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Daniel Cabrera

Publications and source records attributed to Daniel Cabrera.

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Strangeness and charm at FAIR

We study the properties of strange and charm mesons in hot and dense matter within a self-consistent coupled-channel approach for the experimental conditions of density and temperature expected for the CBM experiment at FAIR/GSI. The in-medium solution at finite temperature accounts for Pauli blocking effects, mean-field binding on all the baryons involved, and meson self-energies. In the strange sector, the $\bar K$ spectral function spreads over a wide range of energies, reflecting the melting of the $Λ(1405)$ resonance and the contribution of $(Λ,Σ,Σ^*)N^{-1}$ components at finite temperature. In the case of charm mesons, the dynamically-generated $Λ_c(2593)$ and $Σ_c(2880)$ resonances remain close to their free-space position while acquiring a remarkable width. As a result, the $D$ meson spectral density shows a single pronounced peak for energies close to the $D$ meson free-space mass that broadens with increasing matter density with an extended tail particularly towards lower energies. We also discuss the implications for the $D_{s0}(2317)$, $D_0(2400)$ and the predicted X(3700) resonances at FAIR energies.

hep-ph

The effect of the in-medium $Θ^+$ pentaquark on the kaon optical potential

The kaon nuclear optical potential is studied including the effect of the $Θ^+$ pentaquark. The one-nucleon contribution is obtained using an extension of the Jülich meson-exchange potential as bare kaon-nucleon interaction. Significant differences between a fully self-consistent calculation and the usually employed low-density $Tρ$ approach are observed. The influence of the one-nucleon absorption process, $K N \to Θ^+$, on the kaon optical potential is negligible due to the small width of the pentaquark. In contrast, the two-nucleon mechanism, $K N N \to Θ^+ N$, estimated from the coupling of the pentaquark to a two-meson cloud, provides the required amount of additional kaon absorption to reconcile with data the systematically low $K^+$-nucleus reaction cross sections found by the theoretical models.

hep-ph