Evidence of the four-quark nature of $f_0(980)$ and $f_0(500)$

Abstract

There exists a great deal of concrete evidence in favor of the exotic four-quark nature of light scalars. At the same time, the further expansion of the area of the $q^2{\bar{q}}^2$ model validity for light scalars on ever new processes seems extremely interesting and important. We analyze the BESIII data on the decay $J/\psi \to \gamma {\pi }^0{\pi }^0$ and show that the results of this high-statistics experiment can be interpreted in favor of the four-quark nature of light scalar mesons $f_0(980)$ and $f_0(500)$.

Comments: 6 pages, 3 figures, v2: improved discussion, references corrected, matched the pudlished version in Phys. Rev. D