123586923
A resonance analysis of electroproduction data
We determinedN* electromagnetic transition form factors using π- and η-electroproduction data in the resonance region published till December, 1978. We discuss problems with the results obtained by various experimental groups. The method of analysis is a modification of the procedure used by Devenish and Lyth. Using the new photoproduction results of Barbour and Crawford and the δ- and η-data published till 1978, we are able to parametrise all multipoles in a unique way and to describe the background without further high energy input. Thus a better description of the data with less assumptions is achieved. However, it is still not possible to determine more multipoles than previously.
121817998
Electroproduction cross sections in the resonance region measured at large scattering angles
To complete data on resonance electroproduction we constructed an electron spectrometer with large angular and momentum acceptance. As a first result inclusive cross sections for an invariant hadronic mass 1.2<W<1.7 GeV and a four momentum transfer squared 0.5<Q2<1.5 (GeV/c)2 and for values of the polarization parameter 0.1<ɛ<0.25 are presented. Combining our results with the SLAC 4°-data we obtain σL/σT in the specified kinematical range.
5756648
The inverse mean curvature flow in Robertson-Walker spaces and its application to cosmology
We consider the inverse mean curvature flow in Robertson-Walker spacetimes that satisfy the Einstein equations and have a big crunch singularity and prove that under natural conditions the rescaled inverse mean curvature flow provides a smooth transition from big crunch to big bang. We also construct an example showing that in general the transition flow is only of class $C^3$.
14011136
On the CMC foliation of future ends of a spacetime
We consider spacetimes with compact Cauchy hypersurfaces and with Ricci tensor bounded from below on the set of timelike unit vectors, and prove that the results known for spacetimes satisfying the timelike convergence condition, namely, foliation by CMC hypersurfaces, are also valid in the present situation, if corresponding further assumptions are satisfied. In addition we show that the volume of any sequence of spacelike hypersurfaces, which run into the future singularity, decays to zero provided there exists a time function covering a future end, such that the level hypersurfaces have nonnegative mean curvature and decaying volume.