  States in the $N=28$ nucleus $^{46}$Ar have been studied by a two-neutron
transfer reaction at REX-ISOLDE (CERN). A beam of radioactive $^{44}$ at an
energy of 2.16~AMeV and a tritium loaded titanium target were used to populate
$^{46}$ by the t($^{44}$,p) two-neutron transfer reaction. Protons emitted from
the target were identified in the T-REX silicon detector array. The excitation
energies of states in $^{46}$ have been reconstructed from the measured angles
and energies of recoil protons. Angular distributions for three final states
were measured and based on the shape of the differential cross section an
excited state at 3695~keV has been identified as $J^\pi = 0^+$. The angular
differential cross section for the population of different states are compared
to calculations using a reaction model employing both sequential and direct
transfer of two neutrons. Results are compared to shell model calculations
using state-of-the-art effective interactions.
