Vector meson production and nucleon resonance analysis in a coupled-channel approach for energiesmN<s<2

Abstract

We present a nucleon resonance analysis by simultaneously considering all pion-and photoninduced experimental data on the final states γN , πN , 2πN , ηN , KΛ, KΣ, and ωN for energies from the nucleon mass up to √ s = 2 GeV. In this analysis we find strong evidence for the resonances P31(1750), P13(1900), P33(1920), and D13(1950). The ωN production mechanism is dominated by large P11 (1710) and P13(1900) contributions. In this second part we present the results on the photoproduction reactions and the electromagnetic properties of the resonances. The inclusion of all important final states up to √ s = 2 GeV allows for estimates on the importance of the individual states for the GDH sum rule.

Baryons as relativistic three-quark bound states

“…2.1) by fitting to the electroproduction data. Also based on different K-matrix approximations but including a larger number of channels are for example the SAID parametrization [59,60], the KSU model [61,62], the Giessen coupled-channel approach [63][64][65][66] and the Bonn-Gatchina model [67][68][69].…”

Nuclear reactions at intermediate energies

“…The effective methods that are used to describe the dynamics of meson production reactions, include explicitly the baryon resonance states whose properties are extracted by comparing the predictions of the theory with the experimental data [9][10][11][13][14][15][16][17]. However, for a reliable realization of this goal, a model is required that can analyze different reactions over the entire energy range using a single Lagrangian density, which generates all non-resonance contributions from Born, u-and t-channel contributions without introducing new parameters.…”

“…The effective field theories where hadrons interact via exchange of hadrons, provide a viable alternative to LQCD for the description of the intermediate energy nuclear reactions (see, e.g., Refs. [5][6][7][8][9][10][11]). These theories implement the symmetries of the underlying theory, QCD, by using proper effective Lagrangians.…”

K-Λ and K-Σ photo-production in a coupled channels framework

“…[3], even the present large experimental database in a unitary coupled-channel effective Lagrangian model does not allow to uniquely fix the extracted parameters. One of the reasons for this is the necessity to include empirical formfactors in the model to regularize the matrix elements at higher energies.…”

“…A number of analyses of data on strangeness production have been performed [3,[6][7][8][9], but only few of them are based on a coupled-channel model [3]. In addition different gauge-invariance restoration prescriptions are used, which makes it difficult to compare the parameters.…”