RQM description of PS meson form factors, constraints from space-time translations, and underlying dynamics

Abstract

The role of Poincaré covariant space-time translations is investigated in the case of the pseudoscalar-meson charge form factors. It is shown that this role extends beyond the standard energy-momentum conservation, which is accounted for in all relativistic quantum mechanics calculations. It implies constraints that have been largely ignored until now but should be fulfilled to ensure the full Poincaré covariance. The violation of these constraints, which is more or less important depending on the form of relativistic quantum mechanics that is employed, points to the validity of using a single-particle current, which is generally assumed in calculations of form factors. In short, these constraints concern the relation of the momentum transferred to the constituents to the one transferred to the system. How to account for the related constraints, as well as restoring the equivalence of different relativistic quantum mechanics approaches in estimating form factors, is discussed. Some conclusions relative to the underlying dynamics are given in the pion case.

37 pages, 13 figures; figures completed for notations, revised text with better emphasis on differences with previous works; accepted for publication in EPJA

References in corpus (13)

• Determination of the Charged Pion Form Factor at Q2=1.60 and 2.45 (GeV/c)2
• Charged pion form factor between Q^2=0.60 and 2.45 GeV^2. II. Determination of, and results for, the pion form factor
• The pion form factor from lattice QCD with two dynamical flavours
• A pure S-wave covariant model for the nucleon
• Singular Charge Density at the Center of the Pion?
• Pion form factor at spacelike momentum transfers from local-duality QCD sum rule
• QCD sum rules with nonlocal condensates and the spacelike pion form factor
• Electromagnetic pion and kaon form factors in light-cone resummed perturbative QCD
• The potential of large germanium detector arrays for solar-axion searches utilizing the axio-electric effect for detection
• Form factors in RQM approaches: constraints from space-time translations
• Electromagnetic Hadron Form Factors and Higher Fock Components
• Sea-quark effects in the pion charge form factor
• Form factors in RQM approaches: constraints from space-time translations, extension to constituents with spin-1/2 and unequal masses

Cited by in corpus (1)

• Electromagnetic $N-\Delta (1232)$ transitions within the point-form of relativistic quantum mechanics