Eur. Phys. J. A (2005) 26: 99-106
https://doi.org/10.1140/epja/i2005-10160-9

Original Article

Direct calculation of the K-matrix for pion electro-production in the delta channel

¹ Department of Physics and Centre for Computational Physics, University of Coimbra, 3004-516, Coimbra, Portugal
² Department of Physics, University of Beira Interior, 6201-001, Covilh a, Portugal
³ Faculty of Education, University of Ljubljana and J. Stefan Institute, 1000, Ljubljana, Slovenia
⁴ Faculty of Mathematics and Physics, University of Ljubljana and J. Stefan Institute, 1000, Ljubljana, Slovenia

^* e-mail: bojan.golli@ijs.si

Received: 20 June 2005
Accepted: 28 September 2005
Published online: 26 October 2005

Abstract

We present a method to calculate directly the K-matrix for the pion electro-production processes in the framework of chiral quark models which allows for a clean separation of the resonant amplitudes from the background. The method is applied to the calculation of the multipole amplitudes M₁₊, E₁₊, and S₁₊ in the Δ channel within the Cloudy Bag Model. A good overall description is found in a broad energy range.