\[\widehat{\mathsf{Q}}^{-\mu}_{-\frac{1}{2}+i\tau}\left(\cos\theta\right)=\frac{%
1}{\tau^{\mu}}\left(\frac{\theta}{\sin\theta}\right)^{1/2}K_{\mu}\left(\tau%
\theta\right)\*\left(1+O\left(\ifrac{1}{\tau}\right)\right),\]