Electromagnetic Response of ^{12}C: A First-Principles Calculation.

Area of Science:

• Nuclear Physics
• Computational Physics

Background:

• Understanding nuclear electromagnetic response functions is crucial for nuclear structure.
• Previous calculations often showed discrepancies with experimental data, particularly regarding response quenching.

Purpose of the Study:

• To compute the longitudinal and transverse electromagnetic response functions of carbon-12.
• To investigate the phenomenon of response quenching in nuclear systems.
• To compare theoretical predictions with experimental measurements.

Main Methods:

• Utilized a "first-principles" Green's function Monte Carlo (GFMC) method.
• Employed realistic two- and three-nucleon interactions.
• Incorporated associated one- and two-body currents in the calculations.

Main Results:

• Achieved excellent agreement between theoretical calculations and experimental data for ^{12}C.
• Found no evidence supporting the quenching of the longitudinal electromagnetic response.
• Reanalyzed the Coulomb sum rule, explicitly including contributions from low-lying states.

Conclusions:

• The "first-principles" GFMC approach accurately describes the electromagnetic response of carbon-12.
• The observed agreement challenges existing theories that predict response quenching.
• Accurate inclusion of nuclear states is vital for sum rule analyses.