Diquark confinement in an extended NJL model

被引:86
作者
Hellstern, G
Alkofer, R
Reinhardt, H
机构
[1] Institute for Theoretical Physics, Tübingen University, D-72076 Tübingen
关键词
diquark; meson; NJL model; confinement; Bethe-Salpeter equation;
D O I
10.1016/S0375-9474(97)00412-0
中图分类号
O57 [原子核物理学、高能物理学];
学科分类号
070202 ;
摘要
In a Nambu-Jona-Lasinio model supplemented with an infrared cutoff in addition to the ultraviolet cutoff we study the issue whether diquarks are confined when the model is extended beyond the rainbow-ladder approximation. The gap equation, obtained in a truncation scheme motivated via a non-trivial quark-gluon vertex function, is solved to determine the constituent quark mass if chiral symmetry is spontaneously broken. In a second step, the Bethe-Salpeter equations for mesons and diquarks beyond the ladder approximation are derived, taking care to preserve Goldstone's theorem in the pion channel. While the obtained masses of pseudo-scalar and vector mesons are only moderately shifted compared to the values in the ladder approximation, we observe that scalar diquarks disappear from the physical spectrum and therefore are confined. For axial-vector diquarks we observe indications that the same mechanism may also work, but the NJL model allows no conclusive answer in this channel. (C) 1997 Elsevier Science B.V.
引用
收藏
页码:697 / 712
页数:16
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