HEAVY BOSON PRODUCTION THROUGH THE COLLISION OF AN ULTRAHIGH-ENERGY NEUTRINO ON A TARGET NUCLEON

We discuss W and Z production through the deep inelastic [Formula: see text]-scattering in the context of the standard model SU (3)C× SU (2)L× U (1) of the strong and electroweak interactions. We find the cross-section rates for the process [Formula: see text] for the case of ultrahigh-energy neutrinos (1014 eV ≤Eν≤1017 eV ) colliding on a target nucleon [Formula: see text]. We also calculate [Formula: see text] in order to compare it with [Formula: see text]. We show that the cross-section rates for the process [Formula: see text] did not become so large as one could expect, due to the strong destructive interference between the two different mechanisms which contribute at the lowest order in α (keeping only photon exchange diagrams). This destructive interference mechanism is inherent to the standard model as a non-Abelian gauge theory.

FINAL-STATE INTERACTIONS AND SINGLE-SPIN ASYMMETRIES IN SEMI-INCLUSIVE DEEP INELASTIC SCATTERING

Recent measurements from the HERMES and SMC collaborations show a remarkably large azimuthal single-spin asymmetries AUL and AUT of the proton in semi-inclusive pion leptoproduction γ*(q) p → π X. We show that final-state interactions from gluon exchange between the outgoing quark and the target spectator system leads to single-spin asymmetries in deep inelastic lepton-proton scattering at leading twist in perturbative QCD; i.e., the rescattering corrections are not power-law suppressed at large photon virtuality q2 at fixed xbj. The existence of such single-spin asymmetries requires a phase difference between two amplitudes coupling the proton target with [Formula: see text] to the same final-state, the same amplitudes which are necessary to produce a nonzero proton anomalous magnetic moment. We show that the exchange of gauge particles between the outgoing quark and the proton spectators produces a Coulomb-like complex phase which depends on the angular momentum Lz of the proton's constituents and thus is distinct for different proton spin amplitudes. The single-spin asymmetry which arises from such final-state interactions does not factorize into a product of structure function and fragmentation function, and it is not related to the transversity distribution δq(x,Q) which correlates transversely polarized quarks with the spin of the transversely polarized target nucleon.

Charged-particle pseudorapidity (rapidity) distribution in nucleus–nucleus collisions at alternating-gradient synchrotron energy

The charged-particle pseudorapidity (rapidity) distributions in nucleus–nucleus collisions at the alternating-gradient synchrotron energy (11–15A GeV) have been described by the thermalized cylinder picture. The calculated results are in agreement with the experimental data of the reactions 28Si + Au, Ag, Cu, and Al at 14.6A GeV/c bombarding energy. It is shown that the target stopping power (the leading participant target nucleon rapidity shift with respect to the projectile) increases with the target size, and the projectile penetrating power (the leading participant projectile nucleon rapidity shift with respect to the target) decreases with the increasing of target size. PACS Nos.: 25.75-q, 25.75Dw, and 24.10pa

Direct Reaction Inelastic Scattering to the 2? State of 16O Via a Nonlocal Interaction

A study is made of the effects of a purely nonlocal representation of the reaction mechanism in inelastic scattering. In particular, the inelastic scattering of 30 MeV protons and 65 MeV IX-particles leading to the 2- state of 8�88 MeV excitation in 160 are considered. The reaction mechanisms are represented by separable interactions between the projectile and target nucleon, and a simple spectroscopy for 160 is used in the plane wave Born approximation. The derived cross sections are compared with other calculations and the measured data. The asymmetry in proton inelastic scattering is also discussed.