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IHEP 2004 - 27 (In Russian) | |
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| R.G. Jafarov, V.E. Rochev | ||
| Two regularizations - two different models of Nambu-Jona-Lasinio | ||
| Protvino, 2004. – p. 15, table 4, refs.: 14. | ||
Two variants of the Nambu--Jona-Lasinio model -- the
model with 4-dimensional cutoff and the model with
dimensionally-analytical regularization -- are systematically
compared. It is shown that they are, in essence, two different
models of light-quark interaction. In the mean-field
approximation the distinction becomes apparent in a behavior of
scalar amplitude near the threshold. For 4-dimensional cutoff the
pole term can be extracted, which corresponds to sigma-meson. For
dimensionally-analytical regularization the singularity of the
scalar amplitude is not pole, and this singularity is quite
disappeared at some value of the regularization parameter.
Still more essential distinction of these models exists in the
next-to-leading order of mean-field expansion. The calculations
of meson contributions in the quark chiral condensate and in the
dynamical quark mass demonstrate, that these contributions though
their relatively smallness can destabilize the Nambu--Jona-Lasinio
model with 4-dimensional cutoff. On the contrary, the
Nambu--Jona-Lasinio model with dimensionally-analytical
regularization is stabilized with the next-to-leading order, i.e.
the value of the regularization parameter shifts to the
stability region, where these contributions decrease.
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