Special Issue on Nucleon Resonances

This special issue is a collection of papers presented during the topical workshop “Nucleon Resonances: From Photoproduction to High Photon Virtualities” which took place at the European Center for Theoretical Studies in Nuclear Physics and Related Areas in Trento, Italy from October 12–16, 2015.Nucleon resonances are excited states of nucleon particles, often corresponding to one of the quarks having a flipped spin state, or with different orbital angular momentum when the particle decays. Due to their extraordinarily short lifetimes, many properties of these particles are still under investigation.The studies of the excited nucleon N* spectrum and the structure of these states offer unique  information on many facets of the non-perturbative strong interaction in the generation of excited nucleon states of different quantum numbers. The workshop was devoted to the study of the spectrum and structure of N* states, as they become accessible through the electromagnetic excitation of the nucleon in exclusive meson production.The organizing committee consisted of R.W.Gothe (Chair,USC), V.I. Mokeev (Jefferson Lab), and E. Santopinto (INFN). Previously published as Topical Collection in the journal Few-Body Systems, volume 57, 2016