Y. Ma

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}…

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…

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…

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…

First measurement of the masses of the $Υ_{1} (1 D)$ and $Υ_{3} (1 D)$ states and the energy dependence of the cross sections for $e^{+} e^{-} \to Υ_{J} (1 D) η$ and $e^{+} e^{-} \to Υ_{J} (1 D) π^{+} π^{-}$

Belle, Belle II Collaborations, : +398

We study the processes $e^{+} e^{-} \to Υ_{J} (1 D) η$ and $e^{+} e^{-} \to Υ_{J} (1 D) π^{+} π^{-}$ at center-of-mass energies $s$ =(10.73 -- 11.02) GeV using a $142.5 fb^{- 1}$ data sample, in…

Study of $e^{+} e^{-} \to π^{+} π^{-} Υ (1 D)$ at Belle II

Belle II Collaboration, M. Abumusabh, I. Adachi +404

The bottomonium spectrum, consisting of bound states of a $b$ quark and an anti- $b$ quark, provides an excellent laboratory for probing quantum chromodynamics in the non-pertur…

Study of $e^{+} e^{-} \to h^{+} h^{-} J / ψ (h = π, K, p)$ via initial-state radiation at Belle~II

Belle II Collaboration, M. Abumusabh, I. Adachi +417

Using a data sample of 427.9 fb $^{- 1}$ collected by the Belle~II detector at or near the $Υ (4 S)$ and $Υ (10753)$ resonances, the cross sections for $e^{+} e^{-} \to h^{+} h^{-} J / ψ$ $(h = π / K / p)$ …

hep-ex2025★ 2 cited

First measurements of the branching fractions for the decay modes $Ξ_{c}^{0} \to Λ η$ and $Ξ_{c}^{0} \to Λ η^{'}$ and search for the decay $Ξ_{c}^{0} \to Λ π^{0}$ using Belle and Belle II data

Belle, Belle II Collaborations, : +321

Using data samples of 988.4 fb $^{- 1}$ and 427.9 fb $^{- 1}$ collected with the Belle and Belle II detectors, we present a study of the singly Cabibbo-suppressed decays $Ξ_c^{0} \to Λ…

hep-ex2025★ 1 cited

Search for $C P$ violation in $Ξ_{c}^{+} \to Σ^{+} h^{+} h^{-}$ and $Λ_{c}^{+} \to p h^{+} h^{-}$ at Belle II

Belle II Collaboration, M. Abumusabh, I. Adachi +344

We report decay-rate $C P$ asymmetries of the singly-Cabibbo-suppressed decays $Ξ_{c}^{+} \to Σ^{+} h^{+} h^{-}$ and $Λ_{c}^{+} \to p h^{+} h^{-}$ , with $h = K, π$ , measured using 428 fb $^{- 1}$ of $e^{+} e^{-}$ col…

Search for $e^{+} e^{-} \to γ χ_{b J}$ ( $J$ = 0, 1, 2) near $s = 10.746$ GeV at Belle II

Belle II Collaboration, M. Abumusabh, I. Adachi +399

We search for the $e^{+} e^{-} \to γ χ_{b J}$ ( $J$ = 0, 1, 2) processes at center-of-mass energies $s$ = 10.653, 10.701, 10.746, and 10.804 GeV. These data were collected with the…

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★ 1 cited

Search for lepton-flavor-violating $τ^{-} \to ℓ^{-} K_{s}^{0}$ decays at Belle and Belle II

Belle, Belle II Collaborations, : +419

We present the results of a search for charged-lepton-flavor violating decays $τ^{-} \to ℓ^{-} K_{S}^{0}$ , where $ℓ^{-}$ is either an electron or a muon. We combine $e…

Measurement of the Branching Fraction of $Λ_{c}^{+} \to p K_{S}^{0} π^{0}$ at Belle

The Belle, Belle II Collaborations, : +426

We report a precise measurement of the ratio of branching fractions $B (Λ_{c}^{+} \to p K_{S}^{0} π^{0}) / B (Λ_{c}^{+} \to p K^{-} π^{+})$ using 980 fb $^{- 1}$ of $e^{+} e^{-}$ data from th…

Prospects for Pentaquark Baryon Search with the Upgraded LEPS2 Facility

T. Nakano, S. Ajimura, Y. Asano +33

We present prospects for the $Θ^{+}$ pentaquark baryon search using the newly constructed LEPS2 facility at SPring-8. The LEPS2 detector system features significant improvements in a…

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…

Search for Pcs(4459) and Pcs(4338) in Upsilon(1S,2S) inclusive decays at Belle

I. Adachi, L. Aggarwal, H. Ahmed +402

Using data samples of 102 million Upsilon(1S) events and 158 million Upsilon(2S) events collected by the Belle detector at the KEKB asymmetric-energy $e^{+} e^{-}$ collider, we search f…

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…

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★ 4 cited

Production cross sections of light and charmed mesons in $e^{+} e^{-}$ annihilation near 10.58 GeV

Belle Collaboration, R. Seidl, I. Adachi +131

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^{*+}…

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…

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…

Search for the baryon number and lepton number violating decays $τ^{-} \to Λ π^{-}$ and $τ^{-} \to Λ ˉ π^{-}$ at Belle II

Belle II Collaboration, I. Adachi, L. Aggarwal +371

We present a search for the baryon number $B$ and lepton number $L$ violating decays $τ^{-} \to Λ π^{-}$ and $τ^{-} \to Λ ˉ π^{-}$ produced from the $e^{+} e^{-} \to τ^{+} τ^{-}$ pro…