Some properties of higher spin rest-mass zero fields in general relativity

The propagation of a zero rest-mass test field of arbitrary spins>1 through curved space-time is found to be subject to strong constraints. A null test field is shown to be possible only in a restricted class of spaces previously introduced by Kundt and Thompson. This result is in fact a simultaneous generalization of the theorems of Robinson and of Goldberg and Sachs. For test fields of spin-2 in vacuum spaces, solutions of the propagation equation are restricted, save in a few exceptional cases, to constant multiples of the Weyl spinor. The exceptional cases are discussed, and appear to be physically uninteresting.     

The pressure and composition dependence of mutual diffusion in the system helium-nitrogen at 300 K

Diffusion coefficients for the system helium-nitrogen have been measured as a function of pressure at 300 K from 1 to 12.5 atmospheres. These measurements include composition dependences at 1, 3, 5 and 7 atmospheres. The results show reasonable agreement with the Thorne-Enskog theory for moderately dense gases.     

Platinum catalysed 3,4- and 1,4-diboration of alpha,beta-unsaturated carbonyl compounds using bis-pinacolatodiboron

Bis-pinacolatodiboron reacts with [small alpha],[small beta]-unsaturated carbonyl compounds to give 1,4- and unprecedented 3,4-additions in the presence of a second generation Pt(0) catalyst at ambient temperature.     

Conjugate addition of organocopper reagents to gamma-alkoxybutenolides and application to the synthesis of non-racemic alkyl cyclopentenones

Simple organocopper reagents are shown to undergo anti-stereoselective 1,4-addition to menthyloxy-substituted lactone 1 in the presence of BF3.OEt2; the Lewis acid causes partial epimerisation of the acetal centre after conjugate addition. Enolate alkylation of the adducts leads to di- and trisubstituted lactones that are converted, in favourable cases, into di- and trisubstituted cyclopentenones.     

Integrated approach to the electronic interaction of swift heavy ions with solids and gases

The two most prominent processes of ion-matter interaction are the energy loss and charge exchange, whereby the first depends on the charge state of the ion as determined by the latter. However, up to now there has existed no closed calculation of these two major processes. We herewith present, within an integrated approach, a Monte Carlo calculation which intrinsically entails target ionization/excitation, as well as charge exchange and projectile ionization/excitation on equal footing, especially extended to the situation of ion-solid interaction.     

Inclusive double-pomeron exchange at the fermilab tevatron p p collider

We report results from a study of events with a double-Pomeron exchange topology produced in p p collisions at sqrt[s]=1800 GeV. The events are characterized by a leading antiproton and a large rapidity gap on the outgoing proton side. We find that the differential production cross section agrees in shape with predictions based on Regge theory and factorization, and that the ratio of double-Pomeron exchange to single diffractive production rates is relatively unsuppressed as compared to the O(10) suppression factor previously measured in single diffractive production.