Dalitz analysis ofB→Kπ+ψ′decays and theZ(4430)+

From a Dalitz plot analysis of $B\to K{\pi }^{+}{\psi }^{\prime }$ decays, we find a signal for $Z(4430{)}^{+}\to {\pi }^{+}{\psi }^{\prime }$ with a mass $M=({4443}_{-12-13}^{+15+19})\mathrm{MeV}/c^2$, width $\Gamma =({107}_{-43-56}^{+86+74})\mathrm{MeV}$, product branching fraction $\mathcal{B}({\overline{B}}^0\to K^{-}Z(4430{)}^{+})\times \mathcal{B}(Z(4430{)}^{+}\to {\pi }^{+}{\psi }^{\prime })=({3.2}_{-0.9-1.6}^{+1.8+5.3})\times {10}^{-5}$, and significance of $6.4\sigma$ that agrees with previous Belle measurements based on the same data sample. In addition, we determine the branching fraction $\mathcal{B}(B^0\to K^{*}(892{)}^0{\psi }^{\prime })=({5.52}_{-0.32-0.58}^{+0.35+0.53})\times {10}^{-4}$ and the fraction of $K^{*}(892{)}^0$ mesons that are longitudinally polarized $f_L=({44.8}_{-2.7-5.3}^{+4.0+4.0})\%$. These results are obtained from a $605{\mathrm{fb}}^{-1}$ data sample that contains $657\times {10}^6$ $B\overline{B}$ pairs collected near the ${\rm Y}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider.