Fixed-Angle Elastic Hadron Scattering.pdf

a r X i v : h e p - p h / 9 9 0 4 2 0 2 v 1 1 A p r 1 9 9 9 UNICAL-TH 99/1 BITP-99-2E DFPD 99/TH/6 March 1999 FIXED-ANGLE ELASTIC HADRON SCATTERING ? R. Fiore1?, L. L. Jenkovszky2? , V. K. Magas3?, F. Paccanoni4? 1 Dipartimento di Fisica, Universita? della Calabria, Istituto Nazionale di Fisica Nucleare, Gruppo collegato di Cosenza Arcavacata di Rende, I-87030 Cosenza, Italy 2 Bogoliubov Institute for Theoretical Physics, Academy of Sciences of the Ukraine 252143 Kiev, Ukraine 3 Section of Theoretical Physics (SENTEF) Department of Physics, University of Bergen Allegaten 55, 5007 Bergen, Norway 4 Dipartimento di Fisica, Universita? di Padova, Istituto Nazionale di Fisica Nucleare, Sezione di Padova via F. Marzolo 8, I-35131 Padova, Italy Abstract The scattering amplitude in the dual model with Mandelstam analyticity and trajectory α(s) = α0 ? γ ln [ (1 + β √ s0 ? s)/(1 + β√s0) ] is studied in the limit s, |t| → ∞, s/t = const. By using the saddle point method, a series decomposi- tion for the scattering amplitude is obtained, with the leading and two sub-leading terms calculated explicitly. ?Work supported in part by the Research Council of Norway (programs for nuclear and particle physics, supercomputing, and free projects), in part by the Ministero italiano dell’Universita? e della Ricerca Scientifica e Tecnologica and in part by the INTAS grant 93-1867-extension ?email address: FIORE @CS.INFN.IT ?email address: JENK @GLUK.APC.ORG ?email address: MAGAS @SENTEF2.FI.UIB.NO ?email address: PACCANONI @PADOVA.INFN.IT 1 Introduction: Wide-angle scattering in QCD Although attempts to apply perturbative QCD to wide-angle elastic hadron scatterings have been undertaken in a number of papers [1-10], explicit predictions have been available only for elastic processes involving external photons, such as γ + γ → hadrons, Compton scattering of hadrons, etc. Predictions based on perturbative QCD rest on three premises: 1) hadronic interac- tions become weak at small invaria