Nonelastic nuclear reactions and accompanying gamma radiation

Several aspects of nonelastic nuclear reactions which proceed through the formation of a compound nucleus are dealt with. The full statistical model and the partial statistical model are described and computer programs based on these models are presented along with operating instructions and input and output for sample problems. A theoretical development of the expression for the reaction cross section for the hybrid case which involves a combination of the continuum aspects of the full statistical model with the discrete level aspects of the partial statistical model is presented. Cross sections for level excitation and gamma production by neutron inelastic scattering from the nuclei Al-27, Fe-56, Si-28, and Pb-208 are calculated and compared with avaliable experimental data

Search for antiproton decay at the Fermilab Antiproton Accumulator

A search for antiproton decay has been made at the Fermilab Antiproton Accumulator. Limits are placed on thirteen antiproton decay modes. The results include the first explicit experimental limits on the muonic decay modes of the antiproton, and the first limits on the decay modes e- gamma gamma, and e- omega. The most stringent limit is for the decay mode pbar-> e- gamma. At 90% C.L. we find that tau/B(pbar-> e- gamma) > 7 x 10^5 yr. The most stringent limit for decay modes with a muon in the final state is for the decay pbar-> mu- gamma. At 90% C.L. we find that tau/B(pbar-> mu- gamma) > 5 x 10^4 yr.Comment: 20 pages, 8 figures. Submitted to Phys. Rev. D. Final results on 13 channels (was 15) are presente

Search for New Physics Using QUAERO: A General Interface to D0 Event Data

We describe QUAERO, a method that (i) enables the automatic optimization of searches for physics beyond the standard model, and (ii) provides a mechanism for making high energy collider data generally available. We apply QUAERO to searches for standard model WW, ZZ , and tt̅ production, to searches for these objects produced through a new heavy resonance, and to the first direct search for W′→ WZ. Through this interface, we make three data sets collected by the D0 experiment at √s =1.8 TeV publicly available

Multiple jet production at low transverse energies in \u3ci\u3epp̅\u3c/i\u3e collisions at √\u3ci\u3es\u3c/i\u3e = 1.8 TeV

We present data on multiple production of jets with transverse energies near 20 GeV in pp̅ collisions at √s =1.8 TeV. QCD calculations in the parton-shower approximation of PYTHIA and HERWIG and the next-to-leading order approximation of JETRAD are compared to the data for one, two, three, and four jet inclusive production. Transverse energy spectra and multiple jet angular and summed transverse-energy distributions are adequately described by the shower approximation while next-to-leading order calculations describe the data poorly

Search for Pair Production of Light Scalar Top Quarks in \u3ci\u3epp̅\u3c/i\u3e Collisions at √\u3ci\u3es\u3c/i\u3e = 1.8 TeV

Using 85.2 ± 3.6 pb1 of pp̅ collisions collected at √s = 1.8 TeV with the D0 detector at Fermilab’s Tevatron Collider, we present the results of a search for direct pair production of scalar top quarks (t̃), the supersymmetric partners of the top quark. We examined events containing two or more jets and missing transverse energy, the signature of light scalar top quark decays to charm quarks and neutralinos. After selections, we observe 27 events while expecting 31.1 ± 6.4 events from known standard model processes. Comparing these results to next-to-leading-order production cross sections, we exclude a significant region of t̃ and neutralino phase space. In particular, we exclude the t̃ mass mt̃ \u3c 122 GeV/c2 for a neutralino mass of 45 GeV/c2

Search for Anomalous Heavy-Flavor Quark Production in Association with \u3ci\u3eW\u3c/i\u3e Bosons

We search for anomalous production of heavy-flavor quark jets in association with W bosons at the Fermilab Tevatron pp̅ Collider in final states in which the heavy-flavor quark content is enhanced by requiring at least one tagged jet in an event. Jets are tagged using one algorithm based on semileptonic decays of b/c hadrons, and another on their lifetimes. We compare ℯ+ jets (164 pb-1) and μ+ jets (145 pb-1) channels collected with the D0 detector at √s = 1.96 TeV to expectations from the standard model and set upper limits on anomalous production of such events