First Observations of $\mathit{\Upsilon }\left(1\mathit{S}\right)\to {\mathit{\gamma }\mathit{\pi }}^{+}{\mathit{\pi }}^{-}$ and $\mathit{\Upsilon }\left(1\mathit{S}\right)\to {\mathit{\gamma }\mathit{\pi }}^0{\mathit{\pi }}^0$

We report on a study of exclusive radiative decays of the $\Upsilon \left(1S\right)$ resonance collected with the CLEO II detector operating at the Cornell Electron Storage Ring. We present the first observation of the radiative decays $\Upsilon \left(1S\right)\to \gamma {\pi }^{+}{\pi }^{-}$ and $\Upsilon \left(1S\right)\to \gamma {\pi }^0{\pi }^0$. For the dipion mass regime $m_{\pi \pi }>1.0\mathrm{GeV}$, we obtain $B\left(\Upsilon \right(1S)\to \gamma {\pi }^{+}{\pi }^{-})=(6.3\pm 1.2\pm 1.3)\times {10}^{-5\mathrm{}}$ and $B\left(\Upsilon \right(1S)\to \gamma {\pi }^0{\pi }^0)=(1.7\pm 0.6\pm 0.3)\times {10}^{-5\mathrm{}}$.