$$
\hat{\mu}(z) = \exp\left\{- \frac{a}{2}z^2 + i\gamma z
+ \int_{\R} (e^{izt} -1 -izt\mathbf{1}_{[-1,1]}(t)) \nu(\mathrm{d}t) \right\}, \,\, z \in \mathbb{R}
$$がどう出るかな