Measurement of branching fractions and search for CP violation in D0 → π+π−η, D0 → K+K−η, and D0 → ϕη at Belle

We measure the branching fractions and $CP$ asymmetries for singly Cabibbo-suppressed decays $D^{0}\to\pi^{+}\pi^{-}\eta$, $D^{0}\to K^{+}K^{-}\eta$, $D^{0}\to\phi\eta$, using 980 fb$^{-1}$ of data from Belle experiment at KEKB $e^+e^-$ collider. obtain \begin{eqnarray} \mathcal{B}(D^{0}\to\pi^{+}\pi^{-}\eta) & = [1.22\pm 0.02\,({\rm stat})\pm syst})\pm 0.03\,(\mathcal{B}_{\rm ref})]\times 10^{-3}\,, \nonumber \\ \mathcal{B}(D^{0}\to K^{+}K^{-}\eta) [1.80\,^{+0.07}_{-0.06}\,({\rm 0.04\,({\rm 0.05\,(\mathcal{B}_{\rm 10^{-4}\,, \mathcal{B}(D^{0}\to\phi\eta) [1.84\pm 0.09\,({\rm 0.06\,({\rm \end{eqnarray} where third uncertainty ($\mathcal{B}_{\rm ref}$) is in fraction reference mode K^{-}\pi^{+}\eta$. The color-suppressed decay $D^{0}\to\phi\eta$ observed first time, with very high significance. results are A_{CP}(D^{0}\to\pi^{+}\pi^{-}\eta) [0.9\pm 1.2\,({\rm 0.5\,({\rm syst})]\%\,, A_{CP}(D^{0}\to [-1.4\pm 3.3\,({\rm 1.1\,({\rm A_{CP}(D^{0}\to\phi\eta)&= [-1.9\pm 4.4\,({\rm 0.6\,({\rm syst})]\%\,. $D^{0}\to\pi^{+}\pi^{-}\eta$ a significant improvement over previous results. $A_{CP}$ result such measurements. No evidence violation found any these decays.