Ratio Of Branching Fractions Research Articles

Observation of D+→f0(500)μ+νμ and study of D+→π+π−ℓ+νℓ decay dynamics

Using 2.93 fb−1 of e+e− collision data collected with the BESIII detector at the center-of-mass energy of 3.773 GeV, we investigate the semileptonic decays D+→π+π−ℓ+νℓ (ℓ=e and μ). The D+→f0(500)μ+νμ decay is observed for the first time. By analyzing simultaneously the differential decay rates of D+→f0(500)μ+νμ and D+→f0(500)e+νe in different ℓ+νℓ four-momentum transfer intervals, the product of the relevant hadronic form factor f+f0(0) and the magnitude of the c→d Cabibbo-Kobayashi-Maskawa matrix element |Vcd| is determined to be f+f0(0)|Vcd|=0.143±0.014stat±0.011syst for the first time. With the input of |Vcd| from the global fit in the standard model, we determine f+f0(0)=0.63±0.06stat±0.05syst. The absolute branching fractions of D+→f0(500)(π+π−)μ+νμ and D+→ρ(π+π−)0μ+νμ are determined as (0.72±0.13stat±0.08syst)×10−3 and (1.64±0.13stat±0.10syst)×10−3. Combining these results with those of previous BESIII measurements on their semielectronic counterparts from the same data sample, we test lepton flavor universality by measuring the branching fraction ratios BD+→ρ0μ+νμ/BD+→ρ0e+νe=0.88±0.10 and BD+→f0(500)μ+νμ/BD+→f0(500)e+νe=1.14±0.26, which are compatible with the standard model expectation. Published by the American Physical Society 2024

Test of lepton flavor universality with a measurement of R(D*) using hadronic B tagging at the Belle II experiment

The ratio of branching fractions R(D*)=B(B¯→D*τ−ν¯τ)/B(B¯→D*ℓ−ν¯ℓ), where ℓ is an electron or muon, is measured using a Belle II data sample with an integrated luminosity of 189 fb−1 at the SuperKEKB asymmetric-energy e+e− collider. Data is collected at the ϒ(4S) resonance, and one B meson in the ϒ(4S)→BB¯ decay is fully reconstructed in hadronic decay modes. The accompanying signal B meson is reconstructed as B¯→D*τ−ν¯τ using leptonic τ decays. The normalization decay, B¯→D*ℓ−ν¯ℓ, produces the same observable final-state particles. The ratio of branching fractions is extracted in a simultaneous fit to two signal-discriminating variables in both channels and yields R(D*)=0.262−0.039+0.041(stat)−0.032+0.035(syst). This result is consistent with the current world average and with Standard Model predictions. Published by the American Physical Society 2024

Search for charmed baryons in the Λc+η system and measurement of the branching fractions of Λc(2880)+ and Λc(2940)+ decaying to Λc+η and pD0 relative to Σc(2455)π

We search for excited charmed baryons in the Λc+η system using a data sample corresponding to an integrated luminosity of 980 fb−1. The data were collected by the Belle detector at the KEKB e+e− asymmetric-energy collider. No significant signals are found in the Λc+η mass spectrum, including the known Λc(2880)+ and Λc(2940)+. Clear Λc(2880)+ and Λc(2940)+ signals are observed in the pD0 mass spectrum. We set upper limits at 90% credibility level on ratios of branching fractions of Λc(2880)+ and Λc(2940)+ decaying to Λc+η relative to Σc(2455)π of <0.13 for the Λc(2880)+ and <1.11 for the Λc(2940)+. We measure ratios of branching fractions of Λc(2880)+ and Λc(2940)+ decaying to pD0 relative to Σc(2455)π of 0.75±0.03(stat)±0.07(syst) for the Λc(2880)+ and 3.59±0.21(stat)±0.56(syst) for the Λc(2940)+. Published by the American Physical Society 2024

Amplitude analysis and branching fraction measurement of B+→D∗−Ds+π+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {B}^{+}\ o {D}^{\\ast -}{D}_s^{+}{\\pi}^{+} $$\\end{document} decays

The decays of the B+ meson to the final state D∗−Ds+π+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}^{\\ast -}{D}_s^{+}{\\pi}^{+} $$\\end{document} are studied in proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of 9 fb−1. The ratio of branching fractions of the B+→D∗−Ds+π+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {B}^{+}\ o {D}^{\\ast -}{D}_s^{+}{\\pi}^{+} $$\\end{document} and B0→D∗−Ds+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {B}^0\ o {D}^{\\ast -}{D}_s^{+} $$\\end{document} decays is measured to be 0.173 ± 0.006 ± 0.010, where the first uncertainty is statistical and the second is systematic. Using partially reconstructed Ds∗+→Ds+γ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}_s^{\\ast +}\ o {D}_s^{+}\\gamma $$\\end{document} and Ds+π0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}_s^{+}{\\pi}^0 $$\\end{document} decays, the ratio of branching fractions between the B+→D∗−Ds∗+π+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {B}^{+}\ o {D}^{\\ast -}{D}_s^{\\ast +}{\\pi}^{+} $$\\end{document} and B+→D∗−Ds+π+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {B}^{+}\ o {D}^{\\ast -}{D}_s^{+}{\\pi}^{+} $$\\end{document} decays is determined as 1.31 ± 0.07 ± 0.14. An amplitude analysis of the B+→D∗−Ds+π+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {B}^{+}\ o {D}^{\\ast -}{D}_s^{+}{\\pi}^{+} $$\\end{document} decay is performed for the first time, revealing dominant contributions from known excited charm resonances decaying to the D*−π+ final state. No significant evidence of exotic contributions in the Ds+π+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}_s^{+}{\\pi}^{+} $$\\end{document} or D∗−Ds+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}^{\\ast -}{D}_s^{+} $$\\end{document} channels is found. The fit fraction of the scalar state Tcs¯0∗2900++\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {T}_{c\\overline{s}0}^{\\ast }{(2900)}^{++} $$\\end{document} observed in the B+→D−Ds+π+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {B}^{+}\ o {D}^{-}{D}_s^{+}{\\pi}^{+} $$\\end{document} decay is determined to be less than 2.3% at a 90% confidence level.

Search for the radiative transition χc1(3872)→γψ2(3823)

Using 9.0 fb−1 of e+e− collision data collected at center-of-mass energies from 4.178 to 4.278 GeV with the BESIII detector at the BEPCII collider, we perform the first search for the radiative transition χc1(3872)→γψ2(3823). No signal is observed and the upper limit on the ratio of branching fractions B(χc1(3872)→γψ2(3823),ψ2(3823)→γχc1)/B(χc1(3872)→π+π−J/ψ) is set at 0.075 at the 90% confidence level. Our result contradicts theoretical predictions under the assumption that the χc1(3872) is the pure charmonium state χc1(2P). Published by the American Physical Society 2024

Study of e+e−→ωX(3872) and γX(3872) from 4.66 to 4.95 GeV

Using data samples with an integrated luminosity of 4.5 fb−1 collected by the BESIII detector at center-of-mass energies ranging from 4.66 GeV to 4.95 GeV, we study the processes of e+e−→ωX(3872) and e+e−→γX(3872). With the e+e−→ωX(3872) process, the branching fraction ratio R≡B(X(3872)→γJ/ψ)B(X(3872)→π+π−J/ψ) is measured to be 0.38±0.20stat±0.01syst (R<0.83 at 90% confidence level). In addition, we measure the ratio of the average cross section of e+e−→ωX(3872) to e+e−→ωχc1(ωχc2) to be σωX(3872)/σωχc1(σωX(3872)/σωχc2)=5.2±1.0stat±1.9syst(5.5±1.1stat±2.4syst). Finally, we search for the process of e+e−→γX(3872), and no obvious signal is observed. The upper limit on the ratio of the average cross section of e+e−→γX(3872) to e+e−→ωX(3872) is set as σγX(3872)/σωX(3872)<0.23 at 90% confidence level. Published by the American Physical Society 2024

Semileptonic Ωb→Ωcℓν¯ℓ transition in full QCD

We investigate the semileptonic decay of Ωb→Ωcℓν¯ℓ in three lepton channels. To this end, we use the QCD sum rule method in three point framework to calculate the form factors defining the matrix elements of these transitions. Having calculated the form factors as building blocks, we calculate the decay widths and branching fractions of the exclusive decays in all lepton channels and compare the results with other theoretical predictions. The obtained results for branching ratios and ratio of branching fractions at different leptonic channels may help experimental groups in their search for these weak decays. Comparison of the obtained results with possible future experimental data can be useful to check the order of consistency between the standard model theory predictions and data on the heavy baryon decays. Published by the American Physical Society 2024

Observation of the Ξb−→ψ(2S)Ξ− decay and studies of the Ξb(5945)0 baryon in proton-proton collisions at s=13 TeV

The first observation of the decay Ξb−→ψ(2S)Ξ− and measurement of the branching ratio of Ξb−→ψ(2S)Ξ− to Ξb−→J/ψΞ− are presented. The J/ψ and ψ(2S) mesons are reconstructed using their dimuon decay modes. The results are based on proton-proton colliding beam data from the LHC collected by the CMS experiment at s=13 TeV in 2016–2018, corresponding to an integrated luminosity of 140 fb−1. The branching fraction ratio is measured to be B(Ξb−→ψ(2S)Ξ−)/B(Ξb−→J/ψΞ−)=0.84−0.19+0.21(stat)±0.10(syst)±0.02(B), where the last uncertainty comes from the uncertainties in the branching fractions of the charmonium states. New measurements of the Ξb(5945)0 baryon mass and natural width are also presented, using the Ξb−π+ final state, where the Ξb− baryon is reconstructed through the decays J/ψΞ−, ψ(2S)Ξ−, J/ψΛK−, and J/ψΣ0K−. Finally, the fraction of Ξb− baryons produced from Ξb(5945)0 decays is determined. © 2024 CERN, for the CMS Collaboration 2024 CERN

Observation of Λb0→Λc+D¯(∗)0K-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\varLambda } ^0_{b}} \\!\\rightarrow {{\\varLambda } ^+_{c}} {\\hspace{1.79993pt}\\overline{\\hspace{-1.79993pt}D}} {}^{(*)0}{{K} ^-} $$\\end{document} and Λb0→Λc+Ds∗-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\varLambda } ^0_{b}} \\!\\rightarrow {{\\varLambda } ^+_{c}} {{D} ^{*-}_{s}} $$\\end{document} decays

The decays Λb0→Λc+D¯(∗)0K-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\varLambda } ^0_{b}} \\!\\rightarrow {{\\varLambda } ^+_{c}} {\\hspace{1.79993pt}\\overline{\\hspace{-1.79993pt}D}} {}^{(*)0}{{K} ^-} $$\\end{document} and Λb0→Λc+Ds∗-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\varLambda } ^0_{b}} \\!\\rightarrow {{\\varLambda } ^+_{c}} {{D} ^{*-}_{s}} $$\\end{document} are observed for the first time, in proton-proton collision data at s=13TeV\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sqrt{s} =13\ ext {Te\\hspace{-1.00006pt}V} $$\\end{document}, corresponding to an integrated luminosity of 5.4fb-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext {fb} ^{-1}$$\\end{document} collected with the LHCb detector. Their ratios of branching fractions with respect to the Λb0→Λc+Ds-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\varLambda } ^0_{b}} \\!\\rightarrow {{\\varLambda } ^+_{c}} {{D} ^-_{s}} $$\\end{document} mode are measured to be BΛb0→Λc+D¯0K-BΛb0→Λc+Ds-=0.1908-0.0034+0.0036-0.0018+0.0016±0.0038,BΛb0→Λc+D¯∗0K-BΛb0→Λc+Ds-=0.589-0.017+0.018-0.018+0.017±0.012,BΛb0→Λc+Ds∗-BΛb0→Λc+Ds-=1.668±0.022-0.055+0.061,\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\begin{aligned} \\begin{aligned} \\frac{\\mathcal {B}\\left( {{\\varLambda } ^0_{b}} \\!\\rightarrow {{\\varLambda } ^+_{c}} {{\\hspace{1.79993pt}\\overline{\\hspace{-1.79993pt}D}} {}^0} {{K} ^-} \\right) }{\\mathcal {B}\\left( {{\\varLambda } ^0_{b}} \\!\\rightarrow {{\\varLambda } ^+_{c}} {{D} ^-_{s}} \\right) }&= 0.1908 {}_{-0.0034}^{+0.0036} {}_{-0.0018}^{+0.0016} \\pm 0.0038,\\\\ \\frac{\\mathcal {B}\\left( {{\\varLambda } ^0_{b}} \\!\\rightarrow {{\\varLambda } ^+_{c}} {{\\hspace{1.79993pt}\\overline{\\hspace{-1.79993pt}D}} {}^{*0}} {{K} ^-} \\right) }{\\mathcal {B}\\left( {{\\varLambda } ^0_{b}} \\!\\rightarrow {{\\varLambda } ^+_{c}} {{D} ^-_{s}} \\right) }&= 0.589 {}_{-0.017}^{+0.018} {}_{-0.018}^{+0.017} \\pm 0.012,\\\\ \\frac{\\mathcal {B}\\left( {{\\varLambda } ^0_{b}} \\!\\rightarrow {{\\varLambda } ^+_{c}} {{D} ^{*-}_{s}} \\right) }{\\mathcal {B}\\left( {{\\varLambda } ^0_{b}} \\!\\rightarrow {{\\varLambda } ^+_{c}} {{D} ^-_{s}} \\right) }&= 1.668 \\pm 0.022 {}_{-0.055}^{+0.061}, \\end{aligned} \\end{aligned}$$\\end{document}where the first uncertainties are statistical, the second systematic, and the third, for the Λb0→Λc+D¯(∗)0K-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\varLambda } ^0_{b}} \\!\\rightarrow {{\\varLambda } ^+_{c}} {\\hspace{1.79993pt}\\overline{\\hspace{-1.79993pt}D}} {}^{(*)0}{{K} ^-} $$\\end{document} decays, are due to the uncertainties on the branching fractions of the Ds-→K-K+π-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{D} ^-_{s}} \\!\\rightarrow {{K} ^-} {{K} ^+} {{\\pi } ^-} $$\\end{document} and D¯0→K+π-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\hspace{1.79993pt}\\overline{\\hspace{-1.79993pt}D}} {}^0} \\!\\rightarrow {{K} ^+} {{\\pi } ^-} $$\\end{document} decay modes. The measured branching fractions probe factorization assumptions in effective theories and provide the normalization for future pentaquark searches in Λb0→Λc+D¯(∗)0K-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\varLambda } ^0_{b}} \\!\\rightarrow {{\\varLambda } ^+_{c}} {\\hspace{1.79993pt}\\overline{\\hspace{-1.79993pt}D}} {}^{(*)0}{{K} ^-} $$\\end{document} decay channels.

Calculation of the ratio of branching fractions

The LHCb Collaboration has reported for the first time the branching fraction for the decay as . They measured the branching fraction of this decay relative to that of the normalization channel as . In this work, we have studied the and decays in three scales of μ and strong coupling values mesons using a simple model based on the framework of the factorization approach presented. We have obtained for decay at and for decay at . We have also estimated at which is consistent with the experimental result.

First Measurement of R(Xτ/ℓ) as an Inclusive Test of the b→cτν Anomaly

We measure the tau-to-light-lepton ratio of inclusive B-meson branching fractions R(Xτ/ℓ)≡B(B→Xτν)/B(B→Xℓν), where ℓ indicates an electron or muon, and thereby test the universality of charged-current weak interactions. We select events that have one fully reconstructed B meson and a charged lepton candidate from 189 fb−1 of electron-positron collision data collected with the Belle II detector. We find R(Xτ/ℓ)=0.228±0.016(stat)±0.036(syst), in agreement with standard-model expectations. This is the first direct measurement of R(Xτ/ℓ). Published by the American Physical Society 2024

Measurement of the branching fraction of B0→ J/ψπ0 decays

The ratio of branching fractions between B0 → J/ψπ0 and B+ → J/ψK*+ decays is measured with proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb−1. The measured value isBB0→J/ψπ0BB+→J/ψK∗+=1.153±0.053±0.048×10−2,\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\frac{{\\mathcal{B}}_{B^0\ o J/\\psi {\\pi}^0}}{{\\mathcal{B}}_{B^{+}\ o J/\\psi {K}^{\\ast +}}}=\\left(1.153\\pm 0.053\\pm 0.048\\right)\ imes {10}^{-2}, $$\\end{document}where the first uncertainty is statistical and the second is systematic. The branching fraction for B0 → J/ψπ0 decays is determined using the branching fraction of the normalisation channel, resulting inBB0→J/ψπ0=1.670±0.077±0.069±0.095×10−5,\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\mathcal{B}}_{B^0\ o J/\\psi {\\pi}^0}=\\left(1.670\\pm 0.077\\pm 0.069\\pm 0.095\\right)\ imes {10}^{-5}, $$\\end{document}where the last uncertainty corresponds to that of the external input. This result is consistent with the current world average value and competitive with the most precise single measurement to date.

Observation of the singly Cabibbo-suppressed decay Λc+→Σ−K+π+

The singly Cabibbo-suppressed decay Λc+→Σ−K+π+ is observed for the first time with a statistical significance of 5.4σ by using 4.5 fb−1 of e+e− collision data collected at center-of-mass energies between 4.600 and 4.699 GeV with the BESIII detector at BEPCII. The absolute branching fraction of Λc+→Σ−K+π+ is measured to be (3.8±1.2stat±0.2syst)×10−4 in a model-independent approach. This is the first observation of a Cabibbo-suppressed Λc+ decay involving Σ− in the final state. The ratio of branching fractions between Λc+→Σ−K+π+ and the Cabibbo-favored decay Λc+→Σ−π+π+ is observed to be (0.4±0.1)sc2, where sc≡sinθc=0.2248 with θc the Cabibbo mixing angle. Published by the American Physical Society 2024

Search for the semileptonic decays Ξc0→Ξ0ℓ+ℓ− at Belle

Using the full data sample of 980 fb−1 collected with the Belle detector at the KEKB asymmetric energy electron-positron collider, we report the results of the first search for the rare semileptonic decays Ξc0→Ξ0ℓ+ℓ− (ℓ=e or μ). No significant signals are observed in the Ξ0ℓ+ℓ− invariant-mass distributions. Taking the decay Ξc0→Ξ−π+ as the normalization mode, we report 90% credibility upper limits on the branching fraction ratios B(Ξc0→Ξ0e+e−)/B(Ξc0→Ξ−π+)<6.7×10−3 and B(Ξc0→Ξ0μ+μ−)/B(Ξc0→Ξ−π+)<4.3×10−3 based on the phase-space assumption for signal decays. The 90% credibility upper limits on the absolute branching fractions of B(Ξc0→Ξ0e+e−) and B(Ξc0→Ξ0μ+μ−) are found to be 9.9×10−5 and 6.5×10−5, respectively. Published by the American Physical Society 2024

Search for the light hadron decay χc1(3872)→π+π−η

With a data sample corresponding to an integrated luminosity of 11.5 fb−1 collected with the BESIII detector operating at the BEPCII storage ring, for the first time the light hadron decay χc1(3872)→π+π−η is searched for. While no significant signal is observed, the upper limits at the 90% confidence level for σ[e+e−→γχc1(3872)]B[χc1(3872)→π+π−η] at center of mass energies from 4.13 GeV to 4.34 GeV are determined. By normalizing to the χc1(3872)→π+π−J/ψ decay channel, a 90% confidence level upper limit for the branching fraction ratio R=B[χc1(3872)→π+π−η]/B[χc1(3872)→π+π−J/ψ]<0.12 is given. These measurements provide important inputs for understanding the internal structure of the χc1(3872) resonance. Published by the American Physical Society 2024

Observation of the decay J/ψ→e+e−η(1405) with η(1405)→π0f0(980)

Using a data sample of (10087±44)×106 J/ψ events collected by the BESIII detector in 2009, 2012, 2018 and 2019, the electromagnetic Dalitz process J/ψ→e+e−η(1405) is observed via the decay η(1405)→π0f0(980), f0(980)→π+π−, with a significance of about 9.8σ. The branching fraction of this decay is measured to be B(J/ψ→e+e−η(1405)→e+e−π0f0(980)→e+e−π0π+π−)=(2.04±0.20(stat)±0.08(syst))×10−7. The branching fraction ratio B(J/ψ→e+e−η(1405))/B(J/ψ→γη(1405)) is determined to be (1.36±0.17(stat)±0.06(syst))×10−2. Furthermore, an e+e− invariant mass dependent transition form factor of J/ψ→e+e−η(1405) is presented for the first time. The obtained result provides input for different theoretical models and is valuable for the improved understanding the intrinsic structure of the η(1405) meson. Published by the American Physical Society 2024

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 Ds∗−\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}_s^{\\ast -} $$\\end{document} meson are analysed by reconstructing only the D0 or Ds−\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}_s^{-} $$\\end{document} decay products. This paper presents the first measurement of A\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{A} $$\\end{document}CP(B−→Ds∗−\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}_s^{\\ast -} $$\\end{document}D0) and A\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{A} $$\\end{document}CP(B−→Ds−\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}_s^{-} $$\\end{document}D∗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.

Analysis of some [formula omitted] decay modes beyond the standard model

The experimental results from BaBar, Belle, and LHCb direct us to look for various new physics scenarios beyond the standard model. The observed b-physics anomalies in the b→cτ−ν¯τ transitions motivate the study of decays with similar quark-level transitions. In this work, we focus on these transitions, particularly examining the semileptonic b-baryon Ωb→Ωc(⁎)τ−ν¯τ and Ξb′→Ξc′(⁎)τ−ν¯τ decay modes. We take into account the general effective Hamiltonian for b→cℓν¯ℓ transitions which incorporates new physics contributions into the standard model. We explore the q2-dependency of different observables, such as the differential branching fraction, ratio of branching fractions, forward-backward asymmetry, convexity parameter, and longitudinal polarization of the charged lepton, related to these decay processes in the standard model and beyond.

Test of Light-Lepton Universality in the Rates of Inclusive Semileptonic B-Meson Decays at Belle II.

We present the first measurement of the ratio of branching fractions of inclusive semileptonic B-meson decays, R(X_{e/μ})=B(B→Xeν)/B(B→Xμν), a precision test of electron-muon universality, using data corresponding to 189 fb^{-1} from electron-positron collisions collected with the Belle II detector. In events where the partner B meson is fully reconstructed, we use fits to the lepton momentum spectra above 1.3 GeV/c to obtain R(X_{e/μ})=1.007±0.009(stat)±0.019(syst), which is the most precise lepton-universality test of its kind and agrees with the standard-model expectation.

Form factors in HQEFT and model independent analysis of relevant semileptonic decays with NP effects* *Supported in part by the National Natural Science Foundation of China (12147214)

The form factors of decays into P-wave excited charmed mesons (including , , , and their strange counterparts, denoted generically as ) are systematically calculated via QCD sum rules in the framework of heavy quark effective field theory (HQEFT). We consider contributions up to the next leading order of heavy quark expansion and give all the relevant form factors, including the scalar and tensor ones only relevant for possible new physics effects. The expressions for the form factors in terms of several universal wave functions are derived via heavy quark expansion. These universal functions can be evaluated through QCD sum rules. Then, the numerical results of the form factors are presented. With the form factors given here, a model independent analysis of relevant semileptonic decays is performed, including the contributions from possible new physics effects. Our predictions for the differential decay widths, branching fractions, and ratios of branching fractions may be tested in more precise experiments in the future.