Observation and Polarization Measurements of ${B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}\ensuremath{\phi}{K}_{1}^{\ifmmode\pm\else\textpm\fi{}}$ and ${B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}\ensuremath{\phi}{K}_{2}^{*\ifmmode\pm\else\textpm\fi{}}$

Observation and Polarization Measurements of $B^{\pm} \to ϕ K_{1}^{\pm}$ and $B^{\pm} \to ϕ K_{2}^{* \pm}$

B. Aubert et al. (BABAR Collaboration)

Phys. Rev. Lett. 101, 161801 – Published 15 October 2008

Abstract

With the full BABAR data sample of $465 \times 10^{6}$ $B \bar{B}$ pairs, we observe the decays $B^{\pm} \to φ K_{1} (1270)^{\pm}$ and $B^{\pm} \to φ K_{2}^{*} (1430)^{\pm}$ . We measure the branching fractions $(6.1 \pm 1.6 \pm 1.1) \times 10^{- 6}$ and $(8.4 \pm 1.8 \pm 1.0) \times 10^{- 6}$ and the fractions of longitudinal polarization ${0.46}_{- 0.13 - 0.07}^{+ 0.12 + 0.06}$ and ${0.80}_{- 0.10}^{+ 0.09} \pm 0.03$ , respectively. We also report on the $B^{\pm} \to φ K_{0}^{*} (1430)^{\pm}$ decay branching fraction of $(7.0 \pm 1.3 \pm 0.9) \times 10^{- 6}$ and several parameters sensitive to $C P$ violation and interference in the above three decays. Upper limits are placed on the $B^{\pm}$ decay rates to final states with $φ$ and $K_{1} (1400)^{\pm}$ , $K^{*} (1410)^{\pm}$ , $K_{2} (1770)^{\pm}$ , or $K_{2} (1820)^{\pm}$ . Understanding the observed polarization pattern requires amplitude contributions from an uncertain source.