152 research outputs found
D-mesons in dense nuclear matter
The D-meson properties in dense nuclear matter are studied. The D-meson
spectral density is obtained within the framework of a coupled-channel
self-consistent calculation assuming, as bare meson-baryon interaction, a
separable potential. The resonance is generated dynamically
in our coupled-channel model. The medium modifications of the D-meson
properties due to Pauli blocking and the dressing of D-mesons, nucleons and
pions are also studied. We conclude that the self-consistent coupled-channel
process reduces the in-medium effects on the D-meson compared to previous
literature which do not considered the coupled-channel structureComment: 4 pages, 4 figures, to appear in the proceedings of Hard Probes 2004,
Ericeira, Portugal, November 4-10, 2004 (European Physical Journal C
D-mesons: In-medium effects at FAIR
The -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 resonance. The quasiparticle peak
stays close to the free -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 -mesons in
nucleus-nucleus collisions at FAIR (GSI) will be dominantly on the width and
not, as previously expected, on the mass.Comment: 18 pages, 3 figures, revised version accepted for publication in
Phys. Lett.
The properties of the D-meson in dense matter
We study the D-meson spectral density in dense matter within the framework of
a coupled-channel self-consistent calculation taking, as bare meson-baryon
interaction, a separable potential. Our coupled-channel model generates
dynamically the resonance. The medium modifications of the
D-meson properties due to Pauli blocking and the dressing of D-mesons, nucleons
and pions are also discussed. We found that the coupled-channel effects in the
self-consistent process reduce the in-medium effects on the D-meson compared to
previous works.Comment: 4 pages, 4 figures, to appear in the proceedings of Strangeness in
Quark Matter 2004 (SQM2004), Cape Town, South Africa, 15-20 September 200
Chiral approach to antikaon s- and p-wave interactions in dense nuclear matter
The properties of the antikaons in nuclear matter are investigated from a
chiral unitary approach which incorporates the s- and p-waves of the interaction. To obtain the in-medium meson-baryon amplitudes we include,
in a self-consistent way, Pauli blocking effects, meson self-energies corrected
by nuclear short-range correlations and baryon binding potentials. We pay
special attention to investigating the validity of the on-shell factorization,
showing that it cannot be applied in the evaluation of the in-medium
corrections to the p-wave amplitudes. In nuclear matter at saturation energy,
the and develop an attractive potential of about -30 MeV,
while the pole remains at the free space value although its width
gets sensibly increased to about 80 MeV. The antikaon also develops a moderate
attraction that does not support the existence of very deep and narrow bound
states, confirming the findings of previous self-consistent calculations.Comment: 29 pages, 12 figures, published in Physical Review
ratio in heavy-ion collisions at GSI with an antikaon self-energy in hot and dense matter
The 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 a 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 is very delicate, and depends very strongly on the
approximation adopted for the antikaon self-energy. The use of an energy
dependent spectral density, including both s and p-wave components of
the interaction, lowers substantially the freeze-out temperature
compared to the standard simplified mean-field treatment and gives rise to an
overabundance of 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 ``broad-band
equilibration'' advocated by Brown, Rho and Song due to the additional strength
of the spectral function of the at low energies.Comment: 20 pages, 6 figures, sent to Phys. Rev.
Finite temperature effects on the antikaon optical potential
By solving the Bethe-Goldstone equation, we have obtained the
optical potential from the effective interaction in nuclear matter
at T=0. We have extended the model by incorporating finite temperature effects
in order to adapt our calculations to the experimental conditions in heavy-ion
collisions. In the rank of densities (), the finite temperature
optical potential shows a smooth behaviour if we compare it to the
T=0 outcome. Our model has also been applied to the study of the ratio between
and produced at GSI with around 70 MeV. Our results point at
the necessity of introducing an attractive optical potential.Comment: 7 pages, 4 figures. Contribution to the proceedings of Mesons & Light
Nuclei '01 (2-6th July, Prague
meson in dense matter
We study the properties of mesons in nuclear matter using a
unitary approach in coupled channels within the framework of the local hidden
gauge formalism and incorporating the decay channel in matter. The
in-medium interaction accounts for Pauli blocking effects and
incorporates the self-energy in a self-consistent manner. We also
obtain the (off-shell) spectral function and analyze its behaviour
at finite density and momentum. At normal nuclear matter density, the meson feels a moderately attractive potential while the width
becomes five times larger than in free space. We estimate the transparency
ratio of the reaction, which we propose as
a feasible scenario at present facilities to detect the changes of the
properties of the meson in the nuclear medium.Comment: 26 pages, 9 figures, one new section added, version published in
Phys. ReV. C, http://link.aps.org/doi/10.1103/PhysRevC.82.04521
K^-/K^+ ratio at GSI in hot and dense matter
The ratio in heavy-ion collisions at GSI energies is studied
including the properties of the participating hadrons in hot and dense matter.
The determination of the temperature and chemical potential at freeze-out
conditions compatible with the ratio is very delicate, and depends on
the approach adopted for the antikaon self-energy. Three approaches for the
self-energy are considered: non-interacting , on-shell self-energy
and single-particle spectral density. With respect to the on-shell approach,
the use of an energy dependent spectral density, including both s-
and p-wave components of the interaction, lowers considerably the
freeze-out temperature and gives rise to the "broad-band equilibration"
advocated by Brown, Rho and Song.Comment: 8 pages, 5 figures, talk given at the Strange Quark Matter
Conference, Atlantic Beach, North Carolina, March 12-17, 200
Open-charm enhancement at FAIR?
We have calculated the D-meson spectral density at finite temperature within
a self-consistent coupled-channel approach that generates dynamically the
(2593) resonance. We find a small mass shift for the D-meson in
this hot and dense medium while the spectral density develops a sizeable width.
The reduced attraction felt by the D-meson in hot and dense matter together
with the large width observed have important consequences for the D-meson
production in the future CBM experiment at FAIR.Comment: 4 pages, 2 figures, to appear in the proceedings of 9th International
Conference on Strangeness in Quark Matter (SQM2006), Los Angeles, USA, March
26-31, 200
Open charm meson in nuclear matter at finite temperature beyond the zero range approximation
The properties of open charm mesons, , , and in
nuclear matter at finite temperature are studied within a self-consistent
coupled-channel approach. The interaction of the low lying pseudoscalar mesons
with the ground state baryons in the charm sector is derived from a -channel
vector-exchange model. The in-medium scattering amplitudes are obtained by
solving the Lippmann-Schwinger equation at finite temperature including Pauli
blocking effects, as well as , , and self-energies
taking their mutual influence into account. We find that the in-medium
properties of the meson are affected by the -meson self-energy through
the intermediate loops coupled to states. Similarly, dressing the
meson in the loops has an influence over the properties of
the meson.Comment: 23 pages, 9 figures, 2 table
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