Tetraquarks and Pentaquarks

Abstract

Since 2003 there has been an explosion in the observation of new hadronic states that cannot be classifi ed by the well-tested quark model of mesons (quark-antiquark) and baryons (three quarks or antiquarks). The properties of these states indicate that they are combinations of four,fi ve, or more, quarks and antiquarks, making them manifestly exotic. A recent high-profi le example was the discovery of two penta-quark candidates by the LHCb collaboration at the CERN Large Hadron Collider (LHC). No scientifi c consensus has yet emerged to explain the exotic hadron spectrum, demanding a new set of experimental observations that will feed the development of theoretical models to describe the dynamics of multiquark states. In this Discovery book we will take you on a tour of quantum chromodynamics, explain about the latest research into the physics of exotic hadrons and describe the exciting opportunities that are offered by the next generation of particle physics experiments.