Tetraquarks, their masses and decays in QED₂

Abstract

Recent observations by Belle and BESIII of charged quarkonium-like resonances give new stimulus for theoretical investigation of exotic hadrons in general and heavy tetraquarks in particular. We use QED₂, a confining theory, as a model for the masses and decays of tetraquarks. Here we discuss the states $\left( {Q\overline{Q}q\overline{q}} \right)$ and $\left( {QQ\overline{q}\overline{q}} \right)$ (and its anti-particle), where Q and q are two fermion flavors with masses M and m, so that M >m. Wethendiscussdecaymodesofthesestatesinto $\left( {Q\overline{Q}} \right)$, $\left( {q\overline{q}} \right)$, $\left( {Q\overline{q}} \right)$, $\left( {\overline{Q}q} \right)$. Itturns out that $\left( {Q\overline{Q}q\overline{q}} \right)$ is stable, while $\left( {QQ\overline{q}\overline{q}} \right)$ is not.