117 citations · 318 across the 7 of their papers we have counts for
4 papers · 1 filter
Reconciling threshold and subthreshold expansions for pion-nucleon scattering
D. Siemens, J. Ruiz de Elvira, E. Epelbaum +4
Heavy-baryon chiral perturbation theory (ChPT) at one loop fails in relating the pion-nucleon amplitude in the physical region and for subthreshold kinematics due to loop effects e…
The width of the -resonance at two loop order in baryon chiral perturbation theory
Jambul Gegelia, Ulf-G. Meißner, Dmitrij Siemens +1
We calculate the width of the delta resonance at leading two-loop order in baryon chiral perturbation theory. This gives a correlation between the leading pion-nucleon-delta and pi…
Pion-nucleon scattering in covariant baryon chiral perturbation theory with explicit Delta resonances
De-Liang Yao, D. Siemens, V. Bernard +5
We present the results of a third order calculation of the pion-nucleon scattering amplitude in a chiral effective field theory with pions, nucleons and delta resonances as explici…
Elastic pion-nucleon scattering in chiral perturbation theory: A fresh look
D. Siemens, V. Bernard, E. Epelbaum +3
Elastic pion-nucleon scattering is analyzed in the framework of chiral perturbation theory up to fourth order within the heavy-baryon expansion and a covariant approach based on an…