# 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 $B^{\pm}\to K^{0}_{S}K^{0}_{S}\pi^{\pm}$

## TL;DR

This paper measures the branching fractions and direct CP asymmetry in specific charmless B meson decays using a large data sample from the Belle detector, providing precise results and setting upper limits where signals are not significant.

## Contribution

First precise measurement of branching fractions and CP asymmetry in $B^{
m ext{±}} o K^{0}_{S}K^{0}_{S}K^{
m ext{±}}$ decays, and the first upper limit for $B^{
m ext{±}} o K^{0}_{S}K^{0}_{S}\pi^{
m ext{±}}$.

## Key findings

- Branching fraction for $B^{
m ext{±}} o K^{0}_{S}K^{0}_{S}K^{
m ext{±}}$ is $(10.42 extpm0.43 extpm0.22) imes10^{-6}$.
- CP asymmetry in $B^{
m ext{±}} o K^{0}_{S}K^{0}_{S}K^{
m ext{±}}$ is consistent with zero.
- Upper limit on $B^{
m ext{±}} o K^{0}_{S}K^{0}_{S}\pi^{
m ext{±}}$ is $8.7 imes10^{-7}$ at 90% CL.

## Abstract

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 $772\times 10^6$ $B\bar{B}$ 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 $[10.42\pm0.43(stat)\pm 0.22(syst)]\times10^{-6}$ and [$+1.6\pm3.9(stat)\pm 0.9(syst)$]%, 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 $8.7 \times10^{-7}$.