ar X iv : h ep - p h / 96 02 39 4 v 1 2 6 Fe b 19 96 Low - energy dynamics of the γγ → ππ reaction in the NJL model 1
نویسندگان
چکیده
We calculate the one-quark-loop amplitude for the low energy γγ → ππ collision in the context of the Nambu and Jona-Lasinio model with scalar and pseudoscalar four quark couplings to all orders in the external momenta. We show that the NJL predictions for the γγ → π + π − reaction are not far from the Born amplitude, which is close to the data, and is compatible with the chiral perturbation theory estimations. We determine the corrections given by the NJL model in leading order of 1/N c to the chiral loop amplitude for γγ → π 0 π 0. Numerical results for the γγ → ππ cross sections and for pion polarizabilities are given.
منابع مشابه
ar X iv : h ep - p h / 96 02 40 1 v 1 2 6 Fe b 19 96 UG - FT - 57 / 96 hep - ph / 9602401 February 1996 CHIRAL PERTURBATION THEORY
An introduction to the methods and ideas of Chiral Perturbation Theory is presented in this talk. The discussion is illustrated with some phenomenological predictions that can be compared with available experimental results.
متن کاملar X iv : h ep - t h / 96 02 14 9 v 1 2 7 Fe b 19 96 UAHEP - 9603 DSFNA - T - 9606 ESI - 310 February 1996
Integrability of the Wess–Zumino–Witten model as a non–ultralocal theory * Abstract We consider the 2–dimensional Wess–Zumino–Witten (WZW) model in the canon-ical formalism introduced in [5]. Using an r–s matrix approach to non–ultralocal field theories we find the Poisson algebra of monodromy matrices and of conserved quantities with a new, non–
متن کاملar X iv : h ep - p h / 96 02 42 1 v 1 2 8 Fe b 19 96 BUTP – 96 / 01 Charged Pion Polarizabilities to two Loops 1
We evaluate the electric and magnetic polarizabilities of charged pions in the framework of chiral perturbation theory at next–to–leading order. This requires a two– loop evaluation of the Compton amplitude near threshold. We estimate the two new low–energy constants which enter the chiral expansion at this order with resonance saturation. The numerical results are compared with presently avail...
متن کاملar X iv : h ep - p h / 96 02 28 5 v 1 1 3 Fe b 19 96 hep - ph / 9602285 INP 1715 / PH QCD : Quantum
The first measurements of the diffractive structure function F D(3) 2 at HERA are discussed. A factorisable interpretation in which a partonic structure is assigned to the pomeron is investigated through QCD analyses in which both the quark and gluon densities are permitted to vary freely. A method of measuring the longitudinal structure function of the pomeron without changing the ep centre of...
متن کاملar X iv : h ep - p h / 96 02 28 6 v 1 1 3 Fe b 19 96 Theoretical issues of small x physics
The perturbative QCD predictions concerning deep inelastic scattering at low x are summarized. The theoretical framework based on the leading log 1/x re-summation and k t factorization theorem is described and some recent developments concerning the BFKL equation and its generalization are discussed. The QCD expectations concerning the small x behaviour of the spin dependent structure function ...
متن کامل