Measurement of the Branching Fraction of the Decay B+→π+π−ℓ+νℓ\boldsymbol{B^{+}\to\pi^{+}\pi^{-}\ell^{+}\nu_\ell} in Fully Reconstructed Events at Belle

We present an analysis of the exclusive $B^{+}\to\pi^{+}\pi^{-}\ell^{+}\nu_{\ell}$ decay, where $\ell$ represents an electron or a muon, with the assumption of charge-conjugation symmetry and lepton universality. The analysis uses the full $\Upsilon(4S)$ data sample collected by the Belle detector, corresponding to 711 fb$^{-1}$ of integrated luminosity. We select the events by fully reconstructing one $B$ meson in hadronic decay modes, subsequently determining the properties of the other $B$ meson. We extract the signal yields using a binned maximum-likelihood fit to the missing-mass squared distribution in bins of the invariant mass of the two pions or the momentum transfer squared. We measure a total branching fraction of ${{\cal B}(B^{+}\to \pi^{+}\pi^{-}\ell^{+}\nu_{\ell})= [22.7 ^{+1.9}_{-1.6} (\mathrm{stat}) \pm 3.5(\mathrm{syst}) ]\times 10^{-5}}$, where the uncertainties are statistical and systematic, respectively. This result is the first reported measurement of this decay.Comment: 23 pages, 19 figure

Evidence for a vector charmonium-like state in e+e−→Ds+Ds2∗(2573)−+c.c.e^+e^- \to D^+_sD^*_{s2}(2573)^-+c.c.

We report the measurement of $e^+e^- \to D^+_sD^*_{s2}(2573)^-+c.c.$ via initial-state radiation using a data sample of an integrated luminosity of 921.9 fb$^{-1}$ collected with the Belle detector at the $\Upsilon(4S)$ and nearby. We find evidence for an enhancement with a 3.4$\sigma$ significance in the invariant mass of $D^+_sD^*_{s2}(2573)^- +c.c.$ The measured mass and width are $(4619.8^{+8.9}_{-8.0}({\rm stat.})\pm2.3({\rm syst.}))~{\rm MeV}/c^{2}$ and $(47.0^{+31.3}_{-14.8}({\rm stat.})\pm4.6({\rm syst.}))~{\rm MeV}$, respectively. The mass, width, and quantum numbers of this enhancement are consistent with the charmonium-like state at 4626 MeV/$c^2$ recently reported by Belle in $e^+e^-\to D^+_sD_{s1}(2536)^-+c.c.$ The product of the $e^+e^-\to D^+_sD^*_{s2}(2573)^-+c.c.$ cross section and the branching fraction of $D^*_{s2}(2573)^-\to{\bar D}^0K^-$ is measured from $D^+_sD^*_{s2}(2573)^-$ threshold to 5.6 GeV.Comment: 9 pages, 4 figure

Screening for cerebrovascular disorder on the basis of family history in asymptomatic children

Background: Cerebrovascular disorders represent a group of uncommon, heterogeneous, and complex conditions in children. We reviewed the screening practice for the detection of cerebrovascular disorder in asymptomatic children referred to our neurovascular service on the basis of a positive family history and parental and/or treating physician concern.Methods: Retrospective case-note review of referrals to our neurovascular service (July 2008-April 2018). Patients were included if the referral was made for screening, on the basis of a positive family history of cerebrovascular disorder. Symptomatic children, those with previous cranial imaging, or children under the care of a clinical geneticist (i.e. due to the child or their relative having HHT or mutations in KRIT1) were not eligible for inclusion.Results: Forty-one children were reviewed, 22 males (Median age 10.7 years, range 0.6-15.6 years). This represented 22% of the total number of referrals over a 10-year period. Twenty-nine children had an MRI/MRA brain. Twenty-eight children were referred due to a family history of intracranial aneurysm and/or subarachnoid haemorrhage, but only two had two first-degree relatives affected. Ten children were referred due to a family history of arteriovenous malformation. Three children were referred due to a family history of stroke. No cerebrovascular disease was detected during the study period (n = 29).Conclusions: Parental and/or physician concern generated a substantial number of referrals but no pathology was detected after screening. Whilst general screening guidance exists for the detection of intracranial aneurysms, consensus guidelines for the screening of children with a positive family history do not, but are required both to guide clinical practice and to assuage parental and/or physician concerns

Measurement of the branching fraction and time-dependent CP asymmetry for B⁰ → J/ψπ⁰ decays

We measure the branching fraction and time-dependent CP-violating asymmetry for B0→J/ψπ0 decays using a data sample of 711  fb−1 collected on the Υ(4S) resonance by the Belle experiment running at the KEKB e+e− collider. The branching fraction is measured to be B(B0→J/ψπ0)=[1.62±0.11(stat)±0.06(syst)]×10−5, which is the most precise measurement to date. The measured CP asymmetry parameters are S=−0.59±0.19(stat)±0.03(syst) and A=−0.15±0.14(stat) +0.04 −0.03(syst). The mixing-induced CP asymmetry (S) differs from the case of no CP violation by 3.0 standard deviations, and the direct CP asymmetry (A) is consistent with zero

Measurement of B(Bs_{s} →ds_{s}X) with Bs_{s} semileptonic tagging

We report the first direct measurement of the inclusive branching fraction B(B$_{s}$ →D$_{s}$X) via B$_{s}$ tagging in e$^{+}$e$^{–}$→Υ(5S) events. Tagging is accomplished through a partial reconstruction of semileptonic decays B$_{s}$→D$_{s}$Xℓν, where X denotes unreconstructed additional hadrons or photons and ℓ is an electron or muon. With 121.4 fb$^{–1}$ of data collected at the Υ(5S) resonance by the Belle detector at the KEKB asymmetric-energy e$^{+}$e$^{–}$ collider, we obtain B(B$_{s}$ →D$_{s}$X)=(60.2±5.8±2.3)%, where the first uncertainty is statistical and the second is systematic

Observation of e+^{+}e−^{-} -> π+^{+}π−^{-}π0^{0}χb1,2_{b1,2}(1P\textit{P}) and search for e+^{+}e−^{-} -> ϕχb1,2_{b1,2}(1P\textit{P}) at s\sqrt{s} = 10.96−-11.05 GeV

We report searches for the processes e$^{+}$e$^{-}$ → π$^{+}$π$^{-}$π$^{0}$χ$_{bj}$ and e$^{+}$e$^{-}$ → ϕχ$_{bj}$ (J=1, 2) based on data samples collected by the Belle experiment at the KEKB collider. We report the first observation of the process e$^{+}$e$^{-}$ → $^{+}$π$^{-}$π$^{0}$$_{non−ωχb1}$ and first evidence for e$^{+}$e$^{-}$ → ωχbJ in the vicinity of the Υ(11020) resonance, with center-of-mass energies from 10.96 to 11.05 GeV. The significances for $^{+}$π$^{-}$π$^{0}$$_{non−ωχb1}$ and ωχbJ are greater than 5.3σ and 4.0σ, respectively. We also investigate the energy dependence of the e$^{+}$e$^{-}$ →$^{+}$π$^{-}$π$^{0}$χbJ cross section, but we cannot determine whether the contributions are from the Υ(10860) and Υ(11020) resonances or nonresonant continuum processes. The signals for e$^{+}$e$^{-}$ → ϕ$_{χbj}$ are not significant, and the upper limits of the Born cross sections at the 90% confidence level are 0.7 and 1.0 pb for e$^{+}$e$^{-} → ϕχb1 and ϕχb2, respectively, for center-of-mass energies from 10.96 to 11.05 GeV

Measurement of the branching fraction of Ξc0→Λc+π−\Xi_{c}^{0}\to \Lambda_{c}^{+}\pi^{-} at Belle

Based on a data sample of 983 fb$^{-1}$ collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider, we present the study of the heavy-flavor-conserving decay $\Xi_{c}^{0}\to \Lambda_{c}^{+}\pi^{-}$ with $\Lambda_{c}^{+}$ reconstructed via its $pK^{-} \pi^{+}$ decay mode. The branching fraction ratio $\mathcal{B}(\Xi_{c}^{0}\to \Lambda_{c}^{+}\pi^{-})/\mathcal{B}(\Xi_{c}^{0}\to \Xi^{-}\pi^{+})$ is measured to be $0.38 \pm 0.04 \pm 0.04$. Combing with the world average value of $\mathcal{B}(\Xi_{c}^{0}\to \Xi^{-}\pi^{+})$, the branching fraction $\mathcal{B}(\Xi_{c}^{0}\to \Lambda_{c}^{+}\pi^{-})$ is deduced to be $(0.54 \pm 0.05 \pm 0.05 \pm 0.12)\%$. Here, the uncertainties above are statistical, systematic, and from $\mathcal{B}(\Xi_c^{0} \to \Xi^{-}\pi^{+})$, respectively.Comment: 5 pages, 4 figure