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The D-meson spectral density at finite temperature is obtained within a self-consistent coupled-channel approach. For the bare meson-baryon interaction, a separable potential is taken, whose parameters are fixed by the position and width of the Lambda_c (2593) resonance. The quasiparticle peak stays close to the free D-meson mass, indicating a small change in the effective mass for finite density and temperature. However, the considerable width of the spectral density implies physics beyond the quasiparticle approach. Our results indicate that the medium modifications for the D-mesons in nucleus-nucleus collisions at FAIR (GSI) will be dominantly on the width and not, as previously expected, on the mass.
We study D and DS mesons at finite temperature using an effective field theory based on chiral and heavy-quark spin-flavor symmetries within the imaginary-time formalism. Interactions with the light degrees of freedom are unitarized via a Bethe-Salpeter approach, and the D and self-energies are calculated self-consistently. We generate dynamically the e D∗0(2300)and Ds(2317)state, and study their possible identification as the chiral We study Dand Dsmesons at finite temperature using an effective field theory based on chiral and heavy-quark spin-flavor symmetries within the imaginary-time formalism. Interactions with the light degrees of freedom are unitarized via a Bethe-Salpeter approach, and the Dand Dsself-energies are calculated self-consistently. We generate dynamically the D∗0(2300)and Ds(2317)states, and study their possible identification as the chiral partners of the Dand Dsground states, respectively. We show the evolution of their masses and decay widths as functions of temperature, and provide an analysis of the chiral-symmetry restoration in the heavy-flavor sector below the transition temperature. In particular, we analyse the very special case of the D-meson, for which the chiral partner is associated to the double-pole structure of the D∗0(2300).
In-medium effects in strangeness production in heavy-ion collisions at (sub-) threshold energies
(2022)
We study the in-medium effects in strangeness production in heavyion collisions at (sub-)threshold energies based on the microscopic Parton-Hadron-String Dynamics (PHSD) transport approach. The in-medium modifications of the antikaon properties are described via the self-consistent coupledchannel unitarized scheme based on a SU(3) chiral Lagrangian while the inmedium modification of kaons are accounted via the kaon-nuclear potential, which is assumed to be proportional to the local baryon density. We find that the modifications of (anti)kaon properties in nuclear matter are necessary to explain the experimental data in heavy-ion collisions.
The D-meson spectral density at finite temperature is obtained within a self-consistent coupled-channel approach. For the bare meson–baryon interaction, a separable potential is taken, whose parameters are fixed by the position and width of the Λc(2593) resonance. The quasiparticle peak stays close to the free D-meson mass, indicating a small change in the effective mass for finite density and temperature. Furthermore, the spectral density develops a considerable width due to the coupled-channel structure. Our results indicate that the medium modifications for the D-mesons in nucleus-nucleus collisions at FAIR (GSI) will be dominantly on the width and not, as previously expected, on the mass.
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, KN→Θ+, on the kaon optical potential is negligible due to the small width of the pentaquark. In contrast, the two-nucleon mechanism, KNN→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.
We obtain the D-meson spectral density at finite temperature for the conditions of density and temperature expected at FAIR. We perform a self-consistent coupled-channel calculation taking, as a bare interaction, a separable potential model. The Lambda_c (2593) resonance is generated dynamically. We observe that the D-meson spectral density develops a sizeable width while the quasiparticle peak stays close to the free position. The consequences for the D-meson production at FAIR are discussed.
We study the implications on compact star properties of a soft nuclear equation of state determined from kaon production at subthreshold energies in heavy-ion collisions. On one hand, we apply these results to study radii and moments of inertia of light neutron stars. Heavy-ion data provides constraints on nuclear matter at densities relevant for those stars and, in particular, to the density dependence of the symmetry energy of nuclear matter. On the other hand, we derive a limit for the highest allowed neutron star mass of three solar masses. For that purpouse, we use the information on the nucleon potential obtained from the analysis of the heavy-ion data combined with causality on the nuclear equation of state.
We study odd parity J=1/2 and J=3/2 Ξc resonances using a unitarized coupled-channel framework based on a SU(6)lsf×HQSS-extended Weinberg–Tomozawa baryon–meson interaction, while paying a special attention to the renormalization procedure. We predict a large molecular ΛcK¯ component for the Ξc(2790) with a dominant 0− light-degree-of-freedom spin configuration. We discuss the differences between the 3/2− Λc(2625) and Ξc(2815) states, and conclude that they cannot be SU(3) siblings, whereas we predict the existence of other Ξc-states, one of them related to the two-pole structure of the Λc(2595). It is of particular interest a pair of J=1/2 and J=3/2 poles, which form a HQSS doublet and that we tentatively assign to the Ξc(2930) and Ξc(2970), respectively. Within this picture, the Ξc(2930) would be part of a SU(3) sextet, containing either the Ωc(3090) or the Ωc(3119), and that would be completed by the Σc(2800). Moreover, we identify a J=1/2 sextet with the Ξb(6227) state and the recently discovered Σb(6097). Assuming the equal spacing rule and to complete this multiplet, we predict the existence of a J=1/2 Ωb odd parity state, with a mass of 6360 MeV and that should be seen in the ΞbK¯ channel.
We investigate the structure and formation of charmed meson–nucleus systems, with the aim of understanding the charmed meson–nucleon interactions and the properties of the charmed mesons in the nuclear medium. The D¯ mesic nuclei are of special interest, since they have tiny decay widths due to the absence of strong decays for the D N¯ pair. Employing an effective model for the D N¯ and D N interactions and solving the Klein–Gordon equation for D¯ and D in finite nuclei, we find that the D−–11B system has 1s and 2p mesic nuclear states and that the D0–11B system binds in a 1s state. In view of the forthcoming experiments by the PANDA and CBM Collaborations at the future FAIR facility and the J-PARC upgrade, we calculate the formation spectra of the [D−–11B] and [D0–11B] mesic nuclei for an antiproton beam on a 12C target. Our results suggest that it is possible to observe the 2p D− mesic nuclear state with an appropriate experimental setup.
We analyze the modifications that a dense nuclear medium induces in the 𝐷∗ 𝑠0(2317)± and 𝐷𝑠1(2460)±. In the vacuum, we consider them as isoscalar 𝐷(∗)𝐾 and 𝐷(∗)𝐾 𝑆-wave bound states, which are dynamically generated from effective interactions that lead to different Weinberg compositeness scenarios. Matter effects are incorporated through the two-meson loop functions, taking into account the self energies that the 𝐷(∗), 𝐷(∗), 𝐾, and 𝐾 develop when embedded in a nuclear medium. Although particle-antiparticle [𝐷(∗)𝑠0,𝑠1(2317, 2460)+versus 𝐷(∗)𝑠0,𝑠1(2317, 2460)−] lineshapes are the same in vacuum, we find extremely different density patterns in matter. This charge-conjugation asymmetry mainly stems from the very different kaon and antikaon interaction with the nucleons of the dense medium. We show that the in-medium lineshapes found for these resonances strongly depend on their 𝐷(∗)𝐾/𝐷(∗)𝐾 molecular content, and discuss how this novel feature can be used to better determine/constrain the inner structure of these exotic states.
