Measurement of the inclusive $B\to X_{s+d}\gamma$ branching fraction, photon energy spectrum and HQE parameters

We report a measurement of the inclusive $B\to X_{s+d}\gamma$ and $B\to X_{s} \gamma$branchingfractionsusingadatasetof$(772 \pm 11)\times 10^6$ $B\bar{B}$ pairs collected at the $\mathrm{{\rm Y}}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. Results are presented for photon energy thresholds between 1.7 to 2.0 GeV. For the 1.8 GeV threshold we find $$\mathcal{B}${s\gamma} = (3.01 \pm 0.10~$\text{(stat)}$ \pm 0.18~$\text{(syst)}$ \pm 0.08~$\text{(model)}$)\times 10^{-4}$. The Heavy Quark Expansion parameters that best fit the spectrum in the shape-function scheme are $m_b=(4.626\pm 0.028)\text{GeV}$ and $ \mu{\pi}^{2} = (0.301\pm 0.063) $\text{GeV}$^2$.