Study of $D^{\ast \ast }$ production and light hadronic states in the ${\bar{B}}^0\to D^{\ast +}\ddot{I}‰\ddot{I}{€}^{-}$ decay

Abstract

We report on the first observations of ${\bar{B}}^0\to D_1(2430{)}^0\ddot{I}‰$, ${\bar{B}}^0\to D_1(2420{)}^0\ddot{I}‰$ and ${\bar{B}}^0\to D_2^{\ast }(2460{)}^0\ddot{I}‰$ decays. The ${\bar{B}}^0\to D^{\ast +}\ddot{I}(1450{)}^{-}$ decay is also observed. The branching fraction measurements are based on $(771.6\pm 10.6)\times 10^6$ $B\bar{B}$ events collected at the $\hat{I}\yen (4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. The fractions of longitudinal polarization of the $D^{\ast \ast }$ states as well as partial wave fractions of the $D_1(2430{)}^0$ are obtained. We also set a $90\%$ confidence level upper limit for the product of branching fractions of $\mathcal{B}({\bar{B}}^0\to D^{\ast +}{b}_1(1235{)}^{-})\times \mathcal{B}(b_1(1235{)}^{-}\to \ddot{I}‰\ddot{I}{€}^{-})$. The measurements show evidence of nontrivial final-state interaction phases for the $\ddot{I}$-like amplitudes.

29 pages, 12 figures, submitted to Physical Review D