Speaker
Giorgio Foti
(University of Messina & INFN Catania)
Description
S-matrix theory is one of the most powerful framework to study the (un)stable states that populate QCD spectrum. In particular, it is very useful to extract physical properties of the "exotics" candidates - particles that cannot be described by ordinary quark model - in a non perturbative, phenomenological way. In this talk, I will introduce the so called N/D formalism, which is a technique to impose the analytic properties of the amplitudes. I will show two applications of this formalism to the tetraquark candidate X(3872) and to the still debated (exotic?) Upsilon states in the bottomonium spectrum.
