Search results for "bound state"
showing 10 items of 235 documents
Vector meson-vector meson interaction in a hidden gauge unitary approach
2008
The formalism developed recently to study vector meson-vector meson interaction, and applied to the case of rho rho, is extended to study the interaction of the nonet of vector mesons among themselves. The interaction leads to poles of the scattering matrix corresponding to bound states or resonances. We show that 11 states (either bound or resonant) get dynamically generated in nine strangeness-isospin-spin channels. Five of them can be identified with those reported in the PDG, i.e., the f(0)(1370), f(0)(1710), f(2)(1270), f(2)(')(1525), and K-2(*)(1430). The masses of the latter three tensor states have been used to fine-tune the free parameters of the unitary approach, i.e., the subtrac…
Resonances and the Weinberg-Tomozawa 56-baryon-35-meson interaction
2006
Vector meson degrees of freedom are incorporated into the Weinberg-Tomozawa (WT) meson-baryon chiral Lagrangian by using a scheme which relies on spin--flavor SU(6) symmetry. The corresponding Bethe-Salpeter approximation successfully reproduces previous SU(3)--flavor WT results for the lowest-lying s--wave negative parity baryon resonances, and it also provides some information on the dynamics of the heavier ones. Moreover, it also predicts the existence of an isoscalar spin-parity $\frac32^-$ $K^*N$ bound state (strangeness +1) with a mass around 1.7--1.8 GeV, unstable through $K^*$ decay. Neglecting d-wave KN decays, this state turns out to be quite narrow ($\Gamma \le 15$ MeV) and it mi…
Baryon states with open charm in the extended local hidden gauge approach
2014
In this paper we examine the interaction of $D N$ and $D^* N$ states, together with their coupled channels, by using an extension of the local hidden gauge formalism from the light meson sector, which is based on heavy quark spin symmetry. The scheme is based on the use of the impulse approximation at the quark level, with the heavy quarks acting as spectators, which occurs for the dominant terms where there is the exchange of a light meson. The pion exchange and the Weinberg-Tomozawa interactions are generalized and with this dynamics we look for states generated from the interaction, with a unitary coupled channels approach that mixes the pseudoscalar-baryon and vector-baryon states. We f…
An explanation of the Δ D 35 (1930) as a σΔ bound state
2009
Constituent quark models based on two-body potentials systematically overpredict the mass of ΔD35 (1930). A possible solution to this problem comes out from the application of a schematic hybrid model, containing three-quark as well as meson-baryon components, to the light-quark baryon spectrum. The ΔD35 (1930) and its partners ΔD33 (1940) and ΔD31 (1900) are found to contain a significant σΔ component. Then, through the use of the hidden gauge formalism, it is shown that these resonances can be dynamically generated from the σ-Δ interaction. In particular ΔD35 (1930) can be interpreted as being essentially a σΔ bound state. This interpretation suggests that the inclusion of σΔ as an effect…
Recent Developments in Chiral Unitary Dynamics of Resonances
2007
In this talk I summarize recent findings made on the description of axial vector mesons as dynamically generated states from the interaction of peseudoscalar mesons and vector mesons, dedicating some attention to the two $K_1(1270)$ states. Then I review the generation of open and hidden charm scalar and axial states. Finally, I present recent results showing that the low lying $1/2^+$ baryon resonances for S=-1 can be obtained as bound states or resonances of two mesons and one baryon in coupled channels dynamics.
eta nucleus optical potential in a chiral unitary approach
2002
The self-energy of an eta in a nuclear medium is calculated in a chiral unitary model, and applied to eta states in nuclei. Our calculation predicts an attractive eta nucleus optical potential which can accommodate many eta bound states in different nuclei.
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.
Baryonic Resonances from Baryon Decuplet-Meson Octet Interactions and the Exotic Resonance , ,
2005
Using the lowest order chiral Lagrangian we study s -wave interactions of the baryon decuplet with the octet of pseudoscalar mesons. We find two bound states in the flavour SU (3) limit corresponding to the octet and decuplet representations. These are found to split into eight different trajectories in the complex plane when the SU (3) symmetry is broken gradually. Finally, we are able to provide a reasonable description for a good number of 4-star 3 2 − resonances listed by the Particle Data Group. In particular, the Ξ(1820), the Λ1520) and the Σ(1670) states are well reproduced. We predict a few other resonances and also evaluate the couplings of the observed resonances to the various ch…
X(3872)→J/ψγdecay in theDD¯*molecular picture
2012
From a picture of the X(3872) where the resonance is a bound state of $\bar{D}D^*-c.c.$, we evaluate the decay width into the $J/\psi \gamma$ channel, which is sensitive to the internal structure of this state. For this purpose we evaluate the loops through which the X(3872) decays into its components, and the $J/\psi$ and the photon are radiated from these components. We use the local hidden gauge approach extrapolated to SU(4) with a particular SU(4) breaking. The radiative decay involves anomalous couplings and we obtain acceptable values which are compared to experiments and results of other calculations. Simultaneusly, we evaluate the decay rate for the X(3872) into $J/\psi \omega$ and…
Pion-Photon TDAs in the NJL Model
2008
The pion-photon Transition Distribution Amplitudes (TDAs) are studied, treating the pion as a bound state in the sense of Bethe-Salpeter, in the formalism of the NJL model. The results obtained explicitly verify support, sum rules and polynomiality conditions. The role of PCAC is highlighted.