Level structure and reflection asymmetry in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi mathvariant="normal">Th</mml:mi></mml:mrow><mml:mprescripts/><mml:mrow/><mml:mrow><mml:mn>227</mml:mn></mml:mrow><mml:mrow/><mml:mrow/></mml:mmultiscripts></mml:mrow></mml:math>

The level structure of $^{227}\mathrm{Th}$ has been studied using the electron capture decay of $^{227}\mathrm{Pa}$ and the ${\mathrm{\ensuremath{\beta}}}^{\mathrm{\ensuremath{-}}}$ decay of $^{227}\mathrm{Ac}$ to give a total of 20 levels where only four were previously known. This level structure then makes possible a more complete interpretation of the recently studied $^{231}\mathrm{U}$ alpha decay into $^{227}\mathrm{Th}$. The level structure can be interpreted using both strong coupling and intermediate coupling models in terms of K=1/${2}^{\ifmmode\pm\else\textpm\fi{}}$,K=3/${2}^{\ifmmode\pm\else\textpm\fi{}}$, and more tentative K=5/${2}^{\ifmmode\pm\else\textpm\fi{}}$ parity double bands which implies that $^{227}\mathrm{Th}$ has reflection asymmetry. Futhermore, the detailed interpretation of the level structure of $^{227}\mathrm{Th}$ solves the long standing problem of the ground state spin-parity of $^{227}\mathrm{Th}$ which is shown to be 1/${2}^{+}$.

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