2,010 research outputs found
On the nature of the K*2(1430), K*3(1780), K*4(2045), K*5(2380) and K*6 as K*--multi-rho states
We show that the , , ,
and a not yet discovered resonance are basically molecules made of an
increasing number of and one mesons. The idea relies on
the fact that the vector-vector interaction in s-wave with spins aligned is
very strong both for and . We extend a recent work, where
several resonances showed up as multi- molecules, to the strange
sector including the into the system. The resonant structures show
up in the multi-body scattering amplitudes, which are evaluated in terms of the
unitary two-body vector-vector scattering amplitudes by using the fixed center
approximation to the Faddeev equations
Wave functions for dynamically generated resonances; the two and
In this work we develop a formalism to evaluate wave functions in momentum
and coordinate space for the resonant states dynamically generated in a unitary
coupled channel approach. The on shell approach for the scattering matrix,
commonly used, is also obtained in Quantum Mechanics with a separable
potential, which allows one to write wave functions in a trivial way. We
develop useful relationships among the couplings of the dynamically generated
resonances to the different channels and the wave functions at the origin. The
formalism provides an intuitive picture of the resonances in the coupled
channel approach, as bound states of one bound channel, which decays into open
ones. It also provides an insight and practical rules for evaluating couplings
of the resonances to external sources and how to deal with final state
interaction in production processes. As an application of the formalism we
evaluate the wave functions of the two states in the , and other coupled channels. It also offers a practical way
to study three body systems when two of them cluster into a resonance.Comment: 5pages, 1 figure. To appear in the proceedings of the International
Workshop on Chiral Symmetry in Hadrons and Nuclei (Chiral10), Valencia,
Spain, Jun 21-24, 201
Couplings in coupled channels versus wave functions in the case of resonances: application to the two states
In this paper we develop a formalism to evaluate wave functions in momentum
and coordinate space for the resonant states dynamically generated in a unitary
coupled channel approach. The on shell approach for the scattering matrix,
commonly used, is also obtained in Quantum Mechanics with a separable
potential, which allows one to write wave functions in a trivial way. We
develop useful relationships among the couplings of the dynamically generated
resonances to the different channels and the wave functions at the origin. The
formalism provides an intuitive picture of the resonances in the coupled
channel approach, as bound states of one bound channel, which decays into open
ones. It also provides an insight and practical rules for evaluating couplings
of the resonances to external sources and how to deal with final state
interaction in production processes. As an application of the formalism we
evaluate the wave functions of the two states in the , and other coupled channels.Comment: 23 pages, 3 figures. v2: Added a section to calculate form factor
Experimental status of deeply bound kaonic states in nuclei
We review recent claims of the existence of deeply bound kaonic states in
nuclei. Also we study in details the (K-,p) reaction on C12 with 1 GeV/c
momentum kaon beam, based on which a deep kaon nucleus optical potential was
claimed in [1]. In our Monte Carlo simulation of this reaction we include not
only the quasi-elastic K- p scattering, as in [1], but also K- absorption by
one and two nucleons followed by the decay of the hyperon in pi N, which can
also produce strength in the region of interest. The final state interactions
in terms of multiple scattering of the K-, p and all other primary particles on
their way out of the nucleus is also considered. We will show that all these
additional mechanisms allow us to explain the observed spectrum with a
"standard" shallow kaon nucleus optical potential obtained in chiral models.
[1] T. Kishimoto et al., Prog. Theor. Phys. 118, 181 (2007).Comment: 5 pages, 3 figures. To be published in the Proceedings of the
International Workshop on Chiral Symmetry in Hadrons and Nuclei (Chiral10),
Valencia, Spain, June 21-24, 201
The (K-,p) reaction on nuclei with in-flight kaons
We perform a theoretical study of the spectrum of protons with kinetic
energies of around 600 MeV, emitted following the interaction of 1 GeV/c kaons
with nuclei. A recent experimental analysis of this (K-,p) reaction on 12C,
based on the dominant quasielastic process, has suggested a deeply attractive
kaon nucleus potential. Our Monte Carlo simulation considers, in addition, the
one-and two-nucleon K- absorption processes producing hyperons that decay into
\pi N pairs. We find that this kaon in-flight reaction is not well suited to
determine the kaon optical potential due, essentially, to the limited
sensitivity of the cross section to its strength, but also to unavoidable
uncertainties from the coincidence requirement applied in the experiment. A
shallow kaon nucleus optical potential obtained in chiral models is perfectly
compatible with the observed spectrum.Comment: To appear in the proceedings of the 10th International Conference on
Hypernuclear and Strange Particle Physics, Tokai, Ibaraki (Japan), 14-18
September, 200
The decay of the and resonances in the hidden gauge formalism
Using recent results obtained within the hidden gauge formalism for vector
mesons, in which the and resonances are dynamically
generated resonances from the interaction, we evaluate the
radiative decay of these resonances into . We obtain results for
the width in good agreement with the experimental data for the
state and a width about a factor five smaller for the resonance,
which would agree with preliminary results from the Belle collaboration,
hinting at an order of magnitude smaller width for this resonance than for the
.Comment: 7 pages, 9 figures, proof of gauge invariance adde
Recent topics of mesic atoms and mesic nuclei -- mesic nuclei exist ?--
We study -meson production in nuclei to investigate the in-medium
modification of the -meson spectral function at finite density. We
consider (), () and () reactions to produce a
-meson inside the nucleus and evaluate the effects of the medium
modifications to reaction cross sections. The structures of the bound states,
-mesic nuclei, are also studied. For strong absorptive interaction cases,
we need to know the spectrum shape in a wide energy region to deduce the
properties of .Comment: Talk given at EXA08, Vienna, September 2008. To be published in the
Proceedings, Hyperfine Interactions. 6 pages, 6 figure
Comment on "Localized behavior near the Zn impurity in YBa2Cu4O8 as measured by nuclear quadrupole resonance"
Williams and Kramer [Phys. Rev. B {\bf 64}, 104506 (2001)] have recently
argued against the existence of staggered magnetic moments residing on several
lattice sites around Zn impurities in YBCO superconductors. This claim, which
is in line with an earlier publication by Williams, Tallon and Dupree [Phys.
Rev. B {\bf 61}, 4319 (2000)], is however in contradiction with a large body of
experimental data from different NMR groups. On the contrary, the authors argue
in favor of a very localized spin and charge density on Cu sites first
neighbors to Zn. We show that the conclusions of Williams and Kramer arise from
erroneous interpretations of NMR and NQR data.Comment: 4 page
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