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H. -C. Jean

Publications and source records attributed to H. -C. Jean.

4 recordsLinked to original sources
arXiv1995

Stability Analysis of the Instantaneous Bethe-Salpeter Equation and the Consequences for Meson Spectroscopy

We investigate the light and heavy meson spectra in the context of the instantaneous approximation to the Bethe-Salpeter equation (Salpeter's equation). We use a static kernel consisting of a one-gluon-exchange component and a confining contribution. Salpeter's equation is known to be formally equivalent to a random-phase-approximation equation; as such, it can develop imaginary eigenvalues. Thus, our study can not be complete without first discussing the stability of Salpeter's equation. The stability analysis limits the form of the kernel and reveals that, contrary to the usual assumption, the confining component can not transform as a Lorentz scalar; it must transform as the timelike component of a vector. Moreover, the stability analysis sets an upper limit on the size of the one-gluon-exchange component; the value for the critical coupling is determined through a solution of the ``semirelativistic'' Coulomb problem. These limits place important constraints on the interaction and suggest that a more sophisticated model is needed to describe the light and heavy quarkonia.

nucl-th↗
arXiv1994

Relativistic Quark-Antiquark Bound State Problem with Spin-dependent Interactions in Momentum Space

The work described in this paper is the first step toward a relativistic three-quark bound-state calculation using a Hamiltonian consistent with the Wigner-Bargmann theorem and macroscopic locality. We give an explicit demonstration that we can solve the two-body problem in momentum space with spin-dependent interactions. The form of the potential is a combination of linear+Coulomb+spin-spin+% spin-orbit+tensor, which includes confinement and is of the general form consistent with rotation, space-reflection and time-reversal invariance. Comparison is made with previous calculations using an alternate technique and with the experimental meson mass spectrum. The results obtained suggest that the model is realistic enough to provide a two-body basis for the three quark baryon problem in which the Poincaré group representation is unitary and cluster separability is respected.

hep-ph↗
arXiv1993

Medium Modification to the $Ω$-Meson Mass in the Walecka Model

We calculate the effective mass of the $ω$ meson in nuclear matter in a relativistic random-phase approximation to the Walecka model. The dressing of the meson propagator is driven by its coupling to particle-hole pairs and nucleon-antinucleon ($N\bar{N}$) excitations. We report a reduction in the $ω$-meson mass of about 170~MeV at nuclear-matter saturation density. This reduction arises from a competition between the density-dependent (particle-hole) dressing of the propagator and vacuum polarization ($N\bar{N}$ pairs). While density-dependent effects lead to an increase in the mass proportional to the classical plasma frequency, vacuum polarization leads to an even larger reduction caused by the reduced effective nucleon mass in the medium.

nucl-th↗