Nuclear-matter modification of decay widths in the →e+e- and →k+K- Channels

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

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


The invariant mass spectra of →K+K- are measured in 12 GeV p+A reactions in order to search for the in-medium modification of mesons. The observed K+K- spectra are well reproduced by the relativistic Breit-Wigner function with a combinatorial background shape in three βγ 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 σ(A)=σ0Aα and obtain α →K+K - α →e+e- to be 0.14±0.12. Limits are obtained for the partial decay widths of the mesons in nuclear matter.

Original languageEnglish
Article number152302
JournalPhysical review letters
Issue number15
Publication statusPublished - 2007 Apr 13

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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