Neutron properties in the medium.

Area of Science:

• Nuclear physics
• Quantum chromodynamics
• Hadron structure

Background:

• The electric, GE, and magnetic, GM, form factors of nucleons (protons and neutrons) describe their internal structure.
• Understanding how these form factors change within a nuclear medium is crucial for interpreting electron scattering experiments.

Purpose of the Study:

• To investigate the in-medium modifications of the neutron's GE/GM form factor ratio.
• To predict the impact of these modifications on the neutron recoil polarization transfer process in helium-4.

Main Methods:

• Theoretical analysis focusing on small momentum transfer (Q2).
• Modeling the in-medium effects on the electric charge radius of bound neutrons.

Main Results:

• The in-medium change in the neutron GE/GM ratio is dominated by the alteration of its electric charge radius.
• A significant increase in the in-medium GE/GM ratio for bound neutrons is predicted compared to the free neutron.
• This increase is expected to enhance the cross section for the 4He(e-vector,e'n-vector)3He reaction.

Conclusions:

• In-medium effects on bound neutrons enhance the neutron GE/GM ratio, contrasting with the suppressive effect observed for protons.
• These findings have implications for understanding nuclear structure and interpreting electron-nucleon scattering experiments.
• Experimental measurement of in-medium neutron form factors is feasible within the 0.1