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Author |
Oset, E.; Ramos, A. |
![goto web page (via DOI) doi](img/doi.gif)
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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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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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Elsevier Science Bv |
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English |
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ISSN |
0370-2693 |
ISBN |
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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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Author |
Nagahiro, H.; Hirenzaki, S.; Oset, E.; Ramos, A. |
![goto web page (via DOI) doi](img/doi.gif)
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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 ![sorted by Publisher field, ascending order (up)](img/sort_asc.gif) |
Elsevier Science Bv |
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English |
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0370-2693 |
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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 |
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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Publisher ![sorted by Publisher field, ascending order (up)](img/sort_asc.gif) |
Elsevier Science Bv |
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English |
Summary Language |
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Original Title |
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Abbreviated Series Title |
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ISSN |
0375-9474 |
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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.; 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 ![sorted by Publisher field, ascending order (up)](img/sort_asc.gif) |
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.; Chen, H.X.; Feijoo, A.; Geng, L.S.; Liang, W.H.; Li, D.M.; Lu, J.X.; Magas, V.K.; Nieves, J.; Ramos, A.; Roca, L.; Wang, E.; Xie, J.J. |
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Title |
Study of reactions disclosing hidden charm pentaquarks with or without strangeness |
Type |
Journal Article |
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Year |
2016 |
Publication |
Nuclear Physics A |
Abbreviated Journal |
Nucl. Phys. A |
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Volume |
954 |
Issue |
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Pages |
371-392 |
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Keywords |
Pentaquark reactions; Molecular states with hidden charm |
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Abstract |
We present results for five reactions, Lambda(b) -> J/psi K(-)p, Lambda(b) -> J/psi eta Lambda, Lambda(b) -> J/psi pi(-)p, Lambda(b) -> J/psi K-0 Lambda and Xi(-)(b) -> J/psi K-Lambda, where combining information from the meson baryon interaction, using the chiral unitary approach, and predictions made for molecular states of hidden charm, with or without strangeness, we can evaluate invariant mass distributions for the light meson baryon states, and for those of J/psi p or J/psi Lambda. We show that with the present available information, in all of these reactions one finds peaks where the pentaquark states show up. In the Lambda(b) -> J/psi K(-)p, and Lambda(b) -> J/psi pi(-)p reactions we show that the results obtained from our study are compatible with present experimental observations. |
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Address |
[Oset, Eulogio] Univ Valencia, Ctr Mixto, CSIC, Inst Invest Paterna,Dept Fis Teor, Aptdo 22085, E-46071 Valencia, Spain, Email: oset@ific.uv.es |
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Corporate Author |
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Thesis |
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Publisher ![sorted by Publisher field, ascending order (up)](img/sort_asc.gif) |
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:000381331200025 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2791 |
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Permanent link to this record |