Radiative capture reactions in lattice effective field theory.

Area of Science:

• Nuclear Physics
• Quantum Chromodynamics
• Computational Physics

Background:

• Lattice methods are crucial for studying nuclear reactions.
• Calculating capture reactions, especially at finite volumes, presents significant challenges.
• Effective field theories provide a framework for nuclear interactions.

Purpose of the Study:

• To detail a general lattice method for computing nuclear capture reactions.
• To specifically address the calculation of effective two-body capture reactions at finite volume.
• To demonstrate the method's efficacy through a specific nuclear reaction calculation.

Main Methods:

• Calculating the two-point Green's function with an infrared regulator.
• Determining the capture amplitude to a two-body bound state.
• Applying pionless effective field theory for low-energy radiative neutron capture.

Main Results:

• Successfully calculated the leading M1 contribution to radiative neutron capture on a proton.
• Achieved good agreement between lattice results and exact continuum calculations.
• Validated the effectiveness of the proposed two-body capture reaction method.

Conclusions:

• The developed lattice method provides a robust framework for nuclear capture reactions.
• This approach is applicable to few-body reactions in cold atomic systems.
• The method can be extended to hadronic reactions in lattice quantum chromodynamics.