%0 Journal Article
%T In-Medium rho^0 Spectral Function Study via the 2H, 3He, 12C(gamma,pi+pi-) Reaction
%A G. M. Huber
%A G. J. Lolos
%A Z. Papandreou
%A A. Shinozaki
%A E. J. Brash
%A M. Iurescu
%A G. Garino
%A K. Maruyama
%A K. Maeda
%A T. Suda
%A A. Toyofuku
%A B. K. Jennings
%A A. Sasaki
%A H. Yamashita
%J Physics
%D 2003
%I arXiv
%R 10.1103/PhysRevC.68.065202
%X We report a helicity analysis of sub-threshold rho^0 production on 2H, 3He and 12C at low photo-production energies. The results are indicative of a large longitudinal rho^0 polarization (l=1, m=0) and are consistent with a strong helicity-flip production mechanism. This signature is used to extract in-medium rho^0_L invariant mass distributions for all three nuclei in a manner which is less model-dependent than previous measurements. The results are compared to kinematic and phenomenological models of the rho^0 spectral function. The 2H and 3He data distributions support the role of N*(1520) excitation in shaping the in-medium rho^0_L invariant mass distribution, while the 12C distributions are consistent with quasi-free rho^0_L production. The data support an in-medium modification of the rho^0_L invariant mass distribution.
%U http://arxiv.org/abs/nucl-ex/0310011v1