Pion and vacuum properties in the nonlocal NJL model

Abstract

We formulate the nonlocal NJL model with a momentum dependent constituent quark mass and calculate pion light cone wave functions of twist 2 and 3. The leading twist wave function is not asymptotic and agrees well with the new CLEO data. Normalization conditions for the twist 3 wave functions are used to calculate the quark condensate. A prescription to calculate the gluon condensate is proposed. The numerical value of the gluon condensate nicely agrees with the phenomenological value, whereas the quark condensate is larger than the phenomenological value of $-(250$ MeV${)}^3$. The relation between the $k_T^2$ moments and mixed condensates are used to estimate the mixed quark-gluon condensate of dimension 5.

Comments: 7 pages, 6 figures, talk presented the 8-th Adriatic Meeting, Sept. 4-14, 2001, Dubrovnik, Croatia