Kaon transverse charge density from space- and timelike data

TL;DR

This paper extracts the transverse charge density of the kaon using combined space- and timelike data, including recent high-momentum transfer measurements, providing improved uncertainty estimates and insights into short-distance structure.

Contribution

It introduces a comprehensive analysis combining timelike and spacelike data with new parameterizations to determine the kaon charge density with reduced uncertainties.

Findings

Uncertainty at 5% for b=0.025 fm

Extended kinematic reach with recent data

Potential impact of future Jefferson Lab data

Abstract

We used the world data on the kaon form factor to extract the transverse kaon charge density using a dispersion integral of the imaginary part of the kaon form factor in the timelike region. Our analysis includes recent data from $e^+e^-$ annihiliation measurements extending the kinematic reach of the data into the region of high momentum transfers conjugate to the region of short transverse distances. To calculate the transverse density we created a superset of both timelike and spacelike data and developed an empirical parameterization of the kaon form factor. The spacelike set includes two new data points we extracted from existing cross section data. We estimate the uncertainty on the resulting transverse density to be 5\% at $b$=0.025 fm and significantly better at large distances. New kaon data planned with the 12 GeV Jefferson Lab may have a significant impact on the charge density at distances of $b<$ 0.1fm.