For , the centered Loewner image
is the Boundary-point Bessel flow for SLE, a Bessel process of dimension
When , one has , and the Hitting-zero classification for a Bessel process says that hits zero almost surely. Thus every fixed nonzero boundary point is swallowed in finite time.
A hull generated by a continuous trace cannot swallow a real point while the trace remains strictly inside : before any contact with the real line, the trace is a crosscut-free interior curve and no boundary interval is disconnected from infinity. Consequently finite swallowing forces the trace to meet away from its initial point. SLE therefore almost surely intersects the boundary for every .
For the Bessel process
the scale function of a one-dimensional diffusion is when . If , the boundary hitting probability from a diffusion scale function gives
If , then and . Letting and then shows that the process cannot escape to infinity before reaching zero. The exit time from each bounded interval is finite almost surely, so almost surely.
If , then in absolute value as . Equivalently,
Thus the process does not hit zero. The borderline case has scale function and also does not hit zero. This is the Hitting-zero classification for a Bessel process.