Non-leading Logarithms in Principal Value Resummation

We apply the method of principal value resummation of large momentum-dependent radiative corrections to the calculation of the Drell Yan cross section. We sum all next-to-leading logarithms and provide numerical results for the resummed exponent and the corresponding hard scattering function.Comment: 22 pages (LaTeX), 5 figures not included; available upon request from [email protected], ANL-HEP-PR-94-25, ITP-SB-94-3

Probing small-x parton densities in proton- proton (-nucleus) collisions in the very forward direction

We present calculations of several pp scattering cross sections with potential applications at the LHC. Significantly large rates for momentum fraction, x, as low as 10^-7 are obtained, allowing for possible extraction of quark and gluon densities in the proton and nuclei down to these small x values provided a detector with good acceptance at maximal rapidities is used.Comment: 14 pages, LaTeX, 12 figures, uses revtex.st

Diffractive Production of Jets and Weak Bosons, and Tests of Hard-Scattering Factorization

We extract diffractive parton densities from data on diffractive deep inelastic scattering (DIS) and on diffractive photoproduction of jets. We explore the results of several ansaetze for the functional form of the parton densities. Then we use the fitted parton densities to predict the diffractive production of jets and of W's and Z's in p-pbar collisions at the Tevatron. To fit the photoproduction data requires a large gluon density in the Pomeron. The predictions for the Tevatron cross sections are substantially higher than data; this signals a breakdown of hard-scattering factorization in diffractive hadron-hadron collisions.Comment: 36 pages, RevTeX with psfig and amsfonts, 12 postscript figures. This paper is an updated version of hep-ph/9701374. Further minor corrections added to correspond to journal versio