Revealing pion and kaon structure via generalised parton distributions *

Abstract

Clear windows onto emergent hadron mass (EHM) and modulations thereof by Higgs boson interactions are provided by observable measures of pion and kaon structure, many of which are accessible via generalised parton distributions (GPDs). Beginning with algebraic GPD Ansätze, constrained entirely by hadron-scale and K valence-parton distribution functions (DFs), in whose forms both EHM and Higgs boson influences are manifest, numerous illustrations are provided. They include the properties of electromagnetic form factors, impact parameter space GPDs, gravitational form factors and associated pressure profiles, and the character and consequences of all-orders evolution. The analyses predict that mass-squared gravitational form factors are stiffer than electromagnetic form factors; reveal that K pressure profiles are tighter than profiles, with both mesons sustaining near-core pressures at magnitudes similar to that expected at the core of neutron stars; deliver parameter-free predictions for and K valence, glue, and sea GPDs at the resolving scale GeV; and predict that at this scale the fraction of meson mass-squared carried by glue and sea combined matches that lodged with the valence degrees-of-freedom, with a similar statement holding for mass-squared radii.

Parton distributions of light quarks and antiquarks in the proton

“…We implement evolution by using the all-orders scheme introduced elsewhere [53][54][55] and elucidated in Refs. [75][76][77]. Our practical implementation is based on the process-independent effective charge, α(k 2 ), described in Refs.…”

Concerning pion parton distributions

“…( 23) -modern calculations of groundstate pseudoscalar-meson LFWFs, e.g., Refs. [40,85,88,[100][101][102][103][104][105][106] do not exhibit features that could produce wiggles in the associated valence-quark DFs. Con- sequently, we hereafter represent Eqs.…”

“…Comparisons with such calculations [86,[88][89][90] and also data [91][92][93] show that SCI results are typically a reliable guide for long-wavelength properties of hadrons, such as masses and decay constants, but, unsurprisingly, fail in applications that are sensitive to and/or reveal structural properties. The hadron-scale DF in Eq.…”

Transverse momentum distributions of valence quark in light and heavy vector mesons

“…It has been demonstrated with the pseudoscalar mesons [10,36,37] and then generalized to the case of vector mesons [38]. Based on the dynamically solved BS wave functions, which accumulated lots of success in hadron study within the Dyson-Schwinger equations (DSEs) formalism [39][40][41][42][43][44][45], the parton distribution amplitude [46][47][48], generalized parton distributions (GPDs) and TMDs of pseudoscalar mesons [49,50] are further studied. Exclusive process is also studied, e.g., without introducing any new parameters, the 𝜌 and 𝐽 /𝜓 LF-LFWFs are put into the color dipole model study of diffractive vector meson productions in e-p collison, and agreement is found with data from HERA [38].…”