669 research outputs found
The phase and pole structure of the N*(1535) in piN-->piN and gammaN-->piN
The nature of some baryonic resonances is still an unresolved issue. The case
of the N*(1535) is particularly interesting in this respect due to the nearby
etaN threshold and interference with the N*(1650). The N*(1535) has been
described as a threshold effect, as a genuine 3-quark resonance, or as
dynamically generated from the interaction of the octet of baryons with the
octet of mesons. In the scheme of dynamical generation, predictions for the
interaction of the N*(1535) with the photon can be made. In this study, we
simultaneously analyze the role of the N*(1535) in the piN-->piN and
gammaN-->piN reactions and compare to the respective amplitudes from partial
wave analyses. This test is very sensitive to the meson-baryon components of
the N*(1535).Comment: 22 pages, 16 figures; updated to revised version accepted by EPJ
Recent developments in chiral dynamics of hadrons and hadrons in nuclei
In this talk I present recent developments in the field of hadronic physics
and hadrons in the nuclear medium. I review the unitary chiral approach to
meson baryon interaction and address the topics of the two dynamically
generated resonances, with experiments testing it, the
and resonances, plus the ,
and in the nuclear medium.Comment: 9 pages, 8 figures, Talk at YKIS06 Kyoto Symposium, Kyoto, december
200
High-precision measurement of the half-life of Ga
The beta-decay half-life of 62Ga has been studied with high precision using
on-line mass separated samples. The decay of 62Ga which is dominated by a 0+ to
0+ transition to the ground state of 62Zn yields a half-life of T_{1/2} =
116.19(4) ms. This result is more precise than any previous measurement by
about a factor of four or more. The present value is in agreement with older
literature values, but slightly disagrees with a recent measurement. We
determine an error weighted average value of all experimental half-lives of
116.18(4) ms.Comment: 9 pages, 5 figures, accepted for publication in PR
Magnetization structure of a Bloch point singularity
Switching of magnetic vortex cores involves a topological transition
characterized by the presence of a magnetization singularity, a point where the
magnetization vanishes (Bloch point). We analytically derive the shape of the
Bloch point that is an extremum of the free energy with exchange, dipole and
the Landau terms for the determination of the local value of the magnetization
modulus.Comment: 4 pages, 2 figure
Assessment of pulmonary antibodies with induced sputum and bronchoalveolar lavage induced by nasal vaccination against Pseudomonas aeruginosa: a clinical phase I/II study
<p>Abstract</p> <p>Background</p> <p>Vaccination against <it>Pseudomonas aeruginosa </it>is a desirable albeit challenging strategy for prevention of airway infection in patients with cystic fibrosis. We assessed the immunogenicity of a nasal vaccine based on the outer membrane proteins F and I from <it>Pseudomonas aeruginosa </it>in the lower airways in a phase I/II clinical trial.</p> <p>Methods</p> <p>N = 12 healthy volunteers received 2 nasal vaccinations with an OprF-OprI gel as a primary and a systemic (n = 6) or a nasal booster vaccination (n = 6). Antibodies were assessed in induced sputum (IS), bronchoalveolar lavage (BAL), and in serum.</p> <p>Results</p> <p>OprF-OprI-specific IgG and IgA antibodies were found in both BAL and IS at comparable rates, but differed in the predominant isotype. IgA antibodies in IS did not correlate to the respective serum levels. Pulmonary antibodies were detectable in all vaccinees even 1 year after the vaccination. The systemic booster group had higher IgG levels in serum. However, the nasal booster group had the better long-term response with bronchial antibodies of both isotypes.</p> <p>Conclusion</p> <p>The nasal OprF-OprI-vaccine induces a lasting antibody response at both, systemic and airway mucosal site. IS is a feasible method to non-invasively assess bronchial antibodies. A further optimization of the vaccination schedule is warranted.</p
On the background in the reaction and mixed event simulation
In this paper we evaluate sources of background for the , with the detected through its decay channel, to
compare with the experiment carried out at ELSA. We find background from
followed by decay of a into two ,
recombining one and one , and from the reaction with subsequent decay of the into two photons. This
background accounts for the data at invariant masses beyond 700
MeV, but strength is missing at lower invariant masses which was attributed to
photon misidentification events, which we simulate to get a good reproduction
of the experimental background. Once this is done, we perform an event mixing
simulation to reproduce the calculated background and we find that the method
provides a good description of the background at low invariant
masses but fakes the background at high invariant masses, making background
events at low invariant masses, which are due to misidentification
events, responsible for the background at high invariant masses which is due to
the and reactions.Comment: 10 pages, 5 figure
The , interaction in finite volume and the resonance
In this work the interaction of the coupled channels and
in an SU(4) extrapolation of the chiral unitary theory, where the
resonance appears as dynamically generated from that
interaction, is extended to produce results in finite volume. Energy levels in
the finite box are evaluated and, assuming that they would correspond to
lattice results, the inverse problem of determining the phase shifts in the
infinite volume from the lattice results is solved. We observe that it is
possible to obtain accurate phase shifts and the position of the
resonance, but it requires the explicit consideration of the
two coupled channels. We also observe that some of the energy levels in the box
are attached to the closed channel, such that their use to induce the phase shifts via L\"uscher's formula leads to incorrect results.Comment: 10 pages, 13 figures, accepted for publication in Eur. Phys. J.
Photo- and Electron-Production of Mesons on Nucleons and Nuclei
In these lectures I will show some results obtained with the chiral unitary
approach applied to the photo and electroproduction of mesons. The results for
photoproduction of and , together with
related reactions will be shown, having with common denominator the excitation
of the resonance which is one of those dynamically generated in
the chiral unitary approach. Then I will show results obtained for the reaction which reproduce the bulk of the data except for a
pronounced peak, giving support to a new mesonic resonance, X(2175). Results
will also be shown for the electromagnetic form factors of the
resonance, also dynamically generated in this approach. Finally, I will show
some results on the photoproduction of the in nuclei, showing that
present experimental results claiming a shift of the mass in the
medium are tied to a particular choice of background and are not conclusive.
One the other hand, the same experimental results show unambiguously a huge
increase of the width in the nuclear medium.Comment: Lecture at the "International School of Nuclear Physics", 29th Course
Quarks in Hadrons and Nuclei, Erice, Italy, September 2007. Note added in
Proofs concerning the mixed events technique and other comments on omega
productio
Expressive and Instrumental Offending: Reconciling the Paradox of Specialisation and Versatility
Although previous research into specialisation has been dominated by the debate over the existence of specialisation versus versatility, it is suggested that research needs to move beyond the restrictions of this dispute. The current study explores the criminal careers of 200 offenders based on their criminal records, obtained from a police database in the North West of England, aiming to understand the patterns and nature of specialisation by determining the presence of differentiation within their general offending behaviours and examining whether the framework of Expressive and Instrumental offending styles can account for any specialised tendencies that emerge. Fifty-eight offences were subjected to Smallest Space Analysis. Results revealed that a model of criminal differentiation could be identified and that any specialisation is represented in terms of Expressive and Instrumental offending styles
Dynamically generated resonances
In this talk I report on recent work related to the dynamical generation of
baryonic resonances, some made up from pseudoscalar meson-baryon, others from
vector meson-baryon and a third type from two meson-one baryon systems. We can
establish a correspondence with known baryonic resonances, reinforcing
conclusions previously drawn and bringing new light on the nature of some
baryonic resonances of higher mass.Comment: Talk given at the Workshop on physics of the excited nucleon-NSTAR
2009, Beijing, april 200
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