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D. Hadjimichef

Publications and source records attributed to D. Hadjimichef.

33 records · Page 2Linked to original sources
arXiv2010

Light meson decay in the c3p0 model

Having its origin in a successful mapping technique, the Fock-Tani formalism, the corrected 3P0 model (C3P0) retains the basic aspects of the 3P0 predictions with the inclusion of bound-state corrections. Evaluation of the decay amplitudes has be performed for open-flavor strong decays in the light meson sector. The bound-state corrections introduce a fine-tuning for the former 3P0 model, in particular, the adjustment of the D/S ratios in $b_{1}\toωπ$, $a_{1}\toρπ$ and $h_1\toρπ$ decays.

hep-ph↗
arXiv2008

Meson decay in a corrected $3^P_0$ model

Extensively applied to both light and heavy meson decay and standing as one of the most successful strong decay models is the $3^P_0$ model, in which $q\bar{q}$ pair production is the dominant mechanism. The pair production can be obtained from the non-relativistic limit of a microscopic interaction Hamiltonian involving Dirac quark fields. The evaluation of the decay amplitude can be performed by a diagrammatic technique for drawing quark lines. In this paper we use an alternative approach which consists in a mapping technique, the Fock-Tani formalism, in order to obtain an effective Hamiltonian starting from same microscopic interaction. An additional effect is manifest in this formalism associated to the extended nature of mesons: bound-state corrections. A corrected $3^P_0$ is obtained and applied, as an example, to $b_{1}\toωπ$ and $a_{1}\toρπ$ decays.

hep-ph↗
arXiv2006

Do glueballs contribute in heavy ion collisions?

In heavy ion collision simulations many hadron states and/or parton degrees of freedom are included in order to obtain the observables. Meson spectroscopy, for example, considers the $0^{++}$ meson as a mixture of $q\bar{q}$ and glue. This fact is usually not considered in heavy ion collision physics. In the present work we consider two extreme possibilities for the constitution of the $0^{++}$ meson, either as a pure glueball or as $q\bar{q}$-meson. The scattering amplitude and cross-sections with constituent interchange are determined for the two situations. The comparison showed that the glueball-glueball elastic scattering cross-section for a color singlet state is between one to two orders of magnitude smaller than the corresponding $q\bar{q}$ state. The $2^{++}$ glueball-glueball interaction is also evaluated with similar behavior. Thus, glueball-glueball scattering is not very likely to introduce significant changes in heavy ion collision observables.

hep-ph↗
arXiv2005

Glueball decay in the Fock-Tani formalism

We investigate the two-meson decay modes for $f_0(1500)$. In this calculation we consider this resonance as a glueball. The Fock-Tani formalism is introduced to calculate the decay width.

hep-ph↗
arXiv2005

Meson decay in the Fock-Tani Formalism

The Fock-Tani formalism is a first principle method to obtain effective interactions from microscopic Hamiltonians. Usually this formalism was applied to scattering, here we introduced it to calculate partial decay widths for mesons.

hep-ph↗
arXiv2004

Glueball-glueball scattering in a constituent gluon model

In this work we use a mapping technique to derive in the context of a constituent gluon model an effective Hamiltonian that involves explicit gluon degrees of freedom. We study glueballs with two gluons using the Fock-Tani formalism. In the present work we consider two possibilities for $0^{++}$: (i) as a pure $s\bar{s}$ and calculate, in the context of a quark interchange picture, the cross-section; (ii) as a glueball where a new calculation for this cross-section is made, in the context of the constituent gluon model, with gluon interchange.

hep-ph↗
arXiv2003

Can quark effects be observed in intermediate heavy ion collisions?

In recent years a tentative description of the short-range part of hadron interactions with constituent quark interchange has been developed providing an alternative approach to meson physics. Quark interchange plays a role, for example, in the nucleon-nucleon ($NN$) phase-shifts and cross-section. In heavy ion collision simulations at intermediate energies one of the main features is the $NN$ cross-section in the collisional term, where in most cases it is an input adjusted to the free space value. In this paper we introduce the quark degrees of freedom to the $NN$ cross-section in the Vlasov-Uehling-Uhlenbeck (VUU) model and explore the possibility that these effects appear in the observables at lower energies.

nucl-th↗
arXiv2002

Heavy ion collisions at intermediate energies in a quark-gluon exchange framework

Heavy ion collisions at intermediate energies can be studied in the context of the Vlasov-Uehling-Uhlenbeck (VUU) model. One of the main features in this model is the nucleon-nucleon (NN) cross section in the collisional term. Quark interchange plays a role in the NN interaction and its effect can be observed in the cross section. We explore the possibility that quark interchange effects can appear in observables at energies lower than RHIC.

nucl-th↗
arXiv2002

Short-range repulsion and isospin dependence in the KN system

The short-range properties of the KN interaction are studied within the meson-exchange model of the Juelich group. Specifically, dynamical explanations for the phenomenological short-range repulsion, required in this model for achieving agreement with the empirical KN data, are explored. Evidence is found that contributions from the exchange of a heavy scalar-isovector meson (a_0(980)) as well as from genuine quark-gluon exchange processes are needed. Taking both mechanisms into account a satisfactory description of the KN phase shifts can be obtained without resorting to phenomenological pieces.

nucl-th↗
arXiv2000

Long- and medium-range components of the nuclear force in quark-model based calculations

Quark-model descriptions of the nucleon-nucleon interaction contain two main ingredients, a quark-exchange mechanism for the short-range repulsion and meson-exchanges for the medium- and long-range parts of the interaction. We point out the special role played by higher partial waves, and in particular the 1F3, as a very sensitive probe for the meson-exchange part employed in these interaction models. In particular, we show that the presently available models fail to provide a reasonable description of higher partial waves and indicate the reasons for this shortcoming.

nucl-th↗
arXiv1998

Bound-State Problem in a One-Dimensional Cantor-like Potential

One of the best systems for the study of quantum chaos is the atomic nucleus. A confined particle with general boundary conditions can present chaos and the eigenvalue problem can exhibit this fact. We study a toy model in which the potential has a Cantor-like form. The eigenvalue spectrum presents a Devil's staircase ordering in the semi-classical limit.

quant-ph↗
arXiv1998

Mapping of composite hadrons into elementary hadrons and effective hadronic Hamiltonians

A mapping technique is used to derive in the context of constituent quark models effective Hamiltonians that involve explicit hadron degrees of freedom. The technique is based on the ideas of mapping between physical and ideal Fock spaces and shares similarities with the quasiparticle method of Weinberg. Starting with the Fock-space representation of single-hadron states, a change of representation is implemented by a unitary transformation such that composites are redescribed by elementary Bose and Fermi field operators in an extended Fock space. When the unitary transformation is applied to the microscopic quark Hamiltonian, effective, hermitian Hamiltonians with a clear physical interpretation are obtained. Applications and comparisons with other composite-particle formalisms of the recent literature are made using the nonrelativistic quark model.

hep-ph↗
arXiv1995

Second quantization approach to composite hadron interactions in quark models

Starting from the Fock space representation of hadron bound states in a quark model, a change of representation is implemented by a unitary transformation such that the composite hadrons are redescribed by elementary-particle field operators. Application of the unitary transformation to the microscopic quark Hamiltonian gives rise to effective hadron-hadron, hadron-quark, and quark-quark Hamiltonians. An effective baryon Hamiltonian is derived using a simple quark model. The baryon Hamiltonian is free of the post-prior discrepancy which usually plagues composite-particle effective interactions.

hep-ph↗