Level density of ${}^{56}$Fe and low-energy enhancement of $\gamma$-strength function

The ${}^{55}$Mn$(d,n{)}^{56}$Fe differential cross section is measured at $E_d=7$ MeV@. The ${}^{56}$Fe level density obtained from neutron evaporation spectra is compared to the level density extracted from the ${}^{57}$Fe${(}^3$He,$\alpha \gamma {)}^{56}$Fe reaction by the Oslo-type technique. Good agreement is found between the level densities determined by the two methods. With the level density function obtained from the neutron evaporation spectra, the ${}^{56}$Fe $\gamma$-strength function is also determined from the first-generation $\gamma$ matrix of the Oslo experiment. The good agreement between the past and present results for the $\gamma$-strength function supports the validity of both methods and is consistent with the low-energy enhancement of the $\gamma$ strength below $\sim 4$ MeV first discovered by the Oslo method in iron and molybdenum isotopes.