Narrow Tetraquarks at Large N

TL;DR

This paper explores how the large-N expansion in QCD influences the decay and mixing properties of tetraquarks, highlighting the importance of flavor structure in determining their widths and interactions.

Contribution

It introduces a detailed analysis of tetraquark decay amplitudes and mixing using large-N QCD, emphasizing the role of flavor structure in these processes.

Findings

Tetraquark decay widths depend on flavor structure.

Some tetraquarks can be as narrow as ordinary mesons.

Flavor structure can make tetraquarks even narrower.

Abstract

Following a recent suggestion by Weinberg, we use the large-N expansion in QCD to discuss the decay amplitudes of tetraquarks into ordinary mesons as well as their mixing properties. We find that the flavor structure of the tetraquark is a crucial ingredient to determine both this mixing as well as the decays. Although in some cases tetraquarks should be expected to be as narrow as ordinary mesons, they may get to be even narrower, depending on this flavor structure.