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No Massless Pions in Nambu-Jona-Lasinio Model due to Chiral Fluctuations

H. Kleinert·B. Van den Bossche
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Abstract

In contrast to common belief, the chirally symmetric Nambu--Jona-Lasinio model does not contain massless pions, due to strong chiral fluctuations. Although quarks acquire spontaneously a nonzero constituent mass $M$, pions have a nonzero mass equal to the mass of $ \s $-mesons, both being of the order of $M$. This result is found in several cutoff schemes. Our derivation is nonperturbative, but involves a simple approximation (London limit) which should, however, receive only quantitative, no qualitative corrections.

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H. Kleinert, B. Van den Bossche. 1999-10-24. No Massless Pions in Nambu-Jona-Lasinio Model due to Chiral Fluctuations. https://arxiv.org/abs/hep-ph/9908284

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