EPJ

2024 Impact factor 2.8
EPJ A - Hadrons and Nuclei
Hadrons and Nuclei
Eur. Phys. J. A 17, 83-87 (2003)
DOI: 10.1140/epja/i2002-10146-1

Probing the strange quark condensate by di-electrons from $\mth{\phi}$-meson decays in heavy-ion collisions at SIS energies

B. Kämpfer1, O.P. Pavlenko1, 2 and S. Zschocke1

1  Forschungszentrum Rossendorf, PF 510119 - 01314 Dresden, Germany
2  Institute for Theoretical Physics, 03143 Kiev - 143, Ukraine

kaempfer@fz-rossendorf.de

(Received: 22 November 2002 / Revised version: 23 January 2003 / Published online: 29 April 2003)

Abstract
QCD sum rules predict that the change of the strange quark condensate $\langle \bar s s \rangle$ in hadron matter at finite baryon density causes a shift of the peak position of the di-electron spectra from $\phi$-meson decays. Due to the expansion of hadron matter in heavy-ion collisions, the $\phi$ peak suffers a smearing governed by the interval of density in the expanding fireball, which appears as an effective broadening of the di-electron spectrum in the $\phi$ region. The emerging broadening is sensitive to the in-medium change of $\langle \bar s s \rangle$. This allows to probe directly in-medium modifications of $\langle \bar s s \rangle$ via di-electron spectra in heavy-ion collisions at SIS energies with HADES.

PACS
25.75.-q - Relativistic heavy-ion collisions.
14.60.-z - Leptons.
14.60.Cd - Electrons (including positrons).

© Società Italiana di Fisica, Springer-Verlag 2003

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