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

S. Acharya; F Acosta; D. Adamova; J Adolfsson; MM. Aggarwal; G. Aglieri Rinella; Maria Agnello; N. Agrawl; Z. Ahammed; S.U. Ahn; S. Aiola; A. Akindinov; M. Al-Turany; SN Alam; DSD Albuquerque; D. Aleksandrov; B Alessandro; R. Alfaro-Molina; Yusuf Ali; A. Alici; A. Alkin; J. Alme; T. Alt; Ian Bearden; Christian Alexander Bourjau; Christian Holm Christensen; Ante Bilandzic; bsm989 bsm989; Jens Jørgen Gaardhøje; Katarina Gajdosova; Børge Svane Nielsen; Freja Thoresen; Lais Ozelin De Lima Pimentel; Marek Chojnacki; Vytautas Vislavicius; You Zhou

doi:10.1007/JHEP09(2018)064

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

S. Acharya, F Acosta, D. Adamova, J Adolfsson, MM. Aggarwal, G. Aglieri Rinella, Maria Agnello, N. Agrawl, Z. Ahammed, S.U. Ahn, S. Aiola, A. Akindinov, M. Al-Turany, SN Alam, DSD Albuquerque, D. Aleksandrov, B Alessandro, R. Alfaro-Molina, Yusuf Ali, A. AliciA. Alkin, J. Alme, T. Alt, Ian Bearden, Christian Alexander Bourjau, Christian Holm Christensen, Ante Bilandzic, bsm989 bsm989, Jens Jørgen Gaardhøje, Katarina Gajdosova, Børge Svane Nielsen, Freja Thoresen, Lais Ozelin De Lima Pimentel, Marek Chojnacki, Vytautas Vislavicius, You Zhou

Experimental Particle Physics

9 Citations (Scopus)

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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	064
Journal	Journal of High Energy Physics
Volume	2018
Issue number	9
Number of pages	47
ISSN	1126-6708
DOIs	https://doi.org/10.1007/JHEP09(2018)064
Publication status	Published - 1 Sept 2018

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Acharya, S., Acosta, F., Adamova, D., Adolfsson, J., Aggarwal, MM., Aglieri Rinella, G., Agnello, M., Agrawl, N., Ahammed, Z., Ahn, S. U., Aiola, S., Akindinov, A., Al-Turany, M., Alam, SN., Albuquerque, DSD., Aleksandrov, D., Alessandro, B., Alfaro-Molina, R., Ali, Y., ... Zhou, Y. (2018). Dielectron production in proton-proton collisions at root s=7 TeV. Journal of High Energy Physics, 2018(9), Article 064. https://doi.org/10.1007/JHEP09(2018)064

Acharya, S, Acosta, F, Adamova, D, Adolfsson, J, Aggarwal, MM, Aglieri Rinella, G, Agnello, M, Agrawl, N, Ahammed, Z, Ahn, SU, Aiola, S, Akindinov, A, Al-Turany, M, Alam, SN, Albuquerque, DSD, Aleksandrov, D, Alessandro, B, Alfaro-Molina, R, Ali, Y, Alici, A, Alkin, A, Alme, J, Alt, T, Bearden, I, Bourjau, CA, Christensen, CH, Bilandzic, A, bsm989, B , Gaardhøje, JJ, Gajdosova, K, Nielsen, BS, Thoresen, F, Ozelin De Lima Pimentel, L, Chojnacki, M, Vislavicius, V & Zhou, Y 2018, 'Dielectron production in proton-proton collisions at root s=7 TeV', Journal of High Energy Physics, vol. 2018, no. 9, 064. https://doi.org/10.1007/JHEP09(2018)064

@article{89a776ab281f4f48bb2760205587505c,

title = "Dielectron production in proton-proton collisions at root 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.].",

author = "S. Acharya and F Acosta and D. Adamova and J Adolfsson and MM. Aggarwal and {Aglieri Rinella}, G. and Maria Agnello and N. Agrawl and Z. Ahammed and S.U. Ahn and S. Aiola and A. Akindinov and M. Al-Turany and SN Alam and DSD Albuquerque and D. Aleksandrov and B Alessandro and R. Alfaro-Molina and Yusuf Ali and A. Alici and A. Alkin and J. Alme and T. Alt and Ian Bearden and Bourjau, {Christian Alexander} and Christensen, {Christian Holm} and Ante Bilandzic and bsm989 bsm989 and Gaardh{\o}je, {Jens J{\o}rgen} and Katarina Gajdosova and Nielsen, {B{\o}rge Svane} and Freja Thoresen and {Ozelin De Lima Pimentel}, Lais and Marek Chojnacki and Vytautas Vislavicius and You Zhou",

year = "2018",

month = sep,

day = "1",

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

language = "English",

volume = "2018",

journal = "Journal of High Energy Physics",

issn = "1126-6708",

publisher = "Springer",

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TY - JOUR

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

AU - Acharya, S.

AU - Acosta, F

AU - Adamova, D.

AU - Adolfsson, J

AU - Aggarwal, MM.

AU - Aglieri Rinella, G.

AU - Agnello, Maria

AU - Agrawl, N.

AU - Ahammed, Z.

AU - Ahn, S.U.

AU - Aiola, S.

AU - Akindinov, A.

AU - Al-Turany, M.

AU - Alam, SN

AU - Albuquerque, DSD

AU - Aleksandrov, D.

AU - Alessandro, B

AU - Alfaro-Molina, R.

AU - Ali, Yusuf

AU - Alici, A.

AU - Alkin, A.

AU - Alme, J.

AU - Alt, T.

AU - Bearden, Ian

AU - Bourjau, Christian Alexander

AU - Christensen, Christian Holm

AU - Bilandzic, Ante

AU - bsm989, bsm989

AU - Gaardhøje, Jens Jørgen

AU - Gajdosova, Katarina

AU - Nielsen, Børge Svane

AU - Thoresen, Freja

AU - Ozelin De Lima Pimentel, Lais

AU - Chojnacki, Marek

AU - Vislavicius, Vytautas

AU - Zhou, You

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.].

U2 - 10.1007/JHEP09(2018)064

DO - 10.1007/JHEP09(2018)064

M3 - Journal article

SN - 1126-6708

VL - 2018

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

IS - 9

M1 - 064

ER -

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

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