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At least 73 records · Page 4

Amplitude analysis and branching-fraction measurement of ${D}_s^{+}\to {K}_S^0{\pi}^{+}{\pi}^0$

By using 6.32 fb -1 of data collected with the BESIII detector at center-of-mass energies between 4.178 and 4.226 GeV, we perform an amplitude analysis of the decay $D^+_s$→$K^0_Sπ^+π^0$ and determine the relative fractions and phase differences of different intermediate processes, which include $K^0_Sρ$(770) + ,$K^0_Sρ$(1450) + , $K^*$(892)$^0π^+$, $K^*$(892)$^+π^0$, and $K^*$(1410)$^0π^+$. With the detection efficiency based on the amplitude analysis results, the absolute branching fraction is measured to be $\mathcal{B}$($D^+_s$→$K^0_Sπ^+π^0$)=(5.43±0.30 stat ±0.15 syst )×10 -3 .

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Measurement of CP asymmetries and branching fraction ratios of B – decays to two charm mesons

The CP asymmetries of seven B – decays to two charm mesons are measured using data corresponding to an integrated luminosity of 9 fb –1 of proton-proton collisions collected by the LHCb experiment. Decays involving a D *0 or ${D}_s^{\ast -}$ meson are analysed by reconstructing only the D 0 or ${D}_s^{-}$ decay products. This paper presents the first measurement of $\mathcal{A}$ CP (B – → ${D}_s^{\ast -}$ D 0 ) and $\mathcal{A}$ CP (B – → ${D}_s^{-}$D $\ast$0 ), and the most precise measurement of the other five CP asymmetries. There is no evidence of CP violation in any of the analysed decays. Additionally, two ratios between branching fractions of selected decays are measured.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Amplitude analysis and branching fraction measurement of the decay $\mathrm{D}_s^+$ → $\mathrm{K}^+π^+π^-π^0$

The singly Cabibbo-suppressed decay D$^+_s$ → K + π + π - π 0 is observed by using a data set corresponding to an integrated luminosity of 6.32 fb -1 recorded by the BESIII detector at the centre-of-mass energies between 4.178 and 4.226 GeV. The first amplitude analysis of D$^+_s$ → K + π + π - π 0 reveals the sub-structures in this decay and determines the fractions and relative phases of different intermediate processes. The dominant intermediate process is D$^+_s$ → K *0 ρ + , with a fit fraction of (40.5 ± 2.8 stat. ± 1.5 syst. )%. With the detection efficiency based on our amplitude analysis, the absolute branching fraction for D$^+_s$ → K + π + π - π 0 is measured to be (9.75 ± 0.54 stat. ± 0.17 syst. ) x 10 -3 .

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Measurement of CP asymmetries and branching-fraction ratios for B ± → DK ± and Dπ ± with D → $ {K}_{\textrm{S}}^0 $ K ± π ∓ using Belle and Belle II data

We measure CP asymmetries and branching-fraction ratios for B ± → DK ± and Dπ ± decays with D → $K$$^{0}_{S}$ K ± π ∓ , where D is a superposition of D 0 and $\overline{D}$ 0 . We use the full data set of the Belle experiment, containing 772 × 10 6 $B$$\overline{B}$ pairs, and data from the Belle II experiment, containing 387 × 10 6 $B$$\overline{B}$ pairs, both collected in electron-positron collisions at the Υ(4S) resonance. Our results provide model-independent information on the unitarity triangle angle Φ 3 .

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Measurement of the branching fraction, polarization, and time-dependent C P asymmetry in B 0 → ρ + ρ − decays and constraint on the CKM angle ϕ 2

We present a measurement of the branching fraction and fraction of longitudinal polarization of B 0 → ρ + ρ − decays, which have two π 0 ’s in the final state. We also measure time-dependent C P violation parameters for decays into longitudinally polarized ρ + ρ − pairs. This analysis is based on a data sample containing ( 387 ± 6 ) × 10 6 ϒ ( 4 S ) mesons collected with the Belle II detector at the SuperKEKB asymmetric-energy e + e − collider in 2019–2022. We obtain B ( B 0 → ρ + ρ − ) = ( 2.8 9 − 0.22 + 0.23 − 0.27 + 0.29 ) × 10 − 5 , f L = 0.92 1 − 0.025 + 0.024 − 0.015 + 0.017 , S = − 0.26 ± 0.19 ± 0.08 , and C = − 0.02 ± 0.1 2 − 0.05 + 0.06 , where the first uncertainties are statistical and the second are systematic. We use these results to perform an isospin analysis to constrain the Cabibbo-Kobayashi-Maskawa angle ϕ 2 and obtain two solutions; the result consistent with other Standard Model constraints is ϕ 2 = ( 92.6 − 4.7 + 4.5 ) ° . Published by the American Physical Society 2025

Adachi, I. (ORCID:0000000322870173)↗

Measurement of the W boson decay branching fraction ratio $\mathscr{B}$(W → cq)/$\mathscr{B}$(W →$q\bar{q}'$) in proton-proton collisions at $\sqrt{s}$ = 13 TeV

The most precise measurement to date of the W boson hadronic decay branching fraction ratio $R_{c}^{W} = \mathcal{B}(W \to cq) / \mathcal{B}(W \to q\bar{q}$) is presented. The measurement is based on a sample of proton-proton collision data from the CERN LHC collected by the CMS experiment at a center-of-mass energy of 13 TeV in 2016-2018 with an integrated luminosity of 138 fb$^{-1}$. The large cross section of top quark-antiquark production at the LHC offers a sizable high-purity sample of W bosons suitable for this measurement. Events with one charged lepton (electron or muon) and at least four jets, two tagged as bottom quark jets, are analyzed. Charm jets are tagged using the presence of a muon inside the jet. The result, $R_\mathrm{c}^\mathrm{W}$ = 0.489 $\pm$ 0.020, is consistent with the standard model prediction and is twice as precise as the current world-average value.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Precision measurement of the branching fraction of J / ψ → K + K − via ψ ( 2 S ) → π + π − J / ψ

Using a sample of 448.1 × 10 6 ψ ( 2 S ) events collected with the BESIII detector, we perform a study of the decay J / ψ → K + K − via ψ ( 2 S ) → π + π − J / ψ . The branching fraction of J / ψ → K + K − is determined to be B K + K − = ( 3.072 ± 0.023 ( stat ) ± 0.050 ( syst ) ) × 10 − 4 , which is consistent with previous measurements but with significantly improved precision. Published by the American Physical Society 2024

Astronomy & Astrophysics↗

Measurement of the branching fraction of D s + → ℓ + ν ℓ via e + e − → D s * + D s * −

Based on 10.64 fb − 1 of e + e − collision data taken at center-of-mass energies between 4.237 and 4.699 GeV with the BESIII detector, we study the leptonic D s + decays using the e + e − → D s * + D s * − process. The branching fractions of D s + → ℓ + ν ℓ ( ℓ = μ , τ ) are measured to be B D s + → μ + ν μ = ( 0.547 ± 0.02 6 stat ± 0.01 6 syst ) % and B D s + → τ + ν τ = ( 5.60 ± 0.1 6 stat ± 0.2 0 syst ) % , respectively. The product of the decay constant and Cabibbo-Kobayashi-Maskawa matrix element | V c s | is determined to be f D s + | V c s | = ( 246.5 ± 5.9 stat ± 3.6 syst ± 0.5 input ) μ ν and f D s + | V c s | = ( 252.7 ± 3.6 stat ± 4.5 syst ± 0.6 input ) τ ν MeV , respectively. Taking the value of | V c s | from a global fit in the Standard Model, we obtain f D s + = ( 253.2 ± 6.0 stat ± 3.7 syst ± 0.6 input ) μ ν and f D s + = ( 259.6 ± 3.7 stat ± 4.6 syst ± 0.6 input ) τ ν MeV , respectively. Conversely, taking the value for f D s + from the latest lattice quantum chromodynamics calculation, we obtain | V c s | = ( 0.986 ± 0.02 3 stat ± 0.01 4 syst ± 0.00 3 input ) μ ν and | V c s | = ( 1.011 ± 0.01 4 stat ± 0.01 8 syst ± 0.00 3 input ) τ ν , respectively. Published by the American Physical Society 2024

Astronomy & Astrophysics↗

Measurements of the Branching Fraction, Polarization, and C P Asymmetry for the Decay B 0 → ω ω

We present a comprehensive study of B 0 → ω ω decays using 772 × 10 6 B B ¯ pairs collected with the Belle detector at the KEKB e + e − collider. This process is a suppressed charmless decay into two vector mesons and can exhibit interesting polarization and C P violation. The decay is observed for the first time with a significance of 7.9 standard deviations. We measure a branching fraction B = ( 1.53 ± 0.29 ± 0.17 ) × 10 − 6 , a fraction of longitudinal polarization f L = 0.87 ± 0.13 ± 0.13 , and a time-integrated C P asymmetry A C P = − 0.44 ± 0.43 ± 0.11 , where the first uncertainties listed are statistical and the second are systematic. This is the first observation of B 0 → ω ω and the first measurements of f L and A C P for this decay. Published by the American Physical Society 2024

Physics↗

Measurement of Ω c 0 baryon production and branching-fraction ratio BR ( Ω c 0 → Ω - e + ν e ) / BR ( Ω c 0 → Ω - π + ) in p p collisions at s = 13 TeV

The inclusive production of the charm-strange baryon $Ω^0_c$ is measured for the first time via its semileptonic decay into $Ω$ - e + ν e at midrapidity (|y| < 0.8) in proton-proton (pp) collisions at the center-of mass energy $\sqrt{s}$ = 13 TeV with the ALICE detector at the LHC. The transverse momentum (p T ) differential cross section multiplied by the branching ratio is presented in the interval 2 < p T < 12 GeV=c. The branching-fraction ratio BR($Ω^0_c$ → $Ω$ - e + ν e )/BR($Ω^0_c$→ Ω - π + ) is measured to be 1.12 ± 0.22 (stat) ± 0.27 (syst). Comparisons with other experimental measurements, as well as with theoretical calculations, are presented

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Measurement of branching fractions, C P asymmetry, and isospin asymmetry for B → ρ γ decays using Belle and Belle II data

We present measurements of B + → ρ + γ and B 0 → ρ 0 γ decays using a combined data sample of 772 × 10 6 B B ¯ pairs collected by the Belle experiment and 387 × 10 6 B B ¯ pairs collected by the Belle II experiment in e + e − collisions at the ϒ ( 4 S ) resonance. After an optimized selection, a simultaneous fit to the Belle and Belle II datasets yields 114 ± 12 B + → ρ + γ and 99 ± 12 B 0 → ρ 0 γ decays. The measured branching fractions are ( 13.1 − 1.9 − 1.2 + 2.0 + 1.3 ) × 10 − 7 and ( 7.6 ± 1.3 − 0.8 + 1.0 ) × 10 − 7 for B + → ρ + γ and B 0 → ρ 0 γ decays, respectively, where the first uncertainty is statistical and the second is systematic. We also measure the isospin asymmetry A I ( B → ρ γ ) = ( 10.9 − 11.7 − 7.3 + 11.2 + 7.8 ) % and the direct C P asymmetry A C P ( B + → ρ + γ ) = ( − 8.2 ± 15.2 − 1.3 + 2.0 ) % . Published by the American Physical Society 2025

Adachi, I. (ORCID:0000000322870173)↗

Measurement of branching-fraction ratios and CP asymmetries in B± → DCP±K± decays at Belle and Belle II

Abstract We report results from a study ofB ± → DK ± decays followed byDdecaying to theCP-even final stateK + K − and CP-odd final state$$ {K}_S^0{\pi}^0 $$ K S 0 π 0 , whereDis an admixture ofD 0 and$$ {\overline{D}}^0 $$ D ¯ 0 states. These decays are sensitive to the Cabibbo-Kobayashi-Maskawa unitarity-triangle angleϕ 3 . The results are based on a combined analysis of the final data set of 772×10 6 $$ B\overline{B} $$ B B ¯ pairs collected by the Belle experiment and a data set of 198×10 6 $$ B\overline{B} $$ B B ¯ pairs collected by the Belle II experiment, both in electron-positron collisions at the Υ(4S) resonance. We measure the CP asymmetries to be$$ \mathcal{A} $$ A CP+ = (+12.5±5.8±1.4)% and$$ \mathcal{A} $$ A CP− = (−16.7±5.7±0.6)%, and the ratios of branching fractions to be$$ \mathcal{R} $$ R CP+ = 1.164±0.081±0.036 and$$ \mathcal{R} $$ R CP− = 1.151±0.074±0.019. The first contribution to the uncertainties is statistical, and the second is systematic. The asymmetries$$ \mathcal{A} $$ A CP+ and$$ \mathcal{A} $$ A CP− have similar magnitudes and opposite signs; their difference corresponds to 3.5 standard deviations. From these values we calculate 68.3% confidence intervals of (8.5 ° <ϕ 3 < 16.5 ° ) or (84.5 ° <ϕ 3 < 95.5 ° ) or (163.3 ° <ϕ 3 < 171.5 ° ) and 0.321 B< 0.465.

Physics↗