1303.0342 (Steven Weinberg)

Tetraquark Mesons in Large $N$ Quantum Chromodynamics    [PDF]

Steven Weinberg

It is argued that exotic mesons consisting of two quarks and two antiquarks are not ruled out in quantum chromodynamics with a large number $N$ of colors, as generally thought. They can come in two varieties: short-lived tetraquarks with decay rates proportional to $N$, which would be unobservable if $N$ were sufficiently large, and long-lived tetraquarks with decay rates proportional to 1/N. The $f_0(500)$ and $f_0(980)$ may be examples of these two varieties of exotic mesons.

View original: http://arxiv.org/abs/1303.0342