On the mean exit time from a ball for a symmetric stable process

Abstract

Getoor in [3] calculated the mean exit time from a ball for the standard isotropic $\hat{I}\pm$-stable process in ${\mathbb{R}}^d$ starting from the interior of the ball. The purpose of this note is to show that, up to multplicative constant, the same formula is valid for any symmetric $\hat{I}\pm$-stable process.