We present an exact calculation of S and P wave QQ n¯ n¯ states using different standard
nonrelativistic quark-quark potentials. We explore in detail the charm and bottom sectors
looking for bound states that could be measured within existing facilities. Against the
proliferation of four-quark states sometimes predicted in the literature, we found a small
number of candidates to be stable. We analyze their properties in a trial to distinguish
between compact and molecular states. Possible decay modes are discussed.

We present an exact calculation of S and P wave QQ (n) over bar (n) over bar states using
different standard nonrelativistic quark-quark potentials. We explore in detail the charm and
bottom sectors looking for bound states that could be measured within existing facilities.
Against the proliferation of four-quark states sometimes predicted in the literature, we found
a small number of candidates to be stable. We analyze their properties in a trial to
distinguish between compact and molecular states. Possible decay modes are discussed.