Measurements of branching fraction and direct $C!P$ asymmetry in $B^{pm}to K^{0}_{S}K^{0}_{S}K^{pm}$ and a search for $B^{pm}to K^{0}_{S}K^{0}_{S}pi^{pm}$

We study charmless hadronic decays of charged $B$ mesons to the final states $K^{0}_{S}K^{0}_{S}K^{pm}$ and $K^{0}_{S}K^{0}_{S}pi^{pm}$ using a $711 fb^{-1}$ data sample that contains $772times 10^6$ $Bbar{B}$ pairs, and was collected at the $Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$ collider. For $B^{pm}to K^{0}_{S}K^{0}_{S}K^{pm}$, the measured branching fraction and direct $CP$ asymmetry are $[10.42pm0.43(stat)pm 0.22(syst)]times10^{-6}$ and [$+1.6pm3.9(stat)pm 0.9(syst)$]%, respectively. In the absence of a statistically significant signal for $B^{pm}to K^{0}_{S}K^{0}_{S}pi^{pm}$, we obtain a 90% confidence-level upper limit on its branching fraction as $8.7 times10^{-7}$.