$D_{sJ}^*(2317)$, $D_{J}^*(2308)$ AND $D_{sJ}^*(2632)$ AS CANDIDATES FOR OPEN-CHARM TETRAQUARKS

Abstract

We review the theoretical and experimental evidence for the candidacy of the [Formula: see text], [Formula: see text] and the [Formula: see text] for charmed tetraquarks. We briefly review the 't Hooft interaction's influence on the single-charm ( C =1)[Formula: see text] tetraquark mass spectrum: its consequences for other observed mesons such as the [Formula: see text], as well as its predictions of the (thus far) unobserved exotic tetraquark states. In particular we show that the near mass degeneracy of [Formula: see text] and [Formula: see text] was naturally predicted by the tetraquark model with 't Hooft interaction, and thus may constitute the first "smoking gun" evidence for tetraquark existence. A short outlook of possible future research directions is given.