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J. Vijande

Publications and source records attributed to J. Vijande.

At least 55 records · Page 3Linked to original sources
arXiv2009

Probabilities in nonorthogonal basis: Four--quark systems

Four-quark states may exist as colorless meson-meson molecules or compact systems with two-body colored components. We derive an analytical procedure to expand an arbitrary four--quark wave function in terms of nonorthogonal color singlet--singlet vectors. Using this expansion we develop the necessary formalism to evaluate the probability of physical components with an arbitrary four-quark wave function. Its application to characterize bound and unbound four--quark states as meson-meson, molecular or compact systems is discussed

hep-ph↗
arXiv2009

Dynamically generated resonances

In this talk I report on recent work related to the dynamical generation of baryonic resonances, some made up from pseudoscalar meson-baryon, others from vector meson-baryon and a third type from two meson-one baryon systems. We can establish a correspondence with known baryonic resonances, reinforcing conclusions previously drawn and bringing new light on the nature of some baryonic resonances of higher mass.

hep-ph↗
arXiv2009

The $ρ-ω$ splitting in constituent quark models

In this letter we present a solution to describe simultaneously the light isoscalar and isovector vector mesons in constituent quark models. In Ref. [1] the $q\bar q$ spectrum was studied in a generalized constituent quark model constrained by the $NN$ phenomenology and the baryon spectrum. An overall good fit to the available experimental data was obtained. A major problem of this description was the relative position of the vector $ω$ and $ρ$ mesons. The present results improve the description of the isoscalar meson spectroscopy. They should serve as a step forward in distinguishing conventional quark model mesons from exotic states.

hep-ph↗
arXiv2009

Exotic meson-meson molecules and compact four--quark states

We present an exact calculation of $S$ and $P$ wave $QQ\bar n\bar n$ states using different standard nonrelativistic quark--quark potentials. We explore in detail the charm and bottom sectors looking for bound states that could be measured within existing facilities. Against the proliferation of four--quark states sometimes predicted in the literature, we found a small number of candidates to be stable. We analyze their properties in a trial to distinguish between compact and molecular states. Possible decay modes are discussed.

hep-ph↗
arXiv2009

Screened potential and quarkonia properties at high temperatures

We perform a quark model calculation of the quarkonia $b\overline{b}$ and $c\overline{c}$ spectra using smooth and sudden string breaking potentials. The screening parameter is scale dependent and can be related to an effective running gluon mass that has a finite infrared fixed point. A temperature dependence for the screening mass is motivated by lattice QCD simulations at finite temperature. Qualitatively different results are obtained for quarkonia properties close to a critical value of the deconfining temperature when a smooth or a sudden string breaking potential is used. In particular, with a sudden string breaking potential quarkonia radii remain almost independent of the temperature up to the critical point, only well above the critical point the radii increase significantly. Such a behavior will impact the phenomenology of quarkonia interactions in medium, in particular for scattering dissociation processes.

hep-ph↗
arXiv2009

Four-quark stability

The physics of charm has become one of the best laboratories exposing the limitations of the naive constituent quark model and also giving hints into a more mature description of meson spectroscopy, beyond the simple quark--antiquark configurations. In this talk we review some recent studies of multiquark components in the charm sector and discuss in particular exotic and non-exotic four-quark systems, both with pairwise and many-body forces.

hep-ph↗
arXiv2009

A multiquark description of the $D_{sJ}(2860)$ and $D_{sJ}(2700)$

Within a theoretical framework that accounts for all open-charm mesons, including the $D_0^*(2308)$, the $D_{sJ}^*(2317)$ and the $D_{sJ}(2460)$, we analyze the structure and explore possible quantum number assignments for the $D_{sJ}(2860)$ and the $D_{sJ}(2700)$ mesons reported by BABAR and Belle Collaborations. The open-charm sector is properly described if considered as a combination of conventional quark-antiquark states and four--quark components. All negative parity and $2^+$ states can be understood in terms only of $q\bar q$ components, however the description of the $0^+$ and $1^+$ mesons is improved whenever the mixing between two-- and four--quarks configurations is included. We analyze all possible quantum number assignments for the $D_{sJ}(2860)$ in terms of both $c\bar s$ and $cn\bar s\bar n$ configurations. We discuss the role played by the electromagnetic and strong decay widths as basic tools to distinguish among them. The broad structure reported by BABAR near 2.7 GeV is also analyzed.

hep-ph↗
arXiv2008

An explanation of the $Δ_{5/2^{-}}(1930)$ as a $ρΔ$ bound state

We use the $ρΔ$ interaction in the hidden gauge formalism to dynamically generate $N^{\ast}$ and $Δ^{\ast}$ resonances. We show, through a comparison of the results from this analysis and from a quark model study with data, that the $Δ_{5/2^{-}}(1930),$ $Δ_{3/2^{-}}(1940)$ and $Δ_{1/2^{-}}(1900)$ resonances can be assigned to $ρΔ$ bound states. More precisely the $Δ_{5/2^{-}}(1930)$ can be interpreted as a $ρΔ$ bound state whereas the $Δ_{3/2^{-}}(1940)$ and $Δ_{1/2^{-}}(1900)$ may contain an important $ρΔ$ component. This interpretation allows for a solution of a long-standing puzzle concerning the description of these resonances in constituent quark models. In addition we also obtain degenerate $J^{P}=1/2^{-},3/2^{-},5/2^{-}$ $N^{*}$ states but their assignment to experimental resonances is more uncertain.

hep-ph↗
arXiv2008

A topological charge selection rule for phase singularities

We present an study of the dynamics and decay pattern of phase singularities due to the action of a system with a discrete rotational symmetry of finite order. A topological charge conservation rule is identified. The role played by the underlying symmetry is emphasized. An effective model describing the short range dynamics of the vortex clusters has been designed. A method to engineer any desired configuration of clusters of phase singularities is proposed. Its flexibility to create and control clusters of vortices is discussed.

nlin.PS↗
arXiv2008

Towards an understanding of heavy baryon spectroscopy

The recent observation at CDF and D0 of $Σ_b$, $Σ^*_b$ and $Ξ_b$ baryons opens the door to the advent of new states in the bottom baryon sector. The states measured provide sufficient constraints to fix the parameters of phenomenological models. One may therefore consistently predict the full bottom baryon spectra. For this purpose we have solved exactly the three-quark problem by means of the Faddeev method in momentum space. We consider our guidance may help experimentalists in the search for new bottom baryons and their findings will help in constraining further the phenomenological models. We identify particular states whose masses may allow to discriminate between the dynamics for the light-quark pairs predicted by different phenomenological models. Within the same framework we also present results for charmed, doubly charmed, and doubly bottom baryons. Our results provide a restricted possible assignment of quantum numbers to recently reported charmed baryon states. Some of them are perfectly described by $D-$wave excitations with $J^P=5/2^+$, as the $Λ_c (2880)$, $Ξ_c(3055)$, and $Ξ_c(3123)$.

hep-ph↗
arXiv2008

Angular Pseudomomentum Theory for the Generalized Nonlinear Schrödinger Equation in Discrete Rotational Symmetry Media

We develop a complete mathematical theory for the symmetrical solutions of the generalized nonlinear Schrödinger equation based on the new concept of angular pseudomomentum. We consider the symmetric solitons of a generalized nonlinear Schrödinger equation with a nonlinearity depending on the modulus of the field. We provide a rigorous proof of a set of mathematical results justifying that these solitons can be classified according to the irreducible representations of a discrete group. Then we extend this theory to non-stationary solutions and study the relationship between angular momentum and pseudomomentum. We illustrate these theoretical results with numerical examples. Finally, we explore the possibilities of the generalization of the previous framework to the quantum limit.

nlin.PS↗
arXiv2008

Meson-baryon threshold effects in the light-quark baryon spectrum

We argue that selected $S$ wave meson-baryon channels may play a key role to match poor baryon mass predictions from quark models with data. The identification of these channels with effective inelastic channels in data analysis allows to derive a prescription which could improve the extraction and identification of baryon resonances.

hep-ph↗
arXiv2007

Baryon spectroscopy in constituent quark models

We present a study of the baryon spectra for all flavor sectors within a constituent quark model. We address some of the outstanding problems in baryon spectroscopy, as for example the spin splitting evolution for te different flavor sectors, the flavor independence of confinement and the missing state problem.

hep-ph↗
arXiv2007

Charm Physics: Hints for a Mature Description of Hadrons

The physics of charm has become one of the best laboratories exposing the limitations of the naive constituent quark model and also giving hints into a more mature description of hadron spectroscopy. Recent discoveries are a challenge that have revolutionized our understanding of the hadron spectra. In this talk we address the study of many-quark components in charmonium spectra. To make the physics clear we also discuss exotic many-quark systems.

hep-ph↗
arXiv2007

Quark-model hadron structure

We review some selected recent results on hadron spectroscopy and related theoretical studies based on constituent quark models.

hep-ph↗