| Abstract: | We report on a Belle II measurement of the branching fraction
($mathcal{B}$), longitudinal polarization fraction ($f_L$), and CP asymmetry
($mathcal{A}_{CP}$) of $B^+ o
ho^+
ho^0$ decays. We reconstruct $B^+ o
ho^+( o pi^+pi^0( o gammagamma))
ho^0( o pi^+pi^-)$ decays in a
sample of SuperKEKB electron-positron collisions collected by the Belle II
experiment in 2019, 2020, and 2021 at the $Upsilon$(4S) resonance and
corresponding to 190 fb$^{-1}$ of integrated luminosity. We fit the
distributions of the difference between expected and observed $B$ candidate
energy, continuum-suppression discriminant, dipion masses, and decay angles of
the selected samples, to determine a signal yield of $345 pm 31$ events. The
signal yields are corrected for efficiencies determined from simulation and
control data samples to obtain $mathcal{B}(B^+ o
ho^+
ho^0) = [23.2^{+
2.2}_{- 2.1} (
m stat) pm 2.7 (
m syst)] imes 10^{-6}$, $f_L = 0.943 ^{+
0.035}_{- 0.033} (
m stat)pm 0.027(
m syst)$, and $mathcal{A}_{CP}=-0.069
pm 0.068(
m stat) pm 0.060 (
m syst)$. The results agree with previous
measurements. This is the first measurement of $mathcal{A}_{CP}$ in $B^+ o
ho^+
ho^0$ decays reported by Belle II. |
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