2024/08/25 by Hai-Yang Cheng, Cheng, Hai-Yang, Cheng-Wei Chiang +3
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph) #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2408.13942
openalex publication_date 2024/08/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The internal structure of the light scalar meson a0(980) is explored in the three-body D decays of D→ a0(980)P→ P1P2P through the intermediate state a0(980), where P denotes a pseudoscalar meson. The quasi-two-body D→ a0(980)+P decays are governed by the external W-emission diagram in which a0(980)+ is emitted. The predicted branching fractions in the q q model of a0(980) are too small by one to two orders of magnitude compared to experiment as the amplitude is suppressed by the smallness of the a0(980)+ decay constant, while those for D+→ a0(980)0 P and D0→ a0(980)-P are usually too large. These discrepancies can be resolved provided that a0(980) is a tetraquark state. In this case, there exist two additional T-like topological amplitudes, denoted by T and T which readily account for the discrepancies. An important implication of the tetraquark model is that the Ds+→ a0(980)+π0+a0(980)0π+ decay is not a purely W-annihilation process as in the diquark model of a0(980); it receives dominant contributions from T newly noticed in this work. Therefore, measurements of (D,Ds+)→ a0(980)P decays lend strong support to the tetraquark picture of a0(980).