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dc.contributor.authorALICE Collaboration
dc.date.accessioned2018-09-24T11:36:31Z
dc.date.available2018-09-24T11:36:31Z
dc.date.issued2018
dc.identifier.citationALICE Collaboration. (2018). Dielectron production in proton-proton collisions at √s = 7 TeV. <i>Journal of High Energy Physics</i>, <i>2018</i>(9), Article 64. <a href="https://doi.org/10.1007/jhep09(2018)064" target="_blank">https://doi.org/10.1007/jhep09(2018)064</a>
dc.identifier.otherCONVID_28276095
dc.identifier.otherTUTKAID_78915
dc.identifier.urihttps://jyx.jyu.fi/handle/123456789/59644
dc.description.abstractThe 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/c 2 ), 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/c 2 ), prompt and non-prompt e+e − sources can be separated via the DCAee. In the intermediate-mass region (1.1 < mee < 2.7 GeV/c 2 ), a double-differential fit to the data in mee and pT,ee and a fit of the DCAee distribution allow the total cc and bb 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 cc and bb 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.fi
dc.format.mimetypeapplication/pdf
dc.language.isoeng
dc.publisherSpringer
dc.relation.ispartofseriesJournal of High Energy Physics
dc.rightsCC BY 4.0
dc.subject.otherheavy ion experiments
dc.titleDielectron production in proton-proton collisions at √s = 7 TeV
dc.typearticle
dc.identifier.urnURN:NBN:fi:jyu-201809244215
dc.contributor.laitosFysiikan laitosfi
dc.contributor.laitosDepartment of Physicsen
dc.type.urihttp://purl.org/eprint/type/JournalArticle
dc.date.updated2018-09-24T06:15:10Z
dc.description.reviewstatuspeerReviewed
dc.relation.issn1126-6708
dc.relation.numberinseries9
dc.relation.volume2018
dc.type.versionpublishedVersion
dc.rights.copyright© CERN, for the benefit of the ALICE Collaboration. Article funded by SCOAP3.
dc.rights.accesslevelopenAccessfi
dc.subject.ysohiukkasfysiikka
dc.format.contentfulltext
jyx.subject.urihttp://www.yso.fi/onto/yso/p15576
dc.rights.urlhttps://creativecommons.org/licenses/by/4.0/
dc.relation.doi10.1007/jhep09(2018)064


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