Quark Model of Resonances

The various baryon resonances have been successfully classified by the quark model; they are as if they were made of three quarks. The nucleon octet and the lowest decimet require no "orbit" contribution, but the next set of levels of odd parity are understood as getting their parity and some of their angular momentum from a first excitation of an orbital angular momentum. These "quarks" can be looked upon as abstract indices to describe a wave function values and another 4-space vector index for the angular momentum. The simplest application of the quark model is to calculate matrix elements assuming a nonrelativistic Schrodinger equation for the quarks. The quark theory is an incomplete theory. No definite prescription is given as to what to do next to correct it, or even to use it completely in a correct and consistent manner.