Article

K^-/K^+ ratio in heavy-ion collisions with an antikaon self-energy in hot and dense matter

University of Barcelona, Barcino, Catalonia, Spain
Physical Review C (Impact Factor: 3.88). 08/2003; 68(2). DOI: 10.1103/PhysRevC.68.024903
Source: OAI

ABSTRACT The K-/K+ ratio produced in heavy-ion collisions at GSI energies is studied. The in-medium properties at finite temperature of the hadrons involved are included, paying special attention to the in-medium properties of antikaons. Using a statistical approach, it is found that the determination of the temperature and chemical potential at freeze-out conditions compatible with the ratio K-/K+ is very delicate, and depends very strongly on the approximation adopted for the antikaon self-energy. The use of an energy-dependent K¯ spectral density, including both s- and p-wave components of the K¯N interaction, lowers substantially the freeze-out temperature compared to the standard simplified mean-field treatment and gives rise to an overabundance of K- production in the dense and hot medium. Even a moderately attractive antikaon-nucleus potential obtained from our self-consistent many-body calculation does reproduce the ``broadband equilibration'' advocated by Brown, Rho, and Song due to the additional strength of the spectral function of the K- at low energies.

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