arXiv subjects

H. Garcilazo

Publications and source records attributed to H. Garcilazo.

61 records · Page 4Linked to original sources

arXiv2001

Effect of higher orbital angular momenta in the baryon spectrum

We have performed a Faddeev calculation of the baryon spectrum for the chiral constituent quark model including higher orbital angular momentum states. We have found that the effect of these states is important, although a description of the baryon spectrum of the same quality as the one given by including only the lowest-order configurations can be obtained. We have studied the effect of the pseudoscalar quark-quark interaction on the relative position of the positive- and negative-parity excitations of the nucleon as well as the effect of varying the strength of the color-magnetic interaction.

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arXiv2000

Nonexistence of a $ηNN$ quasibound state

We have solved the Faddeev equations for $ηd$ elastic scattering using realistic separable interactions for the $NN$ and coupled $ηN$-$πN$ subsystems. We found that including explicitly the pion channel in the integral equations drastically reduces the attraction that is present in the system. As a consequence, the existence of a $ηNN$ quasibound state is excluded by the modern $ηN$ amplitude analysis.

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arXiv2000

The Reaction $pp\to ppη$ and the eta-Nucleon and Nucleon-Nucleon Interactions

The $π$, $η$ and $ρ$ exchange contributions to the cross-section for the reaction $pp\to ppη$ near threshold are calculated with a phenomenological description of the intermediate S11 (N(1535)) resonance for all exchange mechanisms. The final state interaction in the $pp$ system is described by realistic nucleon-nucleon interaction models. The sensitivity of the results to the phenomenological models for the $η$-nucleon transition amplitude and the nucleon-nucleon interaction is explored. The $η$ exchange mechanism is found to play a dominant role. The off-shell behavior of the $ηN \to ηN$ amplitude within the $η-$exchange amplitude leads to a result significantly different from that obtained with the constant scattering length approximation. The two-nucleon amplitudes that are associated with the short range components of the nucleon-nucleon interaction contribute significantly to the cross section.

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arXiv2000

eta d scattering in the region of the S11 resonance

We have studied the reaction eta d -> eta d close to threshold within a nonrelativistic three-body formalism. We considered several eta N and NN models, in particular potentials with separable form, fitted to the low-energy eta N and NN data to represent the two-body interactions. We found that with realistic two-body interactions a quasibound state does not exist in this system, although there is an enhancement of the cross section by one order of magnitude, in the region near threshold, which is a genuine three-body effect not predicted within the impulse approximation.

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arXiv1996

Mass and width of the $d'$ resonance in nuclei

We calculated the mass and width of the $d'$ resonance inside nuclei within a nucleon-$Δ$ model by including the self-energy of the $Δ$ in the $NΔ$ propagator. We found that in the nuclear medium the width of the $d'$ is increased by one order of magnitude while its mass changes only by a few MeV. This broadening of the width of the $d'$ resonance embedded in nuclei is consistent with the experimental observations so that the $d'$ can be understood as a $NΔ$ resonance. Thus, given the freedom between either isospin 0 or isospin 2 for the $d'$, our results give weigth to the isospin-2 assignment.

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arXiv1995

Quark Cluster Model Study of Isospin-Two Dibaryons

Based on a quark cluster model for the non-strange sector that reproduces reasonably well the nucleon-nucleon system and the excitation of the $Δ$ isobar, we generate a nucleon-$Δ$ interaction and present the predictions for the several isospin two channels. The only attractive channels are $0^+$ and $0^-$, but not attractive enough to generate a resonance. If a resonance is artificially generated and is required to have the observed experimental mass, then our model predicts a width that agrees with the experimental result.

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arXiv1995

Does the quark cluster model predict any isospin two dibaryon resonance?

We analyze the possible existence of a resonance in the $J^P=0^-$ channel with isospin two by means of nucleon-$Δ$ interactions based on the constituent quark model. We solve the bound state and the scattering problem using two different potentials, a local and a non-local one. The non-local potential results to be the more attractive, although not enough to generate the experimentally predicted resonance.

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