2024/12/17 by Xiaolong Du, Du, Xiaolong, Yun Liang +5
Physics and Astronomy · Computer Science · #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #Computational Physics and Python Applications
paper · pdf · doi:10.48550/arxiv.2412.12855
The scalar meson f0(980) has long posed a perplexing puzzle within the realm of light hadron physics. Conventionally, its mass and width in normal decay processes have been estimated as M=990±20~MeV/c2 and Γ=40-100~MeV, respectively. Theoretical explanations regarding the internal structure of f0(980) range from it being a conventional quark-antiquark meson to a tetraquark state, a KK molecule, or even a quark-antiquark gluon hybrid. However, a definitive consensus has remained elusive over a considerable duration. Recent observations by the BESIII experiment have unveiled anomalously narrow widths of f0(980) in five independent isospin-symmetry-breaking decay channels. Harnessing these experimental findings, we performed a simultaneous fit to the ππ invariant mass distributions, resulting in a refined determination of the mass and width in isospin-symmetry-breaking decays as M=990.0±0.4(stat)±0.1(syst)~MeV/c2 and Γ=11.4±1.1(stat)±0.9(syst)~MeV, respectively. Here, the first errors are statistical and the second are systematic. Furthermore, by employing the parameterized Flatté formula to fit the same ππ invariant mass distributions, we ascertained the values of the two coupling constants, gfππ and g_fKK, as gfππ=0.46±0.03 and g_fKK=1.24±0.32, respectively. Based on the joint confidence regions of gfππ and g_fKK, we draw the conclusion that the experimental data exhibit a propensity to favor the KK molecule model and the quark-antiquark (qq) model, while offering relatively less support for the tetraquarks (q2q2) model and the quark-antiquark gluon (qqg) hybrid model.