Search for theZ(4430)−atBABAR

We report the results of a search for $Z(4430{)}^{-}$ decay to $J/\psi {\pi }^{-}$ or $\psi (2S){\pi }^{-}$ in $B^{-,0}\to J/\psi {\pi }^{-}{K}^{0,+}$ and $B^{-,0}\to \psi (2S){\pi }^{-}{K}^{0,+}$ decays. The data were collected with the BABAR detector at the SLAC PEP-II asymmetric-energy $e^{+}{e}^{-}$ collider operating at center-of-mass energy 10.58 GeV, and the sample corresponds to an integrated luminosity of $413{\mathrm{fb}}^{-1}$. Each $K{\pi }^{-}$ mass distribution exhibits clear $K^{*}(892)$ and $K_2^{*}(1430)$ signals, and the efficiency-corrected spectrum is well described by a superposition of the associated Breit-Wigner intensity distributions, together with an $S$-wave contribution obtained from the LASS $I=1/2$ $K{\pi }^{-}$ scattering amplitude measurements. Each $K{\pi }^{-}$ angular distribution varies significantly in structure with $K{\pi }^{-}$ mass, and is represented in terms of low-order Legendre polynomial moments. We find that each $J/\psi {\pi }^{-}$ or $\psi (2S){\pi }^{-}$ mass distribution is well described by the reflection of the measured $K{\pi }^{-}$ mass and angular distribution structures. We see no significant evidence for a $Z(4430{)}^{-}$ signal for any of the processes investigated, neither in the total $J/\psi {\pi }^{-}$ or $\psi (2S){\pi }^{-}$ mass distribution, nor in the corresponding distributions for the regions of $K{\pi }^{-}$ mass for which observation of the $Z(4430{)}^{-}$ signal was reported. We obtain branching-fraction upper limits $\mathcal{B}(B^{-}\to Z^{-}{\overline{K}}^0,Z^{-}\to J/\psi {\pi }^{-})<1.5\times {10}^{-5}$, $\mathcal{B}(B^0\to Z^{-}{K}^{+},Z^{-}\to J/\psi {\pi }^{-})<0.4\times {10}^{-5}$, $\mathcal{B}(B^{-}\to Z^{-}{\overline{K}}^0,Z^{-}\to \psi (2S){\pi }^{-})<4.7\times {10}^{-5}$, and $\mathcal{B}(B^0\to Z^{-}{K}^{+},Z^{-}\to \psi (2S){\pi }^{-})<3.1\times {10}^{-5}$ at 95% confidence level, where the $Z(4430{)}^{-}$ mass and width have been fixed to the reported central values.