The photoproduction of vector mesons on various nuclei has been studied using the CLAS detector at Jefferson Laboratory. The vector mesons, ρ, ω, and ϕ, are observed via their decay to e+e−, in order to reduce the effects of final-state interactions in the nucleus. Of particular interest are possible in-medium effects on the properties of the ρ meson. The ρ mass spectrum is extracted from the data on various nuclei,2 H, C, Fe, and Ti. We observe no significant mass shift and some broadening consistent with expected collisional broadening for the ρ meson.
Physical Review Letters
Nasseripour, R.; Biselli, Angela; and CLAS Collaboration, "Search for Medium Modifications of the ρ Meson" (2007). Physics Faculty Publications. 65.
R. Nasseripour et al. [CLAS Collaboration],"Search for Medium Modifications of the ρ Meson", Physical Review Letters 99.26 (2007) DOI: 10.1103/PhysRevLett.99.262302