Study of B^{+-} -> K^{+-}(K_S K pi)^0 Decay and Determination of eta_c and eta_c(2S) Parameters

Understand

We report the results of a study of $B^{\pm}\to K^{\pm}\eta_c$ and $B^{\pm}\to K^{\pm}\eta_c(2S)$ decays followed by $\eta_c$ and $\eta_c(2S)$ decays to $(K_SK\pi)^0$.

• The results are obtained from a data sample containing 535 million $B\bar{B}$-meson pairs collected by the Belle experiment at the KEKB $e^+e^-$ collider.
• We measure the products of the branching fractions ${\mathcal B}(B^{\pm}\to K^{\pm}\eta_c){\mathcal B}(\eta_c\to K_S K^{\pm}\pi^{\mp})=(26.7\pm 1.4(stat)^{+2.9}_{-2.6}(syst)\pm 4.9(model))\times 10^{-6}$ and ${\mathcal B}(B^{\pm}\to K^{\pm}\eta_c(2S)){\mathcal B}(\eta_c(2S)\to K_S K^{\pm}\pi^{\mp})=(3.4^{+2.2}_{-1.5}(stat+model)^{+0.5}_{-0.4} syst))\times 10^{-6}$.
• Interference with the non-resonant component leads to significant model uncertainty in the measurement of these product branching fractions.