Partial Widths Research Articles

Measurement of Born cross sections of e+e−→Ξ0Ξ¯0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {e}^{+}{e}^{-}\ o {\\Xi}^0{\\overline{\\Xi}}^0 $$\\end{document} and search for charmonium(-like) states 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} = 3.51–4.95 GeV

Using e+e− collision data collected by the BESIII detector at BEPCII corresponding to an integrated luminosity of 30 fb−1, we measure Born cross sections and effective form factors for the process e+e−→Ξ0Ξ¯0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {e}^{+}{e}^{-}\ o {\\Xi}^0{\\overline{\\Xi}}^0 $$\\end{document} at forty-five center-of-mass energies between 3.51 and 4.95 GeV. The dressed cross section is fitted, assuming a power-law function plus a charmonium(-like) state, i.e., ψ(3770), ψ(4040), ψ(4160), ψ(4230), ψ(4360), ψ(4415) or ψ(4660). No significant charmonium(-like) state decaying into Ξ0Ξ¯0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\Xi}^0{\\overline{\\Xi}}^0 $$\\end{document} is observed. Upper limits at the 90% confidence level on the product of the branching fraction and the electronic partial width are provided for each decay. In addition, ratios of the Born cross sections and the effective form factors for e+e−→Ξ0Ξ¯0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {e}^{+}{e}^{-}\ o {\\Xi}^0{\\overline{\\Xi}}^0 $$\\end{document} and e+e−→Ξ−Ξ¯+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {e}^{+}{e}^{-}\ o {\\Xi}^{-}{\\overline{\\Xi}}^{+} $$\\end{document} are also presented to test isospin symmetry and the vector meson dominance model.

Ab initio calculations of molecular double Auger decay rates.

We report on the application of the recently developed Fano-ADC(2,2) method to compute total and partial Auger decay widths of molecular core-hole states, including explicit evaluation of double Auger decay branching ratios. The method utilizes the fast-convergent intermediate state representation to construct many-electron wave functions and is readily applicable to atoms, molecules, and clusters. The ADC(2,2) scheme describes the initial and final states of the normal Auger decay consistently up to the second order of perturbation theory. In addition, excitations with two electrons in the continuum provide access to three-electron decay modes. The method yields decay widths and the Auger electron spectra in excellent agreement with the experiment, demonstrating the high accuracy of partial widths. The average relative error of double Auger decay branching ratios compared to available experimental data is about 30%, which should be evaluated as an excellent result considering the universality of the method, the complexity of the double decay process, and the neglection of nuclear motion in this study.

Study of lepton flavor universality and angular distributions in D→KJ∗(→Kπ)ℓνℓ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D\\rightarrow K^*_{J} (\\rightarrow K\\pi )\\ell \ u _{\\ell }$$\\end{document}

The decay of the D meson into multibody final states is a complex process that provides valuable insights into the fundamental interactions within the Standard Model of particle physics. This study focuses on the decay cascade D+→KJ∗ℓ+ν→K±π∓ℓ+ν\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D^{+}\\rightarrow K^{*}_{J} \\ell ^{+}\ u \\rightarrow K^{\\pm }\\pi ^{\\mp } \\ell ^{+}\ u $$\\end{document} where the KJ∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$K^*_J$$\\end{document} resonance encompasses the K∗(892),K∗(1410),K0∗(1430)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$K^*(892),K^{*}(1410),K^{*}_0(1430)$$\\end{document} states. We employ the helicity amplitude technique to derive the angular distributions for the decay chain, enabling the extraction of one-dimensional and two-dimensional distributions. Utilizing form factors for the D→K∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D\\rightarrow K^*$$\\end{document} transition derived from the quark model, we calculate the differential and integrated partial decay widths, explicitly considering the electron and muon masses. Decay branching fractions are calculated, the ratios of the branching fractions are found to be Br(D+→K∗(892)(→K-π+)μ+νμ)Br(D+→K∗(892)(→K-π+)e+νe)=0.975\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\frac{\\mathcal {B}r(D^{+}\\rightarrow K^{*}(892)(\\rightarrow K ^{-}\\pi ^{+}) \\, \\mu ^{+}\ u _{\\mu })}{\\mathcal {B}r(D^{+}\\rightarrow K^{*}(892)(\\rightarrow K ^{-}\\pi ^{+}) \\, e^{+}\ u _{e})} = 0.975$$\\end{document}, Br(D+→K∗(1410)(→K-π+)μ+νμ)Br(D+→K∗(1410)(→K-π+)e+νe)=0.714\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\frac{\\mathcal {B}r(D^{+}\\rightarrow K^{*}(1410)(\\rightarrow K ^{-}\\pi ^{+}) \\, \\mu ^{+}\ u _{\\mu })}{\\mathcal {B}r(D^{+}\\rightarrow K^{*}(1410)(\\rightarrow K ^{-}\\pi ^{+}) \\, e^{+}\ u _{e})} = 0.714$$\\end{document} and Br(D+→K0∗(1430)(→K+π-)μ+νμ)Br(D+→K0∗(1430)(→K+π-)e+νe)=0.774\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\frac{\\mathcal {B}r(D^{+}\\rightarrow K^{*}_{0}(1430)(\\rightarrow K ^{+}\\pi ^{-}) \\, \\mu ^{+}\ u _{\\mu })}{\\mathcal {B}r(D^{+}\\rightarrow K^{*}_{0}(1430)(\\rightarrow K ^{+}\\pi ^{-}) \\, e^{+}\ u _{e})} = 0.774$$\\end{document}. Results in this work will serve a calibration for the study of c→s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$c \\rightarrow s $$\\end{document} in D meson decays in future and provide useful information towards the understanding of the properties of the K∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$K^{*}$$\\end{document} meson, as well as Kπ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$K \\pi $$\\end{document} system.

Hidden charm decays of Y(4626) in a Ds*+Ds1(2536)− molecular frame

In this work, we investigate the hidden charm decays properties of Y(4626), where Y(4626) is assigned as a S−wave Ds*+Ds1(2536)− molecular state with JPC=1−−. The partial widths of the processes Y(4626)→J/ψη, J/ψη′, ηcϕ, and χcJϕ,(J={0,1,2}) are estimated by employing the effective Lagrangian approach. The present estimations indicate that the partial widths of the J/ψη and J/ψη′ channels are of the order of 1 MeV, while the one of χc1ϕ is of the order of 0.1 MeV. Thus, we propose to further examine the molecular interpretation of Y(4626) by searching it in the cross sections for the e+e−→J/ψη(′) processes, which should be accessible by the BES III and Belle II. Published by the American Physical Society 2024

Next-to-leading-order electroweak correction to H→Z0γ

Inspired by the recent observation of the Higgs boson radiative decay into Z0 by and Collaborations, we investigate the next-to-leading-order (NLO) electroweak correction to this rare decay process in Standard Model (SM). Implementing the on shell renormalization scheme, we find that the magnitude of the NLO electroweak correction may reach 7% of the leading-order (LO) prediction, much more significant than that of the NLO QCD correction, which is merely about 0.3%. After incorporating the O(α) correction, the predicted partial width from various α schemes tend to converge to each other. Including both NLO electroweak and QCD corrections, the SM prediction for the branching fraction shifts from the LO value of (1.40–1.71)×10−3 to (1.55±0.06)×10−3, considerably lower than the measured value Bexp[H→Z0γ]=(3.4±1.1)×10−3. Resolving this discrepancy clearly calls for further theoretical investigations, and, more importantly, experimental efforts from and the prospective Higgs factories such as and . Published by the American Physical Society 2024

Heavy four-quark mesons [formula omitted]: Scalar particle

Parameters of the heavy four-quark scalar meson Tbcb‾c‾ with content bcb‾c‾ are calculated by means of the sum rule method. This structure is considered as a diquark-antidiquark state built of scalar diquark and antidiquark components. The mass and current coupling of Tbcb‾c‾ are evaluated in the context of the two-point sum rule approach. The full width of this tetraquark is estimated by taking into account two types of its possible strong decay channels. First class includes dissociation of Tbcb‾c‾ to mesons ηcηb, Bc+Bc−, Bc⁎+Bc⁎− and Bc+(13P0)Bc⁎−. Another type of processes are generated by annihilations b‾b→q‾q of constituent b-quarks which produces the final-state charmed meson pairs D+D−, D0D‾0, D⁎+D⁎−, and D⁎0D‾⁎0. Partial width all of these decays are found using the three-point sum rule method which is required to calculate strong couplings at corresponding meson-meson-tetraquark vertices. Predictions obtained for the mass m=(12697±90)MeV and width Γ[Tbcb‾c‾]=(142.4±16.9)MeV of this state are compared with alternative results, and are useful for further experimental investigations of fully heavy resonances.

Studying the Ξ(2030) as a predominantly K¯*Σ molecular state

Since its discovery in 1977, the spin parity of Ξ(2030) has not been fully determined experimentally. The latest Particle Data Group listing suggests it may be a baryon with J=5/2. Therefore, studying the mass spectrum and decay properties of Ξ(2030) has become a current hot topic to definitively establish its spin parity. As the three-quark model fails to explain Ξ(2030), we previously proposed it may be a molecule primarily composed of K¯*Σ with JP=5/2+, based on its mass spectrum study. To verify its molecular state interpretation, this work proposes studying the strong decays of Ξ(2030) assuming it is a P-wave JP=5/2+ meson-baryon molecule predominantly composed of K¯*Σ. We calculated all experimentally measured two-body and three-body final state decay widths of Ξ(2030), including Ξ(2030)→K¯Λ,K¯Σ,πΞ,πΞ*, and Ξ(2030)→ππΞ,πK¯Σ,πK¯Λ. The results indicate that both the total decay width and partial decay widths agree well with experimental values within the error margins. This supports that Ξ(2030) is a molecule with spin-parity JP=5/2+, predominantly composed of K¯*Σ. Compared to the experimental central values, our results are slightly smaller, which suggests that Ξ(2030) may contain additional components besides meson-baryon molecular components, such as three-quark structures. Published by the American Physical Society 2024

Production of a BB¯ bound state via ϒ(4S) radiative decays

Motivated by recent theoretical predictions about the existence of a BB¯ bound state [also denoted as X(10550)], in this work we estimate the production of the S-wave B+B− molecule via ϒ(4S) radiative decays. In particular, we make use of effective Lagrangian approach and the compositeness condition to calculate the X(10550) production rate via ϒ(4S)→γX(10550) decays employing triangle diagrams. Our results show that the partial decay width of this reaction is of the order of 0.5–192 keV for a respective binding energy of 1–100 MeV, corresponding to a branching fraction of 10−5–10−3. These findings suggest that the existence of the X(10550) might be checked via the analysis of the mentioned decay in present and future experiments. Published by the American Physical Society 2024

Semileptonic and nonleptonic decays of in the covariant light-front approach* *This study was partly supported by the National Natural Science Foundation of China (11347030), the Program for Science and Technology Innovation Talents in Universities of Henan Province (14HASTIT037), and the Natural Science Foundation of Henan Province, China (232300420116)

The semileptonic and nonleptonic decays of the b-flavor vector mesons and are investigated within the covariant light-front quark model (CLFQM). By calculating the form factors of the transitions under the CLFQM, with P denoting a pseudoscalar meson, i.e., , we predict and discuss several physical observables, including the branching ratios, polarization fractions , and forward-backward asymmetries . The total widths of the single-photon radiative decay channels for these b-flavor vector mesons are estimated using their partial widths. In these considered decays, one can find that the semileptonic decays and , with being e or , and the nonleptonic channels have the largest branching ratios, which can reach up to the 10-7 order, and are most likely to be accessible at the future high-luminosity LHCb and Belle-II experiments.

Masses and decay widths of the S -wave ΛcΛ¯c bound states

In this work, we investigate possible bound states of the ΛcΛ¯c system in the Bethe-Salpeter formalism in the ladder and instantaneous approximations. By numerically solving the Bethe-Salpeter equation, we confirm the existence of ΛcΛ¯c bound states with quantum numbers JPC=0−+ and JPC=1−−. We further investigate the partial decay widths of the ΛcΛ¯c bound states into NN¯, DD¯, DD¯*, D*D¯*, ππ¯, and KK¯. Our results indicate that the decay width of the ΛcΛ¯c bound state with JPC=1−− is much larger than that with JPC=0−+, and among their decay channels, the DD¯* final state is the main decay mode. We suggest experiments to search for the ΛcΛ¯c bound states in the DD¯* final state. Published by the American Physical Society 2024

Parameterized problems complete for nondeterministic FPT time and logarithmic space

Let XNLP be the class of parameterized problems such that an instance of size n with parameter k can be solved nondeterministically in time f(k)nO(1) and space f(k)log⁡(n) (for some computable function f). We give a wide variety of XNLP-complete problems, such as List Coloring and Precoloring Extension with pathwidth as parameter, Scheduling of Jobs with Precedence Constraints, with both number of machines and partial order width as parameter, Bandwidth and variants of Weighted CNF-Satisfiability. In particular, this implies that all these problems are W[t]-hard for all t.

Form factor for Dalitz decays from J/ψ to light pseudoscalars* *Supported by the National Natural Science Foundation of China (11935017, 12293060, 12293065, 12293061, 12293062, 12293063, 12075253, 12192264, 12175063, 12205311, 12070131001 (CRC 110 by DFG and NNSFC)), the National Key Research and Development Program of China (2020YFA0406400), the Strategic Priority Research Program of Chinese Academy of Sciences (XDB34030302). The Chroma software

We calculate the form factor for the Dalitz decay with being the SU( ) flavor singlet pseudoscalar meson. The difference among the partial widths at different can be attributed in part to the and quark mass dependences induced by the anomaly dominance. in both is well described by the single pole model . Combined with the known experimental results of the Dalitz decays , the pseudoscalar mass dependence of the pole parameter is approximated by with and . These results provide inputs for future theoretical and experimental studies on the Dalitz decays .

Parameters of the tensor tetraquark [formula omitted]

The mass and width of the tensor tetraquark T=bbc‾c‾ with spin-parity JP=2+ are calculated in the context of the QCD sum rule method. The tetraquark T is modeled as a diquark-antidiquark state built of components bTCγμb and c‾γνCc‾T with C being the charge conjugation matrix. The mass m=(12.795±0.095)GeV of the exotic tensor meson T is found by means of the two-point sum rule approach. Its full width Γ is evaluated by considering processes T→Bc−Bc−, Bc−Bc⁎−, and Bc⁎−Bc⁎−. Partial widths of these decays are computed by means of the three-point sum rule approach which is used to determine the strong couplings at relevant tetraquark-meson-meson vertices. Predictions obtained for the width ΓT=55.5−9.9+10.6MeV, as well as the mass of the tetraquark T can be useful in investigations of fully heavy four-quark mesons.

Strong decays of Pcs(4338) and its high isospin cousin via QCD sum rules

In the present work, the strong decays of the newly observed Pcs(4338) as well as its high isospin cousin Pcs(4460) are studied via the QCD sum rules. According to conservation of isospin, spin, and parity, the hadronic coupling constants in four decay channels are obtained; then, the partial decay widths are obtained. The total width of the Pcs(4338) coincides with the experimental data nicely, while the predictions for the Pcs(4460) can be testified in the future experiment and shed light on the nature of the Pcs(4338). Published by the American Physical Society 2024

Charmonium production in hot magnetized hyperonic matter: Effects of the baryonic Dirac sea and pseudoscalar-vector mixing

We investigate the medium modifications of the masses of pseudoscalar open charm (D and D¯) mesons and the charmonium state [ψ(3770)] in hot isospin asymmetric strange hadronic medium in the presence of an external magnetic field within a chiral effective model. The in-medium partial decay widths of ψ(3770) to charged and neutral DD¯ mesons are computed from the medium modifications of the masses of the initial and final state mesons. These are computed using two light quark pair creation models—(I) the P03 model and (II) a field theoretical (FT) model of composite hadrons with quark (and antiquark) constituents. The production cross sections of ψ(3770), arising from scattering of the D and D¯ mesons, are computed from the relativistic Breit-Wigner spectral function expressed in terms of the in-medium masses and the decay widths of the charmonium state. The effects of the magnetic field are considered due to the Dirac sea (DS) of the baryons, the mixing of the pseudoscalar (S=0) and vector (S=1) meson (PV mixing), the Landau level contributions for the charged hadrons. The anomalous magnetic moments (AMMs) of the baryons are also taken into account in the present study. For magnetized nuclear matter, at ρB=ρ0, the effect of Dirac sea leads to inverse magnetic catalysis (IMC), which is drop of the magnitude of the light quark condensates (proportional to the scalar fields) with increase in the magnetic field, contrary to the opposite effect of magnetic catalysis (MC) at ρB=0. The inclusion of hyperons to the nuclear medium is observed to lead to magnetic catalysis. There are observed to be significant effects from the DS and PV mixing on the properties of the charm mesons. The production cross sections of ψ(3770) arising due to scattering of D+D−(D0D¯0) mesons in the hot magnetized strange hadronic matter are observed to have distinct peak positions, when the magnetic field is large. This is because the production cross sections have contributions from the transverse as well as longitudinal components of ψ(3770), which have nondegenerate masses due to PV [ψ(3770)−ηc′] mixing. These can have observable consequences on the dilepton spectra as well as on the production of the charm mesons in ultrarelativistic peripheral heavy ion collision experiments, where the produced magnetic field is huge. Published by the American Physical Society 2024

Investigation of vertex a1>>VP for hadronic tau decays

In the framework of U(3) symmetric quark model, triangular diagrams are calculated that describe the strongly interacting vertices a1>>rhopi and a1>>K*K. The divergences arising when considering quark loops are regularized by covariant cutoff parameter. Based on four-particle hadronic τ decays, the quark structure of the resonance with quantum numbers JPC=1++ was studied. Theoretical estimates of intermediate channels with the meson for the partial decay widths of tau>>pipipinu, tau>>KKpinu and tau>>KKetanu are obtained. Contributions from contact channels describing the direct production of 3pi, KKpi and KKeta mesons by τ lepton current are taken into account. The interference of contact and intermediate axial-vector channels in determining the integral decay widths is studied. The matrix elements of the processes are obtained in the leading approximation of 1/Nc expansion. It is shown that calculations on τ lepton mesonic decays confirm the quark-antiquark structure of the a1 meson and clarify the role of the intermediate non-strange axial-vector channel in determining the integral partial decay widths. The obtained results are compared with experimental data by BaBar and Belle collaborations at the BEPC II and KEK lepton colliders.

Study of the hidden-heavy pentaquarks and Pcs states

Inspired by the recently observed resonance states PψsΛ(4338)0 and Pcs(4459)0 by LHCb Collaboration in J/ψΛ decay channel, we perform a systematical study of all possible hidden-heavy pentaquarks with strangeness S=0,−1,−2,−3, in unified framework of MIT bag model. The color-spin wave functions in terms of Young-Yamanouchi bases and transformed into baryon-meson couplings are utilized to calculate masses, magnetic moments, and relative partial widths of the hidden-heavy pentaquarks, suggesting that the observed PψsΛ(4338)0 is likely to be a 1/2− compact Pcs pentaquark, and the Pcs(4459)0 favors two-peak structure of 3/2− and 1/2− Pcs states. Our computation indicates that hidden-heavy pentaquarks have the masses around 4.35–4.90 GeV for the Pcs, 11.21–11.67 GeV for the Pbs, 4.73–5.02 GeV for the Pcss, and 11.54–11.77 GeV for the Pbss. Published by the American Physical Society 2024

From pole parameters to line shapes and branching ratios

Resonances are uniquely characterized by their complex pole locations and the corresponding residues. In practice, however, resonances are typically identified experimentally as structures in invariant mass distributions, with branching fractions of resonances determined as ratios of count rates. To make contact between these quantities it is necessary to connect line shapes and resonance parameters. In this work we propose such a connection and illustrate the formalism with detailed studies of the ρ(770)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\rho (770)$$\\end{document} and f0(500)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$f_0(500)$$\\end{document} resonances. Based on the line shapes inferred from the resonance parameters along these lines, expressions for partial widths and branching ratios are derived and compared to other approaches in the literature.

Strong decays of the vector tetraquark states with the masses about 4.5 GeV via the QCD sum rules

We suppose that there exist three vector hidden-charm tetraquark states with the JPC=1−− at the energy about 4.5GeV, and investigate the two-body strong decays systematically. We obtain thirty QCD sum rules for the hadronic coupling constants based on rigorous quark-hadron duality, then obtain the partial decay widths, therefore the total widths approximately, which are compatible with the experimental data of the Y(4500) from the BESIII collaboration. The Y(4500) may be one vector tetraquark state having three main Fock components, or consists of three different vector tetraquark states. We can search for the typical decays Y→D¯10D0−D¯0D102, D¯1−D+−D¯−D1+2, D¯00D⁎0−D¯⁎0D002, D¯0−D⁎+−D¯⁎−D0+2, ηcω, J/ψω to diagnose the nature of the Y(4500).

Strong decays of the Λc(2910) and Λc(2940) in the ND* molecular frame

Stimulated by the observation of a new structure, named Λc(2910), in the Σc(2455)0,++π+,− decay channel from B meson decay process by the Belle Collaboration, and the similarity of the Λc(2910)/Λc(2940) and Pc states, we investigate the decay behavior of the Λc(2910) and Λc(2940) in the ND* molecular frame with the possible JP quantum numbers to be 1/2− and 3/2−. We employ an effective Lagrangian approach to evaluate the partial widths of ND, Σcπ, and Σc*π channels. The estimations in the present work indicate that the JP quantum numbers of Λc(2910) and Λc(2940) are preferred to be 1/2− and 3/2−, respectively. From the present estimations, we also find the branching ratio of Λc(3/2)→Σc*π is much larger than that of Λc(1/2)→Σc*π, thus Σc*π could be a good channel to distinguish the JP quantum numbers of Λc(2910) and Λc(2940). Therefore, we suggest searching for the structure in Σc*π invariant mass distribution in Belle II. Published by the American Physical Society 2024