2015/11/15 by Xing-Dao Guo, Guo, Xing-Dao, Xuewen Liu +7
Physics and Astronomy · #Excited state #FOS: Physical sciences #Field (mathematics) #High Energy Physics - Phenomenology (hep-ph) #High-Energy Particle Collisions Research #Interpretation (philosophy) #Isospin #Meson #Multipole expansion #Nuclear physics #Particle physics #Particle physics theoretical and experimental studies #Physics #Pion #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Quantum mechanics #Quark #hep-ph
paper · pdf · doi:10.48550/arxiv.1511.04697
12 pages, 3 figures
arxiv created 2015/11/15 · openalex publication_date 2015/11/15 · arxiv updated 2015/11/17 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The QCD multipole expansion (QCDME) is based on the quantum field theory, so should be more reliable. However, on another aspect, it refers to the non-perturbative QCD , so that has a certain application range. Even though it successfully explains the data of transition among members of the Υ (ψ) family, as Eichten indicates, beyond the production threshold of mediate states it fails to meet data by several orders. In this work, by studying a simple decay mode D^*→ D+π0, where a pion may be emitted before D^* transiting into D, we analyze the contribution of QCD multipole expansion. Whereas as the Dπ portal is open, the dominant contribution is an OZI allowed process where a light quark-pair is excited out from vacuum and its contribution can be evaluated by the 3P0 model. Since the direct pion emission is a process which is OZI suppressed and violates the isospin conservation, its contribution must be much smaller than the dominant one. By a careful calculation, we may quantitatively estimate how small the QCDME contribution should be and offer a quantitative interpretation for Eichten's statement.