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

ALICE Collaboration

Research output: Contribution to journalArticle

Abstract

The measurement of dielectron production is presented as a function of invariant mass and transverse momentum (p T ) at midrapidity (|y e |<0.8) in proton–proton (pp) collisions at a centre-of-mass energy of s=13 TeV. The contributions from light-hadron decays are calculated from their measured cross sections in pp collisions at 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: dσ cc¯ /dy| y=0 =974±138(stat.)±140(syst.)±214(BR)μb and dσ bb¯ /dy| y=0 =79±14(stat.)±11(syst.)±5(BR)μb using PYTHIA simulations and dσ cc¯ /dy| y=0 =1417±184(stat.)±204(syst.)±312(BR)μb and dσ bb¯ /dy| y=0 =48±14(stat.)±7(syst.)±3(BR)μb 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.

Original languageEnglish (US)
Pages (from-to)505-518
Number of pages14
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume788
DOIs
StatePublished - Jan 10 2019

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generators
quarks
collisions
charged particles
cross sections
decay
stems
transverse momentum
hadrons
center of mass
energy
extrapolation
confidence
kinematics
templates
actuators
continuums
intervals
momentum
scaling

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics

Cite this

@article{d8ece49a05264f6484b73aa230d4e38e,
title = "Dielectron and heavy-quark production in inelastic and high-multiplicity proton–proton collisions at s=13TeV",
abstract = "The measurement of dielectron production is presented as a function of invariant mass and transverse momentum (p T ) at midrapidity (|y e |<0.8) in proton–proton (pp) collisions at a centre-of-mass energy of s=13 TeV. The contributions from light-hadron decays are calculated from their measured cross sections in pp collisions at 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: dσ cc¯ /dy| y=0 =974±138(stat.)±140(syst.)±214(BR)μb and dσ bb¯ /dy| y=0 =79±14(stat.)±11(syst.)±5(BR)μb using PYTHIA simulations and dσ cc¯ /dy| y=0 =1417±184(stat.)±204(syst.)±312(BR)μb and dσ bb¯ /dy| y=0 =48±14(stat.)±7(syst.)±3(BR)μb 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.",
author = "{ALICE Collaboration} and S. Acharya and F. Torales-Acosta and D. Adamov{\'a} and J. Adolfsson and Aggarwal, {M. M.} and {Aglieri Rinella}, G. and M. Agnello and N. Agrawal and Z. Ahammed and Ahn, {S. U.} and S. Aiola and A. Akindinov and M. Al-Turany and Alam, {S. N.} and Albuquerque, {D. S.D.} and D. Aleksandrov and B. Alessandro and {Alfaro Molina}, R. and Y. Ali and A. Alici and A. Alkin and J. Alme and T. Alt and L. Altenkamper and I. Altsybeev and Anaam, {M. N.} and C. Andrei and D. Andreou and Andrews, {H. A.} and A. Andronic and M. Angeletti and V. Anguelov and C. Anson and T. Antičić and F. Antinori and P. Antonioli and R. Anwar and N. Apadula and L. Aphecetche and H. Appelsh{\"a}user and S. Arcelli and R. Arnaldi and Arnold, {O. W.} and Arsene, {I. C.} and M. Arslandok and A. Augustinus and R. Averbeck and Azmi, {M. D.} and A. Badal{\`a} and Seger, {Janet E.}",
year = "2019",
month = "1",
day = "10",
doi = "10.1016/j.physletb.2018.11.009",
language = "English (US)",
volume = "788",
pages = "505--518",
journal = "Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics",
issn = "0370-2693",
publisher = "Elsevier",

}

TY - JOUR

T1 - Dielectron and heavy-quark production in inelastic and high-multiplicity proton–proton collisions at s=13TeV

AU - ALICE Collaboration

AU - Acharya, S.

AU - Torales-Acosta, F.

AU - Adamová, D.

AU - Adolfsson, J.

AU - Aggarwal, M. M.

AU - Aglieri Rinella, G.

AU - Agnello, M.

AU - Agrawal, N.

AU - Ahammed, Z.

AU - Ahn, S. U.

AU - Aiola, S.

AU - Akindinov, A.

AU - Al-Turany, M.

AU - Alam, S. N.

AU - Albuquerque, D. S.D.

AU - Aleksandrov, D.

AU - Alessandro, B.

AU - Alfaro Molina, R.

AU - Ali, Y.

AU - Alici, A.

AU - Alkin, A.

AU - Alme, J.

AU - Alt, T.

AU - Altenkamper, L.

AU - Altsybeev, I.

AU - Anaam, M. N.

AU - Andrei, C.

AU - Andreou, D.

AU - Andrews, H. A.

AU - Andronic, A.

AU - Angeletti, M.

AU - Anguelov, V.

AU - Anson, C.

AU - Antičić, T.

AU - Antinori, F.

AU - Antonioli, P.

AU - Anwar, R.

AU - Apadula, N.

AU - Aphecetche, L.

AU - Appelshäuser, H.

AU - Arcelli, S.

AU - Arnaldi, R.

AU - Arnold, O. W.

AU - Arsene, I. C.

AU - Arslandok, M.

AU - Augustinus, A.

AU - Averbeck, R.

AU - Azmi, M. D.

AU - Badalà, A.

AU - Seger, Janet E.

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 (|y e |<0.8) in proton–proton (pp) collisions at a centre-of-mass energy of s=13 TeV. The contributions from light-hadron decays are calculated from their measured cross sections in pp collisions at 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: dσ cc¯ /dy| y=0 =974±138(stat.)±140(syst.)±214(BR)μb and dσ bb¯ /dy| y=0 =79±14(stat.)±11(syst.)±5(BR)μb using PYTHIA simulations and dσ cc¯ /dy| y=0 =1417±184(stat.)±204(syst.)±312(BR)μb and dσ bb¯ /dy| y=0 =48±14(stat.)±7(syst.)±3(BR)μb 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.

AB - The measurement of dielectron production is presented as a function of invariant mass and transverse momentum (p T ) at midrapidity (|y e |<0.8) in proton–proton (pp) collisions at a centre-of-mass energy of s=13 TeV. The contributions from light-hadron decays are calculated from their measured cross sections in pp collisions at 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: dσ cc¯ /dy| y=0 =974±138(stat.)±140(syst.)±214(BR)μb and dσ bb¯ /dy| y=0 =79±14(stat.)±11(syst.)±5(BR)μb using PYTHIA simulations and dσ cc¯ /dy| y=0 =1417±184(stat.)±204(syst.)±312(BR)μb and dσ bb¯ /dy| y=0 =48±14(stat.)±7(syst.)±3(BR)μb 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.

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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, Section B: Nuclear, Elementary Particle and High-Energy Physics

JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

SN - 0370-2693

ER -