The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Xin-heng Guo - One of the best experts on this subject based on the ideXlab platform.
-
Studying the Bound State of the System in the Bethe-Salpeter Formalism
Advances in High Energy Physics, 2019Co-Authors: Zhen-yang Wang, Xin-heng GuoAbstract:In this work, we study the molecule in the Bethe-Salpeter (BS) equation approach. With the kernel containing one-particle-exchange diagrams and introducing two different form factors (monopole form factor and dipole form factor) in the vertex, we solve the BS equation numerically in the covariant Instantaneous Approximation. We investigate the isoscalar and isovector systems, and we find that cannot be a molecule.
-
Residues of ΛQ -type and ΣQ -type baryons in the Bethe-Salpeter equation approach
Physical Review D, 2018Co-Authors: Zhen-yang Wang, Xin-heng GuoAbstract:We study the residues of ΛQ-type baryons (ΛQ and ΞQA) (Q=b,c) and ΣQ-type baryons (ΣQ(*), ΞQS(*) and ΩQ(*)) in the quark-diquark model within the Bethe-Salpeter (BS) formalism. These residues can be used, e.g., in the calculations of the amplitudes in the scattering processes. After constructing the baryonic currents in the BS formalism, we derive the relations between the BS wave functions and the residues for these baryons. The BS equations are solved numerically with the kernel including the scalar confinement and the one-gluon-exchange terms and with the covariant Instantaneous Approximation being employed in the calculations. Finally, we obtain the numerical values of the residues 0.103 GeV∼0.224 GeV for ΛQ, 0.143 GeV∼0.215 GeV for ΞQA, 0.262 GeV∼0.361 GeV for ΣQ(*), 0.313 GeV∼0.460 GeV for ΞQS(*) and 0.473 GeV∼0.571 GeV for ΩQ(*) in the ranges of the parameters in our model.
-
$X(5568)$ as a $B\bar{K}$ molecule in the Bethe-Salpeter equation approach in the heavy quark limit
arXiv: High Energy Physics - Phenomenology, 2018Co-Authors: Zhen-yang Wang, Xin-heng Guo, Chao WangAbstract:In the heavy quark limit, we study the $X(5568)$ state as a $B\bar{K}$ molecule in the Bethe-Salpeter equation approach. With the kernel containing one-particle-exchange diagrams, we solve the Bethe-Salpeter equation numerically in the covariant Instantaneous Approximation and find that the $X(5568)$ can exist as a $B\bar{K}$ molecular state with quantum numbers $I (J^P) = 1(0^+)$. In this picture we calculate the strong decay width of $X(5568)\rightarrow B_s^0\pi^+$ and find it to be in the range 19.83 - 22.45 MeV, which is consistent with the experimental data from the D0 Collaboration.
-
Study of two body hadronic decays Λ b → Λ ( p ) P ( V ) in the Instantaneous Approximation of the Bethe-Salpeter equation approach
Physical Review D, 2015Co-Authors: Ying Liu, Xin-heng Guo, Chao WangAbstract:In this work, we study weak transitions of ${\mathrm{\ensuremath{\Lambda}}}_{b}$ to light baryons $\mathrm{\ensuremath{\Lambda}}$ and $p$ in the Bethe-Salpeter equation approach. In the heavy quark limit, based on the picture that ${\mathrm{\ensuremath{\Lambda}}}_{b}$ is composed of a heavy $b$-quark and a light diquark, the Bethe-Salpeter equation for ${\mathrm{\ensuremath{\Lambda}}}_{b}$ was established in previous works. Although the light baryon $\mathrm{\ensuremath{\Lambda}}(p)$ is composed of various quark-diquark configurations based on the $SU(6)$ spin-flavor wave functions, only the configuration $s(ud{)}_{0,0}$ [$u(ud{)}_{0,0}$] [$(ud{)}_{0,0}$ is a scalar diquark composed of $u$ and $d$ quarks] contributes to ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}$ (${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}p$) transition. We establish the Bethe-Salpeter equations for the systems $s(ud{)}_{0,0}$ and $u(ud{)}_{0,0}$ and calculate their Bethe-Salpeter wave functions in the covariant Instantaneous Approximation with the kernel containing both scalar confinement and one-gluon-exchange terms. Then, the form factors for ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}$ and ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}p$ weak transitions are obtained with Bethe-Salpeter wave functions for ${\mathrm{\ensuremath{\Lambda}}}_{b}$, $\mathrm{\ensuremath{\Lambda}}$, and $p$. Consequently, we calculate the branching ratios of ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}P$, ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}V$, $\mathrm{\ensuremath{\Lambda}}\ensuremath{\rightarrow}pP$, and ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}pV$ ($P$ and $V$ denote pseudoscalar and vector mesons, respectively) in the factorization approach.
-
study of two body hadronic decays λ b λ p p v in the Instantaneous Approximation of the bethe salpeter equation approach
Physical Review D, 2015Co-Authors: Ying Liu, Xin-heng Guo, Chao WangAbstract:In this work, we study weak transitions of ${\mathrm{\ensuremath{\Lambda}}}_{b}$ to light baryons $\mathrm{\ensuremath{\Lambda}}$ and $p$ in the Bethe-Salpeter equation approach. In the heavy quark limit, based on the picture that ${\mathrm{\ensuremath{\Lambda}}}_{b}$ is composed of a heavy $b$-quark and a light diquark, the Bethe-Salpeter equation for ${\mathrm{\ensuremath{\Lambda}}}_{b}$ was established in previous works. Although the light baryon $\mathrm{\ensuremath{\Lambda}}(p)$ is composed of various quark-diquark configurations based on the $SU(6)$ spin-flavor wave functions, only the configuration $s(ud{)}_{0,0}$ [$u(ud{)}_{0,0}$] [$(ud{)}_{0,0}$ is a scalar diquark composed of $u$ and $d$ quarks] contributes to ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}$ (${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}p$) transition. We establish the Bethe-Salpeter equations for the systems $s(ud{)}_{0,0}$ and $u(ud{)}_{0,0}$ and calculate their Bethe-Salpeter wave functions in the covariant Instantaneous Approximation with the kernel containing both scalar confinement and one-gluon-exchange terms. Then, the form factors for ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}$ and ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}p$ weak transitions are obtained with Bethe-Salpeter wave functions for ${\mathrm{\ensuremath{\Lambda}}}_{b}$, $\mathrm{\ensuremath{\Lambda}}$, and $p$. Consequently, we calculate the branching ratios of ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}P$, ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}V$, $\mathrm{\ensuremath{\Lambda}}\ensuremath{\rightarrow}pP$, and ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}pV$ ($P$ and $V$ denote pseudoscalar and vector mesons, respectively) in the factorization approach.
Bernard Metsch - One of the best experts on this subject based on the ideXlab platform.
-
Quark models⋆ - Results from a relativistically covariant constituent quark model
The European Physical Journal A, 2008Co-Authors: Bernard MetschAbstract:The scope of a relativistically covariant constituent quark model of baryons based on the BetheSalpeter equation in Instantaneous Approximation is illustrated by a discussion of various baryon resonance observables such as static electromagnetic moments including a novel calculational procedure form factors and helicity amplitudes, semileptonic decays as well as the systematics of two-body, strong decay widths.
-
Quark models^⋆
The European Physical Journal A, 2008Co-Authors: Bernard MetschAbstract:The scope of a relativistically covariant constituent quark model of baryons based on the Bethe-Salpeter equation in Instantaneous Approximation is illustrated by a discussion of various baryon resonance observables such as static electromagnetic moments --including a novel calculational procedure-- form factors and helicity amplitudes, semileptonic decays as well as the systematics of two-body strong decay widths.
-
Semileptonic decays of baryons in a relativistic quark model
The European Physical Journal A - Hadrons and Nuclei, 2006Co-Authors: S. Migura, Bernard Metsch, D. Merten, H. -r. PetryAbstract:We calculate semileptonic decays of light and heavy baryons in a relativistically covariant constituent quark model. The model is based on the Bethe-Salpeter equation in Instantaneous Approximation. It generates satisfactory mass spectra for mesons and baryons up to the highest observable energies. Without introducing additional free parameters we compute on this basis helicity amplitudes of electronic and muonic semileptonic decays of baryons. We thus obtain form factor ratios and decay rates in good agreement with experiment.
-
Charmed baryons in a relativistic quark model
The European Physical Journal A - Hadrons and Nuclei, 2006Co-Authors: S. Migura, Bernard Metsch, D. Merten, H. -r. PetryAbstract:We calculate mass spectra of charmed baryons within a relativistically covariant quark model based on the Bethe-Salpeter equation in Instantaneous Approximation. Interactions are given by a linearly rising three-body confinement potential and a flavor-dependent two-body force derived from QCD instanton effects. This model has already been successfully applied to the calculation of light flavor baryon spectra and is now extended to heavy baryons. Within the same framework we compare the results to those obtained with the more conventional one-gluon exchange potential.
-
Structure of baryons in a relativistic quark model
Nuclear Physics A, 2004Co-Authors: Bernard MetschAbstract:Abstract Baryonic excitation spectra, electroweak and strong decay properties are discussed within a relativistically covariant constituent quark model based on the Instantaneous Approximation to the three-body Bethe-Salpeter equation.
Chao Wang - One of the best experts on this subject based on the ideXlab platform.
-
$X(5568)$ as a $B\bar{K}$ molecule in the Bethe-Salpeter equation approach in the heavy quark limit
arXiv: High Energy Physics - Phenomenology, 2018Co-Authors: Zhen-yang Wang, Xin-heng Guo, Chao WangAbstract:In the heavy quark limit, we study the $X(5568)$ state as a $B\bar{K}$ molecule in the Bethe-Salpeter equation approach. With the kernel containing one-particle-exchange diagrams, we solve the Bethe-Salpeter equation numerically in the covariant Instantaneous Approximation and find that the $X(5568)$ can exist as a $B\bar{K}$ molecular state with quantum numbers $I (J^P) = 1(0^+)$. In this picture we calculate the strong decay width of $X(5568)\rightarrow B_s^0\pi^+$ and find it to be in the range 19.83 - 22.45 MeV, which is consistent with the experimental data from the D0 Collaboration.
-
Study of two body hadronic decays Λ b → Λ ( p ) P ( V ) in the Instantaneous Approximation of the Bethe-Salpeter equation approach
Physical Review D, 2015Co-Authors: Ying Liu, Xin-heng Guo, Chao WangAbstract:In this work, we study weak transitions of ${\mathrm{\ensuremath{\Lambda}}}_{b}$ to light baryons $\mathrm{\ensuremath{\Lambda}}$ and $p$ in the Bethe-Salpeter equation approach. In the heavy quark limit, based on the picture that ${\mathrm{\ensuremath{\Lambda}}}_{b}$ is composed of a heavy $b$-quark and a light diquark, the Bethe-Salpeter equation for ${\mathrm{\ensuremath{\Lambda}}}_{b}$ was established in previous works. Although the light baryon $\mathrm{\ensuremath{\Lambda}}(p)$ is composed of various quark-diquark configurations based on the $SU(6)$ spin-flavor wave functions, only the configuration $s(ud{)}_{0,0}$ [$u(ud{)}_{0,0}$] [$(ud{)}_{0,0}$ is a scalar diquark composed of $u$ and $d$ quarks] contributes to ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}$ (${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}p$) transition. We establish the Bethe-Salpeter equations for the systems $s(ud{)}_{0,0}$ and $u(ud{)}_{0,0}$ and calculate their Bethe-Salpeter wave functions in the covariant Instantaneous Approximation with the kernel containing both scalar confinement and one-gluon-exchange terms. Then, the form factors for ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}$ and ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}p$ weak transitions are obtained with Bethe-Salpeter wave functions for ${\mathrm{\ensuremath{\Lambda}}}_{b}$, $\mathrm{\ensuremath{\Lambda}}$, and $p$. Consequently, we calculate the branching ratios of ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}P$, ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}V$, $\mathrm{\ensuremath{\Lambda}}\ensuremath{\rightarrow}pP$, and ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}pV$ ($P$ and $V$ denote pseudoscalar and vector mesons, respectively) in the factorization approach.
-
study of two body hadronic decays λ b λ p p v in the Instantaneous Approximation of the bethe salpeter equation approach
Physical Review D, 2015Co-Authors: Ying Liu, Xin-heng Guo, Chao WangAbstract:In this work, we study weak transitions of ${\mathrm{\ensuremath{\Lambda}}}_{b}$ to light baryons $\mathrm{\ensuremath{\Lambda}}$ and $p$ in the Bethe-Salpeter equation approach. In the heavy quark limit, based on the picture that ${\mathrm{\ensuremath{\Lambda}}}_{b}$ is composed of a heavy $b$-quark and a light diquark, the Bethe-Salpeter equation for ${\mathrm{\ensuremath{\Lambda}}}_{b}$ was established in previous works. Although the light baryon $\mathrm{\ensuremath{\Lambda}}(p)$ is composed of various quark-diquark configurations based on the $SU(6)$ spin-flavor wave functions, only the configuration $s(ud{)}_{0,0}$ [$u(ud{)}_{0,0}$] [$(ud{)}_{0,0}$ is a scalar diquark composed of $u$ and $d$ quarks] contributes to ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}$ (${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}p$) transition. We establish the Bethe-Salpeter equations for the systems $s(ud{)}_{0,0}$ and $u(ud{)}_{0,0}$ and calculate their Bethe-Salpeter wave functions in the covariant Instantaneous Approximation with the kernel containing both scalar confinement and one-gluon-exchange terms. Then, the form factors for ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}$ and ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}p$ weak transitions are obtained with Bethe-Salpeter wave functions for ${\mathrm{\ensuremath{\Lambda}}}_{b}$, $\mathrm{\ensuremath{\Lambda}}$, and $p$. Consequently, we calculate the branching ratios of ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}P$, ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}V$, $\mathrm{\ensuremath{\Lambda}}\ensuremath{\rightarrow}pP$, and ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}pV$ ($P$ and $V$ denote pseudoscalar and vector mesons, respectively) in the factorization approach.
Wolfgang Lucha - One of the best experts on this subject based on the ideXlab platform.
-
Instantaneous Bethe-Salpeter Kernel for the Lightest Pseudoscalar Mesons
Physical Review D, 2016Co-Authors: Wolfgang Lucha, Franz F. SchöberlAbstract:Starting from a phenomenologically successful, numerical solution of the Dyson–Schwinger equation that governs the quark propagator, we reconstruct in detail the interaction kernel that has to enter the Instantaneous Approximation to the Bethe–Salpeter equation to allow us to describe the lightest pseudoscalar mesons as quark–antiquark bound states exhibiting the (almost) masslessness necessary for them to be interpretable as the (pseudo) Goldstone bosons related to the spontaneous chiral symmetry breaking of quantum chromodynamics.
-
Light Pseudoscalar Mesons in Bethe-Salpeter Equation with Instantaneous Interaction
Physical Review D, 2015Co-Authors: Wolfgang Lucha, Franz F. SchöberlAbstract:The light pseudoscalar mesons play a twofold role: they may or have to be regarded both as low-lying bound states of the fundamental degrees of freedom of quantum chromodynamics as well as the (pseudo-) Goldstone bosons of the spontaneously broken chiral symmetries of quantum chromodynamics. We interrelate these aspects in a single quantum-field-theoretic approach relying on the Bethe-Salpeter formalism in Instantaneous Approximation by very simple means: the shape of the pseudoscalar-meson Bethe-Salpeter wave function dictated by chiral symmetry is used in Bethe-Salpeter equations for bound states of vanishing mass, in order to deduce analytically the interactions which govern the bound states under study. In this way, we obtain exact Bethe-Salpeter solutions for pseudoscalar mesons, in the sense of establishing the rigorous relationship between, on the one hand, the relevant interactions and, on the other hand, the Bethe-Salpeter amplitudes that characterize the bound states.
-
EXACT-PROPAGATOR Instantaneous BETHE SALPETER EQUATION FOR QUARK ANTIQUARK BOUND STATES
Modern Physics Letters A, 2006Co-Authors: Wolfgang Lucha, F. F. SchoberlAbstract:Recently an Instantaneous Approximation to the Bethe–Salpeter formalism for the analysis of bound states in quantum field theory has been proposed which retains, in contrast to the Salpeter equation, as far as possible the exact propagators of the bound-state constituents, extracted nonperturbatively from Dyson–Schwinger equations or lattice gauge theory. The implications of this improvement for the solutions of this bound-state equation, i.e. the spectrum of the mass eigenvalues of its bound states and the corresponding wave functions, when considering the quark propagators arising in quantum chromodynamics are explored.
-
Instantaneous Bethe–Salpeter equation with exact propagators
Journal of Physics G: Nuclear and Particle Physics, 2005Co-Authors: Wolfgang Lucha, F. F. SchoberlAbstract:Consequent application of the Instantaneous Approximation to both the interaction and all propagators of the bound-state constituents allows us to forge, within the framework of the Bethe?Salpeter formalism for the description of bound states, an Instantaneous form of the Bethe?Salpeter equation with exact (i.e., full) propagators of the bound-state constituents. This Instantaneous equation generalizes the well-known Salpeter equation, the derivation of which needs the additional assumption of free propagation of the bound-state constituents.
-
Instantaneous Bethe-Salpeter Equation with Exact Propagators
arXiv: High Energy Physics - Theory, 2005Co-Authors: Wolfgang Lucha, F. F. SchoberlAbstract:Consequent application of the Instantaneous Approximation to both the interaction and all propagators of the bound-state constituents allows us to forge, within the framework of the Bethe-Salpeter formalism for the description of bound states, an Instantaneous form of the Bethe-Salpeter equation with exact (i.e., full) propagators of the bound-state constituents. This Instantaneous equation generalizes the well-known Salpeter equation the derivation of which needs the additional assumption of free propagation of the bound-state constituents.
Franz F. Schöberl - One of the best experts on this subject based on the ideXlab platform.
-
Instantaneous Bethe-Salpeter Kernel for the Lightest Pseudoscalar Mesons
Physical Review D, 2016Co-Authors: Wolfgang Lucha, Franz F. SchöberlAbstract:Starting from a phenomenologically successful, numerical solution of the Dyson–Schwinger equation that governs the quark propagator, we reconstruct in detail the interaction kernel that has to enter the Instantaneous Approximation to the Bethe–Salpeter equation to allow us to describe the lightest pseudoscalar mesons as quark–antiquark bound states exhibiting the (almost) masslessness necessary for them to be interpretable as the (pseudo) Goldstone bosons related to the spontaneous chiral symmetry breaking of quantum chromodynamics.
-
Light Pseudoscalar Mesons in Bethe-Salpeter Equation with Instantaneous Interaction
Physical Review D, 2015Co-Authors: Wolfgang Lucha, Franz F. SchöberlAbstract:The light pseudoscalar mesons play a twofold role: they may or have to be regarded both as low-lying bound states of the fundamental degrees of freedom of quantum chromodynamics as well as the (pseudo-) Goldstone bosons of the spontaneously broken chiral symmetries of quantum chromodynamics. We interrelate these aspects in a single quantum-field-theoretic approach relying on the Bethe-Salpeter formalism in Instantaneous Approximation by very simple means: the shape of the pseudoscalar-meson Bethe-Salpeter wave function dictated by chiral symmetry is used in Bethe-Salpeter equations for bound states of vanishing mass, in order to deduce analytically the interactions which govern the bound states under study. In this way, we obtain exact Bethe-Salpeter solutions for pseudoscalar mesons, in the sense of establishing the rigorous relationship between, on the one hand, the relevant interactions and, on the other hand, the Bethe-Salpeter amplitudes that characterize the bound states.
-
Instantaneous Bethe-Salpeter Equation: (Semi-)Analytical Solution
arXiv: High Energy Physics - Phenomenology, 2000Co-Authors: Wolfgang Lucha, Khin Maung Maung, Franz F. SchöberlAbstract:The Bethe-Salpeter equation for bound states of a fermion-antifermion pair in the Instantaneous Approximation for the involved interaction kernel is converted into an equivalent matrix eigenvalue problem with explicitly (algebraically) given matrices.
-
Relativistic treatment of fermion-antifermion bound states.
Physical review. D Particles and fields, 1991Co-Authors: Wolfgang Lucha, Heinz Rupprecht, Franz F. SchöberlAbstract:We discuss the relativistic treatment of fermion-antifermion bound states by an effective-Hamiltonian method which imitates their description in terms of nonrelativistic potential models: the effective interaction potential, to be used in a Schr\"odinger equation which incorporates relativistic kinematics, is derived from the underlying quantum field theory. This approach is equivalent to the Instantaneous Approximation to the Bethe-Salpeter equation called the Salpeter equation but comes closer to physical intuition than the latter one.