709 research outputs found
Determining the quantum numbers through a Kaon induced reaction
We study the reaction with kinematical condition suited to
the production of the resonance. It is shown that in this reaction
with the polarization experiment, a combined consideration of the strength at
the peak and the angular dependence of cross section can help determine the
quantum numbers.Comment: 4 pages, 3 figures, Talk given at International Workshop PENTAQUARK04
at SPring-8, Japan, July 20-23, 200
A narrow quasi-bound state
The energies and widths of quasi-bound states with isospin I=1/2 are
evaluated in two methods, the fixed center approximation to the Faddeev
equation and the variational method approach to the effective one-channel
Hamiltonian. The interactions are constructed so that they dynamically
generate the (I=0, ) resonance state. We find
that the system is bound by about 250 MeV from the threshold, MeV. Its width including both the mesonic decay and the
absorption, is estimated to be about 20-40 MeV. The I=0 pair in the
system is found to form a cluster that is similar to the .Comment: 17 pages, 18 figures, 3 table
Structure of Lambda(1405) and chiral dynamics
We report on a recent theoretical work on the structure of the Lambda(1405)
resonance within a chiral unitary approach, in which the resonance is
dynamically generated in meson-baryon scattering. Studying the analytic
structure of the scattering amplitude, we have found that there are two poles
lying around energies of Lambda(1405) with different widths and couplings to
the meson-baryon states. We discuss reactions to conform the double pole
structure in experiment and elastic K^- p scattering at low energies.Comment: 4 pages, LaTeX, 2 eps figures. Talk given at 10th International
Conference on the Structure of Baryons (Baryon 2004) at Palaiseau (France),
25-29 October 200
Determining the quantum numbers through the reaction
We study the reaction with some kinematics suited to the
production of the resonance recently observed. We show that,
independently of the quantum numbers of the , a resonance signal is
always observed in the forward direction. In addition, we also show how a
combined consideration of the strength at the peak, and the angular dependence
of polarization observables can help determine the quantum numbers
using the present reaction.Comment: 21 pages, 8 figures, Version to appear in Phys. Lett.
production in the reaction
We discuss the mechanisms that lead to production in the
reaction. The problem has gained renewed interest
after different works converge to the conclusion that there are two resonances
around the region of 1400 MeV, rather than one, and that they couple
differently to the and channels. We look at the dynamics
of that reaction and find two mechanisms which eventually filter each one of
the resonances, leading to very different shapes of the invariant
mass distributions. The combination of the two mechanisms leads to a shape of
this distribution compatible with the experimental measurements.Comment: RevTeX4, 10 pages, 8 figures, 2 tables, Version to appear in Phys.
Rev.
Hadronic aspects of exotic baryons
In this talk I look into three different topics, addressing first the
possibility that the is a bound state of , exploiting the
results of this study to find out the contribution of two meson and one baryon
components in the baryon antidecuplet and in the third place I present results
on a new resonant exotic baryonic state which appears as dynamically generated
by the Weinberg Tomozawa interaction.Comment: Talk at the International Workshop PENTAQUARK0
On the determination of quantum numbers and other topics of exotic baryons
In this talk I look into three different topics, addressing first a method to
determine the quantum numbers of the , then exploiting the
possibility that the is a bound state of and in the third
place I present results on a new resonant exotic baryonic state which appears
as dynamically generated by the Weinberg Tomozawa interaction.Comment: 9 pags. Talk in the NSTAR04 Workshop, Grenoble, march 200
The nature of Lambda(1405) hyperon resonance in chiral dynamics
The nature of the Lambda(1405) is discussed based on the unitarised
coupled-channels approach with chiral dynamics (chiral unitary model). This
approach describes the Kbar N scattering cross sections and the Lambda(1405)
spectra phenomenologically very well. With this successful description of
Lambda(1405), it is found that the Lambda(1405) is composed by two resonance
states having different coupling nature to the meson-baryon states. As a
consequence, the resonance position in the pi Sigma invariant mass spectrum
depends on the initial channel of the Lambda(1405) production. To observe the
Lambda(1405) initiated by the Kbar N channel, K^- d to Lambda(1405) n is one of
the most favorable reactions. Hadronic molecule states with kaons are also
discussed by emphasizing an important role of Lambda(1405) as a quasibound
state of Kbar N.Comment: 8 pages, three figures. Talk given at 10th International Conference
on Hypernuclear and Strange Particle Physics (HYP-X), Tokai, Ibaraki, Japan,
14-18 Sep 2009
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