1210.1069 (E. V. Zemlyanaya et al.)

Pion-Nucleus Microscopic Optical Potential at Intermediate Energies and
In-Medium Effect on the Elementary $πN$ Scattering Amplitude    [PDF]

E. V. Zemlyanaya, V. K. Lukyanov, K. V. Lukyanov, E. I. Zhabitskaya, M. V. Zhabitsky

Analysis is performed of calculations of the elastic scattering differential cross sections of pions on the $^{28}$Si, $^{40}$Ca, $^{58}$Ni and $^{208}$Pb nuclei at energies from 130 to 290 MeV basing on the microscopic optical potential (OP) constructed as an optical limit of a Glauber theory. Such an OP is defined by the corresponding target nucleus density distribution function and by the elementary $\pi N$ amplitude of scattering. The three (say, "in-medium") parameters of the $\pi N$ scattering amplitude: total cross section, the ratio of real to imaginary part of the forward $\pi N$ amplitude, and the slope parameter, were obtained by fitting them to the data on the respective pion-nucleus cross sections calculated by means of the corresponding relativistic wave equation with the above OP. A difference is discussed between the best-fit "in-medium" parameters and the "free" parameters of the $\pi N$ scattering amplitudes known from the experimental data on scattering of pions on free nucleons.

View original: http://arxiv.org/abs/1210.1069