Search results for "Few-body systems"
showing 8 items of 48 documents
Four-quark spectroscopy within the hyperspherical formalism
2006
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
2009
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
Breaking Symmetry Effects on Heavy Tetraquarks
2017
In this contribution we present symmetry arguments that can be applied to study the stability of four-quark systems with two different masses. The role played by different symmetry breaking effects and the non-Abelian algebra of color forces is discussed in detail. In the particular case of hidden-flavor all-heavy four-quark states, QQ (Q) over bar(Q) over bar, the system becomes unstable for standard color-additive models. Differences and similarities between Qq (Q) over bar(q) over bar and QQ (q) over bar(q) over bar configurations are presented. In the latter case, its stability when the mass ratio M/m increases was established almost forty years ago. In the former case, we find a kind o…
Hall–Post inequalities: Review and application to molecules and tetraquarks
2019
A review is presented of the Hall–Post inequalities that give lower-bounds to the ground-state energy of quantum systems in terms of energies of smaller systems. New applications are given for systems experiencing both a static source and inner interactions, as well as for hydrogen-like molecules and for tetraquarks in some quark models. In the latter case, the Hall–Post inequalities constrain the possibility of deeply-bound exotic mesons below the threshold for dissociation into two quark–antiquark mesons. We also emphasize the usefulness of the Hall–Post bounds in terms of 3-body energies when some 2-body subsystems are ill defined or do not support any bound state.
Microscopic description of the nucleon- Delta interaction in the quark cluster model.
1995
By using a nonrelativistic quark cluster model to describe baryonic systems, we generate a nucleon-{Delta} potential from the elementary interaction between constituents. The basic quark-quark potential used provides, when applied to the nucleon-nucleon system, an adequate description of the scattering phase shifts, the deuteron properties and the nonstrange baryonic spectroscopy. Special attention is paid to the short-range behavior of the interaction and its connection to the quark Pauli principle. This establishes a conceptual difference with meson-exchange models where the interaction, due to the lack of data, is not even well defined.
THE POSSIBLE DI-OMEGA DIBARYON IN QUARK CLUSTER MODEL
2014
The mixing of scalar mesons is introduced into the baryon-baryon system in the chiral SU(3) quark model to further dynamically investigate the Di-omega state by using the same parameters as those in reasonably describing the experimental hyperon-nucleon and nucleon-nucleon scattering data. Two different mixings of scalar mesons, the ideal mixing and 19° mixing, are discussed, and compared with no mixing. The results show that it is still deeply bound state if 19° mixing is adopted, the same as those of no mixing. However, for ideal mixing, the binding energy is reduced quite a lot, yet it is still a bound state.
Precise branching ratios to unbound 12C states from 12N and 12B β-decays
2009
6 pages, 2 tables, 4 figures.--PACS nrs.: 21.45.-v; 23.40.-s; 27.20.+n; 21.60.De.--Printed version published Aug 3, 2009
Measurement of dielectron production in central Pb-Pb collisions at √sNN = 2.76 TeV
2019
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. The first measurement of dielectron (e + e −) production in central (0 – 10 %) Pb – Pb collisions at √sNN=2.76TeV at the LHC is presented. The dielectron invariant-mass spectrum is compared to the expected contributions from hadron decays in the invariant-mass range 0 < mee < 3.5 GeV / c2. The ratio of data and the cocktail of hadronic contributions without vacuum ρ0 is measured in the invariant-mass range 0.15 < mee < 0.7 GeV / c2, w…