Programs in Physics & Physical Chemistry
|[Licence| Download | New Version Template] adpt_v1_0.gz(6 Kbytes)|
|Manuscript Title: Relativistic three-quark bound states in separable two-quark approximation.|
|Authors: M. Oettel, L. van Smekal, R. Alkofer|
|Program title: BSE|
|Catalogue identifier: ADPT_v1_0|
Distribution format: gz
|Journal reference: Comput. Phys. Commun. 144(2002)63|
|Programming language: Fortran.|
|Computer: Workstation DEC Aplha, LINUX PCs (AMD K7).|
|Operating system: True-Unixv5.0, SuSe Linux 7.1.|
|RAM: 10M words|
|Word size: 32|
|Keywords: Linear integral equations, Bethe-Salpeter equation, Nucleon model, Diquarks, Elementary particle physics, Phenomenological model.|
Nature of problem:
Diquarks are introduced as separable correlations in the two-quark Green's function to facilitate the description of baryons as relativistic three-quark bound states. These states then emerge as solutions of Bethe-Salpeter equations for quarks and diquarks that interact via quark exchange.
Chebyshev polynomials are used for an expansion of the Bethe-Salpeter vertex and wave functions and an (approximative) representation of the interaction kernel and propagators. The resulting set of coupled one-dimensional integral equations for the corresponding moments of vertex and wave function is converted to a matrix equation by employing Gaussian quadrature grid points. This equation is then solved iteratively for a certain test mass of the bound state. A bisection method in the bound state mass variable is used to determine the correct mass corresponding to the chosen quark and diquark parameters.
The separable quark-quark correlations are restricted to the leading covariants in the scalar and axialvector (i.e. positive parity) channels.
Programming issue The program has been tested with the following compilers: DEC-f90v5.3, Lahey-Fujitsu-f95-LINUX-Expressv5.5, NagWare-f95.
Depending on the parameters and the desired accuracy between one and ten minutes on 1.2 GHz AMD K7.
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