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Author |
Tolos, L.; Molina, R.; Oset, E.; Ramos, A. |
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Title |
(K)over-bar* mesons in dense matter |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
82 |
Issue |
4 |
Pages |
045210 - 12pp |
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Keywords |
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Abstract |
We study the properties of (K) over bar* mesons in nuclear matter using a unitary approach in coupled channels within the framework of the local hidden gauge formalism and incorporating the (K) over bar pi decay channel in matter. The in-medium (K) over bar *N interaction accounts for Pauli blocking effects and incorporates the (K) over bar* self-energy in a self-consistent manner. We also obtain the (K) over bar* (off-shell) spectral function and analyze its behavior at finite density and momentum. At a normal nuclear matter density, the (K) over bar* meson feels a moderately attractive potential, while the (K) over bar* width becomes five times larger than in free space. We estimate the transparency ratio of the gamma A -> K+K*(-) A` reaction, which we propose as a feasible scenario at the present facilities to detect changes in the properties of the (K) over bar* meson in nuclear medium. |
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Address |
[Tolos, L.] Univ Groningen, Theory Grp KVI, NL-9747 AA Groningen, Netherlands, Email: tolos@kvi.nl |
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Thesis  |
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Publisher |
Amer Physical Soc |
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English |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0556-2813 |
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Expedition |
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Conference |
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Notes |
ISI:000283648400011 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
335 |
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Author |
Magas, V.K.; Yamagata-Sekihara, J.; Hirenzaki, S.; Oset, E.; Ramos, A. |
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Title |
Proton emission off nuclei induced by kaons in flight |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
81 |
Issue |
2 |
Pages |
024609 - 10pp |
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Keywords |
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Abstract |
We study the (K-, p) reaction on nuclei with a 1 GeV/c momentum kaon beam, paying special attention to the region of emitted protons having kinetic energy above 600 MeV, which was used to claim a deeply attractive kaon nucleus optical potential. Our model describes the nuclear reaction in the framework of a local density approach and the calculations are performed following two different procedures: one is based on a many-body method using the Lindhard function and the other is based on a Monte Carlo simulation. The simulation method offers flexibility to account for processes other than kaon quasielastic scattering, such as K- absorption by one and two nucleons, producing hyperons, and allows consideration of final-state interactions of the K-, the p, and all other primary and secondary particles on their way out of the nucleus, as well as the weak decay of the produced hyperons into pi N. We find a limited sensitivity of the cross section to the strength of the kaon optical potential. We also show a serious drawback in the experimental setup-the requirement for having, together with the energetic proton, at least one charged particle detected in the decay counter surrounding the target-as we find that the shape of the original cross section is appreciably distorted, to the point of invalidating the claims made in the experimental paper on the strength of the kaon nucleus optical. |
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Address |
[Magas, V. K.; Ramos, A.] Univ Barcelona, Dept Estructura & Constituents Mat, E-08028 Barcelona, Spain, Email: vladimir@ecm.ub.es |
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Publisher |
Amer Physical Soc |
Place of Publication |
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English |
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0556-2813 |
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Expedition |
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Conference |
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Notes |
ISI:000278341300014 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
432 |
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Author |
Oset, E.; Ramos, A. |
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Title |
Dynamically generated resonances from the vector octet-baryon octet interaction |
Type |
Journal Article |
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Year |
2010 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
44 |
Issue |
3 |
Pages |
445-454 |
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Keywords |
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Abstract |
We study the interaction of vector mesons with the octet of stable baryons in the framework of the local hidden gauge formalism using a coupled-channels unitary approach. We examine the scattering amplitudes and their poles, which can be associated to known J(P) = 1/2(-), 3/2(-) baryon resonances, in some cases, or give predictions in other ones. The formalism employed produces doublets of degenerate J(P) = 1/2(-), 3/2(-) states, a pattern which is observed experimentally in several cases. The findings of this work should also be useful to guide present experimental programs searching for new resonances, in particular in the strange sector where the current information is very poor. |
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Address |
[Oset, E.] Univ Valencia, Ctr Mixto, CSIC, Inst Invest Paterna,Dept Fis Teor, Valencia 46071, Spain, Email: ramos@ecm.ub.es |
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Publisher |
Springer |
Place of Publication |
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English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1434-6001 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000278159300011 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ elepoucu @ |
Serial |
447 |
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Author |
Oset, E.; Ramos, A. |
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Title |
Chiral unitary approach to eta ' N scattering at low energies |
Type |
Journal Article |
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Year |
2011 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
704 |
Issue |
4 |
Pages |
334-342 |
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Keywords |
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Abstract |
We study the eta'N interaction within a chiral unitary approach which includes pi N, eta N and related pseudoscalar meson-baryon coupled channels. Since the SU(3) singlet does not contribute to the standard interaction and the eta' is mostly a singlet, the resulting scattering amplitude is very small and inconsistent with the experimental scattering length. The additional consideration of vector meson-baryon states into the coupled channel scheme, via normal and anomalous couplings of pseudoscalar to vector mesons, enhances substantially the eta'N amplitude. We also exploit the freedom of adding to the Lagrangian a new term, allowed by the symmetries of QCD, which couples baryons to the singlet meson of SU(3). Adjusting the unknown strength to the eta'N scattering length, we obtain predictions for the elastic eta'N -> eta'N and inelastic eta'N -> eta N, pi N, K Lambda, K Sigma cross sections at low eta' energies, and discuss their significance. |
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Address |
[Ramos, A] Univ Barcelona, Dept Estruct & Constituents Mat, E-08028 Barcelona, Spain, Email: ramos@ecm.ub.es |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0370-2693 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000296175500015 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ elepoucu @ |
Serial |
783 |
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| Permanent link to this record |
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Author |
Nagahiro, H.; Hirenzaki, S.; Oset, E.; Ramos, A. |
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Title |
eta '-Nucleus optical potential and possible eta ' bound states |
Type |
Journal Article |
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Year |
2012 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
709 |
Issue |
1-2 |
Pages |
87-92 |
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Keywords |
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Abstract |
Starting from a recent model of the eta'N interaction, we evaluate the eta'-nucleus optical potential, including the contribution of lowest order in density, t rho/2m(eta'), together with the second-order terms accounting for eta' absorption by two nucleons. We also calculate the formation cross section of the eta' bound states from (pi(+), p) reactions on nuclei. The eta'-nucleus potential suffers from uncertainties tied to the poorly known eta'N interaction, which can be partially constrained by the experimental modulus of the eta'N scattering length and/or the recently measured transparency ratios in eta' nuclear photoproduction. Assuming an attractive interaction and taking the claimed experimental value vertical bar a(eta'N)vertical bar = 0.1 fm, we obtain an eta' optical potential in nuclear matter at saturation density of V eta' = -(8.7 + 1.8i) MeV, not attractive enough to produce eta' bound states in light nuclei. Larger values of the scattering length give rise to deeper optical potentials, with moderate enough imaginary parts. For a value vertical bar a(eta'N)vertical bar = 0.3 fm, which can still be considered to lie within the uncertainties of the experimental constraints, the spectra of light and medium nuclei show clear structures associated to eta'-nuclear bound states and to threshold enhancements in the unbound region. |
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Address |
[Nagahiro, H.; Hirenzaki, S.] Nara Womens Univ, Dept Phys, Nara 6308506, Japan, Email: nagahiro@rcnp.osaka-u.ac.jp |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0370-2693 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000302111200013 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
979 |
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| Permanent link to this record |
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Author |
Oset, E.; Ramos, A.; Garzon, E.J.; Molina, R.; Tolos, L.; Xiao, C.W.; Wu, J.J.; Zou, B.S. |
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Title |
Interaction of vector mesons with baryons and nuclei |
Type |
Journal Article |
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Year |
2012 |
Publication |
International Journal of Modern Physics E |
Abbreviated Journal |
Int. J. Mod. Phys. E |
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Volume |
21 |
Issue |
11 |
Pages |
1230011 - 18pp |
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Keywords |
Vector-baryon interaction; vectors in medium; J/psi suppression in nuclei |
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Abstract |
After some short introductory remarks on particular issues on the vector mesons in nuclei, in this paper, we present a short review of recent developments concerning the interaction of vector mesons with baryons and with nuclei from a modern perspective using the local hidden gauge formalism for the interaction of vector mesons. We present results for the vector-baryon interaction and in particular for the resonances which appear as composite states, dynamically generated from the interaction of vector mesons with baryons, taking also the mixing of these states with pseudoscalars and baryons into account. We then venture into the charm sector, reporting on hidden charm baryon states around 4400 MeV, generated from the interaction of vector mesons and baryons with charm, which have a strong repercussion on the properties of the J/Psi N interaction. We also address the interaction of K* with nuclei and make suggestions to measure the predicted huge width in the medium by means of transparency ratio. The formalism is extended to study the phenomenon of J/psi suppression in nuclei via J/psi photo-production reactions. |
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Address |
[Oset, E.; Garzon, E. J.; Xiao, C. W.] Univ Valencia, CSIC, Inst Invest Paterna, Dept Fis Teor, Valencia 46071, Spain, Email: oset@ific.uv.es |
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Corporate Author |
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Thesis |
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Publisher |
World Scientific Publ Co Pte Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0218-3013 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000310855800002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1204 |
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| Permanent link to this record |
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Author |
Tolos, L.; Cabrera, D.; Garcia-Recio, C.; Molina, R.; Nieves, J.; Oset, E.; Ramos, A.; Romanets, O.; Salcedo, L.L. |
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Title |
Strangeness and charm in nuclear matter |
Type |
Journal Article |
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Year |
2013 |
Publication |
Nuclear Physics A |
Abbreviated Journal |
Nucl. Phys. A |
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Volume |
914 |
Issue |
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Pages |
461-471 |
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Keywords |
Strange mesons; Transparency ratio; Dynamically-generated baryon resonances; Open charm in matter; D-mesic nuclei |
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Abstract |
The properties of strange (K, (K) over bar and (K) over bar*) and open-charm (D, (D) over bar and D*) mesons in dense matter are studied using a unitary approach in coupled channels for meson-baryon scattering. In the strangeness sector, the interaction with nucleons always comes through vector-meson exchange, which is evaluated by chiral and hidden gauge Lagrangians. For the interaction of charmed mesons with nucleons we extend the SU(3) Weinberg-Tomozawa Lagrangian to incorporate spin-flavor symmetry and implement a suitable flavor symmetry breaking. The in-medium solution for the scattering amplitude accounts for Pauli blocking effects and meson self-energies. On one hand, we obtain the K, (K) over bar and (K) over bar* spectral functions in the nuclear medium and study their behaviour at finite density, temperature and momentum. We also make an estimate of the transparency ratio of the gamma A -> K+ K*(-) A' reaction, which we propose as a tool to detect in-medium modifications of the (K) over bar* meson. On the other hand, in the charm sector, several resonances with negative parity are generated dynamically by the s-wave interaction between pseudoscalar and vector meson multiplets with 1/2(+) and 3/2(+) baryons. The properties of these states in matter are analyzed and their influence on the open-charm meson spectral functions is studied. We finally discuss the possible formation of D-mesic nuclei at FAIR energies. |
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Address |
[Tolos, Laura] Fac Ciencies, Inst Ciencias Espacio IEEC CSIC, E-08193 Bellaterra, Barcelona, Spain, Email: tolos@ice.csic.es |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0375-9474 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000324847700066 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1598 |
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| Permanent link to this record |
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Author |
Ramos, A.; Tolos, L.; Molina, R.; Oset, E. |
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Title |
The width of the omega meson in the nuclear medium |
Type |
Journal Article |
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Year |
2013 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
49 |
Issue |
11 |
Pages |
148 - 16pp |
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Keywords |
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Abstract |
We evaluate the width of the omega meson in nuclear matter. We consider the free decay mode of the omega into three pions, which is dominated by rho IEuro decay, and replace the rho and pi propagators by their medium-modified ones. We also take into account the quasielastic and inelastic processes induced by a vector-baryon interaction dominated by vector meson exchange, as well as the contributions coming from the mechanism with medium-modified K , propagators. We obtain a substantial increase of the omega width in the medium, reaching a value of 121 +/- 10 MeV at normal nuclear matter density for an omega at rest, which comes mainly from omega N -> pi pi N, omega NN -> pi NN processes associated to the dominant omega -> rho IEuro decay mode. The value of the width increases moderately with momentum, reaching values of around 200MeV at 600MeV/c. |
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Address |
[Ramos, A.] Univ Barcelona, Dept Estruct & Constituents Mat, E-08028 Barcelona, Spain, Email: ramos@ecm.ub.es |
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Corporate Author |
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Thesis |
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Publisher |
Springer |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1434-6001 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000327460400001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1654 |
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| Permanent link to this record |
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Author |
Ramos, A.; Oset, E. |
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Title |
The role of vector-baryon channels and resonances in the gamma p -> K-0 Sigma(+) and gamma n -> K-0 Sigma(0) reactions near the K*Lambda threshold |
Type |
Journal Article |
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Year |
2013 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
727 |
Issue |
1-3 |
Pages |
287-292 |
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Keywords |
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Abstract |
We have studied the gamma p -> K-0 Sigma(+) reaction in the energy region around the K*Lambda and K*Sigma thresholds, where the CBELSA/TAPS cross section shows a sudden drop and the differential cross section experiences a transition from a forward-peaked distribution to a flat one. Our coupled-channel model incorporates the dynamics of the vector meson-baryon interaction which is obtained from the hidden gauge formalism. We find that the cross section in this energy region results from a delicate interference between amplitudes having K*Lambda and K*Sigma intermediate states. The sharp downfall is dictated by the presence of a nearby N* resonance produced by our model, a feature that we have employed to predict its properties. We also show results for the complementary gamma n -> K-0 Sigma(0) reaction, the measurement of which would test the mechanism proposed in this work. |
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Address |
[Ramos, A.] Univ Barcelona, Dept Estruct & Constituents Mat, E-08028 Barcelona, Spain, Email: ramos@ecm.ub.edu |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0370-2693 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000328518400041 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
1681 |
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| Permanent link to this record |
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Author |
Oset, E.; Albaladejo, M.; Xie, J.J.; Ramos, A. |
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Title |
Recent developments on hadron interaction and dynamically generated resonances |
Type |
Journal Article |
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Year |
2014 |
Publication |
International Journal of Modern Physics E |
Abbreviated Journal |
Int. J. Mod. Phys. E |
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Volume |
23 |
Issue |
7 |
Pages |
1461008 - 8pp |
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Keywords |
Hadron interaction; dynamically generated resonances |
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Abstract |
In this talk I report on the recent developments in the subject of dynamically generated resonances. In particular I discuss the gamma p -> K-0 Sigma+ and gamma n -> K-0 Sigma(0) reactions, with a peculiar behavior around the K*(0)Lambda threshold, due to a 1/2(-) resonance around 2035 MeV. Similarly, I discuss a BES experiment, J/psi -> eta K*(0) (K) over bar*(0) decay, which provides evidence for a new h(1) resonance around 1830 MeV that was predicted from the vector-vector interaction. A short discussion is then made about recent advances in the charm and beauty sectors. |
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Address |
[Oset, E.; Albaladejo, M.; Ramos, A.] Univ Valencia, Inst Invest Paterna, Ctr Mixto, Dept Fis Teor,CSIC, Valencia 46071, Spain, Email: oset@ific.uv.es |
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Corporate Author |
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Thesis |
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Publisher |
World Scientific Publ Co Pte Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0218-3013 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000341934000009 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1946 |
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| Permanent link to this record |
