K. Matsuoka

activity

20192025

B^{+} \to K^{+} ν ν ˉ

decays

90 citations · 197 across the 25 of their papers we have counts for

collaborators

31 papers

hep-ex2025

Charged-hadron identification at Belle II

Belle II Collaboration, I. Adachi, H. Ahmed +408

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…

hep-ex2025★ 4 cited

Search for a Dark Higgs Boson Produced in Association with Inelastic Dark Matter at the Belle II Experiment

Belle II Collaboration, I. Adachi, L. Aggarwal +437

Inelastic dark matter models that have two dark matter particles and a massive dark photon can reproduce the observed relic dark matter density without violating cosmological limit…

hep-ex2025

Search for lepton flavor-violating decay modes $B^{0} \to K^{* 0} τ^{\pm} ℓ^{\mp}$ ( $ℓ = e, μ$ ) with hadronic B-tagging at Belle and Belle II

Belle, Belle II Collaborations, : +375

We present the results of a search for the charged-lepton-flavor violating decays $B^{0} \to K^{* 0} τ^{\pm} ℓ^{\mp}$ , where $ℓ^{\mp}$ is either an electron or a muon. The…

physics.ins-det2025

Development of a picosecond-timing Cherenkov detector using gaseous photomultiplification

R. Okubo, K. Matsuoka, T. Iijima +9

Photosensitive gaseous detectors with a simple photoelectron multiplication mechanism as resistive plate chambers are expected to offer both large photo coverage and excellent time…

hep-ex2025★ 4 cited

Measurement of $B^{+} \to τ^{+} ν_{τ}$ branching fraction with a hadronic tagging method at Belle II

Belle II Collaboration, I. Adachi, K. Adamczyk +341

We present a measurement of the branching fraction of $B^{+} \to τ^{+} ν_{τ}$ decays using $(387 \pm 6) \times 1 0^{6}$ $Υ (4 S)$ collected between 2019 and 2022 with the Belle II detector at the S…

hep-ex2024

Measurement of the branching fraction, polarization, and time-dependent $C P$ asymmetry in $B^{0} \to ρ^{+} ρ^{-}$ decays and constraint on the CKM angle $ϕ_{2}$

Belle II Collaboration, I. Adachi, L. Aggarwal +377

We present a measurement of the branching fraction and fraction of longitudinal polarization of $B^{0} \to ρ^{+} ρ^{-}$ decays, which have two $π^{0}$ 's in the final state. We also measure…

hep-ex2024★ 1 cited

Measurement of $B \to K^{*} (892) γ$ decays at Belle II

Belle II Collaboration, I. Adachi, L. Aggarwal +451

We present measurements of $B \to K^{*} (892) γ$ decays using $365 fb^{- 1}$ of data collected from 2019 to 2022 by the Belle~II experiment at the SuperKEKB asymmetric-energy…

hep-ex2024

Measurement of the energy dependence of the $e^{+} e^{-} \to B B ˉ$ , $B B ˉ^{}$ , and $B^{} B ˉ^{*}$ cross sections at Belle~II

Belle II Collaboration, I. Adachi, L. Aggarwal +466

We report measurements of the $e^{+} e^{-} \to B B ˉ$ , $B B ˉ^{*}$ , and $B^{*} B ˉ^{*}$ cross sections at four energies, 10653, 10701, 10746 and 10805 MeV, using data collected b…

hep-ex2024★ 2 cited

Test of light-lepton universality in $τ$ decays with the Belle II experiment

Belle II Collaboration, I. Adachi, K. Adamczyk +428

We present a measurement of the ratio $R_{μ} = B (τ^{-} \to μ^{-} ν ˉ_{μ} ν_{τ}) / B (τ^{-} \to e^{-} ν ˉ_{e} ν_{τ})$ of branching fractions $B$ of the $τ$ lepton decaying t…

hep-ex2024★ 8 cited

Search for lepton-flavor-violating $τ^{-} \to μ^{-} μ^{+} μ^{-}$ decays at Belle II

Belle II Collaboration, I. Adachi, L. Aggarwal +429

We present the result of a search for the charged-lepton-flavor violating decay $τ^{-} \to μ^{-} μ^{+} μ^{-}$ using a $424 f b^{- 1}$ sample of data recorded by the Belle II experiment at the S…

hep-ex2024★ 10 cited

Search for a $μ^{+} μ^{-}$ resonance in four-muon final states at Belle II

Belle II Collaboration, I. Adachi, K. Adamczyk +401

We report on a search for a resonance $X$ decaying to a pair of muons in $e^{+} e^{-} \to μ^{+} μ^{-} X$ events in the 0.212-9.000 GeV/ $c^{2}$ mass range, using 178 fb $^{- 1}$ of…

hep-ex2024★ 13 cited

New graph-neural-network flavor tagger for Belle II and measurement of $sin 2 ϕ_{1}$ in $B^{0} \to J / ψ K_{S}^{0}$ decays

Belle II Collaboration, I. Adachi, L. Aggarwal +413

We present GFlaT, a new algorithm that uses a graph-neural-network to determine the flavor of neutral $B$ mesons produced in $Υ (4 S)$ decays. It improves previous algorithms by usin…

hep-ex2024

A test of lepton flavor universality with a measurement of $R (D^{*})$ using hadronic $B$ tagging at the Belle II experiment

Belle II Collaboration, I. Adachi, K. Adamczyk +434

The ratio of branching fractions $R (D^{*}) = B (B \to D^{*} τ^{-} ν_{τ})$ /$\mathcal{B} (\overline{B} \rightarrow D^{*} \ell^{-} \overlineν_{\ell}…

hep-ex2024

Study of $Υ (10753)$ decays to $π^{+} π^{-} Υ (n S)$ final states at Belle II

Belle II Collaboration, I. Adachi, L. Aggarwal +393

We present an analysis of the process $e^{+} e^{-} \to π^{+} π^{-} Υ (n S)$ (where $n$ = 1, 2, or 3) reconstructed in $19.6$ $f b^{- 1}$ of Belle II data during a special run of the…

hep-ex2023

Search for the $e^{+} e^{-} \to η_{b} (1 S) ω$ and $e^{+} e^{-} \to χ_{b 0} (1 P) ω$ processes at $s = 10.745 GeV$

Belle II Collaboration, I. Adachi, L. Aggarwal +419

We search for the $e^{+} e^{-} \to η_{b} (1 S) ω$ and $e^{+} e^{-} \to χ_{b 0} (1 P) ω$ processes at a center-of-mass energy of 10.745 GeV, which is close to the peak of the $Υ (10753)$ state. We use data…

hep-ex2023★ 90 cited

Evidence for $B^{+} \to K^{+} ν ν ˉ$ decays

Belle II Collaboration, I. Adachi, K. Adamczyk +452

We search for the rare decay $B^{+} \to K^{+} ν ν ˉ$ in a $362 fb^{- 1}$ sample of electron-positron collisions at the $Υ (4 S)$ resonance collected with the Belle II det…

hep-ex2023★ 8 cited

Measurement of branching fractions and direct $C P$ asymmetries for $B \to K π$ and $B \to π π$ decays at Belle II

Belle II Collaboration, I. Adachi, L. Aggarwal +435

We report measurements of the branching fractions and direct $CP$ asymmetries of the decays $B^{0} \to K^{+} π^{-}$ , $B^{+} \to K^{+} π^{0}$ , $B^{+} \to K^{0} π^{+}$ , and $B^{0} \to K^{0} π^{0}$ , and…

hep-ex2023★ 5 cited

Measurement of $C P$ asymmetries and branching-fraction ratios for $B^{\pm} \to D K^{\pm}$ and $D π^{\pm}$ with $D \to K_{S}^{0} K^{\pm} π^{\mp}$ using Belle and Belle II data

Belle, Belle II Collaboration, : +408

We measure $C P$ asymmetries and branching-fraction ratios for $B^{\pm} \to D K^{\pm}$ and $D π^{\pm}$ decays with $D \to K_{S}^{0} K^{\pm} π^{\mp}$ , where $D$ is a superposition of $D^{0}$ and…

hep-ex2023

Measurement of the $τ$ -lepton mass with the Belle~II experiment

Belle II Collaboration, I. Adachi, K. Adamczyk +418

We present a measurement of the $τ$ -lepton mass using a sample of about 175 million $e^{+} e^{-} \to τ^{+} τ^{-}$ events collected with the Belle II detector at the SuperKEKB $e^{+} e^{-}$ collid…

hep-ex2022★ 3 cited

Determination of $∣ V_{u b} ∣$ from untagged $B^{0} \to π^{-} ℓ^{+} ν_{ℓ}$ decays using 2019-2021 Belle II data

Belle II Collaboration, K. Adamczyk, L. Aggarwal +588

We present an analysis of the charmless semileptonic decay $B^{0} \to π^{-} ℓ^{+} ν_{ℓ}$ , where $ℓ = e, μ$ , from 198.0 million pairs of $B B ˉ$ mesons recorded by the Belle II…

hep-ex2022★ 2 cited

Angular analysis of $B^{+} \to ρ^{+} ρ^{0}$ decays reconstructed in 2019, 2020, and 2021 Belle II data

Belle II Collaboration, F. Abudinén, I. Adachi +590

We report on a Belle II measurement of the branching fraction ( $B$ ), longitudinal polarization fraction ( $f_{L}$ ), and CP asymmetry ( $A_{C P}$ ) of $B^{+} \to ρ^{+} ρ^{0}$ …

hep-ex2022

Measurement of the branching fraction of the $B^{0} \to K_{S}^{0} π^{0} γ$ decay using 190 fb $^{- 1}$ of Belle II data

Belle II Collaboration, F. Abudinén, I. Adachi +590

We report the measurement of the branching fraction of the $B^{0} \to K_{S}^{0} π^{0} γ$ decay in $e^{+} e^{-} \to Υ (4 S) \to B B$ data recorded by the Belle II experiment at the Sup…

hep-ex2022★ 9 cited

Measurement of the $Λ_{c}^{+}$ lifetime

Belle II Collaboration, F. Abudinén, L. Aggarwal +360

An absolute measurement of the $Λ_{c}^{+}$ lifetime is reported using $Λ_{c}^{+} \to p K^{-} π^{+}$ decays in events reconstructed from data collected by the Belle II experiment at the…

hep-ex2021

Measurements of the branching fractions for $B \to K^{*} γ$ decays at Belle II

F. Abudinén, I. Adachi, R. Adak +565

This paper reports a study of $B \to K^{*} γ$ decays using $62.8 \pm 0.6$ fb $^{- 1}$ of data collected during 2019--2020 by the Belle II experiment at the SuperKEKB $e^{+} e^{-}$ asymm…

Charged-hadron identification at Belle II

Search for a Dark Higgs Boson Produced in Association with Inelastic Dark Matter at the Belle II Experiment

Search for lepton flavor-violating decay modes B0→K∗0τ±ℓ∓ (ℓ=e,μ) with hadronic B-tagging at Belle and Belle II

Development of a picosecond-timing Cherenkov detector using gaseous photomultiplification

Measurement of B+→τ+ντ​ branching fraction with a hadronic tagging method at Belle II

Measurement of the branching fraction, polarization, and time-dependent CP asymmetry in B0→ρ+ρ− decays and constraint on the CKM angle ϕ2​

Measurement of B→K∗(892)γ decays at Belle II

Measurement of the energy dependence of the e+e−→BBˉ, BBˉ∗, and B∗Bˉ∗ cross sections at Belle~II

Test of light-lepton universality in τ decays with the Belle II experiment

Search for lepton-flavor-violating τ−→μ−μ+μ− decays at Belle II

Search for a μ+μ− resonance in four-muon final states at Belle II

New graph-neural-network flavor tagger for Belle II and measurement of sin2ϕ1​ in B0→J/ψKS0​ decays

A test of lepton flavor universality with a measurement of R(D∗) using hadronic B tagging at the Belle II experiment

Study of Υ(10753) decays to π+π−Υ(nS) final states at Belle II

Search for the e+e−→ηb​(1S)ω and e+e−→χb0​(1P)ω processes at s​=10.745GeV

Evidence for B+→K+ννˉ decays

Measurement of branching fractions and direct CP asymmetries for B→Kπ and B→ππ decays at Belle II

Measurement of CP asymmetries and branching-fraction ratios for B±→DK± and Dπ± with D→KS0​K±π∓ using Belle and Belle II data

Measurement of the τ-lepton mass with the Belle~II experiment

Determination of ∣Vub​∣ from untagged B0→π−ℓ+νℓ​ decays using 2019-2021 Belle II data

Angular analysis of B+→ρ+ρ0 decays reconstructed in 2019, 2020, and 2021 Belle II data

Measurement of the branching fraction of the B0→KS0​π0γ decay using 190 fb−1 of Belle II data

Measurement of the Λc+​ lifetime

Measurements of the branching fractions for B→K∗γ decays at Belle II

Search for lepton flavor-violating decay modes $B^{0} \to K^{* 0} τ^{\pm} ℓ^{\mp}$ ( $ℓ = e, μ$ ) with hadronic B-tagging at Belle and Belle II

Measurement of $B^{+} \to τ^{+} ν_{τ}$ branching fraction with a hadronic tagging method at Belle II

Measurement of the branching fraction, polarization, and time-dependent $C P$ asymmetry in $B^{0} \to ρ^{+} ρ^{-}$ decays and constraint on the CKM angle $ϕ_{2}$

Measurement of $B \to K^{*} (892) γ$ decays at Belle II

Measurement of the energy dependence of the $e^{+} e^{-} \to B B ˉ$ , $B B ˉ^{}$ , and $B^{} B ˉ^{*}$ cross sections at Belle~II

Test of light-lepton universality in $τ$ decays with the Belle II experiment

Search for lepton-flavor-violating $τ^{-} \to μ^{-} μ^{+} μ^{-}$ decays at Belle II

Search for a $μ^{+} μ^{-}$ resonance in four-muon final states at Belle II

New graph-neural-network flavor tagger for Belle II and measurement of $sin 2 ϕ_{1}$ in $B^{0} \to J / ψ K_{S}^{0}$ decays

A test of lepton flavor universality with a measurement of $R (D^{*})$ using hadronic $B$ tagging at the Belle II experiment

Study of $Υ (10753)$ decays to $π^{+} π^{-} Υ (n S)$ final states at Belle II

Search for the $e^{+} e^{-} \to η_{b} (1 S) ω$ and $e^{+} e^{-} \to χ_{b 0} (1 P) ω$ processes at $s = 10.745 GeV$

Evidence for $B^{+} \to K^{+} ν ν ˉ$ decays

Measurement of branching fractions and direct $C P$ asymmetries for $B \to K π$ and $B \to π π$ decays at Belle II

Measurement of $C P$ asymmetries and branching-fraction ratios for $B^{\pm} \to D K^{\pm}$ and $D π^{\pm}$ with $D \to K_{S}^{0} K^{\pm} π^{\mp}$ using Belle and Belle II data

Measurement of the $τ$ -lepton mass with the Belle~II experiment

Determination of $∣ V_{u b} ∣$ from untagged $B^{0} \to π^{-} ℓ^{+} ν_{ℓ}$ decays using 2019-2021 Belle II data

Angular analysis of $B^{+} \to ρ^{+} ρ^{0}$ decays reconstructed in 2019, 2020, and 2021 Belle II data

Measurement of the branching fraction of the $B^{0} \to K_{S}^{0} π^{0} γ$ decay using 190 fb $^{- 1}$ of Belle II data

Measurement of the $Λ_{c}^{+}$ lifetime

Measurements of the branching fractions for $B \to K^{*} γ$ decays at Belle II