Total Photonic and Hadronic Cross - sections 1 Rohini

We discuss total cross-sections within the context of the QCD calculable mini-jet model, highlighting its successes and failures. In particular we show its description of γγ → hadrons and compare it with OPAL and L3 data. We extrapolate this result to γ p total cross-sections and propose a phenomenological ansätz for virtual photon cross-sections. We point out that the good agreement with data obtained with the Eikonal Minijet Model should not hide the many uncertainties buried in the impact parameter distribution. A model obtained from Soft Gluon Summation is briefly discussed and its application to hadronic cross-sections is shown. 1) Talk presented by G.P. at Photon-2000, Ambelside, U.K., Aug 26-31, 2000 Total Photonic and Hadronic Cross-sections R.M. Godbole∗, A. Grau†, G. Pancheri∗∗ Centre for Theoretical Studies, Indian Institute of Science, Bangalore 560 012, India † Departamento de F́ısica Teórica y del Cosmos, Universidad de Granada, Spain ∗∗ INFN Laboratori Nazionali di Frascati, Via E. Fermi 40, I00044 Frascati, Italy Abstract. We discuss total cross-sections within the context of the QCD calculable mini-jet model, highlighting its successes and failures. In particular we show its description of γγ → hadrons and compare it with OPAL and L3 data. We extrapolate this result to γ p total cross-sections and propose a phenomenological ansätz for virtual photon cross-sections. We point out that the good agreement with data obtained with the Eikonal Minijet Model should not hide the many uncertainties buried in the impact parameter distribution. A model obtained from Soft Gluon Summation is briefly discussed and its application to hadronic cross-sections is shown. We discuss total cross-sections within the context of the QCD calculable mini-jet model, highlighting its successes and failures. In particular we show its description of γγ → hadrons and compare it with OPAL and L3 data. We extrapolate this result to γ p total cross-sections and propose a phenomenological ansätz for virtual photon cross-sections. We point out that the good agreement with data obtained with the Eikonal Minijet Model should not hide the many uncertainties buried in the impact parameter distribution. A model obtained from Soft Gluon Summation is briefly discussed and its application to hadronic cross-sections is shown.