Spin-spin correlations and spin asymmetries for the reaction pp → pnπ+ at intermediate energies

Spin-spin correlation parameters A_LL, A_NN, A_SS, A_SL and spin asymmetries A_NO and A_ON have been measured for the reaction $\text{p}\text{p}\text{→}\text{pn}\text{π}{}^{\mathrm{+}}$ with incident beam energies of 510, 465 and 420 MeV. Clean separation of free proton events from the bound proton background has been achieved. A_LL, A_SS and A_NN, were all found to be large and negative indicating domination by the ¹D₂ partial wave. The spin asymmetries were large. Results are compared to the predictions of Dubach, Kloet and Silbar.     

The Artin conjecture for three diagonal cubic forms

Let p be a prime, p ≠ 3or 7. Then any three diagonal cubic forms over the p-adics in at least 28 variables possess a common nontrivial p-adic zero. This verifies the Artin conjecture for three diagonal cubic forms over all p-adic fields with the possible exception of $\text{Q}$₃ and $\text{Q}$₁.     

Measurement of the W boson mass using electrons at large rapidities

We report a measurement of the W boson mass based on an integrated luminosity of 82 pb(-1) from p&pmacr; collisions at sqrt[s] = 1.8 TeV recorded in 1994-1995 by the D0 detector at the Fermilab Tevatron. We identify W bosons by their decays to enu, where the electron is detected in the forward calorimeters. We extract the mass by fitting the transverse mass and the electron and neutrino transverse momentum spectra of 11 089 W boson candidates. We measure M(W) = 80.691+/-0.227 GeV. By combining this measurement with our previously published central calorimeter results from data taken in 1992-1993 and 1994-1995, we obtain M(W) = 80.482+/-0.091 GeV.     

Small-angle muon and bottom-quark production in p&pmacr; collisions at radicals = 1.8 TeV

This Letter describes a measurement of the muon cross section originating from b-quark decay in the forward rapidity range 2.4<| y(&mgr;)|<3.2 in p&pmacr; collisions at sqrt[s] = 1.8 TeV. The data used in this analysis were collected by the D0 experiment at the Fermilab Tevatron. We find that next-to-leading-order QCD calculations underestimate b-quark production by a factor of 4 in the forward rapidity region.     

MECHANICS,MODELLING AND PEDAGOGY: REFLECTIONS ON THE DESIGN OF CONTEXTS FOR NEW TECHNOLOGIES

Little research exists on the use of new technologies in the teaching and learning of the mathematical aspects of mechanics, although it represents a well-developed example of a mathematical model. This paper contains reflections on the possible roles for direct manipulation environments, as a preliminary to the iterative design and development of a computationally based pedagogic setting for learning mechanics. After making a comparison of existing pedagogical settings, the paper goes on to highlight the ways in which direct manipulation environments might be used for teaching and learning, by considering the connections between geometry and the semantic and syntactic structures of Newtonian Mechanics.     

Chemically adjusting plasma temperature, energy, and reactivity (CAPTEAR) method using NOx and combustion for selective synthesis of Sc3N@C80 metallic nitride fullerenes

Goals are (1) to selectively synthesize metallic nitride fullerenes (MNFs) in lieu of empty-cage fullerenes (e.g., C60, C70) without compromising MNF yield and (2) to test our hypothesis that MNFs possess a different set of optimal formation parameters than empty-cage fullerenes. In this work, we introduce a novel approach for the selective synthesis of metallic nitride fullerenes. This new method is "Chemically Adjusting Plasma Temperature, Energy, and Reactivity" (CAPTEAR). The CAPTEAR approach with copper nitrate hydrate uses NOx vapor from NOx generating solid reagents, air, and combustion to "tune" the temperature, energy, and reactivity of the plasma environment. The extent of temperature, energy, and reactive environment is stoichiometrically varied until optimal conditions for selective MNF synthesis are achieved. Analysis of soot extracts indicate that percentages of C60 and Sc3N@C80 are inversely related, whereas the percentages of C70 and higher empty-cage C2n fullerenes are largely unaffected. Hence, there may be a "competitive link" in the formation and mechanism of C60 and Sc3N@C80. Using this CAPTEAR method, purified MNFs (96% Sc3N@C80, 12 mg) have been obtained in soot extracts without a significant penalty in milligram yield when compared to control soot extracts (4% Sc3N@C80, 13 mg of Sc3N@C80). The CAPTEAR process with Cu(NO3)2.2.5H2O uses an exothermic nitrate moiety to suppress empty-cage fullerene formation, whereas Cu functions as a catalyst additive to offset the reactive plasma environment and boost the Sc3N@C80 MNF production.