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 KS0KS0K± and KS0KS0π± using a 711  fb-1 data sample that contains 772×106 BB¯ pairs and was collected at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. For B±→KS0KS0K±, the measured branching fraction and direct CP asymmetry are [10.42±0.43(stat)±0.22(syst)]×10-6 and [+1.6±3.9(stat)±0.9(syst)]%, respectively. In the absence of a statistically significant signal for B±→KS0KS0π±, we obtain a 90% confidence-level upper limit on its branching fraction as 8.7×10-7.