Search results for "constituent"
showing 10 items of 130 documents
Strange tribaryons
2006
We use two-body potentials derived from a constituent quark cluster model to analyze the bound-state problem of the $\Sigma NN$ system. The observables of the two-body subsystems, $NN$ and $\Sigma N$, are well reproduced. We do not find $\Sigma NN$ bound states, but there are two attractive channels with a resonance close above the three-body threshold. These channels are the $(I,J)=(1,1/2)$ and $(0,1/2)$, their quantum numbers, widths and energy ordering consistent with the recently measured strange tribaryons from the $^{4}{\rm He}(K_{{\rm stopped}}^{-},N)$ reactions in the KEK PS E471 experiment.
Quark model description of the tetraquark stateX(3872)in a relativistic constituent quark model with infrared confinement
2010
We explore the consequences of treating the $X(3872)$ meson as a tetraquark bound state. As dynamical framework we employ a relativistic constituent quark model which includes infrared confinement in an effective way. We calculate the decay widths of the observed channels $X\ensuremath{\rightarrow}J/\ensuremath{\psi}+2\ensuremath{\pi}(3\ensuremath{\pi})$ and $X\ensuremath{\rightarrow}{\overline{D}}^{0}+{D}^{0}+{\ensuremath{\pi}}^{0}$ via the intermediate off-shell states $X\ensuremath{\rightarrow}J/\ensuremath{\psi}+\ensuremath{\rho}(\ensuremath{\omega})$ and $X\ensuremath{\rightarrow}\overline{D}+{D}^{*}$. For reasonable values of the size parameter ${\ensuremath{\Lambda}}_{X}$ of the $X(3…
Tetraquarks in a chiral constituent-quark model
2003
We analyze the possibility of heavy-light tetraquark bound states by means of a chiral constituent quark model. The study is done in a variational approach. Special attention is paid to the contribution given by the different terms of the interacting potential and also to the role played by the different color channels. We find a stable state for both $qq\bar{c}\bar{c}$ and $qq\bar{b}\bar{b}$ configurations. Possible decay modes of these structures are analyzed.
The baryonic spectrum in a constituent quark model including a three-body force
1992
We analyze, within a non-relativistic quark model, the low energy part of the baryonic spectrum in the octet and decuplet flavour representations. The relevance of a strong Coulomb potential is emphasized in order to explain its general features. The addition of a three-body force allows to solve the ‘Roper puzzle’, giving a consistent explanation to its relative position in the spectrum.
Entropy development in ideal relativistic fluid dynamics with the Bag Model equation of state
2010
We consider an idealized situation where the Quark-Gluon Plasma (QGP) is described by a perfect, (3 + 1)-dimensional fluid dynamic model starting from an initial state and expanding until a final state where freeze-out and/or hadronization takes place. We study the entropy production with attention to effects of (i) numerical viscosity, (ii) late stages of flow where the Bag Constant and the partonic pressure are becoming similar, (iii) and the consequences of final freeze-out and constituent quark matter formation.
ΛNNandΣNNsystems at threshold. II. The effect ofDwaves
2007
Using the two-body interactions obtained from a chiral constituent quark model, we study allN N andN N states with I = 0, 1, 2a ndJ = 1/2, 3/2 at threshold, taking into account all three-body configurations with S and D wave components. We constrain further the limits for theN spin-triplet scattering length a1/2,1 .U sing the hypertriton binding energy, we find a narrow interval for the possible values of theN spin-singlet scattering length a1/2,0. We find that theN N system has a quasibound state in the (I,J ) = (1, 1/2) channel very near threshold with a width of about 2.1 MeV.
Quark-model hadron structure
2007
We review some selected recent results on hadron spectroscopy and related theoretical studies based on constituent quark models.
Relativistic corrections to the Drell-Hearn-Gerasimov sum rule in the constitutent quark model
1994
Relativistic corrections have been calculated for the Drell-Hearn-Gerasimov sum rule in the framework of the constituent-quark model. These corrections lead to additional absorption strength due to relativistic dipole currents in the case of a hyperfine interaction. The introduction of anomalous magnetic moments requires a subtraction of the dispersion integral at infinity. The additional effects of such anomalous moments, however, are numerically very small within the model.
Semileptonic and nonleptonic decays of B c
2007
Using our relativistic constituent quark model we present results on the exclusive nonleptonic and semileptonic decays of the B c-meson. The nonleptonic decays are studied in the framework of the factorization approximation. We calculate the branching ratios for a large set of exclusive nonleptonic and semileptonic decays of the B c meson and compare our results with the results of other models.
Radiative Decays of the P-Wave Charmed Mesons
1993
Minor (mainly numerical) corrections.