0000000001024297
AUTHOR
Carmen García Recio
Large N-c Weinberg-Tomozawa interaction and negative parity s-wave baryon resonances
It is shown that in the 70 and 700 SU(6) irreducible spaces, the SU(6) extension of the Weinberg-Tomozawa (WT) s-wave meson-baryon interaction incorporating vector mesons (hep-ph/0505233) scales as O(N-c(0)), instead of the well-known O(N-c(-1)) behavior for its SU(3) counterpart. However, the WT interaction behaves as order O(N-c(-1)) within the 56 and 1134 meson-baryon spaces. Explicit expressions for the WT couplings (eigenvalues) in the irreducible SU(2N(F)) spaces, for arbitrary N-F and N-c, are given. This extended interaction is used as a kernel of the Bethe Salpeter equation, to study the large N-c scaling of masses and widths of the lowest-lying negative parity s-wave baryon resona…
Chiral Dynamics of Hadrons in Nuclei
In this talk I report on selected topics of hadron modification in the nuclear medium using the chiral unitary approach to describe the dynamics of the problems. I shall mention how antikaons, $\eta$, and $\phi$ are modified in the medium and will report upon different experiments done or planned to measure the $\phi$ width in the medium.
S=-1 meson-baryon unitarized coupled channel chiral perturbation theory and the S-01 resonances Lambda(1405) and -Lambda(1670)
The s-wave meson-baryon scattering is analyzed for the strangeness S=-1 and isospin I=0 sector in a Bethe-Salpeter coupled channel formalism incorporating chiral symmetry. Four channels have been considered: piSigma, (K) over barN, etaLambda, and KXi. The required input to solve the Bethe-Salpeter equation is taken from lowest order chiral perturbation theory in a relativistic formalism. There appear undetermined low energy constants, as a consequence of the renormalization of the amplitudes, which are obtained from fits to the piSigma-->piSigma mass spectrum, to the elastic (K) over barN-->(K) over barN and (K) over barN-->piSigma t matrices and to the K(-)p-->etaLambda cross section data.…
$K^-$-Nucleus Scattering at Low and Intermediate Energies
We calculate $K^-$-nucleus elastic differential, reaction and total cross sections for different nuclei ($^{12}$C,$^{40}$Ca and $^{208}$Pb) at several laboratory antikaon momenta, ranging from 127 MeV to 800 MeV. We use different antikaon-nucleus optical potentials, some of them fitted to kaonic atom data, and study the sensitivity of the cross sections to the considered antikaon-nucleus dynamics.
Properties of D and D-* mesons in the nuclear medium
We study the properties of D and D-* mesons in nuclear matter within a simultaneous self-consistent coupled-channel unitary approach that implements heavy-quark symmetry. The in-medium solution accounts for Pauli blocking effects and for the D and D-* self-energies in a self-consistent manner. We pay special attention to renormalization of the intermediate propagators in the medium beyond the usual cutoff scheme. We analyze the behavior in the nuclear medium of the rich spectrum of dynamically generated baryonic resonances in the C=1 and S=0 sector and their influence on the self-energy and, hence, the spectral function of D and D-* mesons. The D meson quasiparticle peak mixes with Sigma(c)…
Photon induced Lambda (1520) production and the role of the K* exchange
We study the photon induced Lambda(1520) production in the effective Lagrangian method near threshold, E_��^{LAB}<2 GeV, and in the quark-gluon string model at higher energies 3 GeV < E_��^{LAB} < 5 GeV. In particular, we study the role of the K^* exchange for the production of Lambda(1520) within the SU(6) Weinberg-Tomozowa chiral unitary model proposed in Phys. Rev. D74 (2006) 034025. The coupling of the Lambda(1520) resonance to the N \bar K^* pair, which is dynamically generated, turns out to be relatively small and, thus, the K exchange mechanism dominates the reaction. In the higher energy region, where experimental data are available, the quark-gluon string mechanism with th…
Double $\Lambda$ Hypernuclei and the Nuclear Medium Effective $\Lambda\Lambda$ Interaction
We fit the $^1 S_0 \Lambda\Lambda$ interaction in the nuclear medium to the masses of the experimentally known double-$\Lambda$ hypernuclei: $^{\phantom{6}6}_{\Lambda\Lambda}$He, $^{10}_{\Lambda\Lambda}$Be and $^{13}_{\Lambda\Lambda}$B. We derive this effective interaction from OBE J\"ulich $\Lambda\Lambda$-type potentials and using both Hartree-Fock and variational approaches. We find that the inclusion of $\Lambda\Lambda$ correlations in the variational scheme leads to significant differences and a better understanding of the dynamical features of the system. We investigate the sensitivity of the binding energies and the mesonic decay widths of the above double-$\Lambda$ hypernuclei to th…
Hidden charm N and Delta resonances with heavy-quark symmetry
A model is developed to describe odd-parity baryon resonances generated dynamically through a unitary baryon-meson coupled-channels approach. The scheme applies to channels with light- and/or heavy-quark content. Distinct features of the model are that i) the interaction is an S-wave contact one, ii) it reduces to the SU(3) Weinberg-Tomozawa Hamiltonian when light pseudoscalar mesons are involved, thus respecting chiral symmetry, iii) spin-flavor is preserved in the light-quark sector, and iv) heavy-quark spin symmetry is fulfilled in the heavy-quark sector. In particular, baryon-meson states with different content in c or in (c) over bar do not mix. The model is a minimal one and it contai…