Study of B-meson decays to eta_c K^(*), eta_c(2S) K^(*) and eta_c gamma K^(*)

TL;DR

This paper reports measurements of B-meson decay branching ratios to various charmonium states and kaons, providing new insights into decay dynamics and charmonium properties using data from the BABAR detector.

Contribution

First measurement of certain B-meson decay branching ratios to eta_c, eta_c(2S), and h_c states, along with precise determination of eta_c mass and width.

Findings

Measured BR(B^0→eta_c K^{*0})=(5.7±0.6±0.9)×10^{-4}

Set upper limits on h_c related decay modes

Determined eta_c mass as 2985.8±1.5±3.1 MeV/c^2

Abstract

We study two-body $B$-meson decays to a charmonium state ($\eta_c$, $\eta_c(2S)$ or $h_c$) and a $K^+$ or $K^{*0}(892)$ meson using a sample of $349 fb^{-1}$ of data collected with the BABAR detector at the PEP-II asymmetric-energy $B$ Factory at SLAC. We measure $BR(B^0\to\eta_c K^{*0})=(5.7\pm0.6 (stat)\pm0.9 (syst))\times 10^{-4}$, $BR(B^0\to\eta_c(2S) K^{*0})<3.9\times 10^{-4}$, $BR(B^+\to h_c K^+)\times BR(h_c\to\eta_c\gamma)<4.8\times 10^{-5}$ and $BR(B^0\to h_c K^{*0})\times BR(h_c\to\eta_c\gamma)<2.2\times 10^{-4}$ at the 90% C.L., and $BR(\eta_c(2S)\to K \bar{K} \pi)=(1.9\pm0.4 (stat) \pm1.1 (syst))%$. We also measure the mass and width of the $\eta_c$ meson to be $m(\eta_c)=(2985.8\pm 1.5(stat) \pm 3.1 (syst)) MeV/c^2$ and $\Gamma(\eta_c)=(36.3^{+3.7}_{-3.6} (stat) \pm 4.4 (syst)) MeV$.