## Energy dependence of pion in-medium effects on π-/π+ ratio in heavy-ion collisions    [PDF]

Jun Xu, Lie-Wen Chen, Che Ming Ko, Bao-An Li, Yu-Gang Ma
Within the framework of a thermal model with its parameters fitted to the results from an isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) transport model, we have studied the pion in-medium effect on the charged-pion ratio in heavy-ion collisions at various energies. We find that due to the cancellation between the effects from pion-nucleon s-wave and p-wave interactions in nuclear medium, the \pi-/\pi+ ratio generally decreases after including the pion in-medium effect. The effect is larger at lower collision energies as a result of narrower pion spectral functions at lower temperatures.
View original: http://arxiv.org/abs/1305.0091