HAL : in2p3-00264862, version 1
 arXiv : 0803.0492
 Light Vector Mesons in the Nuclear Medium
 CLAS Collaboration(s)
 (2008)
 The light vector mesons ($\rho$, $\omega$, and $\phi$) were produced in deuterium, carbon, titanium, and iron targets in a search for possible in-medium modifications to the properties of the $\rho$ meson at normal nuclear densities and zero temperature. The vector mesons were detected with the CEBAF Large Acceptance Spectrometer (CLAS) via their decays to $e^{+}e^{-}$. The rare leptonic decay was chosen to reduce final-state interactions. A combinatorial background was subtracted from the invariant mass spectra using a well-established event-mixing technique. The $\rho$ meson mass spectrum was extracted after the $\omega$ and $\phi$ signals were removed in a nearly model-independent way. Comparisons were made between the $\rho$ mass spectra from the heavy targets ($A > 2$) with the mass spectrum extracted from the deuterium target. With respect to the $\rho$-meson mass, we obtain a small shift compatible with zero. Also, we measure widths consistent with standard nuclear many-body effects such as collisional broadening and Fermi motion.
 Thème(s) : Physique/Physique Nucléaire Expérimentale
 Mot(s)-clé(s) : light vector mesons – in-medium modifications – chiral symmetry
 Lien vers le texte intégral : http://fr.arXiv.org/abs/0803.0492
 in2p3-00264862, version 1 http://hal.in2p3.fr/in2p3-00264862 oai:hal.in2p3.fr:in2p3-00264862 Contributeur : Suzanne Robert <> Soumis le : Mardi 18 Mars 2008, 10:53:09 Dernière modification le : Mardi 18 Mars 2008, 11:31:57