A polarization amplitude A$_{{{\mathit D}_{{{1}}}}}$ is a parameter that depends on the initial polarization of the ${{\mathit D}_{{{1}}}}$ and is sensitive to a possible ${\mathit S}{\mathrm -wave}$ contribution to its decay. For ${{\mathit D}_{{{1}}}}$ decays the helicity angle, $\theta _{h}$, distribution varies like 1 + A$_{{{\mathit D}_{{{1}}}}}$cos $^2\theta _{h}$, where $\theta _{h}$ is the angle in the ${{\mathit D}^{*}}$ rest frame between the two pions emitted by the ${{\mathit D}_{{{1}}}}$ $\rightarrow$ ${{\mathit D}^{*}}{{\mathit \pi}}$ and the ${{\mathit D}^{*}}$ $\rightarrow$ ${{\mathit D}}{{\mathit \pi}}$.

Unpolarized ${{\mathit D}_{{{1}}}}$ decaying purely via ${\mathit D}{\mathrm -wave}$ is predicted to give A$_{{{\mathit D}_{{{1}}}}}$ = 3.

VALUE DOCUMENT ID TECN  COMMENT • • We do not use the following data for averages, fits, limits, etc. • • $3.8$ $\pm0.6$ $\pm0.8$ 1 AUBERT 2009 Y BABR ${{\mathit B}^{0}}$ $\rightarrow$ ${{\mathit D}_{{{1}}}^{-}}{{\mathit \ell}^{+}}{{\mathit \nu}_{{{{{\mathit \ell}}}}}}$ 1  Assuming $\Gamma ({{\mathit \Upsilon}{(4S)}}$ $\rightarrow$ ${{\mathit B}^{+}}{{\mathit B}^{-}}$) $/$ $\Gamma ({{\mathit \Upsilon}{(4S)}}$ $\rightarrow$ ${{\mathit B}^{0}}{{\overline{\mathit B}}^{0}}$) = $1.065$ $\pm0.026$ and equal partial widths and helicity angle distributions for charged and neutral ${{\mathit D}_{{{1}}}}$ mesons.

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