Recently, a research team led by Shen Chengping, Professor from the School of Physics and Nuclear Energy Engineering at Beihang University, and co-authors form the University of Science and Technology of China and the Institute of High Energy Physics of the Chinese Academy of Science, published their collaborative results of the BESIII experiment entitled Observation of $a_0^0\left(980\right)\text{−}{f}_0\left(980\right)$ Mixing in Physical Review Letters (PRL) as a letter of “Editors’ Suggestion”.

BESIII is the only high energy collision experiment now in China. Since it first accessed data by collision in 2009, it has been running successfully until now. A large amount of data has been accumulated about charmonium, and a series of significant results have been achieved. One of the vital goals of BESIII is to study lepton-hadron physics with charmonium decay. Although light scalar mesons $a_0^0\left(980\right)$ and $f_0\left(980\right)$ have been well-established in experiments for about 40 years, their structures and properties have always been controversial. Because of the peculiar feature of the two mesons, besides normal quark-antiquark meson state, their theoretical alternative for mulations include tetraquark state, KK molecule, and quark-antiquark gluon hybrid. In the research, the mixing signals of $a_0^0\left(980\right)$ and $f_0\left(980\right)$ are first observed with over 5 of the standard deviation. In addition, they have obtained constraints on ga0K+K− and gf0K+K− by scanning the two coupling constants in the region of [0.0, 6.0] GeV (in Fig.1, colors represent the statistical significance of the mixing signal), which sensitively probe the structures and properties of $a_0^0\left(980\right)$ and $f_0\left(980\right)$.

Fig.1 The statistical significance of the signal scanned in the two-dimensional space of ga0K+K− and gf0K+K−

The research is supported by the Recruitment Program for Young Professionals, National Natural Science Foundation of China for Distinguished Young Scholars and other programs. The corresponding author of this article, Dr. Yan Wencheng, graduated from the Department of Modern Physics of the University of Science and Technology of China in July 2016. In March 2017, he began his postdoctoral research in the team of Prof. Shen Chengping, and participated in the BESIII experiment in Beijing and Belle II high energy experiment in Japan.

The paper is available at https://journals-aps-org-443.e.buaa.edu.cn/prl/abstract/10.1103/PhysRevLett.121.022001

Reported by Cai Hongyan

Edited by Song Chao

Translated by Zhao Yue