On the production mechanism of Sigma-hypernuclear systems in A(K-,pi+-) reactions

It is shown that the new data on the excitation energy Eex spectrum of the residual nuclear system in the Sigma-hypernuclear region in the reactions (K-,pi+-) on Be-9 and in the reaction (K-,pi+) on He-4 and C-12 can be described without the supposition on the existence of excited Sigma-hypernuclear states. The basis is formed by a simultaneous consideration of the quasi-free Sigma production and Sigma-nuclear rescattering (elastic and with Sigma -> Lambda conversion) with account of interference of the respective amplitudes. For final decision of the question about the nature of the irregularities in Eex spectrum, it is proposed to study the picture corresponding to the so-called moving complex singularity of the triangle graph with Sigma rescattering: the position and the width of the peak in Eex distribution must appreciably change with momentum transferred from the initial kaon to the final pion.Comment: 28 pages, 8 Postscript figure

A spectroscopy approach to measure the gravitational mass of antihydrogen

We study a method to induce resonant transitions between antihydrogen ($\bar{H}$) quantum states above a material surface in the gravitational field of the Earth. The method consists of applying a gradient of magnetic field, which is temporally oscillating with the frequency equal to a frequency of transition between gravitational states of antihydrogen. A corresponding resonant change in the spatial density of antihydrogen atoms could be measured as a function of the frequency of applied field. We estimate an accuracy of measuring antihydrogen gravitational states spacing and show how a value of the gravitational mass of the $\bar{H}$ atom could be deduced from such a measurement. We also demonstrate that a method of induced transitions could be combined with a free-fall-time measurement in order to further improve the precision

Investigation of the interaction of ion beams and X-ray quanta with deuterated crystal structures at the HELIS facility

The results of studies of the interaction of ion beams and X-ray quanta with deuterated crystal structures at the HELIS facility (LPI) are presente