E+ e- -pair production in Pb-Au collisions at 158 GeV per nucleon

G. Agakichiev; H. Appelshäuser; J. Bielcikova; R. Baur; P. Braun-Munzinger; A. Cherlin; S. Damjanovic; A. Drees; S. Esumi; U. Faschingbauer; Z. Fraenkel; Ch Fuchs; E. Gatti; P. Glässel; G. Hering; C. P. De Los Heros; P. Holl; Ch Jung; B. Lenkeit; A. Marín; F. Messer; M. Messer; D. Miśkowiec; O. Nix; Yu Panebrattsev; A. Pfeiffer; J. Rak; I. Ravinovich; S. Razin; P. Rehak; M. Richter; M. Sampietro; H. Sako; N. Saveljic; W. Schmitz; J. Schukraft; W. Seipp; S. Shimanskiy; E. Socol; H. J. Specht; J. Stachel; G. Tel-Zur; I. Tserruya; T. Ullrich; C. Voigt; S. Voloshin; C. Weber; J. P. Wessels; T. Wienold; J. P. Wurm; V. Yurevich

doi:10.1140/epjc/s2005-02272-3

E⁺ e^- -pair production in Pb-Au collisions at 158 GeV per nucleon

G. Agakichiev
, H. Appelshäuser
, J. Bielcikova
, R. Baur
, P. Braun-Munzinger
, A. Cherlin
, S. Damjanovic
, A. Drees
, S. Esumi
, U. Faschingbauer
, Z. Fraenkel
, Ch Fuchs
, E. Gatti
, P. Glässel
, G. Hering
, C. P. De Los Heros
, P. Holl
, Ch Jung
, B. Lenkeit
, A. Marín

F. Messer, M. Messer, D. Miśkowiec, O. Nix, Yu Panebrattsev, A. Pfeiffer, J. Rak, I. Ravinovich, S. Razin, P. Rehak, M. Richter, M. Sampietro, H. Sako, N. Saveljic, W. Schmitz, J. Schukraft, W. Seipp, S. Shimanskiy, E. Socol, H. J. Specht, J. Stachel, G. Tel-Zur, I. Tserruya, T. Ullrich, C. Voigt, S. Voloshin, C. Weber, J. P. Wessels, T. Wienold, J. P. Wurm, V. Yurevich

Physics and Astronomy

GSI Helmholtz Centre for Heavy Ion Research
Justus Liebig University Giessen
Heidelberg University
Goethe University Frankfurt
Max Planck Institute for Nuclear Physics
Yale University
Weizmann Institute of Science
CERN
High Energy Accelerator Research Organization, Tsukuba
Polytechnic University of Milan
Uppsala University
Brookhaven National Laboratory
PNSensor GmbH
German Cancer Research Center
Joint Institute for Nuclear Research
Iowa State University
Japan Atomic Energy Agency
Tel Aviv University
Nuclear Research Center-Negev
Wayne State University
University of Münster

Research output: Contribution to journal › Article › peer-review

162 Scopus citations

Abstract

We present the combined results on electron-pair production in 158 GeV/n Pb-Au (√s=17.2GeV) collisions taken at the CERN SPS in 1995 and 1996, and give a detailed account of the data analysis. The enhancement over the reference of neutral meson decays amounts to a factor of 2.31±0.19 (stat.) ± 0.55 (syst.) ± 0.69 (decays) for semi-central collisions (28% σ/σ_geo) when yields are integrated over m > 200 MeV/c² in invariant mass. The measured yield, its stronger-than-linear scaling with N_ch, and the dominance of low pair p_t strongly suggest an interpretation as thermal radiation from pion annihilation in the hadronic fireball. The shape of the excess centring at m ≈ 500 MeV/c², however, cannot be described without strong medium modifications of the ρ meson. The results are put into perspective by comparison to predictions from Brown-Rho scaling governed by chiral symmetry restoration, and from the spectral-function many-body treatment in which the approach to the phase boundary is less explicit.

Original language	English
Pages (from-to)	475-513
Number of pages	39
Journal	European Physical Journal C
Volume	41
Issue number	4
DOIs	https://doi.org/10.1140/epjc/s2005-02272-3
State	Published - Jun 2005

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Agakichiev, G., Appelshäuser, H., Bielcikova, J., Baur, R., Braun-Munzinger, P., Cherlin, A., Damjanovic, S., Drees, A., Esumi, S., Faschingbauer, U., Fraenkel, Z., Fuchs, C., Gatti, E., Glässel, P., Hering, G., De Los Heros, C. P., Holl, P., Jung, C., Lenkeit, B., ... Yurevich, V. (2005). E⁺ e^- -pair production in Pb-Au collisions at 158 GeV per nucleon. European Physical Journal C, 41(4), 475-513. https://doi.org/10.1140/epjc/s2005-02272-3

@article{6d3b51eb9f0b45acab66d2f07683f774,

title = "E+ e- -pair production in Pb-Au collisions at 158 GeV per nucleon",

abstract = "We present the combined results on electron-pair production in 158 GeV/n Pb-Au (√s=17.2GeV) collisions taken at the CERN SPS in 1995 and 1996, and give a detailed account of the data analysis. The enhancement over the reference of neutral meson decays amounts to a factor of 2.31±0.19 (stat.) ± 0.55 (syst.) ± 0.69 (decays) for semi-central collisions (28\% σ/σgeo) when yields are integrated over m > 200 MeV/c2 in invariant mass. The measured yield, its stronger-than-linear scaling with Nch, and the dominance of low pair pt strongly suggest an interpretation as thermal radiation from pion annihilation in the hadronic fireball. The shape of the excess centring at m ≈ 500 MeV/c2, however, cannot be described without strong medium modifications of the ρ meson. The results are put into perspective by comparison to predictions from Brown-Rho scaling governed by chiral symmetry restoration, and from the spectral-function many-body treatment in which the approach to the phase boundary is less explicit.",

author = "G. Agakichiev and H. Appelsh{\"a}user and J. Bielcikova and R. Baur and P. Braun-Munzinger and A. Cherlin and S. Damjanovic and A. Drees and S. Esumi and U. Faschingbauer and Z. Fraenkel and Ch Fuchs and E. Gatti and P. Gl{\"a}ssel and G. Hering and \{De Los Heros\}, \{C. P.\} and P. Holl and Ch Jung and B. Lenkeit and A. Mar{\'i}n and F. Messer and M. Messer and D. Mi{\'s}kowiec and O. Nix and Yu Panebrattsev and A. Pfeiffer and J. Rak and I. Ravinovich and S. Razin and P. Rehak and M. Richter and M. Sampietro and H. Sako and N. Saveljic and W. Schmitz and J. Schukraft and W. Seipp and S. Shimanskiy and E. Socol and Specht, \{H. J.\} and J. Stachel and G. Tel-Zur and I. Tserruya and T. Ullrich and C. Voigt and S. Voloshin and C. Weber and Wessels, \{J. P.\} and T. Wienold and Wurm, \{J. P.\} and V. Yurevich",

year = "2005",

month = jun,

doi = "10.1140/epjc/s2005-02272-3",

language = "English",

volume = "41",

pages = "475--513",

journal = "European Physical Journal C",

issn = "1434-6044",

number = "4",

}

Agakichiev, G, Appelshäuser, H, Bielcikova, J, Baur, R, Braun-Munzinger, P, Cherlin, A, Damjanovic, S, Drees, A, Esumi, S, Faschingbauer, U, Fraenkel, Z, Fuchs, C, Gatti, E, Glässel, P, Hering, G, De Los Heros, CP, Holl, P, Jung, C, Lenkeit, B, Marín, A, Messer, F, Messer, M, Miśkowiec, D, Nix, O, Panebrattsev, Y, Pfeiffer, A, Rak, J, Ravinovich, I, Razin, S, Rehak, P, Richter, M, Sampietro, M, Sako, H, Saveljic, N, Schmitz, W, Schukraft, J, Seipp, W, Shimanskiy, S, Socol, E, Specht, HJ, Stachel, J, Tel-Zur, G, Tserruya, I, Ullrich, T, Voigt, C, Voloshin, S, Weber, C, Wessels, JP, Wienold, T, Wurm, JP & Yurevich, V 2005, 'E⁺ e^- -pair production in Pb-Au collisions at 158 GeV per nucleon', European Physical Journal C, vol. 41, no. 4, pp. 475-513. https://doi.org/10.1140/epjc/s2005-02272-3

TY - JOUR

T1 - E+ e- -pair production in Pb-Au collisions at 158 GeV per nucleon

AU - Agakichiev, G.

AU - Appelshäuser, H.

AU - Bielcikova, J.

AU - Baur, R.

AU - Braun-Munzinger, P.

AU - Cherlin, A.

AU - Damjanovic, S.

AU - Drees, A.

AU - Esumi, S.

AU - Faschingbauer, U.

AU - Fraenkel, Z.

AU - Fuchs, Ch

AU - Gatti, E.

AU - Glässel, P.

AU - Hering, G.

AU - De Los Heros, C. P.

AU - Holl, P.

AU - Jung, Ch

AU - Lenkeit, B.

AU - Marín, A.

AU - Messer, F.

AU - Messer, M.

AU - Miśkowiec, D.

AU - Nix, O.

AU - Panebrattsev, Yu

AU - Pfeiffer, A.

AU - Rak, J.

AU - Ravinovich, I.

AU - Razin, S.

AU - Rehak, P.

AU - Richter, M.

AU - Sampietro, M.

AU - Sako, H.

AU - Saveljic, N.

AU - Schmitz, W.

AU - Schukraft, J.

AU - Seipp, W.

AU - Shimanskiy, S.

AU - Socol, E.

AU - Specht, H. J.

AU - Stachel, J.

AU - Tel-Zur, G.

AU - Tserruya, I.

AU - Ullrich, T.

AU - Voigt, C.

AU - Voloshin, S.

AU - Weber, C.

AU - Wessels, J. P.

AU - Wienold, T.

AU - Wurm, J. P.

AU - Yurevich, V.

PY - 2005/6

Y1 - 2005/6

N2 - We present the combined results on electron-pair production in 158 GeV/n Pb-Au (√s=17.2GeV) collisions taken at the CERN SPS in 1995 and 1996, and give a detailed account of the data analysis. The enhancement over the reference of neutral meson decays amounts to a factor of 2.31±0.19 (stat.) ± 0.55 (syst.) ± 0.69 (decays) for semi-central collisions (28% σ/σgeo) when yields are integrated over m > 200 MeV/c2 in invariant mass. The measured yield, its stronger-than-linear scaling with Nch, and the dominance of low pair pt strongly suggest an interpretation as thermal radiation from pion annihilation in the hadronic fireball. The shape of the excess centring at m ≈ 500 MeV/c2, however, cannot be described without strong medium modifications of the ρ meson. The results are put into perspective by comparison to predictions from Brown-Rho scaling governed by chiral symmetry restoration, and from the spectral-function many-body treatment in which the approach to the phase boundary is less explicit.

AB - We present the combined results on electron-pair production in 158 GeV/n Pb-Au (√s=17.2GeV) collisions taken at the CERN SPS in 1995 and 1996, and give a detailed account of the data analysis. The enhancement over the reference of neutral meson decays amounts to a factor of 2.31±0.19 (stat.) ± 0.55 (syst.) ± 0.69 (decays) for semi-central collisions (28% σ/σgeo) when yields are integrated over m > 200 MeV/c2 in invariant mass. The measured yield, its stronger-than-linear scaling with Nch, and the dominance of low pair pt strongly suggest an interpretation as thermal radiation from pion annihilation in the hadronic fireball. The shape of the excess centring at m ≈ 500 MeV/c2, however, cannot be described without strong medium modifications of the ρ meson. The results are put into perspective by comparison to predictions from Brown-Rho scaling governed by chiral symmetry restoration, and from the spectral-function many-body treatment in which the approach to the phase boundary is less explicit.

UR - https://www.scopus.com/pages/publications/22044448319

U2 - 10.1140/epjc/s2005-02272-3

DO - 10.1140/epjc/s2005-02272-3

M3 - Article

AN - SCOPUS:22044448319

SN - 1434-6044

VL - 41

SP - 475

EP - 513

JO - European Physical Journal C

JF - European Physical Journal C

IS - 4

ER -

E⁺ e^- -pair production in Pb-Au collisions at 158 GeV per nucleon

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