Search

Abstract We argue that if the elastic proton–proton cross section increases with energy, the Froissart-like high energy behaviour of the elastic amplitude (which corresponds to a 'black disk' of radius R (s) = c ln ⁡ s − β ln ⁡ (ln ⁡ s)) is the only possibility to satisfy the unitarity equation at each value of the impact parameter, b. Otherwise the cross section of events with Large Rapidity Gaps grows faster than the total cross section at the same b. That is, these 'gap' events require maximal growth of the high-energy (asymptotic) cross section and of the interaction radius R (s) in order to be consistent with unitarity. [ABSTRACT FROM AUTHOR]

Abstract: Exclusive production, , offers a unique opportunity to determine the gluon density of the proton in the small x domain. We use the available HERA data to determine the gluon distribution in the region and , where the uncertainty on the gluon extracted from the global parton analyses is large. The gluon density is found to be approximately flat at the lower scale; it is compared with those of recent global analyses. [Copyright &y& Elsevier]

We present a ‘new generation’ model for high energy proton–proton ‘soft’ interactions. It allows for a full set of multipomeron vertices as well as for including multichannel eikonal scattering. It describes the behaviour of the proton–proton total, σtot, and elastic, dσel/dt, cross sections together with those for low- and high-mass proton dissociation. Although the model contains a comprehensive set of multipomeron diagrams, it has a simple partonic interpretation. Including the more complicated multipomeron vertices reduces the absorptive effects as compared to the predictions in which only the triple-pomeron vertex is considered. Tuning the model to describe the available ‘soft’ data in the CERN ISR–tevatron energy range, we predict the total, elastic, single- and double-diffractive dissociation cross sections at the LHC energy. An inescapable consequence of including multichannel eikonal and multipomeron effects is that the total cross section is expected to be lower than before: indeed, we find σtot≃ 90 mb at the LHC energy. We also present differential forms of the cross sections. In addition, we calculate soft diffractive central production. [ABSTRACT FROM AUTHOR]

Examines the structure of the proton. Experimental results from the high-energy electron-proton collider HERA; Deep inelastic scattering and scaling; Measurement of the structure functions of the proton.

Examines results of two independent experiments to make measurements of the spin structure of the neutron, the twin particle of the proton. The CERN experiment performed by the Spin Muon Collaboration (SMC); The experiment at the Stanford accelerator in California which used a gas target of polarized helium-3 nuclei; Use of deep in-elastic scattering in both experiments to probe the interior of the neutron; Conclusion; More.