974 research outputs found

    Study of excited nucleon states at EBAC: status and plans

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    We present an overview of a research program for the excited nucleon states in Excited Baryon Analysis Center (EBAC) at Jefferson Lab. Current status of our analysis of the meson production reactions based on the unitary dynamical coupled-channels model is summarized, and the N* pole positions extracted from the constructed scattering amplitudes are presented. Our plans for future developments are also discussed.Comment: Plenary talk given at Workshop on the Physics of Excited Nucleon -- NSTAR2009, Beijing, April 19-22, 2009. 8 pages, 8 figure

    Recent developments in chiral dynamics of hadrons and hadrons in nuclei

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    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 Λ(1405)\Lambda(1405) resonances, with experiments testing it, the Λ(1520)\Lambda(1520) and Δ(1700)\Delta(1700) resonances, plus the Λ(1520)\Lambda(1520), Σ(1385)\Sigma(1385) and ω\omega 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 62^{62}Ga

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    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

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    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

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    <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 γpω(π0γ)p\gamma p \to \omega(\pi^0\gamma) p reaction and mixed event simulation

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    In this paper we evaluate sources of background for the γpωp\gamma p \to \omega p, with the ω\omega detected through its π0γ\pi^0 \gamma decay channel, to compare with the experiment carried out at ELSA. We find background from γpπ0π0p\gamma p \to \pi^0 \pi^0 p followed by decay of a π0\pi^0 into two γ\gamma, recombining one π0\pi^0 and one γ\gamma, and from the γpπ0ηp\gamma p \to \pi^0 \eta p reaction with subsequent decay of the η\eta into two photons. This background accounts for the data at π0γ\pi^0 \gamma 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 π0γ\pi^0 \gamma invariant masses but fakes the background at high invariant masses, making background events at low invariant masses, which are due to γ\gamma misidentification events, responsible for the background at high invariant masses which is due to the γpπ0π0p\gamma p \to \pi^0 \pi^0 p and γpπ0ηp\gamma p \to \pi^0 \eta p reactions.Comment: 10 pages, 5 figure

    Dynamically generated resonances

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    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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