Onset of scaling violation in pion and kaon elastic electromagnetic form factors

Abstract

Using a symmetry-preserving truncation of the quantum field equations describing hadron properties, parameter-free predictions are delivered for pion and kaon elastic electromagnetic form factors, FP=π,K, thereby unifying them with kindred results for nucleon elastic electromagnetic form factors. Regarding positive-charge states, the analysis stresses that the presence of scaling violations in QCD entails that Q2FP(Q2) should exhibit a single maximum on Q2>0. Locating such a maximum is both necessary and sufficient to establish the existence of scaling violations. The study predicts that, for charged π, K mesons, the Q2FP(Q2) maximum lies in the neighbourhood Q2≃5 GeV2. Foreseeable experiments will test these predictions and, providing their Q2 reach meets expectations, potentially also provide details on the momentum dependence of meson form factor scaling violation.

Keywords

• Continuum Schwinger function methods
• Elastic electromagnetic form factors
• Emergence of mass
• Hard exclusive processes
• Nambu-Goldstone bosons
• Scaling violations