Quark-model hadron structure.pdf

a r X i v : 0 7 1 1 .3 0 9 8 v 1 [ h e p - p h ] 2 0 N o v 2 0 0 7 Few-Body Systems 0, 1–6 (2008) Few- Body Systems c? by Springer-Verlag 2008 Printed in Austria Quark-model hadron structure A. Valcarce1, J. Vijande2, P. Gonza?lez2, H. Garcilazo3 1 Departamento de F??sica Fundamental, Universidad de Salamanca, Spain 2 Departamento de F??sica Teo?rica e IFIC, Universidad de Valencia - CSIC, Spain 3 Escuela Superior de F??sica y Matema?ticas, Instituto Polite?cnico Nacional, Mexico Abstract. We review some selected recent results on hadron spectroscopy and related theoretical studies based on constituent quark models. 1 Introduction Hadron spectroscopy has undergone a great renaissance in recent years [1]. The new findings include: low-lying excitations ofD andB mesons, long-awaited miss- ing states and new states near 4 GeV/c2 in the charmonium spectrum, charmed and bottom baryons, and evidence for doubly charmed baryons. The light hadron sector remains also restless reporting new scalar mesons or showing a deep the- oretical interest in the high energy part of both the meson and baryon spectra. The hadron spectra should be described in terms of QCD. Tested to very high accuracy in the perturbative regime, its low energy sector (strong QCD) compris- ing hadron physics, remains challenging because neither lattice nor perturbative methods are accurate. As in most other areas of physics, the keys to a qualitative understanding of strong QCD are to identify the appropriate degrees of freedom and the effective forces between them [2]. All roads lead to valence constituent quarks as the appropriate degrees of freedom [3]. The effective forces, summariz- ing the basic properties of QCD, must at least contain: a confining mechanism, a spin-spin force and a long-range term. This framework is what we know as the constituent quark model. Although quark models differ in their details, the qualitative aspects of their spectra are determined by features that they share in