1. Nuclear-matter modification of decay widths in the $\phi \to e^{+}e^{-}$ and $\phi \to K^{+}K^{-}$ channels
- Author
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Sakuma, F., Chiba, J., En'yo, H., Fukao, Y., Funahashi, H., Hamagaki, H., Ieiri, M., Ishino, M., Kanda, H., Kitaguchi, M., Mihara, S., Miwa, K., Miyashita, T., Murakami, T., Muto, R., Nakura, T., Naruki, M., Ozawa, K., Sasaki, O., Sekimoto, M., Tabaru, T., Tanaka, K. H., Togawa, M., Yamada, S., Yokkaichi, S., and Yoshimura, Y.
- Subjects
Nuclear Experiment - Abstract
The invariant mass spectra of $\phi \to K^{+}K^{-}$ are measured in 12 GeV $p+A$ reactions in order to search for the in-medium modification of $\phi$ mesons. The observed $K^{+}K^{-}$ spectra are well reproduced by the relativistic Breit-Wigner function with a combinatorial background shape in three $\beta\gamma$ regions between 1.0 and 3.5. The nuclear mass-number dependence of the yields of the $K^{+}K^{-}$ decay channel is compared to the simultaneously measured $e^{+}e^{-}$ decay channel for carbon and copper targets. We parameterize the production yields as $\sigma (A) = \sigma_0 \times A^\alpha$ and obtain $\alpha_{\phi\to K^+K^-} - \alpha_{\phi\to e^+e^-}$ to be 0.14 $\pm$ 0.12. Limits are obtained for the partial decay widths of $\phi$ mesons in nuclear matter., Comment: 5 pages, 4 figures
- Published
- 2006
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