arXiv subjects

Jun-Chen Su

Publications and source records attributed to Jun-Chen Su.

At least 19 recordsLinked to original sources

arXiv2006

Strange meson-nucleon states in the quark potential model

The quark potential model and resonating group method are used to investigate the $\bar{K}N$ bound states and/or resonances. The model potential consists of the t-channel and s-channel one-gluon exchange potentials and the confining potential with incorporating the QCD renormalization correction and the spin-orbital suppression effect in it. It was shown in our previous work that by considering the color octet contribution, use of this model to investigate the $KN$ low energy elastic scattering leads to the results which are in pretty good agreement with the experimental data. In this paper, the same model and method are employed to calculate the masses of the $\bar{K}N$ bound systems. For this purpose, the resonating group equation is transformed into a standard Schrödinger equation in which a nonlocal effective $\bar{K}N$ interaction potential is included. Solving the Schrödinger equation by the variational method, we are able to reproduce the masses of some currently concerned $\bar{K}N$ states and get a view that these states possibly exist as $\bar{K}N$ molecular states. For the $KN$ system, the same calculation gives no support to the existence of the resonance $Θ^{+}(1540)$ which was announced recently.

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arXiv2006

Renormalization of the SU(2)-symmetric model of hadrodynamics

It is proved that the SU(2)-symmetric model of hadrodynamics can well be set up on the gauge-invariance principle. The quantization of the model can readily be performed in the Lagrangian path-integral formalisms by using the Lagrangian undetermined multiplier method. Furthermore, it is shown that the quantum theory is invariant with respect to a kind of BRST-transformations. From the BRST-symmetry of the theory, the Ward-Takahashi identities satisfied by the generating functionals of full Green functions, connected Green functions and proper vertex functions are successively derived. As an application of the above Ward-Takahashi identities, the Ward-Takahashi identities obeyed by the propagators and various proper vertices are derived. Based on these identities, the propagators and vertices are perfectly renormalized. Especially, as a result of the renormalization, the Slavnov-Taylor identity satisfied by renormalization constants is natually deduced. To demonstrate the renormalizability of the theory, the one-loop renormalization of the theory is carried out by means of the mass-dependent momentum space subtraction and the renormalization group approach, giving an exact one-loop effective coupling constant and one-loop effective nucleon, pion and $ρ-$meson masses.

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arXiv2006

Renormalization of the quantum chromodynamics with massive gluons

In our previously published papers, it was proved that the chromodynamics with massive gluons can well be set up on the gauge-invariance principle. The quantization of the chromodynamics was perfectly performed in the both of Hamiltonian and Lagrangian path-integral formalisms by using the Lagrangian undetermined multiplier method. In this paper, It is shown that the quantum theory is invariant with respect to a kind of BRST-transformations. From the BRST-invariance of the theory, the Ward-Takahashi identities satisfied by the generating functionals of full Green functions, connected Green functions and proper vertex functions are successively derived. As an application of the above Ward-Takahashi identities, the Ward-Takahashi identities obeyed by the massive gluon and ghost particle propagators and various proper vertices are derived and based on these identities, the propagators and vertices are perfectly renormalized. Especially, as a result of the renormalization, the Slavnov-Taylor identity satisfied by renormalization constants is natually deduced. To demonstrate the renormalizability of the theory, the one-loop renormalization of the theory is carried out by means of the mass-dependent momentum space subtraction scheme and the renormalization group approach, giving an exact one-loop effective coupling constant and one-loop effective gluon and quark masses which show the asymptotically free behaviors as the same as those given in the quantum chromodynamics with massless gluons.

hep-th↗

arXiv2006

Massive Gauge Field Theory Without Higgs Mechanism II. Ward-Takahashi Identities and Proof of Unitarity

In our previously published papers, it was argued that a massive non-Abelian gauge field theory in which all gauge fields have the same mass can well be set up on the gauge-invariance principle. The quantization of the fields was performed by different methods. In this paper, It is proved that the quantum theory is invariant with respect to a kind of BRST-transformations. From the BRST-invariance of the theory, the Ward-Takahashi identities satisfied by the generating functionals of full Green's functions, connected Green's functions and proper vertex functions are successively derived. As an application of the above Ward-Takahashi identity, the Ward-Takahashi identity obeyed by the massive gauge boson propagator is derived and the renormalization of the propagator is discussed. Furthermore, based on the Ward-Takahashi identity, it is exactly proved that the S-matrix elements given by the quantum theory are gauge-independent and hence unitary.

hep-th↗

arXiv2006

059 Massive Gauge Field Theory Without Higgs Mechanism Massive Gauge Field Theory Without Higgs Mechanism III. Proof of Renormalizability

~It is shown that the quantum massive non-Abelian field theory established in the former papers is renormalizable. This conclusion is achieved with the aid of the Ward-Takahashi identities satisfied by the generating functionals which were derived in the preceding paper based on the BRST-symmetry of the theory. By the use of the Ward-Takahashi identity, it is proved that the divergences occurring in the perturbative calculations for the massive gauge field theory can be eliminated by introducing a finite number of counterterms in the effective action. As a result of the proof, it is found that the renormalization constants for the massive gauge field theory comply with the same Slavnov-Taylor identity as that for the massless gauge field theory. The latter identity is re-derived from the Ward-Takahashi identities satisfied by the gluon proper vertices and their renormalization.

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arXiv2006

Rigorous three-dimensional relativistic equation for quark-antiquark bound states at finite temperature derived from the thermal QCD formulated in the coherent-state representation

A rigorous three-dimensional relativistic equation for quark-antiquark bound states at finite temperature is derived from the thermal QCD generating functional which is formulated in the coherent-state representation. The generating functional is derived newly and given a correct path-integral expression. The perturbative expansion of the generating functional is specifically given by means of the stationary-phase method. Especially, the interaction kernel in the three-dimensional equation is derived by virtue of the equations of motion satisfied by some quark-antiquark Green functions and given in a closed form which is expressed in terms of only a few types of Green functions. This kernel is much suitable to use for exploring the deconfinement of quarks. To demonstrate the applicability of the equation derived, the one-gluon exchange kernel is derived and described in detail.

hep-th↗

arXiv2005

Alternative Formulation of The Quantum Electroweak Theory

The quantization of the electroweak theory is performed starting from the Lagrangian given in the so-called unitary gauge in which the unphysical Goldstone fields disappear. In such a Lagrangian, the unphysical longitudinal components of the gauge fields and the residual gauge degrees of freedom are naturally eliminated by introducing the Lorentz gauge condition and the ghost equation. In this way, the quantum theory given in $α$-gauge is perfectly established in the Lagangian formalism by the Faddeev-Popov approach or the Lagrange multiplier method in the framework of SU(2)$\times $U(1) gauge symmetry. The theory established is not only simpler than the ordinary R$_α-$gauge theory, but also explicitly renormalizable. The unitarity of the S-matrix is ensured by the $α-$limiting procedure proposed previously. Especially, it is shown that the electroweak theory without involving the Higgs boson can equally be formulated whitin the $SU(2)\times U(1)$ symmetry and exhibits good renormalizability. The unitarity of such a theory may also be guaranteed by the $α$-limiting procedure.

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arXiv2005

Massive Gauge Field Theory Without Higgs Mechanism IV. Illustration of Unitarsity

To illustrate the unitarity of the massive gauge field theory described in the foregoing papers, we calculate the scattering amplitudes up to the fourth order of perturbation by the optical theorem and the Landau-Cutkosky rule. In the calculations, it is shown that for a given process, if all the diagrams are taken into account, the contributions arising from the unphysical intermediate states included in the longitudinal part of the gauge boson propagator and in the ghost particle propagator are completely cancelled out with each other in the S-matrix elements. Therefore, the unitarity of the S-matrix is perfectly ensured.

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arXiv2005

Retardation Terms in The One-Gluon Exchange Potential

It is pointed out that the retardation terms given in the original Fermi-Breit potential vanish in the center of mass frame. The retarded one-gluon exchange potential is rederived in this paper from the three-dimensional one-gluon exchange kernel which appears in the exact three-dimensional relativistic equation for quark-antiquark bound states. The retardation part of the potential given in the approximation of order $p^2/m^2$ is shown to be different from those derived in the previous literature. This part is off-shell and does no longer vanish in the center of mass frame.

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arXiv2005

New closed expression of the interaction kernel in the Bethe-Salpeter equation for quark-antiquark bound states

The interaction kernel in the Bethe-Salpeter equation for quark-antiquark bound states is derived newly from QCD in the case where the quark and the antiquark are of different flavors. The technique of the derivation is the usage of the irreducible decomposition of the Green's functions involved in the Bethe-Salpeter equation satisfied by the quark-antiquark four-point Green's function. The interaction kernel derived is given a closed and explicit expression which shows a specific structure of the kernel since the kernel is represented in terms of the quark, antiquark and gluon propagators and some kinds of quark, antiquark and/or gluon three, four, five and six-point vertices. Therefore, the expression of the kernel is not only convenient for perturbative calculations, but also suitable for nonperturbative investigations.

hep-th↗

arXiv2005

Closed expression of the interaction kernel in the Bethe-Salpeter equation for quark-antiquark bound states

The interaction kernel in the Bethe-Salpeter equation for quark-antiquark bound states is derived from the Bethe-Salpeter equations satisfied by the quark-antiquark four-point Green's function. The latter equations are established based on the equations of motion obeyed by the quark and antiquark propagators, the four-point Green's function and some other kinds of Green's functions which follow directly from the QCD generating functional. The B-S kernel derived is given an exact and explicit expression which contains only a few types of Green's functions. This expression is not only convenient for perturbative calculations, but also suitable for nonperturbative investigations.

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arXiv2005

Correct path-integral formulation of quantum thermal field theory in coherent-state representation

The path-integral quantization of thermal scalar, vector and spinor fields is performed newly in the coherent-state representation. In doing this, we choose the thermal electrodynamics and $ϕ^4$ theory as examples. By this quantization, correct expressions of the partition functions and the generating functionals for the quantum thermal electrodynamics and $ϕ^4$ theory are obtained in the coherent-state representation. These expressions allow us to perform analytical calculations of the partition functions and generating functionals and therefore are useful in practical applications. Especially, the perturbative expansions of the generating functionals are derived specifically by virtue of the stationary-phase method. The generating functionals formulated in the position space are re-derived from the ones given in the coherent-state representation.

hep-th↗

arXiv2005

Dirac-Schrödinger equation for quark-antiquark bound states and derivation of its interaction kerne

The four-dimensional Dirac-Schrödinger equation satisfied by quark-antiquark bound states is derived from Quantum Chromodynamics. Different from the Bethe-Salpeter equation, the equation derived is a kind of first-order differential equations of Schrödinger-type in the position space. Especially, the interaction kernel in the equation is given by two different closed expressions. One expression which contains only a few types of Green's functions is derived with the aid of the equations of motion satisfied by some kinds of Green's functions. Another expression which is represented in terms of the quark, antiquark and gluon propagators and some kinds of proper vertices is derived by means of the technique of irreducible decomposition of Green's functions. The kernel derived not only can easily be calculated by the perturbation method, but also provides a suitable basis for nonperturbative investigations. Furthermore, it is shown that the four-dimensinal Dirac-Schrödinger equation and its kernel can directly be reduced to rigorous three-dimensional forms in the equal-time Lorentz frame and the Dirac-Schrödinger equation can be reduced to an equivalent Pauli-Schrödinger equation which is represented in the Pauli spinor space. To show the applicability of the closed expressions derived and to demonstrate the equivalence between the two different expressions of the kernel, the t-channel and s-channel one gluon exchange kernels are chosen as an example to show how they are derived from the closed expressions. In addition, the connection of the Dirac-Schrödinger equation with the Bethe-Salpeter equation is discussed.

hep-ph↗

arXiv2005

Lorentz-Covariant Quantization of Massive Non-Abelian Gauge Fields in The Hamiltonian Path-Integral Formalism

The massive non-Abelian gauge fields are quantized Lorentz-covariantly in the Hamiltonian path-integral formalism. In the quantization, the Lorentz condition, as a necessary constraint, is introduced initially and incorporated into the massive Yang-Mills Lagrangian by the Lagrange multiplier method so as to make each temporal component of a vector potential to have a canonically conjugate counterpart. The result of this quantization is confirmed by the quantization performed in the Lagrangian path-integral formalism by applying the Lagrange multiplier method which is shown to be equivalent to the Faddeev-Popov approach.

hep-th↗

arXiv2005

Massive gauge field theory without Higgs mechanism

It is argued that the massive gauge field theory without the Higgs mechanism can well be set up on the gauge-invariance principle based on the viewpoint that a massive gauge field must be viewed as a constrained system and the Lorentz condition, as a constraint, must be introduced from the beginning and imposed on the Yang-Mills Lagrangian. The quantum theory for the massive gauge fieldis may perfectly be established by the quantization performed in the Hamiltonian or the Lagrangian path-integral formalism by means of the Lagrange undetermined multiplier method and shows good renormalizability and unitarity.

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arXiv2005

Glueball spectrum based on a rigorous three-dimensional relativistic equation for two-gluon bound states I: Derivation of the relativistic equation

A rigorous three-dimensional relativistic equation satisfied by two-gluon bound states is derived from the QCD with massive gluons. With the gluon fields and the quark fields being expanded in terms of the gluon multipole fields and the spherical Dirac spinors respectively, the equation is well established in the angular momentum representation and hence is much convenient for solving the problem of two-gluon glueball spectra. In particular, the interaction kernel in the equation is exactly derived and given a closed expression which includes all the interactions taking place in the two-gluon glueballs. The kernel contains only a few types of Green's functions and commutators. Therefore, it is not only easily calculated by the perturbation method, but also provides a suitable basis for nonperturbative investigations.

hep-ph↗

arXiv2005

Glueball spectrum based on a rigorous three-dimensional relativistic equation for two-gluon bound states II: calculation of the glueball spectrum

In the preceding paper, a rigorous three-dimensional relativistic equation for two-gluon bound states was derived from the QCD with massive gluons and represented in the angular momentum representation. In order to apply this equation to calculate the glueball spectrum, in this paper, the equation is recast in an equivalent three-dimensional relativistic equation satisfied by the two-gluon positive energy state amplitude. The interaction Hamiltonian in the equation is exactly derived and expressed as a perturbative series. The first term in the series describes the one-gluon exchange interaction which includes fully the retardation effect in it. This term plus the linear confining potential are chosen to be the interaction Hamiltonian and employed in the practical calculation. With the integrals containing three and four spherical Bessel functions in the QCD vertices being analytically calculated, the interaction Hamiltonian is given an explicit expression in the angular momentum representation. Numerically solving the relativistic equation with taking the contributions arising from the retardation effect and the longitudinal mode of gluon fields into account, a set of masses for the $0^{++},0^{-+},1^{++},1^{-+},2^{++}$ and $2^{-+\text{}}$ glueball states are obtained and are in fairly good agreement with the predictions given by the lattice simulation

hep-ph↗

arXiv2005

Renormalization of the Sigma-Omega model within the framework of U(1) gauge symmetry

It is shown that the Sigma-Omega model which is widely used in the study of nuclear relativistic many-body problem can exactly be treated as an Abelian massive gauge field theory. The quantization of this theory can perfectly be performed by means of the general methods described in the quantum gauge field theory. Especially, the local U(1) gauge symmetry of the theory leads to a series of Ward-Takahashi identities satisfied by Green's functions and proper vertices. These identities form an uniquely correct basis for the renormalization of the theory. The renormalization is carried out in the mass-dependent momentum space subtraction scheme and by the renormalization group approach. With the aid of the renormalization boundary conditions, the solutions to the renormalization group equations are given in definite expressions without any ambiguity and renormalized S-matrix elememts are exactly formulated in forms as given in a series of tree diagrams provided that the physical parameters are replaced by the running ones. As an illustration of the renormalization procedure, the one-loop renormalization is concretely carried out and the results are given in rigorous forms which are suitable in the whole energy region. The effect of the one-loop renormalization is examined by the two-nucleon elastic scattering.

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