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Title: Dielectron Production in {sup 12}C+{sup 12}C Collisions at 2A GeV with the HADES Spectrometer

Abstract

The invariant-mass spectrum of e{sup +}e{sup -} pairs produced in {sup 12}C+{sup 12}C collisions at an incident energy of 2 GeV per nucleon has been measured for the first time. The measured pair production probabilities span over 5 orders of magnitude from the {pi}{sup 0}-Dalitz to the {rho}/{omega} invariant-mass region. Dalitz decays of {pi}{sup 0} and {eta} account for all the yield up to 0.15 GeV/c{sup 2}, but for only about 50% above this mass. A comparison with model calculations shows that the excess pair yield is likely due to baryon-resonance and vector-meson decays. Transport calculations based on vacuum spectral functions fail, however, to describe the entire mass region.

Authors:
; ; ; ; ; ; ; ; ; ;  [1]; ; ; ; ; ; ; ; ;  [2]
  1. II.Physikalisches Institut, Justus Liebig Universitaet Giessen, 35392 Giessen (Germany)
  2. Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, 95125 Catania (Italy) (and others)
Publication Date:
OSTI Identifier:
20955421
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 98; Journal Issue: 5; Other Information: DOI: 10.1103/PhysRevLett.98.052302; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CARBON 12 BEAMS; CARBON 12 REACTIONS; CARBON 12 TARGET; COLLIDING BEAMS; ELECTRON-POSITRON INTERACTIONS; ELECTRONS; ETA MESONS; MASS SPECTRA; PAIR PRODUCTION; PARTICLE DECAY; PIONS NEUTRAL; POSITRONS; PROBABILITY; RESONANCE PARTICLES; SPECTRAL FUNCTIONS; SPECTROMETERS; VECTOR MESONS

Citation Formats

Agakichiev, G., Gilardi, C., Kuehn, W., Lehnert, J., Lins, E., Metag, V., Pechenov, V., Perez, T., Ritman, J., Spruck, B., Toia, A., Agodi, C., Bellia, G., Coniglione, R., Cosentino, L., Finocchiaro, P., Maiolino, C., Piattelli, P., Sapienza, P., and Vassiliev, D.. Dielectron Production in {sup 12}C+{sup 12}C Collisions at 2A GeV with the HADES Spectrometer. United States: N. p., 2007. Web. doi:10.1103/PHYSREVLETT.98.052302.
Agakichiev, G., Gilardi, C., Kuehn, W., Lehnert, J., Lins, E., Metag, V., Pechenov, V., Perez, T., Ritman, J., Spruck, B., Toia, A., Agodi, C., Bellia, G., Coniglione, R., Cosentino, L., Finocchiaro, P., Maiolino, C., Piattelli, P., Sapienza, P., & Vassiliev, D.. Dielectron Production in {sup 12}C+{sup 12}C Collisions at 2A GeV with the HADES Spectrometer. United States. doi:10.1103/PHYSREVLETT.98.052302.
Agakichiev, G., Gilardi, C., Kuehn, W., Lehnert, J., Lins, E., Metag, V., Pechenov, V., Perez, T., Ritman, J., Spruck, B., Toia, A., Agodi, C., Bellia, G., Coniglione, R., Cosentino, L., Finocchiaro, P., Maiolino, C., Piattelli, P., Sapienza, P., and Vassiliev, D.. Fri . "Dielectron Production in {sup 12}C+{sup 12}C Collisions at 2A GeV with the HADES Spectrometer". United States. doi:10.1103/PHYSREVLETT.98.052302.
@article{osti_20955421,
title = {Dielectron Production in {sup 12}C+{sup 12}C Collisions at 2A GeV with the HADES Spectrometer},
author = {Agakichiev, G. and Gilardi, C. and Kuehn, W. and Lehnert, J. and Lins, E. and Metag, V. and Pechenov, V. and Perez, T. and Ritman, J. and Spruck, B. and Toia, A. and Agodi, C. and Bellia, G. and Coniglione, R. and Cosentino, L. and Finocchiaro, P. and Maiolino, C. and Piattelli, P. and Sapienza, P. and Vassiliev, D.},
abstractNote = {The invariant-mass spectrum of e{sup +}e{sup -} pairs produced in {sup 12}C+{sup 12}C collisions at an incident energy of 2 GeV per nucleon has been measured for the first time. The measured pair production probabilities span over 5 orders of magnitude from the {pi}{sup 0}-Dalitz to the {rho}/{omega} invariant-mass region. Dalitz decays of {pi}{sup 0} and {eta} account for all the yield up to 0.15 GeV/c{sup 2}, but for only about 50% above this mass. A comparison with model calculations shows that the excess pair yield is likely due to baryon-resonance and vector-meson decays. Transport calculations based on vacuum spectral functions fail, however, to describe the entire mass region.},
doi = {10.1103/PHYSREVLETT.98.052302},
journal = {Physical Review Letters},
number = 5,
volume = 98,
place = {United States},
year = {Fri Feb 02 00:00:00 EST 2007},
month = {Fri Feb 02 00:00:00 EST 2007}
}