Decay Branching Fractions Research Articles

Analyzing the semileptonic and nonleptonic Bc → J/ψ, ηc decays

This study focuses on the decay of the Bc meson to S-wave charmonia. Starting with lattice inputs on Bc → J/ψ form factors, we have obtained the Bc → ηc form factors using heavy quark spin symmetry (HQSS) relations between the associated form factors after parametrizing and extracting the possible symmetry breaking corrections. Using the q2 shapes of these form factors, we have computed the branching fractions B(Bc− → ηcℓ−ν¯) (with ℓ = τ, μ(e)) and the decay rate distributions and have predicted the Standard model estimate for the observable R(ηc) = Γ(Bc− → ηcτ−ν¯)/Γ(Bc−→ ηcμ−ν¯) = 0.310 ± 0.042. In addition, we have estimated the radial wave functions ψBcR (0), ψJ/ψR (0) and ψηcR (0) at small Bc J/ψ ηc quark-antiquark distances from the available information on the form factors from lattice, the lattice inputs on the decay constants fJ/ψ, fηc, fBc and experimental data on radiative and rare decays of the J/ψ and ηc mesons. To do so, we choose the theory framework of non-relativistic QCD (NRQCD) effective theory. Using our results, we have predicted the branching fractions of a few non-leptonic decays of Bc → J/ψ or ηc and other light mesons. We have also updated the numerical estimates of the cross sections σ(e+e− → J/ψηc, ηcγ) and predicted the branching fractions of Z boson decays to either J/ψ or ηc final states or both.

Measurements of decay branching fractions of the Higgs boson to hadronic final states at the CEPC

Abstract The Circular Electron Positron Collider (CEPC) is a large-scale particle accelerator designed to collide electrons and positrons at high energies. One of the primary goals of the CEPC is to achieve high-precision measurements of the properties of the Higgs boson, facilitated by the large number of Higgs bosons that can be produced with significantly low contamination. The measurements of Higgs boson branching fractions into bb/cc/gg and tautau/WW*/ZZ*, where the W or Z bosons decay hadronically, are presented in the context of the CEPC experiment, assuming a scenario with 5600 fb-1 of collision data at a center-of-mass energy of 240 GeV. In this study the Higgs bosons are produced in association with a Z boson, with the Z boson decaying into a pair of muons (μ+μ-), which have high efficiency and high resolution. In order to separate all decay channels simultaneously with high accuracy, the Particle Flow Network (PFN), a graph-based machine learning model, is considered. The precise classification provided by the PFN is employed in measuring the branching fractions using the migration matrix method, which accurately corrects for detector effects in each decay channel. The statistical uncertainty of the measured branching ratio is estimated to be 0.55% in H → bb final state, and approximately 1.5%-16% in H → cc/gg/tautau/WW*/ZZ* final states. In addition, the main sources of systematic uncertainties to the measurement of the branching fractions are discussed. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Search for ηc(2S)→K+K−η′ decay

Using (2.712±0.014)×109 ψ(2S) events collected with the BESIII detector operating at the BEPCII, we search for the ηc(2S)→K+K−η′ decay. Its decay branching fraction is measured to be (11.11±4.67(stat)±1.82(syst)±4.24(extr))×10−4, where the first uncertainty is statistical, the second is systematic, and the third uncertainty is from the branching fraction of the ψ(2S)→γηc(2S) decay. The statistical significance is 2.8σ. The upper limit on the product branching fraction B[ψ(2S)→γηc(2S)]×B[ηc(2S)→K+K−η′] is set to be 0.94×10−6 at 90% confidence level. In addition, the branching fractions of χc1→K+K−η′ and χc2→K+K−η′ are updated to be (8.48±0.10(stat)±0.47(syst))×10−4 and (1.53±0.04(stat)±0.08(syst))×10−4, respectively. The precision is improved by twofold. Published by the American Physical Society 2025

Evidence of h_{b}(2P)→ϒ(1S)η Decay and Search for h_{b}(1P,2P)→ϒ(1S)π^{0} with the Belle Detector.

We report the first evidence for the h_{b}(2P)→ϒ(1S)η transition with a significance of 3.5 standard deviations. The decay branching fraction is measured to be B[h_{b}(2P)→ϒ(1S)η]=(7.1_{-3.2}^{+3.7}±0.8)×10^{-3}, which is noticeably smaller than expected. We also set upper limits on π^{0} transitions of B[h_{b}(2P)→ϒ(1S)π^{0}]<1.8×10^{-3}, and B[h_{b}(1P)→ϒ(1S)π^{0}]<1.8×10^{-3}, at the 90% confidence level. These results are obtained with a 131.4 fb^{-1} data sample collected near the ϒ(5S) resonance with the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider.

A Generic Analysis of Nucleon Decay Branching Fractions in Flipped SU(5) Grand Unification

In flipped SU(5) grand unified theories, the partial decay lifetimes of certain nucleon decay channels depend generically on an unknown unitary matrix, which arises when left-handed lepton fields are embedded into anti-fundamental representations of SU(5). This dependency is particularly relevant when the neutrino mass matrix has a generic structure, introducing uncertainty in the prediction of nucleon decay branching fractions within flipped SU(5). In this paper, we demonstrate that this uncertainty can be parametrized using two parameters, which can be determined by measuring the partial lifetimes of p→π0e+, p→π0μ+, and n→π0ν¯. In addition, we establish upper limits on the ratios of the decay widths of these channels, offering a potential method to test flipped SU(5) in future nucleon decay experiments.

Search for Rare Decays of D_{s}^{+} to Final States π^{+}e^{+}e^{-}, ρ^{+}e^{+}e^{-}, π^{+}π^{0}e^{+}e^{-}, K^{+}π^{0}e^{+}e^{-}, and K_{S}^{0}π^{+}e^{+}e^{-}.

Using 7.33 fb^{-1} of e^{+}e^{-} collision data collected by the BESIII detector at center-of-mass energies in the range of sqrt[s]=4.128-4.226 GeV, we search for the rare decays D_{s}^{+}→h^{+}(h^{0})e^{+}e^{-}, where h represents a kaon or pion. By requiring the e^{+}e^{-} invariant mass to be consistent with a ϕ(1020), 0.98<M(e^{+}e^{-})<1.04 GeV/c^{2}, the decay D_{s}^{+}→π^{+}ϕ, ϕ→e^{+}e^{-} is observed with a statistical significance of 7.8σ, and evidence for the decay D_{s}^{+}→ρ^{+}ϕ, ϕ→e^{+}e^{-} is found for the first time with a statistical significance of 4.4σ. The decay branching fractions are measured to be B(D_{s}^{+}→π^{+}ϕ,ϕ→e^{+}e^{-})=(1.17_{-0.21}^{+0.23}±0.03)×10^{-5}, and B(D_{s}^{+}→ρ^{+}ϕ,ϕ→e^{+}e^{-})=(2.44_{-0.62}^{+0.67}±0.16)×10^{-5}, where the first uncertainties are statistical and the second systematic. No significant signals for the three four-body decays of D_{s}^{+}→π^{+}π^{0}e^{+}e^{-}, D_{s}^{+}→K^{+}π^{0}e^{+}e^{-}, and D_{s}^{+}→K_{S}^{0}π^{+}e^{+}e^{-} are observed. For D_{s}^{+}→π^{+}π^{0}e^{+}e^{-}, the ϕ mass region is vetoed to minimize the long-distance effects. The 90%confidence level upper limits set on the branching fractions of these decays are in the range of (7.0-8.1)×10^{-5}.

Measurements of the branching fractions of the P -wave charmonium spin-singlet state hc(P11)→h+h−π0/η

Based on (2712.4±14.3)×106 ψ(3686) events, we investigate four hadronic decay modes of the P-wave charmonium spin-singlet state hc(1P1)→h+h−π0/η (h=π or K) via the process ψ(3686)→π0hc at BESIII. The hc→π+π−π0 decay is observed with a significance of 9.6σ after taking into account systematic uncertainties. Evidences for hc→K+K−π0 and hc→K+K−η are found with significances of 3.5σ and 3.3σ, respectively, after considering the systematic uncertainties. The branching fractions of these decays are measured to be B(hc→π+π−π0)=(1.36±0.16±0.14)×10−3, B(hc→K+K−π0)=(3.26±0.84±0.36)×10−4, and B(hc→K+K−η)=(3.13±1.08±0.38)×10−4, where the first uncertainties are statistical and the second are systematic. No significant signal of hc→π+π−η is found, and the upper limit of its decay branching fraction is determined to be B(hc→π+π−η)&lt;4.0×10−4 at the 90% confidence level. Published by the American Physical Society 2024

Charm physics with overlap fermions on 2+1-flavor domain wall fermion configurations* *Supported in part by the National Key Research and Development Program of China (2020YFA0406400, 2023YFA1606002), the National Natural Science Foundation of China (12075253, 11935017, 12192264, 12293060, 12293065, 12293063, 12070131001), CRC 110 by DFG and NNSFC. Keh-Fei Liu is supported by the U.S. DOE Grant (DE-SC0013065) and DOE Grant (DEAC05-06OR23177),

Decay constants of pseudoscalar mesons D, , and vector mesons , , are determined from the lattice QCD at a lattice spacing fm. For vector mesons, the decay constants defined by tensor currents are given in the scheme at GeV. The calculation is performed on domain wall fermion configurations generated by the RBC-UKQCD collaborations and the overlap fermion action is used for the valence quarks. Comparing the current results with our previous results at a coarser lattice spacing fm provides a better understanding of the discretization error. We obtain with a better precision than our previous result. Combining our MeV with the total width of determined in a recent study gives a branching fraction for leptonic decay.

Predicting isovector charmonium-like states from X(3872) properties

Using chiral effective field theory, we predict that there must be isovector charmonium-like DD¯∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ D{\\overline{D}}^{\\ast } $$\\end{document} hadronic molecules with JPC = 1++ denoted as Wc1. The inputs are the properties of the X(3872), including its mass and the ratio of its branching fractions of decays into J/ψρ0 and J/ψω. The predicted states are virtual state poles of the scattering matrix, pointing at a molecular nature of the X(3872) as well as its spin partners. They should show up as either a mild cusp or dip at the DD¯∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ D{\\overline{D}}^{\\ast } $$\\end{document} thresholds, explaining why they are elusive in experiments. The so far negative observation also indicates that the X(3872) is either a bound state with non-vanishing binding energy or a virtual state, only in these cases the X(3872) signal dominates over that from the Wc10\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {W}_{c1}^0 $$\\end{document}. The pole positions are 3881.2−0.0+0.8\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {3881.2}_{-0.0}^{+0.8} $$\\end{document}−i1.6−0.9+0.7\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ i{1.6}_{-0.9}^{+0.7} $$\\end{document} MeV for Wc10\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {W}_{c1}^0 $$\\end{document} on the fourth Riemann sheet of the D0D¯∗0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}^0{\\overline{D}}^{\\ast 0} $$\\end{document}-D+D∗− coupled-channel system, and 3866.9−7.7+4.6\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {3866.9}_{-7.7}^{+4.6} $$\\end{document}− i(0.07 ± 0.01) MeV for Wc1±\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {W}_{c1}^{\\pm } $$\\end{document} on the second Riemann sheet of the DD¯∗±\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\left(D{\\overline{D}}^{\\ast}\\right)}^{\\pm } $$\\end{document} single-channel system. The findings imply that the peak in the J/ψπ+π− invariant mass distribution is not purely from the X(3872) but contains contributions from Wc10\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {W}_{c1}^0 $$\\end{document} predicted here. The states should have isovector heavy quark spin partners with JPC = 0++, 2++ and 1+−, with the last one corresponding to Zc. We suggest to search for the charged 0++, 1++ and 2++ states in J/ψπ±π0.

Study of the decays χcJ→ΛΛ¯ϕ

Based on (2712.4±14.3)×106 e+e−→ψ(3686) events collected with the BESIII detector operating at the BEPCII Collider, we report the first evidence of χc0→ΛΛ¯ϕ decays and the first observation of χc1,2→ΛΛ¯ϕ decays, with significances of 4.1σ, 11.3σ and 13.0σ, respectively. The decay branching fractions of χc0,1,2→ΛΛ¯ϕ are measured to be (2.99±1.24±0.19)×10−5, (6.01±0.90±0.40)×10−5, and (7.13±0.81±0.36)×10−5, where the first uncertainties are statistical and the second systematic. No obvious enhancement near the ΛΛ¯ production threshold or excited Λ state is found in the Λϕ (or Λ¯ϕ) system. Published by the American Physical Society 2024

Structure of ccc¯c¯ tetraquarks and interpretation of LHC states

Motivated by recent experimental evidence for apparent ccc¯c¯ states by LHCb, CMS and ATLAS, we consider how the mass spectrum and decays of such states can be used to discriminate among their possible theoretical interpretations, with a particular focus on identifying whether quarks or diquarks are the most relevant degrees of freedom. Our preferred scenario is that X(6600) and its apparent partner state X(6400) are the tensor (2++) and scalar (0++) states of an S-wave multiplet of ccc¯c¯ states. Using tetraquark mass relations which are independent of (or only weakly dependent on) model parameters, we give predictions for the masses of additional partner states with axial and scalar quantum numbers. Additionally, we give predictions for relations among decay branching fractions to J/ψJ/ψ, J/ψηc, ηcηc, and D(*)D¯(*) channels. The scenario we consider is consistent with existing experimental data on J/ψJ/ψ, and our predictions for partner states and their decays can be confronted with future experimental data, to discriminate between quark and diquark models. Published by the American Physical Society 2024

Search for two-body B meson decays to Λ0 and Ωc(*)0

We report the results of the first search for Standard Model and baryon-number-violating two-body decays of the neutral B mesons to Λ0 and Ωc(*)0 using 711 fb−1 of data collected at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. We observe no evidence of signal from any such decays and set 95% confidence-level upper limits on the products of B0 and B¯0 branching fractions for these two-body decays with B(Ωc0→π+Ω−) in the range between 9.5×10−8 and 31.2×10−8. 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

Model dependent analysis of decays in beyond standard model

Motivated by the recent experimental results of branching fractions for decays, which deviate from their SM predictions, we hve investigated these decays in model and scalar leptoquark model to determine potential signatures of new physics (NP) in semileptonic charm decays induced by transitions. Using recent experimental results of branching fractions for semileptonic meson decays, new coupling parameters are predicted for the aforementioned NP models. Branching fraction, forward-backward asymmetry, and lepton polarization asymmetry are examined by considering the predicted NP coupling parameters. The results of branching fractions in scalar leptoquark model are found very close to the experimental results and exist around the range of deviation. We presented a comparative study of the NP models to check their sensitivity on these decays. We anticipate that further research on these decays will significantly support our findings.

Search for a new resonance decaying into two spin-0 bosons in a final state with two photons and two bottom quarks in proton-proton collisions at s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\sqrt{s} $$\\end{document} = 13 TeV

A search for a new boson X is presented using CERN LHC proton-proton collision data collected by the CMS experiment at s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\sqrt{s} $$\\end{document} = 13 TeV in 2016–2018, and corresponding to an integrated luminosity of 138 fb−1. The resonance X decays into either a pair of Higgs bosons HH of mass 125 GeV or an H and a new spin-0 boson Y. One H subsequently decays to a pair of photons, and the second H or Y, to a pair of bottom quarks. The explored mass ranges of X are 260–1000 GeV and 300–1000 GeV, for decays to HH and to HY, respectively, with the Y mass range being 90–800 GeV. For a spin-0 X hypothesis, the 95% confidence level upper limit on the product of its production cross section and decay branching fraction is observed to be within 0.90–0.04 fb, depending on the masses of X and Y. The largest deviation from the background-only hypothesis with a local (global) significance of 3.8 (below 2.8) standard deviations is observed for X and Y masses of 650 and 90 GeV, respectively. The limits are interpreted using several models of new physics.

Accessing CKM suppressed top decays at the LHC

We propose an extension of the existing experimental strategy for measuring branching fractions of top quark decays, targeting specifically t\to j_q Wt→jqW, where j_qjq is a light quark jet. The improved strategy uses orthogonal bb- and qq-taggers, and adds a new observable, the number of light-quark-tagged jets, to the already commonly used observable, the fraction of bb-tagged jets in an event. Careful inclusion of the additional complementary observable significantly increases the expected statistical power of the analysis, with the possibility of excluding |V_{tb}|=1|Vtb|=1 at 95\%95% C.L. at the HL-LHC, and accessing directly the standard model value of |V_{td}|^2+|V_{ts}|^2|Vtd|2+|Vts|2.

First Observation of a Three-Resonance Structure in e+e−→Nonopen Charm Hadrons

We report the measurement of the inclusive cross sections for e+e−→nOCH (where nOCH denotes non-open charm hadrons) with improved precision at center-of-mass (c.m.) energies from 3.645 to 3.871 GeV. We observe three resonances: R(3760), R(3780), and R(3810) with significances of 8.1σ, 13.7σ, and 8.8σ, respectively. The R(3810) state is observed for the first time, while the R(3760) and R(3780) states are observed for the first time in the nOCH cross sections. Two sets of resonance parameters describe the energy-dependent line shape of the cross sections well. In set I [set II], the R(3810) state has mass (3805.7±1.1±2.7) [(3805.7±1.1±2.7)] MeV/c2, total width (11.6±2.9±1.9) [(11.5±2.8±1.9)] MeV, and an electronic width multiplied by the nOCH decay branching fraction of (10.9±3.8±2.5) [(11.0±3.4±2.5)] eV. In addition, we measure the branching fractions B[R(3760)→nOCH]=(25.2±16.1±30.4)%[(6.4±4.8±7.7)%] and B[R(3780)→nOCH]=(12.3±6.6±8.3)%[(10.4±4.8±7.0)%] for the first time. The R(3760) state can be interpreted as an open-charm (OC) molecular state, but containing a simple four-quark state component. The R(3810) state can be interpreted as a hadrocharmonium state. Published by the American Physical Society 2024

Ground state spectra, decay properties of B and D mesons in a relativistic square root potential

We look at the mass spectra of the [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] mesons using a relativistic square root potential. Before looking at the mass spectra, we have to figure out the model parameters, which are [Formula: see text][Formula: see text]GeV and [Formula: see text][Formula: see text]GeV. The calculated result of [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], findings of this study exhibit a notable concurrence with the experimental observations and pertinent theoretical projections. We estimate the decay constant, leptonic decay width, semileptonic decay width, and branching fractions of pseudoscalar and vector mesons, specifically B and D mesons, while keeping the model parameters unchanged. The pseudoscalar decay constants and partial decay widths of “B and D-mesons” reasonably agree with the theoretical predictions, lattice quantum chromodynamics (LQCD) calculations, and experimental data. Moreover, we have efficiently found the values for these mesons’ leptonic decay width and branching fraction, matching the experimental findings and theoretical forecasts. The calculated values of semileptonic decays are [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text], [Formula: see text], [Formula: see text], the proximity of the observed results to experimental and certain theoretical models is evident.

Z -boson decays into S -wave quarkonium plus a photon up to O(αsv2) corrections

In this paper, we calculate the decay widths and branching fractions for the decays Z→H+γ up to O(αsv2) accuracy within the framework of nonrelativistic QCD, where H stands for the S-wave quarkonium ηc, J/ψ, ηb, or ϒ, respectively. To compare with the leading-order terms, those corrections show good perturbative behavior as expected. It is found that contributions from the next-to-leading order QCD correction O(αsv0), the relativistic correction O(αs0v2) and their joint correction O(αsv2) are sizable and comparable to each other, especially for the charmonium case. Thus we need to take all of them into consideration for a sound estimation. For a high luminosity electron-positron collider running around the Z pole, due to Z-boson resonance effect, sizable events could be produced from those rare decay channels. Published by the American Physical Society 2024

Higher twist corrections to B -meson decays into a proton and dark antibaryon from QCD light-cone sum rules

The B-mesogenesis framework anticipates decays of B mesons into a dark antibaryon Ψ and various Standard Model baryons. Here, we focus on the exclusive decay process B→pΨ observed as a proton and missing energy in the final state and determine the decay width by employing the QCD light-cone sum rule framework. We include all contributions up to twist six to the nucleon distribution amplitudes in order to parametrize the nonperturbative effects in the operator product expansion. We obtain the decay width and branching fraction with respect to the mass mΨ of the dark antibaryon Ψ. Published by the American Physical Society 2024