Evidence for the decay B0->eta pi^0

We report a search for the charmless hadronic decay $B^0\to \eta {\pi }^0$ with a data sample corresponding to an integrated luminosity of 694 $\mathrm{f}{\mathrm{b}}^{-1}$ containing $753\times {10}^6$ $B\bar{B}$ pairs. The data were collected by the Belle experiment running on the $\mathrm{{\rm Y}}(4S)$ resonance at the KEKB $e^{+}{e}^{-}$ collider. We measure a branching fraction $\mathcal{B}(B^0\to \eta {\pi }^0)=(4.1_{-1.5-0.7}^{+1.7+0.5})\times {10}^{-7}$, where the first uncertainty is statistical and the second is systematic. Our measurement gives an upper limit of $$\mathcal{B}$(B^0\to\eta\pi^0)<6.5\times 10^{-7}$at90\mathrm{\%}confidencelevel\mathrm{.}Thesignalhasasignificanceof$3.0$ standard deviations and constitutes the first evidence for this decay mode.