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Résumé |
We consider asymptotically free gauge theories with gauge group SU(Nc) and Nf
quarks with mass mq < < LambdaQCD that undergo chiral symmetry breaking and
confinement. We propose a bootstrap method to compute the S-matrix of the pseudo-
Goldstone bosons (pions) that dominate the low energy physics. For the important
case of Nc = 3, Nf = 2, a numerical implementation of the method gives the phase
shifts of the S0, P1 and S2 waves in good agreement with experimental results. The
method incorporates gauge theory information (Nc, Nf, mq, LambdaQCD) by using the
form-factor bootstrap recently proposed by Karateev, Kuhn and Penedones together
with a finite energy version of the SVZ sum rules. At low energy we impose
constraints from chiral symmetry breaking. The only low energy numerical inputs
are the pion mass and the quark and gluon condensates. |
