Ultraviolet pole ($1/{ϵ}_{\mathrm{UV}}$)

An ultraviolet divergence appears as a pole of a dimensionally continued Feynman integral. In $d=4-2ϵ$, a logarithmically divergent one-loop integral typically has a $1/ϵ$ term. Dimensional regularization can also produce infrared divergences with the same formal regulator, so the origin must be identified before interpreting a pole as an ultraviolet counterterm.