Electromagnetic form factors of baryons in nuclear medium

TL;DR

This paper investigates how the electromagnetic structure of octet baryons changes in nuclear medium by estimating double ratios of form factors using a covariant quark model, highlighting flavor-dependent modifications.

Contribution

It provides theoretical estimates of medium modifications of baryon electromagnetic form factors, incorporating pion cloud effects, for various nuclear densities.

Findings

Different baryons show enhancement or quenching of form factor ratios.

Results depend on baryon flavor content and nuclear density.

Estimates can guide future experimental measurements.

Abstract

The electromagnetic structure of the baryons is modified in the nuclear medium. The modifications can be inferred from the comparison between the electromagnetic form factors in medium with the respective form factor in vacuum. Of particular interest is the ratio between the electric and magnetic form factors in medium ($G_E^*/G_M^*$) and vacuum ($G_E/G_M$) of the octet baryon. The deviation of the double ratios ($G_E^*/G_M^*)/(G_E/G_M)$ from unity measures the impact of the medium modification of the electromagnetic structure in a nuclear medium. Measurements of the double ratios $(G_E^*/G_M^*)/(G_E/G_M)$ for different nuclear densities may become available in a near future using the polarization-transfer method developed at Jefferson Lab. We present estimates of the double ratios of octet baryons based on a covariant constituent quark model, which takes into account pion cloud excitations of the baryon cores,for different nuclear densities. Our results manifest different features, namely, enhancement or quenching depending on the baryon flavor content.