified particleto-pion ratios are shown to depend solely on charged-particle multiplicity density, regardless of system type and collision energy. The evolution of the spectral shapes with multiplicity and hadron mass shows patterns that are similar to those observed in p-Pb and Pb-Pb collisions at Large Hadron Collider energies. The obtained p(T), distributions and yields are compared to expectations from QCD-based pp event generators as well as to predictions from thermal and hydrodynamic models. These comparisons indicate that traces of a collective, equilibrated system are already present in high-multiplicity pp collisions.

KW - 114 Physical sciences

KW - PB-PB COLLISIONS

KW - TRANSVERSE-MOMENTUM

KW - FREEZE-OUT

KW - STATISTICAL HADRONIZATION

KW - PARTICLE

KW - RESONANCES

KW - PHYSICS

KW - PROTON

KW - PIONS

KW - MODEL

U2 - 10.1103/PhysRevC.99.024906

DO - 10.1103/PhysRevC.99.024906

M3 - Article

VL - 99

JO - Physical Review C

JF - Physical Review C

SN - 2469-9985

IS - 2

M1 - 024906

ER -