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Forward-backward asymmetries inΛ_(b)→Λl^(+)l^(-)in the bethe-salpeter equation approach

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Chinese Physics C 2022年第9期46卷 94-102页

作者： Liang-Liang Liu Su-Jun Cui Jing Xu Xin-Heng Guo College of Physics and information engineering Shanxi Normal UniversityTaiyuan 030031China Department of Physics Yan-Tai UniversityYantai 264005China College of Nuclear Science and Technology Beijing Normal UniversityBeijing 100875China

Using the bethe-salpeter equation(BSE),we investigate the forward-backward asymmetries(AFB)inΛb→Λl^(+)l^(-)(l=e,μ,τ)in the quark-diquark *** approach provides precise form factors that are different from those of quantum chromodynamics(QCD)sum *** calculate the rare decay form factors forΛb→Λl^(+)l^(-)b and investigate the(integrated)forward-backward asymmetries in these decay *** observe the integrated A l FB,ˉA l FB(Λb→Λe^(+)e^(-)=-0.1371,ˉA l FB(Λb→Λμ^(+)μ^(-))=-0.1376,andˉA l FB(Λb→Λτ^(+)τ^(-))=-0.1053;the hadron side asymmetriesˉA h FB(Λb→Λμ^(+)μ^(-))=-0.2315;the lepton-hadron side asymmetriesˉA lh FB(Λb→Λμ^(+)μ^(-))^(-)0.0827;and the longitudinal polarization fractionsˉF L(Λb→Λμ^(+)μ^(-))^(-)0.5681.

关键词： rare decay bethe-salpeter equation heavy flavor physics

Ground State Mass Spectrum for Scalar Diquarks with bethe-salpeter equation

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Communications in Theoretical Physics 2007年第2期47卷 287-292页

作者： WANG Zhi-Gang WAN Shao-Long YANG Wei-Min Department of Physics North China Electric Power University Baoding 071003 China Department of Modern Physics University of Science and Technology of China Hefei 230026 China

In this article, we study the structures of the pseudoscalar mesons π, K and the scalar diquarks U^a, D^a, Sa in the framework of the coupled rainbow Schwinger-Dyson equation and ladder bethe-salpeter equation with the confining effective potential. The u, d, s quarks have small current masses, and the renormalization is very large, the mass poles in the timelike region are absent which implements confinement naturally. The bethe-salpeter wavefunctions of the pseudoscalar mesons π, K, and the scalar diquarks U^a, D^a, S^a have the same type （Gaussian type） momentum dependence, center around zero momentum and extend to the energy scale about q^2 = 1 GeV^2, which happens to be the energy scale for the chiral symmetry breaking, the strong interactions in the infrargd region result in bound （or quasl-bound） states. The numerical results for the masses and decay constants of the π and K mesons can reproduce the experimental values, and the ground state masses of the scalar diquarks U^a, D^a, S^a are consistent with the existing theoretical calculations. We suggest a new Lagrangian which may explain the uncertainty of the masses of the scalar diauarks.

关键词： Schwinger-Dyson equation bethe-salpeter equation diquark confinement

Electromagnetic form factors of Λ_c in the space-like momentum region

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Chinese Physics C 2018年第10期42卷 44-50页

作者： Liang-Liang Liu Chao Wang Xin-Heng Guo College of Physics and Information Engineering Shanxi Normal UniversityLinfen 041004China Center for Ecological and Environmental Sciences Key Laboratory for Space Bioscience and BiotechnologyNorthwestern Polytechnical UniversityXi＇an710072China College of Nuclear Science and Technology Beijing Normal UniversityBeijing 100875China

We studied the electromagnetic form factors （EMFFs） of Ac and the contributions of the quark and diquark currents to the EMFFs of Ac in the space-like region in the bethe-salpeter equation approach with instantaneous approximation. In this picture, baryon Ac can be regarded as a two-body c（ud） system. We found that for different values of parameters the contribution of quark and diquark currents to the EMFFs of Ac is very different, while their total contribution to the EMFFs of Ac is similar. The EMFFs of ∧c are similar to those of other baryons （proton,≡ , and ∑＋） with a peak at ω= 1, where ω=v＇.v is the velocity transfer between the initial state （with velocity v） and the final state （with velocity vr） of Ac.

关键词： bethe-salpeter equation Ac baryon electromagnetic form factors quark-diquark model

Decay properties of D^(*)_(s0)(2317)^(+) as a conventional cs meson

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Chinese Physics C 2023年第7期47卷 15-21页

作者：韩萌李威裴苏岩刘婷婷王国利 Department of Physics and Technology Hebei UniversityBaoding 071002China Hebei Key Laboratory of High-Precision Computation and Application of Quantum Field Theory Baoding 071002China Research Center for Computational Physics of Hebei Province Baoding 071002China

Taking D^(*)_(s0)(2317)^(+)as a conventional cs meson,we calculate its dominant strong and electromagnetic decays in the framework of the bethe-salpeter *** results areΓ(D^(∗+)_(s0)→D^(+)_(s)π^(0))=7.83^(+1.97)_(-1.55)keV andΓ(D^(∗+)_(s0)→D^(∗+)_(s)γ)=2.55^(+0.37)_(-0.45)*** contributions of the different partial waves from the initial and final state wave functions to the decay width are also calculated,and we find that the relativistic corrections in both decay processes are very large.

关键词： D^(s)(2317) relativistic bethe-salpeter equation

Isgur-Wise function in Bc decays to charmonium with the bethe-salpeter method

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Chinese Physics C 2021年第1期45卷 47-66页

作者： Zi-Kan Geng Yue Jiang Tianhong Wang Hui-Wen Zheng Guo-Li Wang Department of Physics Harbin Institute of TechnologyHarbin 150001China

The heavy quark effective theory vastly reduces the weak-decay form factors of hadrons containing one heavy quark. Many works attempt to directly apply this theory to hadrons with multiple heavy quarks. In this paper,we examine this confusing application by the instantaneous bethe-salpeter method from a phenomenological perspective, and give the numerical results for Bc decays to charmonium where the final states include 1S, 1P, 2S, and 2P. Our results indicate that the form factors parameterized by a single Isgur-Wise function deviate substantially from the full ones, especially when excited states are involved. The relativistic corrections(1/mQcorrections) require the introduction of more non-perturbative universal functions, similar to the Isgur-Wise function, which are the overlapping integrals of the wave functions with the relative momentum between the quark and antiquark.

关键词： Isgur-Wise function relativistic correction bethe-salpeter equation semileptonic decay

Study on the possible molecular state composed of D^∗sD^¯s1 within the bethe-salpeter framework

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Chinese Physics C 2020年第9期44卷 40-52页

作者： Hong-Wei Ke Xiao-Hai Liu Xue-Qian Li School of Science Tianjin UniversityTianjin 300072China School of Physics Nankai UniversityTianjin 300071China

Recently,a vector charmonium-like state Y(4626)was observed in the portal of D+sDs1(2536)−.This intrigues an active discussion on the structure of the resonance because it has obvious significance for gaining a better understanding on its hadronic structure that contains suitable inner ***,this observation concerns the general theoretical framework about possible structures of exotic *** the mass of Y(4626)is slightly above the production threshold of D+sDs1(2536)−,whereas it is below that of D^∗sD^¯s1(2536)with the same quark contents as that of D+sDs1(2536)−,it is natural to conjecture that Y(4626)is a molecular state of D^∗sD^¯s1(2536),as suggested in the *** or negating this allegation would shed light on the goal we are concerned *** calculate the mass spectrum of a system composed of a vector meson and an axial vector i.e.,D^∗sD^¯s1(2536)within the framework of the bethe-salpeter *** numerical results show that the dimensionless parameterλin the form factor,which is phenomenologically introduced to every vertex,is far beyond the reasonable range for inducing even a very small binding energyΔ*** implies that the D^∗sD^¯s1(2536)system cannot exist in the nature as a hadronic molecule in this ***,we may not be able to assume the resonance Y(4626)to be a bound state of D^∗sD^¯s1(2536),and instead,it could be attributed to something else,such as a tetraquark.

关键词： molecular states bethe-salpeter equation strong decay

Hadron properties from QCD bound-state equations: A status report

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Chinese Physics C 2010年第9期34卷 1175-1180页

作者： R.Alkofer G.Eichmann A.Krassnigg D.Nicmorus Institut für Physik Karl-Franzens-Universitt Graz Institute for Nuclear Physics Darmstadt University of Technology

Employing an approach based on the Green functions of Landau-gauge QCD,some selected results from a calculation of meson and baryon properties are presented.A rainbow-ladder truncation to the quark Dyson-Schwinger equation is used to arrive at a unified description of mesons and baryons by solving bethesalpeter and covariant Faddeev equations,respectively.

关键词： functional approaches bethe-salpeter equation covariant Faddeev equation

Spectra of Free Diquark in the bethe-salpeter Approach

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Communications in Theoretical Physics 2006年第6X期46卷 1031-1039页

作者： YU Yan-Ming KE Hong-Wei DING Yi-Bing GUO Xin-Heng JIN Hong-Ying LI Xue-Qian SHEN Peng- Nian WANG Guo-Li Department of Physics Nankai University Tianjin 300071 China Department of Physics Graduate School of the Chinese Academy of Sciences Beijing 100049 China Institute of Low-Energy Nuclear Physics Beijing Normal University Beijing 100875 China Institute of Modern Physics Zhejiang University Hangzhou 310027 China Institute of High Energy Physics the Chinese Academy of Sciences P.O. Box 918-4 Beijing 100049 China Department of Physics Harbin Institute of Technology Harbin 150001 China

In this work, we employ the bethe-salpeter （B-S） equation to investigate the spectra of free diquarks and their B-S wave functions. We find that the B-S approach can be consistently applied to study the diqaurks with two heavy quarks or one heavy and one light quarks, but for two light-quark systems, the results are not reliable. There are a few free parameters in the whole scenario which can only be fixed phenomenologically. Thus, to determine them, one has to study baryons which are composed of quarks and diquarks.

关键词： bethe-salpeter equation diquark spectra

Instantaneous Formulation for Transitions Between Two Instantaneous Bound States and Its Gauge Invariance

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Communications in Theoretical Physics 2006年第3X期46卷 467-480页

作者： CHANG Chao-Hsi CHEN Jiao-Kai WANG Guo-Li Institute for Advanced Study Princeton New Jersey 08540 USA CCAST (World Laboratory) P.O. Box 8730 Beijing 100080 China Institute of Theoretical Physics the Chinese Academy of Sciences P.O. Box 2735 Beijing 100080 China Department of Physics Harbin Institute of Technology Harbin 150006 China

We have precisely derived a ＂rigorous instantaneous formulation＂ for transitions between two bound states when the bound states are well-described by instantaneous bethe-salpeter （BS） equation （i.e. the kernel of the equation is instantaneous ＂occasionally＂）. The obtained rigorous instantaneous formulation, in fact, is expressed as an operator sandwiched by two ＂reduced BS wave functions＂ properly, while the reduced BS wave functions appearing in the formulation are the rigorous solutions of the instantaneous BS equation, and they may relate to Schroedinger wave functions straightforwardly. We also show that the rigorous instantaneous formulation is gauge-invariant with respect to the Uem（1） transformation precisely, if the concerned transitions are radiative. Some applications of the formulation are outlined.

关键词： instantaneous formulation transitions between bound states bethe-salpeter equation