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

Show full item record




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 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

Title: Dielectron production in proton-proton collisions at root s=7 TeV
Author: 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.
Contributor organization: Helsinki Institute of Physics
Date: 2018-09-12
Language: eng
Number of pages: 47
Belongs to series: Journal of High Energy Physics
ISSN: 1029-8479
DOI: https://doi.org/10.1007/JHEP09(2018)064
URI: http://hdl.handle.net/10138/298495
Abstract: The first measurement of e(+)e(-) pair production at mid-rapidity (vertical bar eta vertical bar(e) < 0.8) in pp collisions at root s = 7TeV with ALICE at the LHC is presented. The dielectron production is studied as a function of the invariant mass (m(ee )< 3.3 GeV/c(2)), 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/c(2)), 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/c(2)), 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 cc and bb 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) over bar and b (b) over bar 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.
Subject: 114 Physical sciences
Peer reviewed: Yes
Rights: cc_by
Usage restriction: openAccess
Self-archived version: publishedVersion

Files in this item

Total number of downloads: Loading...

Files Size Format View
Acharya2018_Art ... onProductionInProton_p.pdf 2.208Mb PDF View/Open

This item appears in the following Collection(s)

Show full item record