R. Kowalewski

activity

20242026

collaborators

11 papers

hep-ex2026

Observation of the decays $B^{+} \to I^£_{c} (2455)^{++} I^ˉ _{c}^{' -}$ and $B^{0} \to I^£_{c} (2455)^{0} I^ˉ _{c}^{'0}$

Belle, Belle II Collaborations, : +403

We report the first observation of the decays $B^{+} \to I^£_{c} (2455)^{++} I^ˉ _{c}^{' -}$ and $B^{0} \to I^£_{c} (2455)^{0} I^ˉ _{c}^{'0}$ , with significances of $6.4\,…

hep-ex2026

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^{(*)+} \,Ï^- \, \overlineÎ½_Ï)}{{\cal B}(\overline{B}{}^0…

hep-ex2025

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

Observation of $e^{+} e^{-} \to I^\cdot I^¥ (2 S)$ and search for $e^{+} e^{-} \to I^\cdot I^¥ (1 S), I^^{3} X_{b}$ at $s$ near 10.75 GeV

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

We present an analysis of the processes $e^{+} e^{-} \to I^\cdot I^¥ (1 S)$ , $I^\cdot I^¥ (2 S)$ , and $I^^{3} X_{b}$ with $X_{b} \to I ¨ ^{+} I ¨ ^{-} I ¨ _{b J}, I ¨ _{b J} \to I^^{3} I^¥ (1 S)$ $(J = 1, 2)$ reconstructed from $Î³Î³Ï^+Ï^…

hep-ex2025

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

Belle, Belle II Collaborations, : +396

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

hep-ex2025

Measurement of the $D^{0} \to K^{-} I ¨ ^{+} e^{+} e^{-}$ branching fraction and search for $D^{0} \to I ¨ ^{+} I ¨ ^{-} e^{+} e^{-}$ and $D^{0} \to K^{+} K^{-} e^{+} e^{-}$ decays at Belle

Belle, Belle II Collaborations, : +481

We present a study of the rare charm meson decays $D^{0} \to K^{+} K^{-} e^{+} e^{-}$ , $I ¨ ^{+} I ¨ ^{-} e^{+} e^{-}$ , and $K^{-} I ¨ ^{+} e^{+} e^{-}$ using a 942 fb $^{- 1}$ data se…

Observation of the decays B+→I^£c​(2455)++I^ˉc′−​ and B0→I^£c​(2455)0I^ˉc′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 a Dark Higgs Boson Produced in Association with Inelastic Dark Matter at the Belle II Experiment

Observation of e+e−→I^⋅I^¥(2S) and search for e+e−→I^⋅I^¥(1S), I^3Xb​ at s​ near 10.75 GeV

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

Measurement of the D0→K−I¨+e+e− branching fraction and search for D0→I¨+I¨−e+e− and D0→K+K−e+e− decays at Belle

Observation of the decays $B^{+} \to I^£_{c} (2455)^{++} I^ˉ _{c}^{' -}$ and $B^{0} \to I^£_{c} (2455)^{0} I^ˉ _{c}^{'0}$

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

Observation of $e^{+} e^{-} \to I^\cdot I^¥ (2 S)$ and search for $e^{+} e^{-} \to I^\cdot I^¥ (1 S), I^^{3} X_{b}$ at $s$ near 10.75 GeV

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

Measurement of the $D^{0} \to K^{-} I ¨ ^{+} e^{+} e^{-}$ branching fraction and search for $D^{0} \to I ¨ ^{+} I ¨ ^{-} e^{+} e^{-}$ and $D^{0} \to K^{+} K^{-} e^{+} e^{-}$ decays at Belle