I would like to calculate "explicitly" the following integral, which is a Fourier transform: let $\alpha>0$ be a parameter, for $x\in \mathbb R$, we define $$ I(\alpha, x)=\int_\mathbb R \cos(xt) e^{-\alpha \cosh t} dt. $$ It is easy to see that $I(\alpha, \cdot)$ is a rapidly decreasing (even) smooth function, but I would like to have an explicit formula.