A. Ishikawa
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View article: Radiation damage study of Belle II silicon strip sensors with 90 MeV electron irradiation
Radiation damage study of Belle II silicon strip sensors with 90 MeV electron irradiation Open
The silicon strip sensors of the Belle II silicon vertex detector were irradiated with 90 MeV electron beams up to an equivalent 1-MeV-neutron fluence of $3.0\times 10^{13}~{\rm n}_{\rm eq}/{\rm cm^2}$. We measure changes in sensor propert…
View article: Search for a pentaquark state decaying into pJ/ψ in Υ(1, 2S) inclusive decays at Belle
Search for a pentaquark state decaying into pJ/ψ in Υ(1, 2S) inclusive decays at Belle Open
A bstract Using the data samples of 102 million Υ(1 S ) and 158 million Υ(2 S ) events collected by the Belle detector, we search for a pentaquark state in the pJ/ψ final state from Υ(1 , 2 S ) inclusive decays. Here, the charge-conjugate …
View article: Search for lepton-flavor-violating tau decays to ℓα at Belle
Search for lepton-flavor-violating tau decays to ℓα at Belle Open
A bstract We report a search for the lepton-flavor-violating decays τ ± → ℓ ± α ( ℓ = e , μ ), where α is an undetected spin-0 particle, such as an axion-like particle using 736 × 10 6 tau lepton pairs collected by the Belle detector at th…
View article: Charged-hadron identification at Belle II
Charged-hadron identification at Belle II Open
The Belle II experiment's ability to identify particles critically affects the sensitivity of its measurements. We describe Belle II's algorithms for identifying charged particles and evaluate their performance in separating pions, kaons, …
View article: The Silicon Vertex Detector of the Belle II Experiment
The Silicon Vertex Detector of the Belle II Experiment Open
International audience
View article: Reinstallation and performance of the Belle II Silicon Vertex Detector
Reinstallation and performance of the Belle II Silicon Vertex Detector Open
At the beginning of 2024, the data taking of the Belle II experiment resumed after the long-shutdown 1, required to install a new two-layer DEPFET detector (PXD) and upgrade accelerator components. The whole silicon tracker (VXD) was extra…
View article: Production cross sections of light and charmed mesons in $e^+e^-$ annihilation near 10.58 GeV
Production cross sections of light and charmed mesons in $e^+e^-$ annihilation near 10.58 GeV Open
We report measurements of production cross sections for $ρ^+$, $ρ^0$, $ω$, $K^{*+}$, $K^{*0}$, $ϕ$, $η$, $K_S^0$, $f_0(980)$, $D^+$, $D^0$, $D_s^+$, $D^{*+}$, $D^{*0}$, and $D^{*+}_s$ in $e^+e^-$ collisions at a center-of-mass energy near …
View article: Operational experience and performance of the Belle II silicon vertex detector after the first SuperKEKB long shutdown
Operational experience and performance of the Belle II silicon vertex detector after the first SuperKEKB long shutdown Open
The Belle II experiment searches for beyond-the-standard-model physics using the Belle II detector and SuperKEKB collider. The silicon vertex detector (SVD) is crucial for particle tracking. After the 1.5-year shutdown from June 2022, Run …
View article: Evidence of $h_{b}(\text{2P}) \to Υ(\text{1S})η$ decay and search for $h_{b}(\text{1P,2P}) \to Υ(\text{1S})π^0$ with the Belle detector
Evidence of $h_{b}(\text{2P}) \to Υ(\text{1S})η$ decay and search for $h_{b}(\text{1P,2P}) \to Υ(\text{1S})π^0$ with the Belle detector Open
We report the first evidence for the $h_{b}(\text{2P}) \to Υ(\text{1S})η$ transition with a significance of $3.5$ standard deviations. The decay branching fraction is measured to be $\mathcal{B}[h_{b}(\text{2P}) \to Υ(\text{1S})η]=(7.1 ~^{…
View article: The Belle II Detector Upgrades Framework Conceptual Design Report
The Belle II Detector Upgrades Framework Conceptual Design Report Open
We describe the planned near-term and potential longer-term upgrades of the Belle II detector at the SuperKEKB electron-positron collider operating at the KEK laboratory in Tsukuba, Japan. These upgrades will allow increasingly sensitive s…
View article: The Silicon Vertex Detector of the Belle II Experiment
The Silicon Vertex Detector of the Belle II Experiment Open
International audience
View article: The Vertex Detector Upgrade of the Belle II Experiment
The Vertex Detector Upgrade of the Belle II Experiment Open
International audience
View article: Search for a heavy neutral lepton that mixes predominantly with the tau neutrino
Search for a heavy neutral lepton that mixes predominantly with the tau neutrino Open
We report a search for a heavy neutral lepton (HNL) that mixes predominantly with ντ. The search utilizes data collected with the Belle detector at the KEKB asymmetric energy e+e− collider. The data sample was collected at and just below t…
View article: Search for Two-Body $B$ Meson Decays to $Λ^{0}$ and $Ω^{(*)0}_{c}$
Search for Two-Body $B$ Meson Decays to $Λ^{0}$ and $Ω^{(*)0}_{c}$ Open
We report the results of the first search for Standard Model and baryon-number-violating two-body decays of the neutral $B$ mesons to $Λ^{0}$ and $Ω^{(*)0}_c$ using 711~${\rm fb^{-1}}$ of data collected at the $Υ(4S)$ resonance with the Be…
View article: Angular analysis of $B \to K^* e^+ e^-$ in the low-$q^2$ region with new electron identification at Belle
Angular analysis of $B \to K^* e^+ e^-$ in the low-$q^2$ region with new electron identification at Belle Open
We perform an angular analysis of the $B\to K^* e^+ e^-$ decay for the dielectron mass squared, $q^2$, range of $0.0008$ to $1.1200 ~\text{GeV}^2 /c^4$ using the full Belle data set in the $K^{*0} \to K^+ π^-$ and $K^{*+} \to K_S^0 π^+$ ch…
View article: Search for a pentaquark state decaying into $pJ/ψ$ in $Υ(1,2S)$ inclusive decays at Belle
Search for a pentaquark state decaying into $pJ/ψ$ in $Υ(1,2S)$ inclusive decays at Belle Open
Using the data samples of 102 million $Υ(1S)$ and 158 million $Υ(2S)$ events collected by the Belle detector, we search for a pentaquark state in the $pJ/ψ$ final state from $Υ(1,2S)$ inclusive decays. Here, the charge-conjugate $\bar{p}J/…
View article: Search for charged-lepton flavor violation in Υ(2S) → ℓ∓τ± (ℓ = e, μ) decays at Belle
Search for charged-lepton flavor violation in Υ(2S) → ℓ∓τ± (ℓ = e, μ) decays at Belle Open
A bstract We report a search for the charged-lepton flavor violation in Υ(2 S ) → ℓ ∓ τ ± ( ℓ = e, μ ) decays using a 25 fb − 1 Υ(2 S ) sample collected by the Belle detector at the KEKB e + e − asymmetric-energy collider. We find no evide…
View article: Silicon vertex detector of the Belle II experiment
Silicon vertex detector of the Belle II experiment Open
The silicon vertex detector (SVD) is installed at the heart of the Belle II experiment, taking data at the high-luminosity B-Factory SuperKEKB since 2019. The SVD is a four-layer double-sided strip detector with tracking and particle-ident…
View article: Search for Baryon-Number-Violating Processes in $B^-$ Decays to the $\barΞ_{c}^{0} \barΛ_{c}^{-}$ Final State
Search for Baryon-Number-Violating Processes in $B^-$ Decays to the $\barΞ_{c}^{0} \barΛ_{c}^{-}$ Final State Open
We report the results of the first search for $B^-$ decays to the $\barΞ_{c}^{0} \barΛ_{c}^{-}$ final state using 711~${\rm fb^{-1}}$ of data collected at the $Υ(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+ e^-…
View article: Belle II observation prospects for axionlike particle production from <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>B</mml:mi></mml:math> meson annihilation decay
Belle II observation prospects for axionlike particle production from meson annihilation decay Open
We investigate a new production mechanism of axionlike particle (ALP) from B meson annihilation decays and its observation potential at the Belle and Belle II experiments. This mechanism allows for the production of ALP from B meson decays…
View article: Measurements of the branching fraction, polarization, and $CP$ asymmetry for the decay $B^0\rightarrow ωω$
Measurements of the branching fraction, polarization, and $CP$ asymmetry for the decay $B^0\rightarrow ωω$ Open
We present a measurement of $B^{0} \rightarrow ωω$, a charmless decay into two vector mesons, using 772 $\times 10^6$ $B\overline{B}$ pairs collected with the Belle detector at the KEKB $e^+e^-$ collider. The decay is observed with a signi…
View article: The Silicon Vertex Detector of the Belle II Experiment
The Silicon Vertex Detector of the Belle II Experiment Open
The Belle II experiment started data-taking in March 2019. \nThe silicon vertex detector (SVD), part of the Belle II tracking system, has been operating smoothly and reliably.\nThe data quality has been confirmed through various metrics su…
View article: Silicon Vertex Detector of the Belle II Experiment
Silicon Vertex Detector of the Belle II Experiment Open
The silicon vertex detector (SVD) is installed at the heart of the Belle II experiment, taking data at the high-luminosity $B$-Factory SuperKEKB since 2019. The detector has shown a stable and above-99\% hit efficiency, with a large signal…
View article: Search for the semileptonic decays $Ξ_c^0 \to Ξ^0\ell^+\ell^-$ at Belle
Search for the semileptonic decays $Ξ_c^0 \to Ξ^0\ell^+\ell^-$ at Belle Open
Using the full data sample of 980 $\mathrm{fb}^{-1}$ collected with the Belle detector at the KEKB asymmetric energy electron-positron collider, we report the results of the first search for the rare semileptonic decays $Ξ_c^0 \to Ξ^0\ell^…
View article: Search for a Heavy Neutrino in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>τ</mml:mi></mml:math> Decays at Belle
Search for a Heavy Neutrino in Decays at Belle Open
We report on a search for a heavy Majorana neutrino in the decays τ^{-}→π^{-}ν_{h}, ν_{h}→π^{±}l^{∓}, l=e, μ. The results are obtained using the full data sample of 988 fb^{-1} collected with the Belle detector at the KEKB asymmetric energ…
View article: Search for the decay $B_s^0\to J/ψπ^0$ at Belle experiment
Search for the decay $B_s^0\to J/ψπ^0$ at Belle experiment Open
We have analyzed 121.4 fb$^{-1}$ of data collected at the $Υ(5S)$ resonance by the Belle experiment using the KEKB asymmetric-energy $e^+e^-$ collider to search for the decay $B_s^0\to J/ψπ^0$. We observe no signal and report an upper limi…
View article: Measurement of the Ratio of Partial Branching Fractions of Inclusive $\overline{B} \to X_u \ell \overlineν$ to $\overline{B} \to X_{c} \ell \overlineν$ and the Ratio of their Spectra with Hadronic Tagging
Measurement of the Ratio of Partial Branching Fractions of Inclusive $\overline{B} \to X_u \ell \overlineν$ to $\overline{B} \to X_{c} \ell \overlineν$ and the Ratio of their Spectra with Hadronic Tagging Open
We present a measurement of the ratio of partial branching fractions of the semi-leptonic inclusive decays, $\overline{B} \to X_{u} \ell \overlineν$ to $\overline{B} \to X_{c} \ell \overlineν$, where $\ell = (e, μ)$, using the full Belle s…