Strange mesons in nuclear matter at finite temperature

Abstract

We study the properties of K andK mesons in nuclear matter at finite temperature from a chiral unitary approach in coupled channels that incorporates the s and p waves of the kaon-nucleon interaction. The in-medium solution accounts for Pauli blocking effects, mean-field binding on all the baryons involved, and π and kaon self-energies. We calculate K andK (off-shell) spectral functions and single-particle properties. TheK effective mass gets lowered by about −50 MeV in cold nuclear matter at saturation density and by half this reduction at T = 100 MeV. The p-wave contribution to theK optical potential, due to , , and * excitations, becomes significant for momenta larger than 200 MeV/c and reduces the attraction felt by theK in the nuclear medium. TheK spectral function spreads over a wide range of energies, reflecting the melting of the (1405) resonance and the contribution of Y N −1 components at finite temperature. In the KN sector, we find that the low-density theorem is a good approximation for the K self-energy close to saturation density due to the absence of resonance-hole excitations. The K potential shows a moderate repulsive behavior, whereas the quasiparticle peak is considerably broadened with increasing density and temperature. We discuss the implications for the decay of the φ meson at GSI Schwerionen Synchrotron energies as well as in the future Facility for Antiproton and Ion Research project.

S= −1 meson-baryon interaction in hot and dense nuclear matter: chiral symmetry, many-body and unitarization for a road to GSI/FAIR

“…Our results are complementary to the ones obtained in our previous work [11], where theK spectral function and nuclear optical potential were provided. Altogether, they permit a systematic accounting of medium effects in the S = −1 sector within transport approaches such as PHSD and IQMD, not only regarding binary reactions but also the production and propagation of light strange hadrons.…”

“…On the right panel of Fig. 4 we show the φ spectral function in hot and dense nuclear matter with K andK dressing as reported in [11] (the small mass shift obtained for the φ in [29] is neglected here). The φ is considerably broadened at the quasiparticle peak with a sizable dependence on the temperature of the medium.…”

“…The properties of strange mesons in nuclear matter at finite temperature were studied within a self-consistent coupled-channel approach based on the S U(3) meson-baryon chiral Lagrangian (see [10,11] and references therein). Such kind of approaches successfully describe theK meson interactions in nuclear matter, accounting for a shallow attractiveK potential at nuclear matter density (40-60 MeV) and a broad spectral function.…”

K* dynamics in heavy ion collisions

“…For theK * in a dense nuclear medium the major effects come both from theKπ decay channel, where theK is largely modified [3][4][5], and from the highly inelasticK * N interaction [1], leading to decay widths as large as 200 MeV at normal matter density ρ 0 . The K * interaction with the medium is much more moderate.…”

“…They can either scatter elastically or be reabsorbed. Furthermore the K/K and the π are also modified by the medium [3][4][5][6], which further distorts the signal from the initial decay reaction.…”