2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 | 2014 | 2013 | 2012 | 2011 | 2010 | 2009 | 2008
Pion electro-production in the Roper region in chiral quark models
Authors: B. Golli, S. Sirca, M. Fiolhais
Ref.: The European Physical Journal A - Hadrons and Nuclei 42, 185-193 (2009)
Abstract: We present a method to calculate pion electro-production amplitudes in a coupled-channel framework incorporating quasi-bound quark-model states. The method offers a clear prescription how to extract the resonant part of the amplitudes, even in the presence of different decay channels and a strong mixing of neighbouring resonances. The method is applied to the calculation of the M1− and the S1− amplitudes in the P11 partial wave in a simple chiral quark model. A good agreement with the observed M1− amplitude is found with a significant contribution from the pion cloud. The same effect is also prominent in the S1− amplitude but a rather uncertain data prevent us to draw a definitive conclusion.
