A polarization amplitude A$_{{{\mathit D}}}$ is a parameter that depends on the initial polarization of the ${{\mathit D}_{{3}}^{*}{(2750)}}$. For ${{\mathit D}_{{3}}^{*}{(2750)}}$ decays the helicity angle, ${{\mathit \theta}_{{H}}}$, distribution varies like 1 + A$_{{{\mathit D}}}$ cos $({{\mathit \theta}_{{H}}})$, where ${{\mathit \theta}_{{H}}}$ is the angle in the ${{\mathit D}^{*}}$ rest frame between the two pions emitted by the ${{\mathit D}_{{3}}^{*}{(2750)}}$ $\rightarrow$ ${{\mathit D}^{*}}{{\mathit \pi}}$ and ${{\mathit D}^{*}}$ $\rightarrow$ ${{\mathit D}}{{\mathit \pi}}$ .

VALUE EVTS DOCUMENT ID TECN  COMMENT • • We do not use the following data for averages, fits, limits, etc. • • $-0.33$ $\pm0.28$ 23.5k 1 DEL-AMO-SANCH.. 2010 P BABR ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit D}^{*+}}{{\mathit \pi}^{-}}{{\mathit X}}$ 1  Systematic uncertainties not estimated. The states observed in the ${{\mathit D}^{*}}{{\mathit \pi}}$ and ${{\mathit D}}{{\mathit \pi}}$ final states are not necessarily the same.

References:

DEL-AMO-SANCHEZ 2010P PR D82 111101 Observation of New Resonances Decaying to ${{\mathit D}}{{\mathit \pi}}$ and ${{\mathit D}^{*}}{{\mathit \pi}}$ in Inclusive ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions near $\sqrt {s }$ = 10.58 GeV