New Trends in Hadron Physics: A Few-Body Perspective

Abstract

The motivations for this issue are found in the intense experimental and theoretical efforts being pursued worldwide in hadron physics, which straddles the border between nuclear and particle physics. Experiment sees the operation, construction and planning of many facilities, e.g. BESIII at the Beijing electron positron collider; COMPASS and (approved) COMPASS++/AMBER at CERN; Jefferson Lab running at 12 GeV; KLOE at DAΦNE; the relativistic heavy ion collider at Brookhaven National Laboratory; the large hadron collider beauty experiment; the Facility for Antiproton and Ion Research (FAIR); the Nuclotron-based Ion Collider fAcility (NICA); and electron ion colliders in the USA (EIC) and China (EicC). On the phenomenology and theory sides, with the work of bridging themes in nuclear and particle physics, there is ample room for exploitation of methods introduced and tested in the study of few body systems. These are most straightforwardly employed in connection with few-nucleon systems, light hypernuclei and constituent-quark dynamics for baryons and multiquark systems. On the other side of this coin are attempts at ab initio analyses of mesons, baryons, and hybrid bound-states using quantum field theory equations of motions, which include such few-body physics staples as the Bethe–Salpeter, Faddeev and Faddeev–Yakubowski equations, etc. In the quantum field theory context, although the equation names are familiar, new challenges are encountered in formulating and solving these equations; notably, the demands of Poincaré-covariance and the veracious treatment of symmetries and the patterns by which they are broken.