Novel QCD Aspects of Hard Diffraction, Antishadowing, and Single-Spin Asymmetries
arXiv:hep-ph/0411028
Abstract
It is usually assumed -- following the parton model -- that the leading-twist structure functions measured in deep inelastic lepton-proton scattering are simply the probability distributions for finding quarks and gluons in the target nucleon. In fact, gluon exchange between the outgoing quarks and the target spectators effects the leading-twist structure functions in a profound way, leading to diffractive leptoproduction processes, shadowing and antishadowing of nuclear structure functions, and target spin asymmetries, physics not incorporated in the light-front wavefunctions of the target computed in isolation. In particular, final-state interactions from gluon exchange lead to single-spin asymmetries in semi-inclusive deep inelastic lepton-proton scattering which are not power-law suppressed in the Bjorken limit. The shadowing and antishadowing of nuclear structure functions in the Gribov-Glauber picture is due respectively to the destructive and constructive interference of amplitudes arising from the multiple-scattering of quarks in the nucleus. The effective quark-nucleon scattering amplitude includes Pomeron and Odderon contributions from multi-gluon exchange as well as Reggeon quark-exchange contributions. Part of the anomalous NuTeV result for could be due to the non-universality of nuclear antishadowing for charged and neutral currents. Detailed measurements of the nuclear dependence of individual quark structure functions are thus needed to establish the distinctive phenomenology of shadowing and antishadowing and to make the NuTeV results definitive. I also discuss diffraction dissociation as a tool for resolving hadron substructure Fock state by Fock state and for producing leading heavy quark systems.
arXiv commentPresented at the 34th International Symposium on Multiparticle Dynamics (ISMD 2004), Sonoma State University, Rohnert Park, California, July 26-August 1, 2004
References in corpus (15)
- Quantum Chromodynamics and Other Field Theories on the Light Cone
- Leading-twist Single-transverse-spin asymmetries: Drell-Yan and Deep-Inelastic Scattering
- Single-spin asymmetries in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target
- Universality of soft and collinear factors in hard-scattering factorization
- Confirmation of the Double Charm Baryon Xi_cc+ via its Decay to p D+ K-
- Structure Functions are not Parton Probabilities
- Small-x physics beyond the Kovchegov equation
- Measurement of Beam-Spin Asymmetries for Deep Inelastic Electroproduction
- Coherent QCD multiple scattering in proton-nucleus collisions
- Hard diffraction from parton rescattering in QCD
- Diffraction and the Pomeron
- Transversity and Meson Photoproduction
- Single-Spin Beam Asymmetry in Semi-Exclusive Deep-Inelastic Electroproduction
- High-Energy Neutrino Astronomy
- QCD coherence effects in high energy reactions with nuclei