The Total and Jet Photoproduction Cross Sections at HERA and Fermilab
Abstract
Description
We present results of calculations of the total and jet photoproduction cross sections at HERA and Fermilab energies$^1$. The calculations take into account the high-energy QCD structure of the photon and are performed for different photon structure functions. We discuss how recent measurements of the total photoproduction cross section at HERA energies$^2$ can provide an important information on the low $x$ behavior of the photon structure function and in a more general context, to the nature of strong interactions. In addition, we show that the photoproduction cross section measurements at Fermilab E683 energies could provide a firmer value for $p_{T}^{min}$, the lower bound on the transverse momentum of outgoing jets, which signals the onset of hard scattering. The extrapolation of our cross section to ultra-high energies, of relevance to the cosmic ray physics, gives significant contribution to the ``conventional'' value, but cannot account for the anomalous muon content observed in the cosmic ray air-showers associated with astrophysical point sources$^4$.
talk presented at the International Conference on Elastic and Diffractive Scattering (Vth Blois Workshop), Providence, RI, June 8-12, 1993; University of Arizona preprint, AZPH-TH/93-18, PlainTex, 5 pages, 1 fig. (available upon request)
talk presented at the International Conference on Elastic and Diffractive Scattering (Vth Blois Workshop), Providence, RI, June 8-12, 1993; University of Arizona preprint, AZPH-TH/93-18, PlainTex, 5 pages, 1 fig. (available upon request)