Dielectron and heavy-quark production in inelastic and high-multiplicity proton-proton collisions at root s=13 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

The measurement of dielectron production is presented as a function of invariant mass and transverse momentum (p(T)) at midrapidity (vertical bar ye vertical bar < 0.8) in proton-proton (pp) collisions at a centre-of-mass energy of root s = 13 TeV. The contributions from light-hadron decays are calculated from their measured cross sections in pp collisions at root s = 7 TeV or 13 TeV. The remaining continuum stems from correlated semileptonic decays of heavy-flavour hadrons. Fitting the data with templates from two different MC event generators, PYTHIA and POWHEG, the charm and beauty cross sections at midrapidity are extracted for the first time at this collision energy: d sigma(c<(c)over bar>)/dy vertical bar(y=0) = 974 +/- 138 (stat.) +/- 140 (syst.) +/- 214(BR) mu b and d sigma(b (b) over bar)/dy vertical bar(y=0) = 79 +/- 14 (stat.) +/- 11 (syst.) +/- 5(BR) mu b using PYTHIA simulations and d sigma(c (c) over bar)/dy vertical bar(y=0) = 1417 +/- 184 (stat.) +/- 204 (syst.) +/- 312(BR) mu b and d sigma(b (b) over bar)/dy vertical bar(y=0) = 48 +/- 14 (stat.) +/- 7 (syst.) +/- 3(BR) mu b for POWHEG. These values, whose uncertainties are fully correlated between the two generators, are consistent with extrapolations from lower energies. The different results obtained with POWHEG and PYTHIA imply different kinematic correlations of the heavy-quark pairs in these two generators. Furthermore, comparisons of dielectron spectra in inelastic events and in events collected with a trigger on high charged-particle multiplicities are presented in various p(T) intervals. The differences are consistent with the already measured scaling of light-hadron and open-charm production at high charged-particle multiplicity as a function of p(T). Upper limits for the contribution of virtual direct photons are extracted at 90% confidence level and found to be in agreement with pQCD calculations. (C) 2018 The Author. Published by Elsevier B.V.
Original languageEnglish
JournalPhysics Letters B
Volume788
Pages (from-to)505-518
Number of pages14
ISSN0370-2693
DOIs
Publication statusPublished - 10 Jan 2019
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 114 Physical sciences
  • PLUS AU COLLISIONS
  • PB-PB COLLISIONS
  • PP COLLISIONS
  • TRANSVERSE-MOMENTUM
  • PHOTON PRODUCTION
  • ROOT-S(NN)=200 GEV
  • J/PSI PRODUCTION
  • MESON PRODUCTION
  • COLLECTIVITY
  • DEPENDENCE

Cite this

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. / Dielectron and heavy-quark production in inelastic and high-multiplicity proton-proton collisions at root s=13 TeV. In: Physics Letters B. 2019 ; Vol. 788. pp. 505-518.
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abstract = "The measurement of dielectron production is presented as a function of invariant mass and transverse momentum (p(T)) at midrapidity (vertical bar ye vertical bar < 0.8) in proton-proton (pp) collisions at a centre-of-mass energy of root s = 13 TeV. The contributions from light-hadron decays are calculated from their measured cross sections in pp collisions at root s = 7 TeV or 13 TeV. The remaining continuum stems from correlated semileptonic decays of heavy-flavour hadrons. Fitting the data with templates from two different MC event generators, PYTHIA and POWHEG, the charm and beauty cross sections at midrapidity are extracted for the first time at this collision energy: d sigma(c<(c)over bar>)/dy vertical bar(y=0) = 974 +/- 138 (stat.) +/- 140 (syst.) +/- 214(BR) mu b and d sigma(b (b) over bar)/dy vertical bar(y=0) = 79 +/- 14 (stat.) +/- 11 (syst.) +/- 5(BR) mu b using PYTHIA simulations and d sigma(c (c) over bar)/dy vertical bar(y=0) = 1417 +/- 184 (stat.) +/- 204 (syst.) +/- 312(BR) mu b and d sigma(b (b) over bar)/dy vertical bar(y=0) = 48 +/- 14 (stat.) +/- 7 (syst.) +/- 3(BR) mu b for POWHEG. These values, whose uncertainties are fully correlated between the two generators, are consistent with extrapolations from lower energies. The different results obtained with POWHEG and PYTHIA imply different kinematic correlations of the heavy-quark pairs in these two generators. Furthermore, comparisons of dielectron spectra in inelastic events and in events collected with a trigger on high charged-particle multiplicities are presented in various p(T) intervals. The differences are consistent with the already measured scaling of light-hadron and open-charm production at high charged-particle multiplicity as a function of p(T). Upper limits for the contribution of virtual direct photons are extracted at 90{\%} confidence level and found to be in agreement with pQCD calculations. (C) 2018 The Author. Published by Elsevier B.V.",
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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",
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Dielectron and heavy-quark production in inelastic and high-multiplicity proton-proton collisions at root s=13 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: Physics Letters B, Vol. 788, 10.01.2019, p. 505-518.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Dielectron and heavy-quark production in inelastic and high-multiplicity proton-proton collisions at root s=13 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 - 2019/1/10

Y1 - 2019/1/10

N2 - The measurement of dielectron production is presented as a function of invariant mass and transverse momentum (p(T)) at midrapidity (vertical bar ye vertical bar < 0.8) in proton-proton (pp) collisions at a centre-of-mass energy of root s = 13 TeV. The contributions from light-hadron decays are calculated from their measured cross sections in pp collisions at root s = 7 TeV or 13 TeV. The remaining continuum stems from correlated semileptonic decays of heavy-flavour hadrons. Fitting the data with templates from two different MC event generators, PYTHIA and POWHEG, the charm and beauty cross sections at midrapidity are extracted for the first time at this collision energy: d sigma(c<(c)over bar>)/dy vertical bar(y=0) = 974 +/- 138 (stat.) +/- 140 (syst.) +/- 214(BR) mu b and d sigma(b (b) over bar)/dy vertical bar(y=0) = 79 +/- 14 (stat.) +/- 11 (syst.) +/- 5(BR) mu b using PYTHIA simulations and d sigma(c (c) over bar)/dy vertical bar(y=0) = 1417 +/- 184 (stat.) +/- 204 (syst.) +/- 312(BR) mu b and d sigma(b (b) over bar)/dy vertical bar(y=0) = 48 +/- 14 (stat.) +/- 7 (syst.) +/- 3(BR) mu b for POWHEG. These values, whose uncertainties are fully correlated between the two generators, are consistent with extrapolations from lower energies. The different results obtained with POWHEG and PYTHIA imply different kinematic correlations of the heavy-quark pairs in these two generators. Furthermore, comparisons of dielectron spectra in inelastic events and in events collected with a trigger on high charged-particle multiplicities are presented in various p(T) intervals. The differences are consistent with the already measured scaling of light-hadron and open-charm production at high charged-particle multiplicity as a function of p(T). Upper limits for the contribution of virtual direct photons are extracted at 90% confidence level and found to be in agreement with pQCD calculations. (C) 2018 The Author. Published by Elsevier B.V.

AB - The measurement of dielectron production is presented as a function of invariant mass and transverse momentum (p(T)) at midrapidity (vertical bar ye vertical bar < 0.8) in proton-proton (pp) collisions at a centre-of-mass energy of root s = 13 TeV. The contributions from light-hadron decays are calculated from their measured cross sections in pp collisions at root s = 7 TeV or 13 TeV. The remaining continuum stems from correlated semileptonic decays of heavy-flavour hadrons. Fitting the data with templates from two different MC event generators, PYTHIA and POWHEG, the charm and beauty cross sections at midrapidity are extracted for the first time at this collision energy: d sigma(c<(c)over bar>)/dy vertical bar(y=0) = 974 +/- 138 (stat.) +/- 140 (syst.) +/- 214(BR) mu b and d sigma(b (b) over bar)/dy vertical bar(y=0) = 79 +/- 14 (stat.) +/- 11 (syst.) +/- 5(BR) mu b using PYTHIA simulations and d sigma(c (c) over bar)/dy vertical bar(y=0) = 1417 +/- 184 (stat.) +/- 204 (syst.) +/- 312(BR) mu b and d sigma(b (b) over bar)/dy vertical bar(y=0) = 48 +/- 14 (stat.) +/- 7 (syst.) +/- 3(BR) mu b for POWHEG. These values, whose uncertainties are fully correlated between the two generators, are consistent with extrapolations from lower energies. The different results obtained with POWHEG and PYTHIA imply different kinematic correlations of the heavy-quark pairs in these two generators. Furthermore, comparisons of dielectron spectra in inelastic events and in events collected with a trigger on high charged-particle multiplicities are presented in various p(T) intervals. The differences are consistent with the already measured scaling of light-hadron and open-charm production at high charged-particle multiplicity as a function of p(T). Upper limits for the contribution of virtual direct photons are extracted at 90% confidence level and found to be in agreement with pQCD calculations. (C) 2018 The Author. Published by Elsevier B.V.

KW - 114 Physical sciences

KW - PLUS AU COLLISIONS

KW - PB-PB COLLISIONS

KW - PP COLLISIONS

KW - TRANSVERSE-MOMENTUM

KW - PHOTON PRODUCTION

KW - ROOT-S(NN)=200 GEV

KW - J/PSI PRODUCTION

KW - MESON PRODUCTION

KW - COLLECTIVITY

KW - DEPENDENCE

U2 - 10.1016/j.physletb.2018.11.009

DO - 10.1016/j.physletb.2018.11.009

M3 - Article

VL - 788

SP - 505

EP - 518

JO - Physics Letters B

JF - Physics Letters B

SN - 0370-2693

ER -