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: Muon identification with Deep Neural Network in the Belle II K-Long and Muon detector
Muon identification with Deep Neural Network in the Belle II K-Long and Muon detector Open
View article: Study of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>χ</mml:mi></mml:mrow><mml:mrow><mml:mi>b</mml:mi><mml:mi>J</mml:mi></mml:mrow></mml:msub><mml:mo stretchy="false">(</mml:mo><mml:mn>2</mml:mn><mml:mi>P</mml:mi><mml:mo stretchy="false">)</mml:mo><mml:mo stretchy="false">→</mml:mo><mml:mi>ω</mml:mi><mml:mi mathvariant="normal">ϒ</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mn>1</mml:mn><mml:mi>S</mml:mi><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:math> at Belle
Study of at Belle Open
We report a study of the hadronic transitions χbJ(2P)→ωϒ(1S), with ω→π+π−π0, using 28.2×106 ϒ(3S) mesons recorded by the Belle detector. We present the first evidence for the near-threshold transition χb0(2P)→ωϒ(1S), the analog of the nea…
View article: Operational experience and performance of the Silicon Vertex Detector after the first long shutdown of Belle II
Operational experience and performance of the Silicon Vertex Detector after the first long shutdown of Belle II Open
Measurement of the ratio of partial branching fractions of inclusive to and the ratio of their spectra with hadronic tagging Open
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: Production cross sections of light and charmed mesons in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>e</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>e</mml:mi><mml:mo>−</mml:mo></mml:msup></mml:math> annihilation near 10.58 GeV
Production cross sections of light and charmed mesons in annihilation near 10.58 GeV Open
We report measurements of production cross sections for ρ+, ρ0, ω, K*+, K*0, ϕ, η, KS0, f0(980), D+, D0, Ds+, D*+, D*0, and Ds*+ in e+e− collisions at a center-of-mass energy near 10.58 GeV. The data were recorded by the Belle experiment, …
Observation of and measurement of the effective couplings of Ω(2012)− to and Open
Evidence of Decay and Search for with the Belle Detector Open
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: Angular analysis of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>B</mml:mi><mml:mo stretchy="false">→</mml:mo><mml:msup><mml:mi>K</mml:mi><mml:mo>*</mml:mo></mml:msup><mml:msup><mml:mi>e</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>e</mml:mi><mml:mo>−</mml:mo></mml:msup></mml:math> in the low-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>q</mml:mi><mml:mn>2</mml:mn></mml:msup></mml:math> region with new electron identification at Belle
Angular analysis of in the low- region with new electron identification at Belle Open
We perform an angular analysis of the B→K*e+e− decay for the dielectron mass squared, q2, range of 0.0008–1.1200 GeV2/c4 using the full Belle dataset in the K*0→K+π− and K*+→KS0π+ channels, incorporating new methods of electron identifica…
View article: Measurement of Angular Coefficients of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mover accent="true"><mml:mrow><mml:mi>B</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">¯</mml:mo></mml:mrow></mml:mover><mml:mo stretchy="false">→</mml:mo><mml:msup><mml:mrow><mml:mi>D</mml:mi></mml:mrow><mml:mrow><mml:mo>*</mml:mo></mml:mrow></mml:msup><mml:mo>ℓ</mml:mo><mml:msub><mml:mrow><mml:mover accent="true"><mml:mrow><mml:mi>ν</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">¯</mml:mo></mml:mrow></mml:mover></mml:mrow><mml:mrow><mml:mo>ℓ</mml:mo></mml:mrow></mml:msub></mml:mrow></mml:math>: Implications for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mo stretchy="false">|</mml:mo><mml:msub><mml:mrow><mml:mi>V</mml:mi></mml:mrow><mml:mrow><mml:mi>c</mml:mi><mml:mi>b</mml:mi></mml:mrow></mml:msub><mml:mo stretchy="false">|</mml:mo></mml:mrow></mml:math> and Tests of Lepton Flavor Universality
Measurement of Angular Coefficients of : Implications for and Tests of Lepton Flavor Universality Open
We measure the complete set of angular coefficients Ji for exclusive B¯→D*ℓν¯ℓ decays (ℓ=e, μ). Our analysis uses the full 711 fb−1 Belle dataset with hadronic tag-side reconstruction. The results allow us to extract the form factors desc…
View article: Measurements of the Branching Fraction, Polarization, and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>C</mml:mi><mml:mi>P</mml:mi></mml:math> Asymmetry for the Decay <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>B</mml:mi><mml:mn>0</mml:mn></mml:msup><mml:mo stretchy="false">→</mml:mo><mml:mi>ω</mml:mi><mml:mi>ω</mml:mi></mml:math>
Measurements of the Branching Fraction, Polarization, and Asymmetry for the Decay Open
We present a comprehensive study of B0→ωω decays using 772×106 BB¯ pairs collected with the Belle detector at the KEKB e+e− collider. This process is a suppressed charmless decay into two vector mesons and can exhibit interesting polariza…
View article: Search for Baryon-Number-Violating Processes in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>B</mml:mi><mml:mo>−</mml:mo></mml:msup></mml:math> Decays to the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msubsup><mml:mover accent="true"><mml:mi mathvariant="normal">Ξ</mml:mi><mml:mo stretchy="false">¯</mml:mo></mml:mover><mml:mi>c</mml:mi><mml:mn>0</mml:mn></mml:msubsup><mml:msubsup><mml:mover accent="true"><mml:mi mathvariant="normal">Λ</mml:mi><mml:mo stretchy="false">¯</mml:mo></mml:mover><mml:mi>c</mml:mi><mml:mo>−</mml:mo></mml:msubsup></mml:math> Final State
Search for Baryon-Number-Violating Processes in Decays to the Final State Open
We report the results of the first search for B− decays to the Ξ¯c0Λ¯c− final state using 711 fb−1 of data collected at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. The results are interpreted i…
View article: Search for two-body <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>B</mml:mi></mml:math> meson decays to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">Λ</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msubsup><mml:mrow><mml:mi mathvariant="normal">Ω</mml:mi></mml:mrow><mml:mrow><mml:mi>c</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">(</mml:mo><mml:mo>*</mml:mo><mml:mo stretchy="false">)</mml:mo><mml:mn>0</mml:mn></mml:mrow></mml:msubsup></mml:mrow></mml:math>
Search for two-body meson decays to and 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 Λ0 and Ωc(*)0 using 711 fb−1 of data collected at the ϒ(4S) resonance with the Belle detector at the KEKB …
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 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 the semileptonic decays <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msubsup><mml:mi mathvariant="normal">Ξ</mml:mi><mml:mi>c</mml:mi><mml:mn>0</mml:mn></mml:msubsup><mml:mo stretchy="false">→</mml:mo><mml:msup><mml:mi mathvariant="normal">Ξ</mml:mi><mml:mn>0</mml:mn></mml:msup><mml:msup><mml:mo>ℓ</mml:mo><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mo>ℓ</mml:mo><mml:mo>−</mml:mo></mml:msup></mml:math> at Belle
Search for the semileptonic decays at Belle Open
Using the full data sample of 980 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 Ξc0→Ξ0ℓ+ℓ− (ℓ=e or μ). No signif…
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: Search for the decay <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msubsup><mml:mrow><mml:mi>B</mml:mi></mml:mrow><mml:mrow><mml:mi>s</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msubsup><mml:mo stretchy="false">→</mml:mo><mml:mi>J</mml:mi><mml:mo>/</mml:mo><mml:mi>ψ</mml:mi><mml:msup><mml:mrow><mml:mi>π</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math> at Belle experiment
Search for the decay 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 Bs0→J/ψπ0. We observe no signal and report an upper limit on the branching…
View article: Search for baryon and lepton number violating decays <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>D</mml:mi><mml:mo stretchy="false">→</mml:mo><mml:mi>p</mml:mi><mml:mo>ℓ</mml:mo></mml:mrow></mml:math>
Search for baryon and lepton number violating decays Open
We search for the baryon and lepton number violating charm decays, D→pℓ, where D is either a D0 or a D¯0 and ℓ is a muon or an electron, using a data sample of 921 fb−1 collected by the Belle detector at the KEKB asymmetric energy e+e− co…