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We present the novel implementation of a non-differentiable metric approximation and a corresponding loss-scheduling aimed at the search for new particles of unknown mass in high energy physics experiments. We call the loss-scheduling, based on the minimisation of a figure-of-merit related function typical of particle physics, a Punzi-loss function, and the neural network that utilises this loss function a Punzi-net. We show that the Punzi-net outperforms standard multivariate analysis techniques and generalises well to mass hypotheses for which it was not trained. This is achieved by training a single classifier that provides a coherent and optimal classification of all signal hypotheses over the whole search space. Our result constitutes a complementary approach to fully differentiable analyses in particle physics. We implemented this work using PyTorch and provide users full access to a public repository containing all the codes and a training example.

We present the first model-independent measurement of the CKM unitarity triangle angle ϕ3 using B±→ D(KS0\\[ {K}_{\\mathrm{S}}^0 \\]π+π−π0) K± decays, where D indicates either a D0 or D¯\\[ \\overline{D} \\]0 meson. Measurements of the strong-phase difference of the D →KS0\\[ {K}_{\\mathrm{S}}^0 \\]π+π−π0 amplitude obtained from CLEO-c data are used as input. This analysis is based on the full Belle data set of 772 × 106BB¯\\[ \\overline{B} \\] events collected at the Υ(4S) resonance. We obtain ϕ3 = (5.7−8.8+10.2\\[ {5.7}_{-8.8}^{+10.2} \\]±3.5±5.7)° and the suppressed amplitude ratio rB = 0.323±0.147±0.023±0.051. Here the first uncertainty is statistical, the second is the experimental systematic, and the third is due to the precision of the strong-phase parameters measured from CLEO-c data. The 95% confidence interval on ϕ3 is (−29.7, 109.5)°, which is consistent with the current world average.

We present a measurement of the Cabibbo-Kobayashi-Maskawa unitarity triangle angle ϕ ₃(also known as γ) using a model-independent Dalitz plot analysis of B ⁺→ D ( K_(S)⁰ h ⁺ h ⁻ )h ⁺ , where D is either a D ⁰or D̅ ⁰meson and h is either a π or K. This is the first measurement that simultaneously uses Belle and Belle II data, combining samples corresponding to integrated luminosities of 711 fb ⁻¹and 128 fb ⁻¹ , respectively. All data were accumulated from energy-asymmetric e ⁺ e ⁻collisions at a centre-of-mass energy corresponding to the mass of the Υ(4S) resonance. We measure ϕ ₃= (78.4 ± 11.4 ± 0.5 ± 1.0)°, where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is from the uncertainties on external measurements of the D-decay strong-phase parameters.[graphic not available: see fulltext]

We present the first measurement of the branching fraction of the singly Cabibbo-suppressed (SCS) decay \\( {\\Lambda}_c^{+} \\) → pη' with η' → ηπ+π–, using a data sample corresponding to an integrated luminosity of 981 fb–1, collected by the Belle detector at the KEKB e+e– asymmetric-energy collider. A significant \\( {\\Lambda}_c^{+} \\) → pη' signal is observed for the first time with a signal significance of 5.4σ. The relative branching fraction with respect to the normalization mode \\( {\\Lambda}_c^{+} \\) → pK–π+ is measured to be $$ \\frac{\\mathcal{B}\\left({\\Lambda}_c^{+}\\to p\\eta^{\\prime}\\right)}{\\mathcal{B}\\left({\\Lambda}_c^{+}\\to {pK}^{-}{\\pi}^{+}\\right)}=\\left(7.54\\pm 1.32\\pm 0.73\\right)\\times {10}^{-3}, $$ where the uncertainties are statistical and systematic, respectively. Using the world-average value of \\( \\mathcal{B}\\left({\\Lambda}_c^{+}\\to {pK}^{-}{\\pi}^{+}\\right) \\) = (6.28 ± 0.32) × 10–2, we obtain $$ \\mathcal{B}\\left({\\Lambda}_c^{+}\\to p\\eta^{\\prime}\\right)=\\left(4.73\\pm 0.82\\pm 0.46\\pm 0.24\\right)\\times {10}^{-4}, $$ where the uncertainties are statistical, systematic, and from \\( \\mathcal{B}\\left({\\Lambda}_c^{+}\\to {pK}^{-}{\\pi}^{+}\\right) \\) , respectively.

We present the first measurement of the branching fraction of the singly Cabibbo-suppressed (SCS) decay$$ {\\Lambda}_c^{+} $$Λ c + → pη ′ with η ′ → ηπ + π − , using a data sample corresponding to an integrated luminosity of 981 fb − 1 , collected by the Belle detector at the KEKB e + e − asymmetric-energy collider. A significant$$ {\\Lambda}_c^{+} $$Λ c + → pη ′ signal is observed for the first time with a signal significance of 5.4 σ . The relative branching fraction with respect to the normalization mode$$ {\\Lambda}_c^{+} $$Λ c + → pK − π + is measured to be$$ \\frac{\\mathcal{B}\\left({\\Lambda}_c^{+}\\to p\\eta^{\\prime}\\right)}{\\mathcal{B}\\left({\\Lambda}_c^{+}\\to {pK}^{-}{\\pi}^{+}\\right)}=\\left(7.54\\pm 1.32\\pm 0.73\\right)\\times {10}^{-3}, $$B Λ c + → pη ′ B Λ c + → pK − π + = 7.54 ± 1.32 ± 0.73 × 10 − 3 , where the uncertainties are statistical and systematic, respectively. Using the world-average value of$$ \\mathcal{B}\\left({\\Lambda}_c^{+}\\to {pK}^{-}{\\pi}^{+}\\right) $$B Λ c + → pK − π + = (6 . 28 ± 0 . 32) × 10 − 2 , we obtain$$ \\mathcal{B}\\left({\\Lambda}_c^{+}\\to p\\eta^{\\prime}\\right)=\\left(4.73\\pm 0.82\\pm 0.46\\pm 0.24\\right)\\times {10}^{-4}, $$B Λ c + → pη ′ = 4.73 ± 0.82 ± 0.46 ± 0.24 × 10 − 4 , where the uncertainties are statistical, systematic, and from$$ \\mathcal{B}\\left({\\Lambda}_c^{+}\\to {pK}^{-}{\\pi}^{+}\\right) $$B Λ c + → pK − π + , respectively.

We present a measurement of the Cabibbo-Kobayashi-Maskawa unitarity triangle angle φ3 (also known as γ) using a model-independent Dalitz plot analysis of B+ → D( K_(S)⁰ h+h–)h+, where D is either a Do or Do¯ meson and h is either a π or K. This is the first measurement that simultaneously uses Belle and Belle II data, combining samples corresponding to integrated luminosities of 711 fb–1 and 128 fb–1, respectively. All data were accumulated from energy-asymmetric e+e– collisions at a centre-of-mass energy corresponding to the mass of the Υ(4S) resonance. We measure φ3 = (78.4 ± 11.4 ± 0.5 ± 1.0)°, where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is from the uncertainties on external measurements of the D-decay strong-phase parameters.

We present a measurement of the Cabibbo-Kobayashi-Maskawa unitarity triangle angle φ3 (also known as γ) using a model-independent Dalitz plot analysis of B+ → D( K_(S)⁰ h+h–)h+, where D is either a Do or Do¯ meson and h is either a π or K. This is the first measurement that simultaneously uses Belle and Belle II data, combining samples corresponding to integrated luminosities of 711 fb–1 and 128 fb–1, respectively. All data were accumulated from energy-asymmetric e+e– collisions at a centre-of-mass energy corresponding to the mass of the Υ(4S) resonance. We measure φ3 = (78.4 ± 11.4 ± 0.5 ± 1.0)°, where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is from the uncertainties on external measurements of the D-decay strong-phase parameters.

We present a measurement of the Cabibbo-Kobayashi-Maskawa unitarity triangle angle ϕ ₃(also known as γ) using a model-independent Dalitz plot analysis of B ⁺→ D ( K_(S)⁰ h ⁺ h ⁻ )h ⁺ , where D is either a D ⁰or D̅ ⁰meson and h is either a π or K. This is the first measurement that simultaneously uses Belle and Belle II data, combining samples corresponding to integrated luminosities of 711 fb ⁻¹and 128 fb ⁻¹ , respectively. All data were accumulated from energy-asymmetric e ⁺ e ⁻collisions at a centre-of-mass energy corresponding to the mass of the Υ(4S) resonance. We measure ϕ ₃= (78.4 ± 11.4 ± 0.5 ± 1.0)°, where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is from the uncertainties on external measurements of the D-decay strong-phase parameters.[graphic not available: see fulltext]

Charged lepton flavor violation is forbidden in the Standard Model but possible in several new physics scenarios. In many of these models, the radiative decays τ± → ℓ±γ (ℓ = e, μ) are predicted to have a sizeable probability, making them particularly interesting channels to search at various experiments. An updated search via τ± → ℓ±γ using full data of the Belle experiment, corresponding to an integrated luminosity of 988 fb–1, is reported for charged lepton flavor violation. No significant excess over background predictions from the Standard Model is observed, and the upper limits on the branching fractions, B(τ± → μ±γ) ≤ 4.2 × 10–8 and B(τ± → e±γ) ≤ 5.6 × 10–8, are set at 90% confidence level.