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Experimental Signature of Medium Modifications for rho and omega Mesons in the 12 GeV p + A Reactions

M. Naruki·H. Funahashi·Y. Fukao·M. Kitaguchi·M. Ishino·H. Kanda·S. Mihara·T. Miyashita·K. Miwa·T. Murakami·T. Nakura·F. Sakuma·M. Togawa·S. Yamada·Y. Yoshimura·H. En'yo·R. Muto·T. Tabaru·S. Yokkaichi·J. Chiba·M. Ieiri·O. Sasaki·M. Sekimoto·K. H. Tanaka·K. Ozawa·H. Hamagaki
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Abstract

The invariant mass spectra of e+e- pairs produced in 12-GeV proton-induced nuclear reactions are measured at the KEK Proton-Synchrotron. On the low-mass side of the omega meson peak, a significant enhancement over the known hadronic sources has been observed. The mass spectra, including the excess, are well reproduced by a model that takes into account the density dependence of the vector meson mass modification, as theoretically predicted.

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M. Naruki, H. Funahashi, Y. Fukao, M. Kitaguchi, M. Ishino, H. Kanda, S. Mihara, T. Miyashita, K. Miwa, T. Murakami, T. Nakura, F. Sakuma, M. Togawa, S. Yamada, Y. Yoshimura, H. En'yo, R. Muto, T. Tabaru, S. Yokkaichi, J. Chiba, M. Ieiri, O. Sasaki, M. Sekimoto, K. H. Tanaka, K. Ozawa, H. Hamagaki. 2006-03-15. Experimental Signature of Medium Modifications for rho and omega Mesons in the 12 GeV p + A Reactions. https://doi.org/10.1103/physrevlett.96.092301

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