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.
|Journal||Physical review letters|
|Publication status||Published - 2007 Apr 13|
ASJC Scopus subject areas
- Physics and Astronomy(all)