Low-pT e+ e- pair production in Au+Au collisions at √sNN=200 GeV and U+U collisions at √sNN=193 GeV at STAR
We report first measurements of e+e− pair production in the mass region 0.4<Mee<2.6 GeV/c2 at low transverse momentum (pT<0.15 GeV/c) in noncentral Au+Au collisions at √sNN=200 GeV and U+U collisions at √sNN=193 GeV. Significant enhancement factors, expressed as ratios of data over known ha...
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| Hauptverfasser: | , , |
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| Dokumenttyp: | Article (Journal) |
| Sprache: | Englisch |
| Veröffentlicht: |
25 September 2018
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Physical review letters
Year: 2018, Jahrgang: 121, Heft: 13 |
| ISSN: | 1079-7114 |
| DOI: | 10.1103/PhysRevLett.121.132301 |
| Online-Zugang: | Verlag, Volltext: https://doi.org/10.1103/PhysRevLett.121.132301 Verlag, Volltext: https://link.aps.org/doi/10.1103/PhysRevLett.121.132301 
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| Verfasserangaben: | J. Adam, I.M. Deppner, N. Herrmann [und 347 weitere] (STAR Collaboration) |
| Zusammenfassung: | We report first measurements of e+e− pair production in the mass region 0.4<Mee<2.6 GeV/c2 at low transverse momentum (pT<0.15 GeV/c) in noncentral Au+Au collisions at √sNN=200 GeV and U+U collisions at √sNN=193 GeV. Significant enhancement factors, expressed as ratios of data over known hadronic contributions, are observed in the 40%-80% centrality of these collisions. The excess yields peak distinctly at low pT with a width (√⟨p2T⟩) between 40 and 60 MeV/c. The absolute cross section of the excess depends weakly on centrality, while those from a theoretical model calculation incorporating an in-medium broadened ρ spectral function and radiation from a quark gluon plasma or hadronic cocktail contributions increase dramatically with an increasing number of participant nucleons. Model calculations of photon-photon interactions generated by the initial projectile and target nuclei describe the observed excess yields but fail to reproduce the p2T distributions. |
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| Beschreibung: | Gesehen am 05.07.2019 Im Titel steht der Ausdruck "sNN" unter dem Wurzelsymbol, "NN" ist dabei tiefgestellt |
| Beschreibung: | Online Resource |
| ISSN: | 1079-7114 |
| DOI: | 10.1103/PhysRevLett.121.132301 |