32917384
Analytic calculation of the vacuum wave function for (2+1)-dimensional SU(2) lattice gauge theory.
The long wavelength vacuum wave function of (2+1)-dimensional SU(2) lattice gauge theory is calculated by the method of truncated eigenvalue equation. Third order results are consistent with Monte Carlo measurement and display a good scaling behavior extending to the deep weak coupling region.
120641266
$K^-$-Nuclear Bound States in Relativistic Mean-Field Theory
122969926
K− Nucleus Elastic Scattering and Momentum-Dependent Optical Potentials
The K− nucleus differential elastic scattering cross section for 12C and 40Ca at is calculated with three momentum-dependent optical potential models, which are density-dependent, relativistic mean field, and hybrid model, respectively. It is found that the forms of momentum-dependent optical potential models proposed by us are reasonable and gain success in the calculations and the momentum-dependent hybrid model is the best model for the K− nucleus elastic scattering.
122405140
Effects of Delta Degrees of Freedom on Quark Condensate in Hot and Dense Matter
The relativistic mean-field theory is applied to study the quark condensate systematically in nuclear matter at zero and finite temperature in terms of the relative importance of delta degrees of freedom. Calculations have included the high-order contributions to quark condensate in nuclear medium due to the baryon-baryon interactions. Numerical results are presented for the nuclear density up to five times larger than the normal density and temperature up to 120 MeV. It is found that the delta resonance in nuclear matter can cause substantial decreases to in-medium quark condensate.
18809945
Quark mass and phase transition for strange matter
We have derived the popularly used mass parametrization formula for light quarks and modified the corresponding formula for strange quarks with the mass-densitydependent model. A simple expression for the critical density of phase transition of strange quark matter at zero temperature is thus found and its value is estimated to be over 6 times the normal nuclear density.
124229961
A light-cone QCD inspired effective Hamiltonian model for pseudoscalar and scalar mesons
Considering the one-gluon exchange interaction and phenomenological quark confinement potential, an improved light-cone effective Hamiltonian for mesons and the corresponding radial mass eigen equations in angular momentum representation is obtained. Solving the J = 0 eigen equations numerically and using a set of adjustable parameters, the obtained solutions for ground states and radial excited states can simultaneously describe both pseudoscalar and scalar flavour-off-diagonal mesons. Some radial excited states are also predicted and wait for experimental test. More results for the vector and axial vector mesons are expected.
17940028
Perturbative QCD analysis of B meson decays.
The resummation of large QCD radiative corrections, including leading and next-to-leading logarithms, in the pion electromagnetic form factor is reviewed. A similar formalism is applied to exclusive processes involving heavy mesons, and leads to Sudakov suppression for the semileptonic decay {ital B}{r_arrow}{pi}{ital l}{nu}. It is found that, with the inclusion of Sudakov effects, a perturbative QCD analysis of this decay is reliable for the energy fraction of the pion above 0.4. Combining predictions from soft pion theorems we estimate that the upper limit of the matrix element {parallel}{ital V}{sub {ital ub}}{parallel} is 2.8{endash}4.8{times}10{sup {minus}3} from different models of the {ital B} meson wave function. {copyright} {ital 1996 The American Physical Society.}
45165928
Self-consistent solutions for vacuum currents around a magnetic flux string.
We consider the feedback effects of the vacuum currents induced by a magnetic flux string in 2+1 dimensions. Self-consistent induced charge and current densities that satisfy both the Dirac and Maxwell equations are given for the dimensionless coupling constant [ital g]==[ital e][sup 2]/[ital m][r arrow]0 and [ital g][r arrow][infinity]. These quantities for arbitrary [ital g] are inferred from the results of the two limiting cases, and also studied numerically.
27837585
Screw Instability and the Blandford-Znajek Mechanism.
When magnetic field lines thread a rotating black hole's horizon and connect with remote astrophysical loads, the rotational energy of the black hole can be extracted through the Blandford-Znajek mechanism. Due to the rotation of the black hole, the magnetic field lines are twisted and toroidal components are generated. Thus, poloidal electric currents are induced and the black hole's rotational energy is transported to the astrophysical loads through Poynting flux. The Blandford-Znajek mechanism has been considered to be a possible process for powering extragalactic jets. In this Letter, we show that because of the screw instability of the magnetic field, the toroidal components of the magnetic field, and thus the poloidal currents, cannot exceed the limits given by the Kruskal-Shafranov criterion. This significantly lowers the power of the Blandford-Znajek mechanism when the loads are far from the black hole. So the Blandford-Znajek mechanism can only work efficiently within the neighborhood of the black hole. The implications of the results for the scenario of extragalactic jets powered by the Blandford-Znajek mechanism are discussed.
15089471
Gauge invariant electromagnetic two-point function for heavy-light quark systems.
A gauge invariant electromagnetic two-point function, crucial to the investigations of the violation of isospin symmetry, is derived for heavy-light quark systems. Thus QED can be consistently introduced into the QCD sum rule method, which was not previously possible.
9459591
Applicability of perturbative QCD to B-->D decays.
We examine the applicability of perturbative QCD to {ital B} meson decays into {ital D} mesons. We find that the perturbative QCD formalism, which includes Sudakov effects at intermediate energy scales, is applicable to the semileptonic decay {ital B}{r_arrow}{ital Dl}{nu}, when the {ital D} meson recoils fast. Following this conclusion, we analyze the two-body nonleptonic decays {ital B}{r_arrow}{ital D}{pi} and {ital B}{r_arrow}{ital DD}{sub {ital s}}. By comparing our predictions with experimental data, we extract the matrix element {vert_bar}{ital V}{sub {ital c}{ital b}}{vert_bar}=0.044.