Probing gluon polarization in hadronic direct photon production.
Inclusive direct photon production at large transverse momentum in proton-proton interactions with a longitudinally polarized beam and target is an incisive probe of the polarized gluon density in a proton. To help motivate future experiments and assist in their design, we provide predictions of the polarization asymmetry for a range of reasonable choices of the polarized gluon density. The cross sections are small at fixed-target energies, but the effort to measure them is necessary if the polarized gluon density /Delta//ital G/(/ital x/,/ital Q//sup 2/) is to be determined. In order to obtain our predictions, we parametrize spin-dependent parton densities and compute their evolution with /ital Q//sup 2/. Our densities provide good agreement with the spin-dependent structure function /ital g//sub 1//sup /ital p//(x,/ital Q//sup 2/) measured in deep-inelastic lepton scattering.

title: CORRELATIONS IN HIGH-ENERGY PRODUCTION PROCESSES.

title: Heavy flavor production at fixed target and collider energies
abstract: A review is presented of heavy quark production in /bar p/p, p, and pp interactions at fixed target and collider energies. Calculations of total cross sections are described including contributions through next-to-leading order in QCD perturbation theory. Comparisons with available data on charm and bottom quark production show good agreement for reasonable values of charm and bottom quark masses and other parameters. Open issues in the interpretation of results are summarized. A discussion is presented of signatures, backgrounds, and expected event rates for top quark production. 19 refs., 4 figs.

title: Comparison of bottom-quark production rates in ISAGET with a full QCD 2-->3 calculation.
abstract: High-statistics samples of events have been generated with the ISAGET Monte Carlo simulation program in a study of bottom-quark production in proton-antiproton collisions at {radical}{ital s} =630 and 1800 GeV. These samples include lowest-order QCD production, flavor excitation, and gluon splitting contributions. Both Eichten-Hinchliffe-Lane-Quigg and Diemoz-Ferroni-Longo-Martinelli structure functions have been used. The integral transverse-momentum distribution {sigma}{sub {ital T}}({ital p}{sub {ital T},}{ital b}{gt}{ital p}{sub {ital T},min}) is presented for each data set. Results are compared to a full analytical next-to-leading-order calculation of Nason, Dawson, and Ellis. We find that ISAGET cross sections at large {ital p}{sub {ital T}} are greater than the results obtained in the analytical calculation. In addition, the ratio of the full cross section to the lowest-order result ({ital K} factor) can be as large as a factor of 2 greater than the analytical result, depending on {radical}{ital s} and {ital p}{sub {ital T}}. We discuss the implications of these overestimates that relate to the phenomenology of heavy-flavor production, notably searches for the top quark.

title: Inclusive production of t {bar t} pairs in hadronic collisions
abstract: We summarize our calculation of the total cross section for top quark production at hadron colliders within the context of perturbative quantum chromodynamics, including resummation of the effects of initial-state soft gluon radiation to all orders in the strong coupling strength.

title: Massive Lepton Pair Production — the Drell-Yan Process — with Nuclear Targets
abstract: The Drell-Yan process, hA → (μμ-)X, in which a massive lepton-pair is produced inclusively from a nuclear target, offers the possibility for gaining unique insight into the A dependence of the quark and antiquark densities of nuclei, qA(x,Q2) and q-A(x,Q2). Measurements are crucial for testing whether the A dependence of deep-inelastic structure functions, known as the EMC effect, is a universal, process independent property of parton densities. Precise experiments with pion and nucleon beams on nuclear targets would extend knowledge of the A dependence of quark and antiquark densities of nuclei into important intervals of the fractional longitudinal momentum variable x which are not accessible easily in deep inelastic scattering. Models constructed to interpret the EMC effect are used to obtain predictions for the A dependence of massive lepton pair production. For tests of quantum chromodynamics, isolating nuclear dependence is necessary before definite conclusions can be drawn on the behavior of the pion structure function and on the magnitude and kinematic variation of predicted higher order terms (K factor). I indicate the sensitive regions of phase space and the increased level of experimental precision which is needed if a contribution is to be made to isolating the A dependence of quark and antiquark densities from the Drell-Yan process.

title: Limits on flavor changing neutral currents in D0 meson decays.
abstract: Using the CLEO II detector at the Cornell Electron Storage Ring, we have searched for flavor changing neutral currents and lepton family number violations in D^0 meson decays. The upper limits on the branching fractions for D^0→l^+l^- and D^0→X^0l^+l^- are in the range 10^(-5) to 10^(-4), where X^0 can be a π^0, K_s^0, η, ρ^0, ω, K^(*0), or φ meson, and the l^+l^- pair can be e^+e^-, μ^+μ^-, or e^±μ^∓. Although these limits are above the theoretical predictions, most are new or an order of magnitude lower than previous limits.

title: Search for CP violation in D0 decay.
abstract: R. Balest, K. Cho, W.T. Ford, M. Lohner, H. Park, P. Rankin, and J.G. Smith University of Colorado, Boulder, Colorado 80809 0890J.P. Alexander, C. Bebek, B.E. Berger, K. Berkelman, K. Bloom, T.E. Browder, * D.G. Cassel, H.A. Cho, D.M. Coffman, D.S. Crowcroft, M. Dickson, P.S. Drell, D.J. Dumas, R. Ehrlich, R. Elia, P. Gaidarev, M. Garcia-Sciveres, B. Gittelman, S.W. Gray, D.L. Hartill, B.K. Heltsley, S. Henderson, C.D. Jones, S.L. Jones, J. Kandaswamy, N. Katayama, P.C. Kim, D.L. Kreinick, T. Lee, Y. Liu, G.S. Ludwig, J. Masui, J. Mevissen, N.B. Mistry, C.R. Ng, E. Nordberg, J.R. Patterson, D. Peterson, D. Riley, and A. So8'er Cornell University, Ithaca, New York 1/858

title: Effect of differences in proton and neutron density distributions on fission barriers
abstract: The neutron and proton density distributions obtained in constrained Hartree-Fock-Bogolyubov calculations with the Gogny force along the fission paths of 232Th, 236U, 238U, and 240Pu are analyzed. Significant differences in the multipole deformations of neutron and proton densities are found. The effect on potential energy surfaces and on barrier heights is studied under an additional constraint by imposing similar spatial distributions to neutrons and protons, as assumed in macroscopic-microscopic models.

title: Preliminary selection of candidates for shape isomerism from even-even nuclei with masses A<208.
abstract: This theoretical work represents the first stage in our efforts to establish an extensive list of nonfissile even-even nuclei located inside or near the valley of stability which might develop shape isomers. Our selection relies upon whether a secondary minimum takes place along an elongation axis in the potential energy surfaces of nuclei spread over the mass region A<208. These surfaces are determined through a joint use of the Hartree-Fock-Bogoliubov and Strutinsky methods. More than seventy nuclei located inside the region 40

title: Mean-field description of ground-state properties of drip-line nuclei: Pairing and continuum effects.
abstract: Ground-state properties of exotic even-even nuclei with extreme neutron-to-proton ratios are described in the framework of self-consistent mean-field theory with pairing formulated in coordinate space. This theory properly accounts for the influence of the particle continuum, which is particularly important for weakly bound systems. The pairing properties of nuclei far from stability are studied with several interactions emphasizing different aspects, such as the range and density dependence of the effective interaction. Measurable consequences of spatially extended pairing fields are presented, and the sensitivity of the theoretical predictions to model details is discussed.