Author's notes dated 22 October 2019. Section 2, equation (2), defines the positive Bessel diffusion up to its first zero; the following discussion relates dimension to the drift parameter and identifies the squared radial process. Section 3 discusses reflecting continuations. No global singular-drift equation across zero is inferred for dimensions below one.
Section 4.1, equation (15), defines loop measure by normalized planar Brownian bridges with density 1/(2 pi t squared); Proposition 6 proves conformal invariance. The introduction defines loop soups as Poisson samples of this measure. The arXiv PDF date displayed by the current rendering is not used as the journal publication date.