K. Nakamura

activity

20102026

most citedMeasurement of long-range angular correlation and quadrupole anisotropy of pions and (anti)protons in central

d

+

Au collisions at

s_{_{N N}}

=200 GeV

175 citations · 948 across the 67 of their papers we have counts for

collaborators

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58 papers · 1 filter

hep-ex2026

Test of lepton flavor universality with $B ˉ \to D^{()} τ^{-} ν ˉ_{τ}$ and $B ˉ \to D^{()} ℓ^{-} ν ˉ_{ℓ}$ decays at Belle II

Belle II Collaboration, M. Abumusabh, I. Adachi +494

We test lepton flavor universality with a measurement of the branching-fraction ratios $R(D^{(*)}) \equiv \mathcal{B}(\bar{B} \rightarrow D^{(*)} τ^{-} \barν_τ)/\mathcal{B}(\bar{B}…

hep-ex2026

Search for the lepton-flavor-violating decay $τ^{\pm} \to μ^{\pm} γ$ at Belle II

Belle II Collaboration, M. Abumusabh, I. Adachi +466

We present a search for the lepton-flavor-violating decay $τ^{\pm} \to μ^{\pm} γ$ using a data sample that corresponds to an integrated luminosity of 428 fb $^{- 1}$ recorded by the Bel…

hep-ex2026

Search for the $B^{0} \to K_{S}^{0} τ^{+} τ^{-}$ decay

Belle, Belle II Collaborations, : +432

We present the first search for $B^{0} \to K_{S}^{0} τ^{+} τ^{-}$ decays. We look for signal decays in $B^{0} B ˉ^{0}$ events produced in asymmetric-energy electron-positron collisions. T…

hep-ex2026

Search for axion-like particles decaying to two photons at Belle II

Belle II Collaboration, M. Abumusabh, I. Adachi +450

Axion-like particles (ALPs) are predicted in many extensions of the Standard Model and provide a well-motivated portal between visible and hidden sectors through their coupling to…

hep-ex2026

Charged-lepton identification at Belle~II

Belle II Collaboration, M. Abumusabh, I. Adachi +409

Effective particle identification capabilities are a strategic priority for the physics program of the Belle~II experiment. We describe the algorithms used at Belle~II for identify…

hep-ex2026

First evidence of $X (3872) \to π^{0} χ_{c 0} (1 P)$ and search for $X (3915) \to π^{0} χ_{c 1} (1 P)$

Belle, Belle II Collaborations, : +412

We search for the pionic transitions $X (3872) \to π^{0} χ_{c J} (1 P)$ $(J = 0, 1, 2)$ and $X (3915) \to π^{0} χ_{c 1}$ in $B^{+} \to π^{0} χ_{c J} K^{+}$ decays using the Belle and Belle~II data samples c…

hep-ex2026

Measurement of mixing-induced CP violation in the decay $B^{0} \to π^{0} π^{0}$

Belle II Collaboration, M. Abumusabh, I. Adachi +437

Measurements of charge-parity (CP) violation in quark transitions provide stringent tests of the current theory and sensitive probes of particles or interactions beyond it. We repo…

hep-ex2025★ 5 cited

Test of lepton flavor universality with measurements of $R (D^{+})$ and $R (D^{*+})$ using semileptonic $B$ tagging at the Belle II experiment

Belle II Collaboration, I. Adachi, K. Adamczyk +450

We report measurements of the ratios of branching fractions ${\cal R}(D^{(*)+}) = \frac{{\cal B}(\overline{B}{}^0 \to D^{(*)+} \,τ^- \, \overlineν_τ)}{{\cal B}(\overline{B}{}^0 \to…

hep-ex2024

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

Belle, Belle II Collaborations, : +425

We present the first search for the lepton flavor-violating decay modes $B^{0} \to K_{S}^{0} τ^{\pm} ℓ^{\mp} (ℓ = μ, e)$ using the 711 fb $^{- 1}$ and 365 fb $^{- 1}$ data samples re…

hep-ex2024

Measurement of branching fractions, CP asymmetry, and isospin asymmetry for $B \to ργ$ decays using Belle and Belle II data

Belle II Collaboration, I. Adachi, K. Adamczyk +407

We present measurements of $B^{+} \to ρ^{+} γ$ and $B^{0} \to ρ^{0} γ$ decays using a combined data sample of $772 \times 1 0^{6}$ $B B$ pairs collected by the Bel…

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

Determination of the CKM angle $ϕ_{3}$ from a combination of Belle and Belle II results

Belle, Belle II Collaborations, : +399

We report a determination of the CKM angle $ϕ_{3}$ , also known as $γ$ , from a combination of measurements using samples of up to 711~fb $^{- 1}$ from the Belle experiment and up to 3…

hep-ex2024★ 7 cited

Search for Rare $b \to d ℓ^{+} ℓ^{-}$ Transitions at Belle

Belle, Belle II Collaborations, : +393

We present the results of a search for the $b \to d ℓ^{+} ℓ^{-}$ flavor-changing neutral-current rare decays $B^{+, 0} \to (η, ω, π^{+, 0}, ρ^{+, 0}) e^{+} e^{-}$ and $B^{+, 0} \to (η, ω…

hep-ex2024

Measurement of $C P$ asymmetries in $B^{0} \to K_{S}^{0} K_{S}^{0} K_{S}^{0}$ decays at Belle II

Belle II Collaboration, I. Adachi, L. Aggarwal +450

We report a measurement of decay-time dependent charge-parity ( $C P$ ) asymmetries in $B^{0} \to K_{S}^{0} K_{S}^{0} K_{S}^{0}$ decays. We use $387 \times 1 0^{6} B B ˉ$ pairs collected at…

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★ 4 cited

Silicon Vertex Detector of the Belle II Experiment

S. Mondal, K. Adamczyk, L. Aggarwal +72

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…

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★ 10 cited

Search for a $τ^{+} τ^{-}$ resonance in $e^{+} e^{-} \to μ^{+} μ^{-} τ^{+} τ^{-}$ events with the Belle II experiment

Belle II Collaboration, I. Adachi, K. Adamczyk +464

We report the first search for a non-standard-model resonance decaying into $τ$ pairs in $e^{+} e^{-} \to μ^{+} μ^{-} τ^{+} τ^{-}$ events in the 3.6-10 GeV/ $c^{2}$ mass range. We u…

hep-ex2023

Search for lepton-flavor-violating $τ^{-} \to ℓ^{-} ϕ$ decays in 2019-2021 Belle II data

Belle II Collaboration, F. Abudinén, I. Adachi +575

We report a search for lepton-flavor-violating decays $τ^{-} \to ℓ^{-} ϕ$ ( $ℓ^{-} = e^{-}, μ^{-}$ ) at the Belle II experiment, using a sample of electron-positron data produced at the Su…

hep-ex2023★ 2 cited

Observation of $B \to D^{(*)} K^{-} K_{S}^{0}$ decays using the 2019-2022 Belle II data sample

Belle II Collaboration, F. Abudinén, I. Adachi +575

We present a measurement of the branching fractions of four $B^{0, -} \to D^{(*) +, 0} K^{-} K_{S}^{0}$ decay modes. The measurement is based on data from SuperKEKB electron-positron colli…

hep-ex2023★ 6 cited

Measurement of the branching fraction and $CP$ asymmetry of $B^{0} \to π^{0} π^{0}$ decays using $198 \times 1 0^{6}$ $B B$ pairs in Belle II data

Belle II Collaboration, F. Abudinén, I. Adachi +425

We report measurements of the branching fraction and $CP$ asymmetry in $B^{0} \to π^{0} π^{0}$ decays reconstructed at Belle II in an electron-positron collision sample contain…

hep-ex2023★ 3 cited

Measurement of the $B^{0} \to D^{*-} ℓ^{+} ν_{ℓ}$ branching ratio and $∣ V_{c b} ∣$ with a fully reconstructed accompanying $B$ meson in 2019-2021 Belle II data

F. Abudinén, I. Adachi, K. Adamczyk +581

We present a measurement of the $B^{0} \to D^{*-} ℓ^{+} ν_{ℓ}$ ( $ℓ = e, μ$ ) branching ratio and of the CKM parameter $∣ V_{c b} ∣$ using signal decays accompanied by a f…

hep-ex2023★ 19 cited

A test of light-lepton universality in the rates of inclusive semileptonic $B$ -meson decays at Belle II

Belle II Collaboration, L. Aggarwal, H. Ahmed +349

We present the first measurement of the ratio of branching fractions of inclusive semileptonic $B$ -meson decays, $R(X_{e/μ}) = \mathcal{B}(B\to X \, e \, ν) / \mathcal{B}(B\to X \,…

Test of lepton flavor universality with Bˉ→D(∗)τ−νˉτ​ and Bˉ→D(∗)ℓ−νˉℓ​ decays at Belle II

Search for the lepton-flavor-violating decay τ±→μ±γ at Belle II

Search for the B0→KS0​τ+τ− decay

Search for axion-like particles decaying to two photons at Belle II

Charged-lepton identification at Belle~II

First evidence of X(3872)→π0χc0​(1P) and search for X(3915)→π0χc1​(1P)

Measurement of mixing-induced CP violation in the decay B0→π0π0

Test of lepton flavor universality with measurements of R(D+) and R(D∗+) using semileptonic B tagging at the Belle II experiment

Search for lepton flavor-violating decay modes B0→KS0​τ±ℓ∓ (ℓ=μ,e) with hadronic B-tagging at Belle and Belle II

Measurement of branching fractions, CP asymmetry, and isospin asymmetry for B→ργ decays using Belle and Belle II data

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

Determination of the CKM angle ϕ3​ from a combination of Belle and Belle II results

Search for Rare b→dℓ+ℓ− Transitions at Belle

Measurement of CP asymmetries in B0→KS0​KS0​KS0​ decays at Belle II

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

Silicon Vertex Detector of the Belle II Experiment

Evidence for B+→K+ννˉ decays

Search for a τ+τ− resonance in e+e−→μ+μ−τ+τ− events with the Belle II experiment

Search for lepton-flavor-violating τ−→ℓ−ϕ decays in 2019-2021 Belle II data

Observation of B→D(∗)K−KS0​ decays using the 2019-2022 Belle II data sample

Measurement of the branching fraction and CP asymmetry of B0→π0π0 decays using 198×106 BB pairs in Belle II data

Measurement of the B0→D∗−ℓ+νℓ​ branching ratio and ∣Vcb​∣ with a fully reconstructed accompanying B meson in 2019-2021 Belle II data

A test of light-lepton universality in the rates of inclusive semileptonic B-meson decays at Belle II

Test of lepton flavor universality with $B ˉ \to D^{()} τ^{-} ν ˉ_{τ}$ and $B ˉ \to D^{()} ℓ^{-} ν ˉ_{ℓ}$ decays at Belle II

Search for the lepton-flavor-violating decay $τ^{\pm} \to μ^{\pm} γ$ at Belle II

Search for the $B^{0} \to K_{S}^{0} τ^{+} τ^{-}$ decay

First evidence of $X (3872) \to π^{0} χ_{c 0} (1 P)$ and search for $X (3915) \to π^{0} χ_{c 1} (1 P)$

Measurement of mixing-induced CP violation in the decay $B^{0} \to π^{0} π^{0}$

Test of lepton flavor universality with measurements of $R (D^{+})$ and $R (D^{*+})$ using semileptonic $B$ tagging at the Belle II experiment

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

Measurement of branching fractions, CP asymmetry, and isospin asymmetry for $B \to ργ$ decays using Belle and Belle II data

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

Determination of the CKM angle $ϕ_{3}$ from a combination of Belle and Belle II results

Search for Rare $b \to d ℓ^{+} ℓ^{-}$ Transitions at Belle

Measurement of $C P$ asymmetries in $B^{0} \to K_{S}^{0} K_{S}^{0} K_{S}^{0}$ decays 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

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

Search for a $τ^{+} τ^{-}$ resonance in $e^{+} e^{-} \to μ^{+} μ^{-} τ^{+} τ^{-}$ events with the Belle II experiment

Search for lepton-flavor-violating $τ^{-} \to ℓ^{-} ϕ$ decays in 2019-2021 Belle II data

Observation of $B \to D^{(*)} K^{-} K_{S}^{0}$ decays using the 2019-2022 Belle II data sample

Measurement of the branching fraction and $CP$ asymmetry of $B^{0} \to π^{0} π^{0}$ decays using $198 \times 1 0^{6}$ $B B$ pairs in Belle II data

Measurement of the $B^{0} \to D^{*-} ℓ^{+} ν_{ℓ}$ branching ratio and $∣ V_{c b} ∣$ with a fully reconstructed accompanying $B$ meson in 2019-2021 Belle II data

A test of light-lepton universality in the rates of inclusive semileptonic $B$ -meson decays at Belle II