Dielectron production in proton-proton collisions at √s=7 TeV

The ALICE collaboration

doi:10.1007/JHEP09(2018)064

Dielectron production in proton-proton collisions at √s=7 TeV

The ALICE collaboration

Physics Education

CERN
Variable Energy Cyclotron Centre India
University of California at Berkeley
Czech Academy of Sciences
Lund University
Panjab University
Polytechnic University of Turin
Indian Institute of Technology Bombay
Korea Institute of Science and Technology Information
Yale University
Alikhanov Institute for Theoretical and Experimental Physics
GSI Helmholtz Centre for Heavy Ion Research
Universidade Estadual de Campinas
Russian Research Centre Kurchatov Institute
National Institute for Nuclear Physics
Universidad Nacional Autónoma de México
COMSATS University Islamabad
Enrico Fermi Center
NASU - Bogolyubov Institute for Theoretical Physics
University of Bergen
Goethe University Frankfurt
St. Petersburg State University
Central China Normal University
Horia Hulubei National Institute of Physics and Nuclear Engineering
University of Birmingham
University of Münster
Heidelberg University
Creighton University
Ruder Boskovic Institute
University of Houston
Lawrence Berkeley National Laboratory
Nantes Université
Technical University of Munich
Technische Universität München
University of Oslo
Aligarh Muslim University

Research output: Contribution to journal › Journal article › peer-review

26 Scopus citations

Abstract

The first measurement of e⁺e⁻ pair production at mid-rapidity (|η_e| < 0.8) in pp collisions at s=7 TeV with ALICE at the LHC is presented. The dielectron production is studied as a function of the invariant mass (m_ee < 3.3 GeV/c²), the pair transverse momentum (p_T,ee < 8 GeV/c), and the pair transverse impact parameter (DCA_ee), i.e., the average distance of closest approach of the reconstructed electron and positron tracks to the collision vertex, normalised to its resolution. The results are compared with the expectations from a cocktail of known hadronic sources and are well described when PYTHIA is used to generate the heavy-flavour contributions. In the low-mass region (0.14 < m_ee < 1.1 GeV/c²), prompt and non-prompt e⁺e⁻ sources can be separated via the DCA_ee. In the intermediate-mass region (1.1 < m_ee < 2.7 GeV/c²), a double-differential fit to the data in m_ee and p_T,ee and a fit of the DCA_ee distribution allow the total c c ¯ and b b ¯ cross sections to be extracted. Two different event generators, PYTHIA and POWHEG, can reproduce the shape of the two-dimensional m_ee and p_T,ee spectra, as well as the shape of the DCA_ee distribution, reasonably well. However, differences in the c c ¯ and b b ¯ cross sections are observed when using the generators to extrapolate to full phase space. Finally, the ratio of inclusive to decay photons is studied via the measurement of virtual direct photons in the transverse-momentum range 1 < p_T < 8 GeV/c. This is found to be unity within the statistical and systematic uncertainties and consistent with expectations from next-to-leading order perturbative quantum chromodynamic calculations.[Figure not available: see fulltext.].

Original language	English
Article number	64
Journal	Journal of High Energy Physics
Volume	2018
Issue number	9
DOIs	https://doi.org/10.1007/JHEP09(2018)064
State	Published - 2018.09.1

Keywords

Heavy Ion Experiments

Quacquarelli Symonds(QS) Subject Topics

Physics & Astronomy

Access to Document

10.1007/JHEP09(2018)064

Cite this

@article{6c1fe467fae942a599b6fb5ddaf2435d,

title = "Dielectron production in proton-proton collisions at √s=7 TeV",

abstract = "The first measurement of e+e− pair production at mid-rapidity (|ηe| < 0.8) in pp collisions at s=7 TeV with ALICE at the LHC is presented. The dielectron production is studied as a function of the invariant mass (mee < 3.3 GeV/c2), the pair transverse momentum (pT,ee < 8 GeV/c), and the pair transverse impact parameter (DCAee), i.e., the average distance of closest approach of the reconstructed electron and positron tracks to the collision vertex, normalised to its resolution. The results are compared with the expectations from a cocktail of known hadronic sources and are well described when PYTHIA is used to generate the heavy-flavour contributions. In the low-mass region (0.14 < mee < 1.1 GeV/c2), prompt and non-prompt e+e− sources can be separated via the DCAee. In the intermediate-mass region (1.1 < mee < 2.7 GeV/c2), a double-differential fit to the data in mee and pT,ee and a fit of the DCAee distribution allow the total c c ¯ and b b ¯ cross sections to be extracted. Two different event generators, PYTHIA and POWHEG, can reproduce the shape of the two-dimensional mee and pT,ee spectra, as well as the shape of the DCAee distribution, reasonably well. However, differences in the c c ¯ and b b ¯ cross sections are observed when using the generators to extrapolate to full phase space. Finally, the ratio of inclusive to decay photons is studied via the measurement of virtual direct photons in the transverse-momentum range 1 < pT < 8 GeV/c. This is found to be unity within the statistical and systematic uncertainties and consistent with expectations from next-to-leading order perturbative quantum chromodynamic calculations.[Figure not available: see fulltext.].",

keywords = "Heavy Ion Experiments",

author = "\{The ALICE collaboration\} and S. Acharya and Acosta, \{F. T.\} 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. Anti{\v c}i{\'c} 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 B. Audurier and A. Augustinus and R. Averbeck and Azmi, \{M. D.\} and Kim, \{E. J.\}",

note = "Publisher Copyright: {\textcopyright} 2018, The Author(s).",

year = "2018",

month = sep,

day = "1",

doi = "10.1007/JHEP09(2018)064",

language = "English",

volume = "2018",

journal = "Journal of High Energy Physics",

issn = "1029-8479",

number = "9",

}

TY - JOUR

T1 - Dielectron production in proton-proton collisions at √s=7 TeV

AU - The ALICE collaboration

AU - Acharya, S.

AU - Acosta, F. T.

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 - Audurier, B.

AU - Augustinus, A.

AU - Averbeck, R.

AU - Azmi, M. D.

AU - Kim, E. J.

PY - 2018/9/1

Y1 - 2018/9/1

N2 - The first measurement of e+e− pair production at mid-rapidity (|ηe| < 0.8) in pp collisions at s=7 TeV with ALICE at the LHC is presented. The dielectron production is studied as a function of the invariant mass (mee < 3.3 GeV/c2), the pair transverse momentum (pT,ee < 8 GeV/c), and the pair transverse impact parameter (DCAee), i.e., the average distance of closest approach of the reconstructed electron and positron tracks to the collision vertex, normalised to its resolution. The results are compared with the expectations from a cocktail of known hadronic sources and are well described when PYTHIA is used to generate the heavy-flavour contributions. In the low-mass region (0.14 < mee < 1.1 GeV/c2), prompt and non-prompt e+e− sources can be separated via the DCAee. In the intermediate-mass region (1.1 < mee < 2.7 GeV/c2), a double-differential fit to the data in mee and pT,ee and a fit of the DCAee distribution allow the total c c ¯ and b b ¯ cross sections to be extracted. Two different event generators, PYTHIA and POWHEG, can reproduce the shape of the two-dimensional mee and pT,ee spectra, as well as the shape of the DCAee distribution, reasonably well. However, differences in the c c ¯ and b b ¯ cross sections are observed when using the generators to extrapolate to full phase space. Finally, the ratio of inclusive to decay photons is studied via the measurement of virtual direct photons in the transverse-momentum range 1 < pT < 8 GeV/c. This is found to be unity within the statistical and systematic uncertainties and consistent with expectations from next-to-leading order perturbative quantum chromodynamic calculations.[Figure not available: see fulltext.].

AB - The first measurement of e+e− pair production at mid-rapidity (|ηe| < 0.8) in pp collisions at s=7 TeV with ALICE at the LHC is presented. The dielectron production is studied as a function of the invariant mass (mee < 3.3 GeV/c2), the pair transverse momentum (pT,ee < 8 GeV/c), and the pair transverse impact parameter (DCAee), i.e., the average distance of closest approach of the reconstructed electron and positron tracks to the collision vertex, normalised to its resolution. The results are compared with the expectations from a cocktail of known hadronic sources and are well described when PYTHIA is used to generate the heavy-flavour contributions. In the low-mass region (0.14 < mee < 1.1 GeV/c2), prompt and non-prompt e+e− sources can be separated via the DCAee. In the intermediate-mass region (1.1 < mee < 2.7 GeV/c2), a double-differential fit to the data in mee and pT,ee and a fit of the DCAee distribution allow the total c c ¯ and b b ¯ cross sections to be extracted. Two different event generators, PYTHIA and POWHEG, can reproduce the shape of the two-dimensional mee and pT,ee spectra, as well as the shape of the DCAee distribution, reasonably well. However, differences in the c c ¯ and b b ¯ cross sections are observed when using the generators to extrapolate to full phase space. Finally, the ratio of inclusive to decay photons is studied via the measurement of virtual direct photons in the transverse-momentum range 1 < pT < 8 GeV/c. This is found to be unity within the statistical and systematic uncertainties and consistent with expectations from next-to-leading order perturbative quantum chromodynamic calculations.[Figure not available: see fulltext.].

KW - Heavy Ion Experiments

UR - https://www.scopus.com/pages/publications/85053272489

U2 - 10.1007/JHEP09(2018)064

DO - 10.1007/JHEP09(2018)064

M3 - Journal article

AN - SCOPUS:85053272489

SN - 1029-8479

VL - 2018

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

IS - 9

M1 - 64

ER -

Dielectron production in proton-proton collisions at √s=7 TeV

Abstract

Keywords

Quacquarelli Symonds(QS) Subject Topics

Access to Document

Other files and links

Fingerprint

Cite this