Exploring hyperon structure with electromagnetic transverse densities

TL;DR

This paper investigates the internal charge and magnetization distributions of hyperons using a novel approach combining chiral effective field theory and dispersion analysis, revealing insights into their peripheral structure and pion cloud effects.

Contribution

It introduces a new method to compute hyperon transverse densities at large distances, incorporating two-pion exchange and vector meson contributions, advancing understanding of hyperon structure.

Findings

Pion cloud in charged Sigma hyperons is comparable to nucleons.

Pion cloud in Xi hyperons is suppressed.

Lambda-Sigma^0 transition density is purely isovector, highlighting two-pion dynamics.

Abstract

We explore the structure of the spin-1/2 flavor-octet baryons (hyperons) through their electromagnetic transverse densities. The transverse densities describe the distribution of charge and magnetization at fixed light-front time and enable a spatial representation of the baryons as relativistic systems. At peripheral distances b~1/M_pi the transverse densities are computed using a new method that combines chiral effective field theory and dispersion analysis. The peripheral isovector densities arise from two-pion exchange, which includes the rho-meson resonance through elastic unitarity. The isoscalar densities are estimated from vector meson exchange (omega, phi). We find that the "pion cloud" in the charged Sigma hyperons is comparable to the nucleon, while in the Xi it is suppressed. The Lambda-Sigma^0 transition density is pure isovector and represents a clear manifestiation of peripheral two-pion dynamics.