0000000000185656
AUTHOR
Gad Eilam
Higher-order effects for the coupling constant in asymptotically free theories
It is shown that the two-loop contribution to the Callan-Symanzik $\ensuremath{\beta}$ function leads to an effective coupling constant which may be quite different from the value obtained from the standard one-loop calculation. This correction is larger than that due to finite quark masses. Possible implications for the comparison between asymptotically free theories and experiment are discussed.
Large-photon-number limit and the essential singularity in finite quantum electrodynamics
It is shown that the essential singularity in finite quantum electrodynamics can be located by considering only those diagrams with a large number of photons exchanged in the single-fermion loop, without photons emitted and absorbed on a fermion line. (AIP)
Production ofWbosons in proton-nucleus collisions
It is shown that nuclear effects can cause an enhancement in the cross section for production of $W$ bosons in a proton-nucleus collision. The cross section near threshold is a few orders of magnitude higher than expected from a linear dependence on the atomic number. Encouraging implications for experiments with fixed targets at laboratory energies of ${10}^{3}$ GeV and higher are discussed. We also discuss lepton-pair production off nuclei.
Reconciling high-transverse-momentum dimuon production with quantum chromodynamics
It is shown that by taking into account nuclear effects in a phenomenological model-independent way, the recent Fermilab data for of muon pairs may be reduced to values compatible with quantum-chromodynamics predictions. The sensitivity of this reduction to uncertainties in the assumed nuclear dependence are discussed.