Electromagnetic form factors of baryons in nuclear medium

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 ( * / * ) and vacuum ( / ) of the octet baryons. The deviation of the double ratios ( * / * )/( / ) from unity measures the impact of the medium modification of the electromagnetic structure in a nuclear medium. Measurements of the double ratios ( * / * )/( / ) for different nuclear densities may become available in the 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.