Low-mass e+e- pair production in 158 A GeV Pb-Au collisions at the CERN SPS, its dependence on multiplicity and transverse momentum

被引：260

作者：

Agakichiev, G ^{[1
]}

Baur, R

Braun-Munzinger, P

Ceretto, F

Drees, A

Esumi, S

Faschingbauer, U

Fraenkel, Z

Fuchs, C

Gatti, E

Glassel, P

de los Heros, CP

Holl, P

Jung, C

Lenkeit, B

Messer, M

Panebrattsev, Y

Pfeiffer, A

Rak, J

Ravinovich, I

Razin, S

Rehak, P

Richter, M

Sampietro, M

Saveljic, N

Schukraft, J

Shimansky, S

Seipp, W

Socol, E

Specht, HJ

Stachel, J

Tel-Zur, G

Tserruya, I

Ullrich, T

Voigt, C

Weber, C

Wessels, JP

Wienold, T

Wurm, JP

Yurevich, V

机构：

[1] JINR, Dubna, Russia

[2] Univ Heidelberg, D-6900 Heidelberg, Germany

[3] GSI Darmstadt, D-6100 Darmstadt, Germany

[4] Max Planck Inst Kernphys, D-69117 Heidelberg, Germany

[5] Weizmann Inst Sci, IL-76100 Rehovot, Israel

[6] Politecn Milan, I-20133 Milan, Italy

[7] Brookhaven Natl Lab, Upton, NY 11973 USA

[8] CERN, Geneva, Switzerland

来源：

PHYSICS LETTERS B | 1998年 / 422卷 / 1-4期

关键词：

D O I：

10.1016/S0370-2693(98)00083-5

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We report a measurement of low-mass electron pairs observed in 158 GeV/nucleon Pb-Au collisions. The pair yield integrated over the range of invariant masses 0.2 less than or equal to m less than or equal to 2.0 GeV/c(2) is enhanced by a factor of 3.5 +/- 0.4 (stat) +/- 0.9 (syst) over the expectation from neutral meson decays. As observed previously in S-Au collisions, the enhancement is most pronounced in the invariant-mass region 300-700 MeV/c(2). For Pb-Au we find evidence for a strong increase of the enhancement with centrality. In addition, we show that the enhancement covers a wide range in transverse momentum, but is largest at the lowest observed p(perpendicular to). (C) 1998 Published by Elsevier Science B.V.

引用

页码：405 / 412

页数：8

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