A. Gellrich

activity

20242026

collaborators

6 papers

hep-ex2026

A search for feebly-interacting particles in $B$ decays with missing energy at Belle

Belle, Belle II Collaborations, : +406

We present a search for an invisible hidden-sector particle $X_{inv}$ , produced in $B^{0} \to D ˉ^{0} X_{inv}$ and $B^{\pm} \to h X_{inv}$ decays, where $h = π^{\pm}$ , $…

hep-ex2025

Measurements of the mass difference $m (B^{0}) - m (B^{+})$ and the energy dependence of the cross-section ratio $σ (e^{+} e^{-} \to B^{0} B ˉ^{0}) / σ (e^{+} e^{-} \to B^{+} B^{-})$ at Belle and Belle II

Belle, Belle II Collaborations, : +396

Using data samples collected by the Belle and Belle II experiments at the $Υ (4 S)$ resonance with integrated luminosities of 571 fb $^{- 1}$ and 365 fb $^{- 1}$ , respectively, we measur…

hep-ex2025

Observation of $e^{+} e^{-} \to η Υ (2 S)$ and search for $e^{+} e^{-} \to η Υ (1 S), γ X_{b}$ at $s$ near 10.75 GeV

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

We present an analysis of the processes $e^{+} e^{-} \to η Υ (1 S)$ , $η Υ (2 S)$ , and $γ X_{b}$ with $X_{b} \to π^{+} π^{-} χ_{b J}, χ_{b J} \to γ Υ (1 S)$ $(J = 1, 2)$ reconstructed from $γγπ^+π^-\ell^+\ell^-~(…

hep-ex2025

Measurement of the CP asymmetry in $D^{+} \to π^{+} π^{0}$ decays at Belle II

Belle II Collaboration, I. Adachi, L. Aggarwal +402

We measure the CP asymmetry in $D^{+} \to π^{+} π^{0}$ decays reconstructed in $e^{+} e^{-}$ collisions at the Belle II experiment using a data set corresponding to an integrated luminosity…

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…

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…

A search for feebly-interacting particles in B decays with missing energy at Belle

Measurements of the mass difference m(B0)−m(B+) and the energy dependence of the cross-section ratio σ(e+e−→B0Bˉ0)/σ(e+e−→B+B−) at Belle and Belle II

Observation of e+e−→ηΥ(2S) and search for e+e−→ηΥ(1S), γXb​ at s​ near 10.75 GeV

Measurement of the CP asymmetry in D+→π+π0 decays at Belle II

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

A search for feebly-interacting particles in $B$ decays with missing energy at Belle

Measurements of the mass difference $m (B^{0}) - m (B^{+})$ and the energy dependence of the cross-section ratio $σ (e^{+} e^{-} \to B^{0} B ˉ^{0}) / σ (e^{+} e^{-} \to B^{+} B^{-})$ at Belle and Belle II

Observation of $e^{+} e^{-} \to η Υ (2 S)$ and search for $e^{+} e^{-} \to η Υ (1 S), γ X_{b}$ at $s$ near 10.75 GeV

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