arXiv subjects

S. S. Wu

Publications and source records attributed to S. S. Wu.

5 recordsLinked to original sources

arXiv2006

Extension of Renormalizability

Arguments are provided which show that extension of renormalizability in quantum field theory is possible. A dressed scheme for the perturbation expansion is proposed. It is proven that in this scheme a nonrenormalizable interaction becomes renormalizable in the restrictive sense, i.e. its ultraviolet divergences can be cancelled by a finite number of counterterms included in the Lagrangian. As an illustration, the renormalization of the $π$-nucleon pseudovector interaction is discussed in some detail.

hep-ph↗

arXiv2006

Dirac Sea Contribution in Relativistic Random Phase Approximation

In the hadrodynamics (QHD) there are two methods to take account of the contribution of negative-energy states in the relativistic random phase approximation (RRPA). Dawson and Furnstahl made the ansatz that the Dirac sea were empty, while according to the Dirac hole theory the sea should be fully occupied. The two methods seem contradictory. Their close relationship and compatibility are explored and in particular the question of the ground-state (GS) instability resulting from Dawson-Furnstanhl's ansatz is discussed.

nucl-th↗

arXiv2003

Effects on the hadron propagators due to $k_μk_ν$ terms in the vector meson propagator

In an approximation where the baryon current conservation is violated, the contribution of the $k_μk_ν$ terms in the vector meson propagator may not vanish. Their effects on the baryon and meson spectral functions and on the consequences of self-consistency are studied in the relativistic self-consistent Hartree-Fock approximation by means of the $σ-ω$ model. Two cases where the $k_μk_ν$ terms are and are not neglected are compared. It is found that there is a marked change in the baryon spectral function which becomes more peaked in the latter case. Such a change remains even by a proper readjustment of parameters. The effects of self-consistency in the $σ-ω$ model are qualitatively the same in both cases, though quantitatively there is some significant difference.

nucl-th↗

arXiv2001

Vector Meson Propagator and Baryon Current Conservation

If baryons couple only with $ω$-mesons, one found the baryon spectral function may be negative. We show this unacceptable result is caused by the $k_μk_ν$-terms in the $ω$-meson propagator. Their contribution may not vanish in approximate calculations which violate the baryon current conserves. A rule is suggested, by which the calculated baryon spectral function is well behaved.

nucl-th↗

arXiv2001

Coupled Dyson-Schwinger Equations and Effects of Self-Consistency

Using the $σ-ω$ model as an effective tool, the effects of self-consistency are studied in some detail. A coupled set of Dyson-Schwinger equations for the renormalized baryon and meson propagators in the $σ-ω$ model is solved self-consistently according to the dressed Hartree-Fock scheme, where the hadron propagators in both the baryon and meson self-energies are required to also satisfy this coupled set of equations. It is found that the self-consistency affects the baryon spectral function noticeably, if only the interaction with $σ$ mesons is considered. However, there is a cancellation between the effects due to the $σ$ and $ω$ mesons and the additional contribution of $ω$ mesons makes the above effect insignificant. In both the $σ$ and $σ-ω$ cases the effects of self-consistency on meson spectral function are perceptible, but they can nevertheless be taken account of without a self-consistent calculation. Our study indicates that to include the meson propagators in the self-consistency requirement is unnecessary and one can stop at an early step of an iteration procedure to obtain a good approximation to the fully self-consistent results of all the hadron propagators in the model, if an appropriate initial input is chosen. Vertex corrections and their effects on ghost poles are also studied.

nucl-th↗