Eta-meson production in the resonance energy region

We perform an updated coupled-channel analysis of eta-meson production including all recent photoproduction data on the proton. The dip observed in the differential cross sections at c.m. energies W=1.68 GeV is explained by destructive interference between the $S_{11}(1535)$ and $S_{11}(1560)$ states. The effect from $P_{11}(1710)$ is found to be small but still important to reproduce the correct shape of the differential cross section. For the $\pi^- N \to \eta N$ scattering we suggest a reaction mechanism in terms of the $S_{11}(1535)$, $S_{11}(1560)$, and $P_{11}(1710)$ states. Our conclusion on the importance of the $S_{11}(1535)$, $S_{11}(1560)$, and $P_{11}(1710)$ resonances in the eta-production reactions is in line with our previous results. No strong indication for a narrow state with a width of 15 MeV and the mass of 1680 MeV is found in the analysis. $\eta N$ scattering length is extracted and discussed.Comment: replaced with a published version, pole parameters and scattering lengths are adde

η\eta production off the proton in a Regge-plus-chiral quark approach

A chiral constituent quark model approach, embodying s- and u-channel exchanges,complemented with a Reggeized treatment for t-channel is presented. A model is obtained allowing data for $\pi^- p \to \eta n$ and $\gamma p \to \eta p$ to be describe satisfactorily. For the latter reaction, recently released data by CLAS and CBELSA/TAPS Collaborations in the system total energy range $1.6 \lesssim W \lesssim 2.8$ GeV are well reproduced due to the inclusion of Reggeized trajectories instead of simple $\rho$ and $\omega$ poles. Contribution from "missing" resonances is found to be negligible in the considered processes.Comment: 23 pages.4 figures,4 tables, to appear in Phys.Rev.

Combined study of gamma p to eta p and pi-p to eta n in a chiral constituent quark approach

Within a chiral constituent quark model approach, $\eta$-meson production on the proton {\it via} electromagnetic and hadron probes are studied. With few parameters, differential cross-section and polarized beam asymmetry for \gamma p \to \eta p$and differential cross section for$\pi^- p\to \eta n$processes are calculated and successfully compared with the data in the center-of-mass energy range from threshold up to 2 GeV. The five known resonances$S_{11}(1535)$,$S_{11}(1650)$,$P_{13}(1720)$,$D_{13}(1520)$, and$F_{15}(1680)$are found to be dominant in the reaction mechanisms in both channels. Possible roles plaied by new resonances are also investigated and in the photoproduction channel, significant contribution from$S_{11}$- and$D_{15}$-resonances, with masses around 1715 MeV and 2090 MeV, respectively, are deduced. For the so-called missing resonances, no evidence is found within the investigated reactions. The helicity amplitudes and decay widths of$N^* \to \pi N, \eta N$ are also presented, and found consistent with the PDG values.Comment: 23 pages,5 figure

Regenbogenfamilien - Sind homosexuelle Paare Eltern zweiter Klasse?: Kurzfassung

Universität Erfurt, Kurzfassung der Bachelorarbeit, erstellt 08/201

Chiral Dynamics and the S11(1535)S_{11}(1535) Nucleon Resonance

The $SU(3)$ chiral effective lagrangian at next-to-leading order is applied to the S-wave meson-baryon interaction in the energy range around the $\eta N$ threshold. Potentials are derived from this lagrangian and used in a coupled channel calculation of the $\pi N$, $\eta N$, $K \Lambda$, $K \Sigma$ system in the isospin-$1/2$, $l=0$ partial wave. Using the same parameters as obtained from a fit to the low energy $\overline{K} N$ data it is found that a quasi-bound $K \Sigma$-state is formed, with properties remarkably similar to the $S_{11}(1535)$ nucleon resonance. In particular, we find a large partial decay width into $\eta N$ consistent with the empirical data.Comment: 9 pages, 6 postscript figures, e-mail: [email protected] ; [email protected] [email protected]

Regenbogenfamilien - Sind homosexuelle Paare Eltern zweiter Klasse?

Univ. Erfurt, Bachelorarbeit Neben dem konventionellen Familienmodell besteht in unserer heutigen Gesellschaft eine Vielzahl alternativer Familienkonzepte. Während beispielsweise Patchworkfamilien und alleinerziehende Elternteile bereits große Akzeptanz genießen, ist das Modell der Regenbogenfamilie bislang nur wenigen ein Begriff und kämpft scheinbar noch immer um seine Gleichstellung mit traditionellen Familienbildern. Regenbogenfamilien, die sich aus einem oder zwei zusammenlebenden homosexuellen Elternteilen zusammensetzen, lastet der Ruf an, für Kinder keine adäquate Familienform darzustellen, was sich allein auf der Sexualität der Eltern begründet. Im Rahmen unserer Bachelorarbeit gingen wir diesen Vorurteilen nach und führten eine qualitative Studie dazu durch

Study of \pi^{-}p \to \eta n at low energies in a chiral constituent quark model

A chiral quark model approach is extended to the study of the $\pi N$ scattering at low energies. The process of $\pi^{-}p \to \eta n$ near threshold is investigated. The model is successful in describing the differential cross sections and total cross section near the $\eta$ production threshold. The roles of the resonances in $n\leq 2$ shells are clarified. Near threshold, the $S_{11}(1535)$ dominates the reactions, while the interferences from the $S_{11}(1650)$ turn out to be destructive around $W\lesssim 1.6$ GeV. The $D_{13}(1520)$ is crucial to give correct shapes of the differential cross sections. The nucleon pole term contributions are significant. The $P_{11}(1710)$ plays an important role around the c.m. energy $W=1.7$ GeV, it is crucial to produce an enhancement in the region of $W>1.6$ GeV as suggested by the data for total cross section. The $t$-channel is negligible in the reactions.Comment: 17 pages, 5 figures. Version accepted by PRC. Some changes in the t-channel due to an error in the cod

Biopsy proven acute interstitial nephritis after treatment with moxifloxacin

<p>Abstract</p> <p>Background</p> <p>Acute interstitial nephritis (AIN) is an important cause of reversible acute kidney injury. At least 70% of AIN is caused by various drugs, mainly penicillines and non-steroidal anti-inflammatory drugs. Quinolones are only rarely known to cause AIN and so far cases have been mainly described with older fluoroquinolones.</p> <p>Case Presentation</p> <p>Here we describe a case of biopsy proven interstitial nephritis after moxifloxacin treatment. The patient presented with fever, rigors and dialysis dependent acute kidney injury, just a few days after treatment of a respiratory tract infection with moxifloxacin. The renal biopsy revealed dense infiltrates mainly composed of eosinophils and severe interstitial edema. A course of oral prednisolone (1 mg/kg/day) was commenced and rapidly tapered to zero within three weeks. The renal function improved, and the patient was discharged with a creatinine of 107 μmol/l.</p> <p>Conclusion</p> <p>This case illustrates that pharmacovigilance is important to early detect rare side effects, such as AIN, even in drugs with a favourable risk/benefit ratio such as moxifloxacin.</p

Baryon Resonance Analysis from SAID

We discuss the analysis of data from piN elastic scattering and single pion photo- and electroproduction. The main focus is a study of low-lying non-strange baryon resonances. Here we concentrate on some difficulties associated with resonance identification, in particular the Roper and higher P11 states.Comment: 4 pages, 6 figures; Nstar2009 Conf Proceedings; small revisio