The Ultraviolet Critical Dimension of Half-Maximal Supergravity at Three Loops

We determine the minimum dimension at which divergences first occur in half-maximal 16-supercharge supergravity at three loops. For the four-point amplitudes, we find that the critical dimension is D=14/3 and give the explicit form of the divergence. We also give the divergence of an additional piece that gives us access to theories with higher degrees of supersymmetry, in particular 20- and 32-supercharge supergravities. We give the divergences of half-maximal supergravity when matter vector multiplets are included as well. Explicit forms of various divergences at one and two loops are also given.