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Title: Dielectron production in Ar + KCl collisions at 1.76A GeV

Abstract

We present results on dielectron production in {sup 40}Ar+KCl collisions at 1.76A GeV. For the first time {omega} mesons could be reconstructed in a heavy-ion reaction at a bombarding energy which is well below the production threshold in free nucleon-nucleon collisions. The {omega} multiplicity has been extracted and compared to the yields of other particles, in particular of the {phi} meson. At intermediate e{sup +}e{sup -} invariant masses, we find a strong enhancement of the pair yield over a reference spectrum from elementary nucleon-nucleon reactions, suggesting the onset of nontrivial effects of the nuclear medium. Transverse-mass spectra and angular distributions have been reconstructed in three invariant mass bins. In the former unexpectedly large slopes are found for high-mass pairs. The latter, in particular the helicity-angle distributions, are largely consistent with expectations for a pair cocktail dominated at intermediate masses by {Delta} Dalitz decays.

Authors:
; ; ; ;  [1]; ; ; ; ; ; ; ;  [2]; ; ; ;  [3]; ; ;  [4]
  1. Joint Institute of Nuclear Research, RU-141980 Dubna (Russian Federation)
  2. Smoluchowski Institute of Physics, Jagiellonian University of Cracow, PL-30-059 Krakow (Poland)
  3. Departamento de Fisica de Particulas, Univ. de Santiago de Compostela, E-15706 Santiago de Compostela (Spain)
  4. LIP-Laboratorio de Instrumentacao e Fisica Experimental de Particulas, P-3004-516 Coimbra (Portugal)
Publication Date:
OSTI Identifier:
21596599
Resource Type:
Journal Article
Journal Name:
Physical Review. C, Nuclear Physics
Additional Journal Information:
Journal Volume: 84; Journal Issue: 1; Other Information: DOI: 10.1103/PhysRevC.84.014902; (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0556-2813
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ANGULAR DISTRIBUTION; ARGON 40; ATOM-MOLECULE COLLISIONS; COLLISIONS; DALITZ PLOT; ELECTRONS; GEV RANGE 01-10; HEAVY ION REACTIONS; HELICITY; MASS; MASS SPECTRA; MESONS; MULTIPLICITY; NUCLEAR DECAY; NUCLEON REACTIONS; NUCLEON-NUCLEON INTERACTIONS; NUCLEONS; POSITRONS; POTASSIUM CHLORIDES; ALKALI METAL COMPOUNDS; ANTILEPTONS; ANTIMATTER; ANTIPARTICLES; ARGON ISOTOPES; ATOM COLLISIONS; BARYON REACTIONS; BARYON-BARYON INTERACTIONS; BARYONS; BOSONS; CHLORIDES; CHLORINE COMPOUNDS; DECAY; DIAGRAMS; DISTRIBUTION; ELEMENTARY PARTICLES; ENERGY RANGE; EVEN-EVEN NUCLEI; FERMIONS; GEV RANGE; HADRON REACTIONS; HADRON-HADRON INTERACTIONS; HADRONS; HALIDES; HALOGEN COMPOUNDS; INFORMATION; INTERACTIONS; ISOTOPES; LEPTONS; LIGHT NUCLEI; MATTER; MOLECULE COLLISIONS; NUCLEAR REACTIONS; NUCLEI; PARTICLE INTERACTIONS; PARTICLE PROPERTIES; POTASSIUM COMPOUNDS; SCATTERPLOTS; SPECTRA; STABLE ISOTOPES

Citation Formats

Agakishiev, G., Belyaev, A., Chernenko, S., Fateev, O., Zanevsky, Y., Balanda, A., Dybczak, A., Michalska, B., Otwinowski, J., Przygoda, W., Salabura, P., Trebacz, R., Wisniowski, M., Belver, D., Cabanelas, P., Castro, E., Garzon, J. A., Blanco, A., Fonte, P., and Lopes, L. Dielectron production in Ar + KCl collisions at 1.76A GeV. United States: N. p., 2011. Web. doi:10.1103/PHYSREVC.84.014902.
Agakishiev, G., Belyaev, A., Chernenko, S., Fateev, O., Zanevsky, Y., Balanda, A., Dybczak, A., Michalska, B., Otwinowski, J., Przygoda, W., Salabura, P., Trebacz, R., Wisniowski, M., Belver, D., Cabanelas, P., Castro, E., Garzon, J. A., Blanco, A., Fonte, P., & Lopes, L. Dielectron production in Ar + KCl collisions at 1.76A GeV. United States. doi:10.1103/PHYSREVC.84.014902.
Agakishiev, G., Belyaev, A., Chernenko, S., Fateev, O., Zanevsky, Y., Balanda, A., Dybczak, A., Michalska, B., Otwinowski, J., Przygoda, W., Salabura, P., Trebacz, R., Wisniowski, M., Belver, D., Cabanelas, P., Castro, E., Garzon, J. A., Blanco, A., Fonte, P., and Lopes, L. Fri . "Dielectron production in Ar + KCl collisions at 1.76A GeV". United States. doi:10.1103/PHYSREVC.84.014902.
@article{osti_21596599,
title = {Dielectron production in Ar + KCl collisions at 1.76A GeV},
author = {Agakishiev, G. and Belyaev, A. and Chernenko, S. and Fateev, O. and Zanevsky, Y. and Balanda, A. and Dybczak, A. and Michalska, B. and Otwinowski, J. and Przygoda, W. and Salabura, P. and Trebacz, R. and Wisniowski, M. and Belver, D. and Cabanelas, P. and Castro, E. and Garzon, J. A. and Blanco, A. and Fonte, P. and Lopes, L.},
abstractNote = {We present results on dielectron production in {sup 40}Ar+KCl collisions at 1.76A GeV. For the first time {omega} mesons could be reconstructed in a heavy-ion reaction at a bombarding energy which is well below the production threshold in free nucleon-nucleon collisions. The {omega} multiplicity has been extracted and compared to the yields of other particles, in particular of the {phi} meson. At intermediate e{sup +}e{sup -} invariant masses, we find a strong enhancement of the pair yield over a reference spectrum from elementary nucleon-nucleon reactions, suggesting the onset of nontrivial effects of the nuclear medium. Transverse-mass spectra and angular distributions have been reconstructed in three invariant mass bins. In the former unexpectedly large slopes are found for high-mass pairs. The latter, in particular the helicity-angle distributions, are largely consistent with expectations for a pair cocktail dominated at intermediate masses by {Delta} Dalitz decays.},
doi = {10.1103/PHYSREVC.84.014902},
journal = {Physical Review. C, Nuclear Physics},
issn = {0556-2813},
number = 1,
volume = 84,
place = {United States},
year = {2011},
month = {7}
}