π+π- emission in high-energy nuclear collisions

Realistic vacuum pipi interactions are employed to investigate thermal pi(+)pi(-) emission spectra from the late stages of heavy-ion reactions at ultrarelativistic energies. Hadronic in-medium effects, including many-body rho-meson spectral functions used earlier to describe the dilepton excess observed at CERN-SPS energies, are implemented to assess resulting modifications in relation to recent measurements of pi(+)pi(-) invariant-mass spectra by the STAR Collaboration in p-p and Au-Au collisions at root(S)NN = 200 GeV. Statistical model estimates for the rho(0)/pi(-) and K*/K ratios close to the expected thermal freezeout are also given. (C) 2003 Elsevier B.V. All rights reserved.