Evidence for the decay B0→ppˉπ0B^0\to p\bar{p}\pi^0

International audienceWe report a search for the charmless baryonic decay B0→pp¯π0 with a data sample corresponding to an integrated luminosity of 711  fb-1 containing (772±10)×106 BB¯ pairs. The data were collected by the Belle experiment running on the ϒ(4S) resonance at the KEKB e+e- collider. We measure a branching fraction B(B0→pp¯π0)=(5.0±1.8±0.6)×10-7, where the first uncertainty is statistical and the second is systematic. The signal has a significance of 3.1 standard deviations and constitutes the first evidence for this decay mode. We also search for the intermediate two-body decays B0→Δ+p¯ and B0→Δ¯-p, and set an upper limit on the branching fraction, B(B0→Δ+p¯)+B(B0→Δ¯-p)<1.6×10-6 at 90% confidence level

Study of χbJ(nP)→ωΥ(1S)\chi_{bJ}(nP) \rightarrow \omega \Upsilon(1S) at Belle

We report results from a study of hadronic transitions of the $\chi_{bJ}(nP)$ states of bottomonium at Belle. The $P$-wave states are reconstructed in transitions to the $\Upsilon(1S)$ with the emission of an $\omega$ meson. The transitions of the $n=2$ triplet states provide a unique laboratory in which to study nonrelativistic quantum chromodynamics, as the kinematic threshold for production of an $\omega$ and $\Upsilon(1S)$ lies between the $J=0$ and $J=1$ states. A search for the $\chi_{bJ}(3P)$ states is also reported

Rediscovery of B0→J/ψKL0B^0 \rightarrow J/\psi K^0_L at Belle II

We present preliminary results on the reconstruction of the $B^0\to J\mskip 1mu / \psi\mskip 2mu K^0_{\scriptscriptstyle L}$ decay, where $J\mskip 1mu / \psi\mskip 2mu\to\mu^+\mu^-$ or $e^+e^-$. Using a dataset corresponding to a luminosity of 62.8\pm0.6\mbox{fb}^{-1} collected by the Belle II experiment at the SuperKEKB asymmetric energy $e^+e^-$ collider, we measure a total of $267\pm21$ candidates with $J\mskip 1mu / \psi\mskip 2mu\to\mu^+\mu^-$ and $226\pm20$ with with $J\mskip 1mu / \psi\mskip 2mu\to e^+e^-$. The quoted errors are statistical only

Measurements of branching fractions and direct CP-violating asymmetries in B+→K+π0B^+ \to K^+ \pi^0 and π+π0\pi^+ \pi^0 decays using 2019 and 2020 Belle II data

We report measurements of branching fractions ($\mathcal B$) and direct ${\it CP}$-violating asymmetries ($\mathcal A_{\it CP}$) for the decays $B^+\to K^+\pi^0$ and $B^+ \to \pi^+\pi^0$ reconstructed with the Belle II detector in a sample of asymmetric-energy electron-positron collisions at the $\Upsilon(4S)$ resonance corresponding to 62.8 $\text{fb}^{-1}$ of integrated luminosity. The results are $\mathcal{B}(B^+ \to K^+\pi^0) = [11.9 ^{+1.1}_{-1.0} (\rm stat)\pm 1.6(\rm syst)]\times 10^{-6}$, $\mathcal{B}(B^+ \to \pi^+\pi^0) = [5.5 ^{+1.0}_{-0.9} (\rm stat)\pm 0.7(\rm syst)]\times 10^{-6}$, $\mathcal A_{\it CP}(B^+ \to K^+\pi^0) = -0.09 \pm 0.09 (\rm stat)\pm 0.03(\rm syst)$, and $\mathcal A_{\it CP}(B^+ \to \pi^+\pi^0) = -0.04 \pm 0.17 (\rm stat)\pm 0.06(\rm syst)$. The results are consistent with previous measurements and show a detector performance comparable with early Belle performance

Measurement of the BB−^{-} →\rightarrow DD0^{0}ℓ\ell−^{-}νˉ\bar{\nu}ℓ_{\ell} Branching Fraction in 62.8 fb−1^{-1} of Belle II data

We report a measurement of the branching fraction of the semileptonic decay $B$$^{-}$ $\rightarrow$ $D$$^{0}$$\ell$$^{-}$$\bar{\nu}$$_{\ell}$ (and its charge conjugate) using 62.8 fb$^{-1}$ of $\Upsilon$(4$S$) $\rightarrow$ $B$$\bar{B}$ data recorded by the Belle II experiment at the SuperKEKB asymmetric-energy $e$$^{+}$ $e$$^{-}$ collider. The neutral charm meson is searched for in the decay mode $D$$^{0}$ $\rightarrow$ $K$$^{-}$ $\pi$$^{+}$ and combined with a properly charged identified lepton (electron or muon) to reconstruct this decay. No reconstruction of the second $B$ meson in the $\Upsilon$(4$S$) event is performed. We obtain $B$($D$$^{0}$$\ell$$^{-}$$\bar{\nu}$$_{\ell}$) = (2.29 $\pm$ 0.05 $_{stat}$ $\pm$ 0.08$_{syst}$, in agreement with the world average of this decay. We also determine the ratio of the electron to muon branching fractions to be $R$($e$/$\mu$) = 1.04 $\pm$ 0.05$_{stat}$ $\pm$ 0.03$_{syst}$ and observe no deviation from lepton universality

Measurement of the BB−^{-} →\rightarrow DD0^{0}ℓ\ell−^{-}νˉ\bar{\nu}ℓ_{\ell} Branching Fraction in 62.8 fb−1^{-1} of Belle II data

We report a measurement of the branching fraction of the semileptonic decay $B$$^{-}$ $\rightarrow$ $D$$^{0}$$\ell$$^{-}$$\bar{\nu}$$_{\ell}$ (and its charge conjugate) using 62.8 fb$^{-1}$ of $\Upsilon$(4$S$) $\rightarrow$ $B$$\bar{B}$ data recorded by the Belle II experiment at the SuperKEKB asymmetric-energy $e$$^{+}$ $e$$^{-}$ collider. The neutral charm meson is searched for in the decay mode $D$$^{0}$ $\rightarrow$ $K$$^{-}$ $\pi$$^{+}$ and combined with a properly charged identified lepton (electron or muon) to reconstruct this decay. No reconstruction of the second $B$ meson in the $\Upsilon$(4$S$) event is performed. We obtain $B$($D$$^{0}$$\ell$$^{-}$$\bar{\nu}$$_{\ell}$) = (2.29 $\pm$ 0.05 $_{stat}$ $\pm$ 0.08$_{syst}$, in agreement with the world average of this decay. We also determine the ratio of the electron to muon branching fractions to be $R$($e$/$\mu$) = 1.04 $\pm$ 0.05$_{stat}$ $\pm$ 0.03$_{syst}$ and observe no deviation from lepton universality

First search for direct CPCP-violating asymmetry in B0→K0π0B^0 \to K^0 \pi^0 decays at Belle II

We report on the first measurement of the direct $CP$-violating asymmetry ($\mathcal{A}$) in the charmless decay $B^0 \to K^0\pi^0$ at Belle II and an updated measurement of its branching fraction ($\mathcal{B}$). We use a sample of electron-positron collisions collected in 2019 and 2020 at the $\Upsilon(4S)$ resonance and corresponding to $62.8$$\text{fb}^{-1}$ of integrated luminosity. We reconstruct and select about $50$$B^0 \to K_S^0 \pi^0$ candidates, and we measure $\mathcal{A}_{{K^0\pi^0}} = -0.40_{-0.44}^{+0.46} (\text{stat}) \pm 0.04 (\text{syst})$ and $\mathcal{B}(B^0 \to K^0 \pi^0) = [8.5_{-1.6}^{+1.7} (\text{stat}) \pm 1.2 (\text{syst})] \times 10^{-6}$. This is the first measurement of $CP$ violation in $B^0 \to K^0\pi^0$ decays reported by Belle II. The results agree with previous determinations and show a detector performance comparable with the best Belle results

Measurement of the branching fraction for B0→π0π0B^{0} \rightarrow \pi^{0} \pi^{0} decays reconstructed in 2019-2020 Belle II data

International audienceWe report the first reconstruction of the $B^{0} \to \pi^{0} \pi^{0}$ decay mode at Belle II using samples of 2019 and 2020 data that correspond to 62.8 fb$^{-1}$ of integrated luminosity. We find $14.0^{+6.8}_{-5.6}$ signal decays, corresponding to a significance of 3.4 standard deviations and determine a branching ratio of $\mathcal{B}(B^{0} \rightarrow \pi^{0} \pi^{0}) = [0.98^{+0.48}_{-0.39} \pm 0.27] \times 10^{-6}$. The results agree with previous determinations and contribute important information to an early assessment of detector performance and Belle II's potential for future determinations of $\alpha/\phi_2$ using $B \rightarrow \pi \pi$ modes

Rediscovery of B0→J/ψKL0B^0 \rightarrow J/\psi K^0_L at Belle II

We present preliminary results on the reconstruction of the $B^0\to J\mskip 1mu / \psi\mskip 2mu K^0_{\scriptscriptstyle L}$ decay, where $J\mskip 1mu / \psi\mskip 2mu\to\mu^+\mu^-$ or $e^+e^-$. Using a dataset corresponding to a luminosity of 62.8\pm0.6\mbox{fb}^{-1} collected by the Belle II experiment at the SuperKEKB asymmetric energy $e^+e^-$ collider, we measure a total of $267\pm21$ candidates with $J\mskip 1mu / \psi\mskip 2mu\to\mu^+\mu^-$ and $226\pm20$ with with $J\mskip 1mu / \psi\mskip 2mu\to e^+e^-$. The quoted errors are statistical only

Measurements of branching fractions and CP-violating charge asymmetries in multibody charmless BB decays reconstructed in 2019-2020 Belle II data

We report on measurements of branching fractions ($\mathcal{B}$) and CP-violating charge asymmetries ($\mathcal{A}_{\rm CP}$) of multibody charmless $B$ decays reconstructed by the Belle II experiment at the SuperKEKB electron-positron collider. We use a sample of collisions collected in 2019 and 2020 at the $\Upsilon(4S)$ resonance and corresponding to $62.8$ fb$^{-1}$ of integrated luminosity. We use simulation to determine optimized event selections. The $\Delta E$ and $M_{\rm bc}$ distributions of the resulting samples are fit to determine signal yields of approximately 690, 840, and 380 decays for the channels $B^+ \to K^+K^-K^+$, $B^+ \to K^+\pi^-\pi^+$, and $B^0 \to K^+\pi^-\pi^0$, respectively. These yields are corrected for efficiencies determined from simulation and control data samples to obtain $\mathcal{B}(B^+ \to K^+K^-K^+) = [35.8 \pm 1.6(\rm stat) \pm 1.4 (\rm syst)]\times 10^{-6}$, $\mathcal{B}(B^+ \to K^+\pi^-\pi^+) = [67.0 \pm 3.3 (\rm stat)\pm 2.3 (\rm syst)]\times 10^{-6}$, $\mathcal{B}(B^0 \to K^+\pi^-\pi^0) = [38.1 \pm 3.5 (\rm stat)\pm 3.9 (\rm syst)]\times 10^{-6}$, $\mathcal{A}_{\rm CP}(B^+ \to K^+K^-K^+) = -0.103 \pm 0.042(\rm stat) \pm 0.020 (\rm syst)$, $\mathcal{A}_{\rm CP}(B^+ \to K^+\pi^-\pi^+) = -0.010 \pm 0.050 (\rm stat)\pm 0.021(\rm syst)$, and $\mathcal{A}_{\rm CP}(B^0 \to K^+\pi^-\pi^0) = 0.207 \pm 0.088 (\rm stat)\pm 0.011(\rm syst)$. Results are consistent with previous measurements and demonstrate detector performance comparable with the best Belle results