Tetraquarks with heavy flavors

In the framework of a simple nonrelativistic potential model, we have previously studied the stability of a system of two quarks and two antiquarks of identical light flavor. Here, we extend our analysis to quarks (antiquarks) of different masses and discuss the role of heavy flavors on the stability of the system. This analysis is performed by using a simple variational method which proved powerful in the treatment of other few-body systems. We compare our results with other results from the literature and single out a few characteristics of the spectrum of the tetraquarks.