Cold radiative neutron-deuteron capture and Wigner-SU(4) Symmetry

Few-nucleon systems are critical for understanding how nuclear phenomena arise from fundamental symmetries. We use pionless effective field theory, which has been successfully applied to low-energy few-body nuclear systems, to study triton and neutron-deuteron ($nd$) systems involving external currents. In particular, I will focus on low-energy radiative cold $nd$ capture up to next-to-next-to-leading order and how this process can help gain insights into the utility of Wigner-SU(4) symmetry. This study will be extended to investigate asymmetries, including parity violation.