A polarization amplitude A$_{{{\mathit D}_{{{J}}}}}$ is a parameter that depends on the initial polarization of the ${{\mathit D}_{{{J}}}}$. For ${{\mathit D}_{{{J}}}}$ decays the helicity angle, ${{\mathit \theta}_{{{H}}}}$, distribution varies like 1 + A$_{{{\mathit D}_{{{J}}}}}$ cos $^2{{\mathit \theta}_{{{H}}}}$, where ${{\mathit \theta}_{{{H}}}}$ is the angle in the ${{\mathit D}_{{{J}}}}$ rest frame between the two pions emitted in the ${{\mathit D}_{{{J}}}}$ $\rightarrow$ ${{\mathit D}^{*}}{{\mathit \pi}}$ and ${{\mathit D}^{*}}$ $\rightarrow$ ${{\mathit D}}{{\mathit \pi}}$ decays.

VALUE EVTS DOCUMENT ID TECN  COMMENT • • We do not use the following data for averages, fits, limits, etc. • • $3.1$ $\pm2.2$ 7.7k 1 AAIJ 2013 CC LHCB ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit D}^{*+}}{{\mathit \pi}^{-}}{{\mathit X}}$ 1  Systematic uncertainty not estimated.

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