2009/06/10 by B. Desplanques, Bertrand Desplanques · 9 citations
Mathematics · Physics and Astronomy · #Charge (physics) #Charge conservation #Form factor (electronics) #Geometry #High-Energy Particle Collisions Research #Mathematics #Operator (biology) #Particle physics theoretical and experimental studies #Physics #Pion #Quantum Chromodynamics and Particle Interactions #Quantum electrodynamics #Quantum mechanics #Scalar (mathematics) #hep-ph #nucl-th
paper · pdf · doi:10.1140/epja/i2009-10864-8
published in The European Physical Journal A 42(2) (Springer Science+Business Media) · 30 pages, 10 figures
arxiv created 2009/06/10 · openalex publication_date 2009/10/08 · arxiv updated 2010/02/26 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The pion charge and scalar form factors, F1(Q2) and F0(Q2), are first calculated in different forms of relativistic quantum mechanics. This is done using the solution of a mass operator that contains both confinement and one-gluon-exchange interactions. Results of calculations, based on a one-body current, are compared to experiment for the first one. As it could be expected, those point-form, and instant and front-form ones in a parallel momentum configuration fail to reproduce experiment. The other results corresponding to a perpendicular momentum configuration (instant form in the Breit frame and front form with q+=0) do much better. The comparison of charge and scalar form factors shows that the spin-1/2 nature of the constituents plays an important role. Taking into account that only the last set of results represents a reasonable basis for improving the description of the charge form factor, this one is then discussed with regard to the asymptotic QCD-power-law behavior Q-2. The contribution of two-body currents in achieving the right power law is considered while the scalar form factor, F0(Q2), is shown to have the right power-law behavior in any case. The low-Q2 behavior of the charge form factor and the pion-decay constant are also discussed.