299 research outputs found
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
Narrow Bound States of the DNN System
We report on a recent calculation of the properties of the DNN system, a charmed meson with two nucleons. The system is analogous to the system substituting a strange quark by a charm quark. Two different methods are used to evaluate the binding and width, the Fixed Center approximation to the Faddeev equations and a variational calculation. In both methods we find that the system is bound by about 200 MeV and the width is smaller than 40 MeV, a situation opposite to the one of the system and which makes this state well suited for experimental observation
Electromagnetic mean squared radii of Lambda(1405) in chiral dynamics
The electromagnetic mean squared radii, _E and _M, of Lambda(1405)
are calculated in the chiral unitary model. We describe the excited baryons as
dynamically generated resonances in the octet meson and octet baryon
scattering. We evaluate values of _E and _M for the Lambda(1405) on
the resonance pole and obtain their complex values. We also consider
Lambda(1405) obtained by neglecting decay channels. For the latter case, we
obtain negative and larger absolute electric mean squared radius than that of
typical ground state baryons. This implies that Lambda(1405) has structure that
K^- is widely spread around p.Comment: 7 pages, 4 figures, use elsart3p.cl
Signature of strange dibaryon in kaon-induced reaction
We examine how the signature of the strange-dibaryon resonances in the
barKNN-piSigmaN system shows up in the scattering amplitude on the physical
real energy axis within the framework of Alt-Grassberger-Sandhas (AGS)
equations. The so-called point method is applied to handle the three-body
unitarity cut in the amplitudes. We also discuss the possibility that the
strange-dibaryon production reactions can be used for discriminating between
existing models of the two-body barKN-piSigma system with Lambda(1405).Comment: 4 pages, 6 figures, talk given at The Fifth Asia-Pacific Conference
on Few-Body Problems in Physics 2011 (APFB2011), held in Seoul, Korea, August
22-26, 201
A search for deeply bound kaonic nuclear states
We have measured proton and neutron energy spectra by stopping negative kaons
on liquid helium4. Two distinct peak structures were found on both spectra,
which were assigned to the formation of new kinds of strange stribaryons. In
this paper, we summarize both results.Comment: 7 pages, 3 figures, HYP2003 conference proceeding
A new perspective on the Faddeev equations and the system from chiral dynamics and unitarity in coupled channels
We review recent work concerning the interaction and Faddeev
equations with chiral dynamics which allow us to look at the from a
different perspective and pay attention to problems that have been posed in
previous studies on the subject. We show results which provide extra
experimental evidence on the existence of two states. We then
show the findings of a recent approach to Faddeev equations using chiral
unitary dynamics, where an explicit cancellation of the two body off shell
amplitude with three body forces stemming from the same chiral Lagrangians
takes place. This removal of the unphysical off shell part of the amplitudes is
most welcome and renders the approach unambiguous, showing that only on shell
two body amplitudes need to be used. With this information in mind we use an
approximation to the Faddeev equations within the fixed center approximation to
study the system, providing answers within this approximation to
questions that have been brought before and evaluating binding energies and
widths of this three body system. As a novelty with respect to recent work on
the topic we find a bound state of the system with spin S=1, like a bound state
of -deuteron, less bound that the one of S=0, where all recent efforts
have been devoted. The width is relatively large in this case, suggesting
problems in a possible experimental observation.Comment: 18 pages, 7 figures, one misprint corrected, Nuclear Physics A in
pres
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
Diagnostic uncertainty of Takotusbo cardiomyopathy in a woman with cardiovascular risk factors hijacked at gunpoint: a case report
Tako-tsubo cardiomyopathy after administration of ergometrine following elective caesarean delivery: a case report
<p>Abstract</p> <p>Introduction</p> <p>Tako-tsubo cardiomyopathy (stress-induced cardiomyopathy or transient left ventricular ballooning) is characterized by clinical suspicion of an acute myocardial infarction with transient apical or midventricular dyskinesia of the left ventricle without significant coronary stenosis on angiography. The etiology of this disease remains obscure. One of the possible causes is myocardial ischemia induced by coronary vasospasm due to sympathetic activation. It has been hypothesized that the application of ergometrine could induce tako-tsubo cardiomyopathy.</p> <p>Case presentation</p> <p>We report the case of a 28-year-old Turkish woman who developed tako-tsubo cardiomyopathy after administration of ergometrine for release of placenta and prevention of bleeding during the post-partum phase in the course of an elective caesarean delivery. Tako-tsubo cardiomyopathy was diagnosed by echocardiography and urgent cardiac magnetic resonance imaging. A coronary angiography was not performed because of the absence of myocardial necrosis or ischemia and signs of myocarditis on cardiac magnetic resonance imaging.</p> <p>Conclusion</p> <p>This life-threatening disease should be excluded in the differential diagnosis by comparing the symptoms with those of typical heart failure, particularly after use of ergometrine.</p
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