The energies and residues of the nucleon resonances N(1535) and N(1650)

We extract pole positions for the N(1535) and N(1650) resonances using two different models. The positions are determined from fits to different subsets of the existing $\pi N\to\pi N$, $\pi N\to\eta N$ and $\gamma p\to\eta p$ data and found to be 1515(10)--i85(15)MeV and 1660(10)--i65(10)MeV, when the data is described in terms of two poles. Sensitivity to the choice of fitted data is explored. The corresponding $\pi \pi$ and $\eta \eta$ residues of these poles are also extracted.Comment: 9 page

Are classically singular spacetimes quantum mechanically singular as well?

Are the classical singularities of general relativistic spacetimes, normally defined by the incompleteness of classical particle paths, still singular if quantum mechanical particles are used instead? This is the question we will attempt to answer for particles obeying the quantum mechanical wave equations for scalar, null vector and spinor particles. The analysis will be restricted to certain static general relativistic spacetimes that classically contain the mildest true classical singularities, quasiregular singularities.Comment: 3 pages, no figures, submitted to the Proceedings of the Tenth Marcel Grossmann Meeting on General Relativity, Rio de Janeiro, July 20-26, 200

Experimental verification of the Heisenberg uncertainty principle for hot fullerene molecules

The Heisenberg uncertainty principle for material objects is an essential corner stone of quantum mechanics and clearly visualizes the wave nature of matter. Here we report a demonstration of the Heisenberg uncertainty principle for the most massive, complex and hottest single object so far, the fullerene molecule C70 at a temperature of 900 K. We find a good quantitative agreement with the theoretical expectation: dx * dp = h, where dx is the width of the restricting slit, dp is the momentum transfer required to deflect the fullerene to the first interference minimum and h is Planck's quantum of action.Comment: 4 pages, 4 figure

Comment on piNN Coupling from High Precision np Charge Exchange at 162 MeV

In this updated and expanded version of our delayed Comment we show that the np backward cross section, as presented by the Uppsala group, is seriously flawed (more than 25 sd.). The main reason is the incorrect normalization of the data. We show also that their extrapolation method, used to determine the charged piNN coupling constant, is a factor of about 10 less accurate than claimed by Ericson et al. The large extrapolation error makes the determination of the coupling constant by the Uppsala group totally uninteresting.Comment: 5 pages, latex2e with a4wide.sty. This is an updated and extended version of the Comment published in Phys. Rev. Letters 81, 5253 (1998

Sensitivity to the pion-nucleon coupling constant in partial-wave analyses of elastic pi-N and NN scattering and pion photoproduction

We summarize results obtained in our studies of the pion-nucleon coupling constant. Several different techniques have been applied to pi-N and NN elastic scattering data, and the existing database for single-pion photoproduction. The most reliable determination comes from pi-N elastic scattering. The sensitivity in this reaction was found to be greater, by at least a factor of 3, when compared with analyses of NN elastic scattering or single-pion photoproduction.Comment: 10 pages, 1 figure. Talk given at the Uppsala workshop on the pion-nucleon coupling constan

Agriculture as a strategic asset class: ethnics, ecology and economics

This paper strives for reviewing the increasing importance of agriculture as an asset class in a multi-crisis framework and reflects on the required policies and the ethics of an urgently needed,,non-exponential growth culture”

Matter-wave interferometer for large molecules

We demonstrate a near-field Talbot-Lau interferometer for C-70 fullerene molecules. Such interferometers are particularly suitable for larger masses. Using three free-standing gold gratings of one micrometer period and a transversally incoherent but velocity-selected molecular beam, we achieve an interference fringe visibility of 40 % with high count rate. Both the high visibility and its velocity dependence are in good agreement with a quantum simulation that takes into account the van der Waals interaction of the molecules with the gratings and are in striking contrast to a classical moire model.Comment: revtex4, 4 pages, 3 figure