2006/06/24 by M.B. Voloshin, M. B. Voloshin
Physics and Astronomy · #Amplitude #High-Energy Particle Collisions Research #Nuclear physics #Particle physics #Particle physics theoretical and experimental studies #Physics #Pion #Quantum Chromodynamics and Particle Interactions #Quantum mechanics #Quark #Quarkonium #Spectrum (functional analysis) #State (computer science) #hep-ph
paper · pdf · doi:10.1103/physrevd.74.054022
published as Phys.Rev.D74:054022,2006 · 23 pages, 2 figures
arxiv created 2006/06/24 · openalex publication_date 2006/09/18 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Two-pion transitions in charmonium and bottomonium are considered with the leading relativistic effects taken into account. It is estimated that the contribution of the chromo-magnetic interaction of the charmed quarks to the amplitude of the decay \ensuremathψ(2S)\ensuremath→\ensuremathπ\ensuremathπJ/\ensuremathψ is at the level of (15--20)%. This contribution is enhanced by a factor of 3 in the decay \ensuremathηc(2S)\ensuremath→\ensuremathπ\ensuremathπ\ensuremathηc, producing a significant modification of the rate and the spectrum in the latter decay. It is also suggested that the peculiar observed spectrum in the decay \ensuremathΥ(3S)\ensuremath→\ensuremathπ\ensuremathπ\ensuremathΥ can be explained by a relative prominence of the relativistic terms, if the leading nonrelativistic quarkonium amplitude is dynamically suppressed. Also discussed are the effects of the final state interaction between the pions.