Nπ scattering in the Roper channel
Institüt für Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany
2 Institute of Physics, University of Graz, A-8010 Graz, Austria
3 Department of Physics, University of Arizona, Tucson, AZ 85721, USA
4 Faculty of Mathematics and Physics, University of Ljubljana, 1000 Ljubljana, Slovenia
5 Jozef Stefan Institute, 1000 Ljubljana, Slovenia
* Speaker e-mail: Padmanath.M@physik.uni-regensburg.de
Published online: 26 March 2018
We present results from our recent lattice QCD study of Nπ scattering in the positive-parity nucleon channel, where the puzzling Roper resonance N*(1440) resides in experiment. Using a variety of hadron operators, that include qqq-like, Nπ in p-wave and Nσ in s-wave, we systematically extract the excited lattice spectrum in the nucleon channel up to 1.65 GeV. Our lattice results indicate that Nπ scattering in the elastic approximation alone does not describe a low-lying Roper. Coupled channel effects between Nπ and Nππ seem to be crucial to render a low-lying Roper in experiment, reinforcing the notion that this state could be a dynamically generated resonance. After giving a brief motivation for studying the Roper channel and the relevant technical details to this study, we will discuss the results and the conclusions based on our lattice investigation and in comparison with other lattice calculations.
© The Authors, published by EDP Sciences, 2018
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (http://creativecommons.org/licenses/by/4.0/).