Understanding the Low-Energy Enhancement of the $gamma$-ray Strength Function of $^{56}$Fe

A model-independent technique was used to determine the $gamma$-ray Strength Function ($gamma$SF) of $^{56}$Fe down to $gamma$-ray energies less than 1 MeV for the first time with GRETINA using the $(p,p)$ reaction at 16 MeV. No difference was observed in the energy dependence of the $gamma$SF built on $2^{+}$ and $4^{+}$ final states, supporting the Brink hypothesis. In addition, angular distribution and polarization measurements were performed. The angular distributions are consistent with dipole radiation. The polarization results show a small bias towards magnetic character in the region of the enhancement.