TY  - THES
A1  - Wolkanowski-Gans, Thomas
T1  - Dynamical generation of hadronic resonances in effective models with derivative interactions
N2  - Light scalar mesons can be understood as dynamically generated resonances. They arise as 'companion poles' in the propagators of quark-antiquark seed states when accounting for hadronic loop contributions to the self-energies of the latter. Such a mechanism may explain the overpopulation in the scalar sector - there exist more resonances with total spin J=0 than can be described within a quark model.
Along this line, we study an effective Lagrangian approach where the isovector state a_{0}(1450) couples via both non-derivative and derivative interactions to pseudoscalar mesons. It is demonstrated that the propagator has two poles: a companion pole corresponding to a_{0}(980) and a pole of the seed state a_{0}(1450). The positions of these poles are in quantitative agreement with experimental data. Besides that, we investigate similar models for the isodoublet state K_{0}^{*}(1430) by performing a fit to pion-kaon phase shift data in the I=1/2, J=0 channel. We show that, in order to fit the data accurately, a companion pole for the K_{0}^{*}(800), that is, the light kappa resonance, is required. A large-N_{c} study confirms that both resonances below 1 GeV are predominantly four-quark states, while the heavy states are quarkonia.
Y1  - 2016
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/41414
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-414141
N1  - Zusammenfassung auf Deutsch
PB  - Univ.-Bibliothek
CY  - Frankfurt am Main
ER  -