QCD Phenomenology of Charm Production at HERA

We compare different schemes for the treatment of heavy quark production in Deep-Inelastic Scattering (DIS). For fully-integrated quantities such as $F_{2}(x,Q^{2})$, we advocate the use of the General-Massive Variable-Flavor-Number (GM-VFN) scheme; we present some results showing the progress of a Next-to-Leading Order calculation in this scheme. For differential quantities, the Fixed-Flavor-Number (FFN) scheme provides a more appropriate starting point. We present a new calculation of the azimuthal distribution of charm quark production in DIS. All results have been obtained using a Monte Carlo program under development.Comment: 5 pages, Latex/aipproc, 4 figures, presented at DIS 97, Chicago, IL, April 14-18,199

An Effective Higgsless Theory: Satisfying Electroweak Constraints and a Heavy Top Quark

The main challenge faced by Higgsless models of electroweak symmetry breaking is to reconcile the experimental constraints imposed by the precision electroweak data and the top quark phenomenology with the unitarity constraints imposed by longitudinal gauge boson scattering amplitudes. In this paper we expand on previous work, giving details of how delocalized fermions can be used to adjust the $S$ parameter to zero, while keeping the $T$ and $U$ parameters naturally suppressed. We also show that it is possible to obtain the top quark mass, without affecting the delay of unitarity violation of the $W^+ W^-\to W^+W^-$ scattering amplitude, by separating the mass scales of the fermion sector ($1/R_f$) from that of the gauge sector ($1/R_g$). The fermion sector scale $1/R_f$ is only weakly constrained by unitarity of the $t\bar{t}\to W^+ W^-$ scattering amplitude; thus the ratio $R_g/R_f$ can be quite large, and the top mass can be easily achieved. Anomalous right-handed couplings involving the third generation quarks also avoid constraints from experimental data if $1/R_f$ is sufficiently large.Comment: 26 pages, JHEP forma

Transverse Momentum Distributions in Large-rapidity Dijet Production at the Tevatron

In this contribution we examine the transverse momentum distributions in dijet production at large rapidity intervals at the Tevatron, using the BFKL resummation.Comment: 6 pages (1 uu-compressed encapsulated PS figure appended), DESY 94-163, SCIPP 94/2