121708777
A class of homogeneous Einstein-Maxwell fields
The author considers solutions of the Einstein-Maxwell field equations satisfying the conditions Fij;k+lk=fFij+, Fij;k+nk=gFij+ where Fij+ is the self-dual Maxwell bivector and li and ni are the principal null vectors of Fij+. The fields are algebraically general and the most general solution is found in closed form when li and ni have non-zero twist. Several twist-free solutions are also obtained. Vacuum space-times admitting a test Maxwell field are also considered. In all cases the metric admits a three-parameter group of motions acting transitively on three-dimensional orbits. Fields satisfying the dual conditions with li and ni replaced by mi and mi are also investigated and similar results are obtained.
119366478
On the symmetries of the Edgar?Ludwig metric
The conformal Killing equations for the most general (non-plane wave) conformally flat pure radiation field are solved to find the conformal Killing vectors. As expected 15 independent conformal Killing vectors exist, but in general the metric admits no Killing or homothetic vectors. However for certain special cases a one-dimensional group of homotheties or motions may exist and in one very special case, overlooked by previous investigators, a two-dimensional homethety group exists. No higher dimensional groups of motions or homotheties are admitted by these metrics.
13652721
Irreducible Killing Tensors from Conformal Killing Vectors
Koutras has proposed some methods to construct reducible proper conformal Killing tensorsand Killing tensors (which are, in general, irreducible) when a pair of orthogonal conformalKilling vectors exist in a given space. We give the completely general result demonstratingthat this severe restriction of orthogonality is unnecessary. In addition we correct andextend some results concerning Killing tensors constructed from a single conformal Killingvector. We give as an example a Kimura metric and demonstrate how it is possible toconstructalargerclassofreducibleproperconformalKillingtensorsandKillingtensorsthanpermitted by the Koutras algorithms. In addition, from our new result that all conformalKilling tensors are reducible in conformally ﬂat spaces, we have a method of constructingall conformal Killing tensors and hence all the Killing tensors (which will in general beirreducible) of conformally ﬂat spaces using their conformal Killing vectors.
118984350
Comment on"Conformally flat stationary axisymmetric metrics"
Garcia and Campuzano claim to have found a previously overlooked family of stationary and axisymmetric conformally flat spacetimes, contradicting an old theorem of Collinson. In both these papers it is tacitly assumed that the isometry group is orthogonally transitive. Under the same assumption, we point out here that Collinson's result still holds if one demands the existence of an axis of symmetry on which the axial Killing vector vanishes. On the other hand if the assumption of orthogonal transitivity is dropped, a wider class of metrics is allowed and it is possible to find explicit counterexamples to Collinson's result.
118861611
Observation of inclusive. omega. production at large transverse momentum
We have observed the production of ..omega.. mesons at large transverse momentum produced in 200-GeV/c pBe interactions. The ratio of inclusive production of ..omega.. to ..pi../sup 0/ at transverse momenta above 2.2 GeV/c is 0.44 +- 0.08 near x=0. The upper limit for eta' to eta production is <1.4 in the same kinematic region.