0000000000025317
AUTHOR
N. Barnea
Docc¯nn¯bound states exist?
The four-quark system $c\overline{c}n\overline{n}$ is studied in the framework of the constituent quark model. Using different types of quark-quark potentials, we solve the four-body Schr\"odinger equation by means of the hyperspherical harmonic formalism. Exploring the low laying ${J}^{\mathrm{PC}}$ states for different isospin configurations no four-quark bound states have been found. Of particular interest is the possible four-quark structure of the $X(3872)$. We rule out the possibility that this particle is a compact tetraquark system, unless additional correlations, either in the form of diquarks or at the level of the interacting potential, not considered in simple quark models do co…
On the existence of exotic and non-exotic multiquark meson states
To obtain an exact solution of a four-body system containing two quarks and two antiquarks interacting through two-body terms is a cumbersome task that has been tackled with more or less success during the last decades. We present an exact method for the study of four-quark systems based on the hyperspherical harmonics formalism that allows us to solve it without resorting to further approximations, like for instance the existence of diquark components. We apply it to systems containing two heavy and two light quarks using different quark-quark potentials. While $QQ\bar n \bar n$ states may be stable in nature, the stability of $Q\bar Qn \bar n$ states would imply the existence of quark cor…
Are there compact heavy four-quark bound states?
6 pages, 1 figure.-- PACS nrs.: 12.39.Jh; 14.40.Lb.-- ISI Article Identifier: 000251327200050.-- ArXiv pre-print available at: http://arxiv.org/abs/0710.2516
Four-quark spectroscopy within the hyperspherical formalism
We present a generalization of the hyperspherical harmonic formalism to study systems made of quarks and antiquarks of the same flavor. This generalization is based on the symmetrization of the $N-$body wave function with respect to the symmetric group using the Barnea and Novoselsky algorithm. The formalism is applied to study four-quark systems by means of a constituent quark model successful in the description of the two- and three-quark systems. The results are compared to those obtained by means of variational approaches. Our analysis shows that four-quark systems with exotic $0^{+-}$ and non-exotic $2^{++}$ quantum numbers may be bound independently of the mass of the quark. $2^{+-}$ …
Exotic meson-meson molecules and compact four-quark states
PACS numbers: 12.39.Jh, 14.40.Lb, 21.45.-v, 31.15.xj.-- ArXiv pre-print avaible at: http://arxiv.org/abs/0903.2949v1
Hyperspherical harmonic formalism for tetraquarks
5 pages, 2 tables.-- ISI Article Identifier: 000250926800050.-- ArXiv pre-print available at: http://arxiv.org/abs/hep-ph/0610124