Possibility to study eta-mesic nuclei and photoproduction of slow eta-mesons at the GRAAL facility

A new experiment is proposed with the aim to study eta-mesic nuclei and low-energy interactions of eta with nuclei. Two decay modes of eta produced by a photon beam inside a nucleus will be observed, namely a collisional decay \eta N \to \pi N inside the nucleus and the radiative decay \eta \to \gamma \gamma outside. In addition, a collisional decay of stopped S_{11}(1535) resonance inside the nucleus, S_{11}(1535) N \to N N, will be studied. The experiment can be performed using the tagged photon beam at ESRF with the end-point energy 1000 MeV and the GRAAL detector which includes a high-resolution BGO calorimeter and a large acceptance lead-scintillator time-of-flight wall. Some results of simulation and estimates of yields are given.Comment: 20 pages, 19 figure

Creation and decay of eta-mesic nuclei

First experimental results on photoproduction of eta-mesic nuclei are analyzed. In an experiment performed at the 1 GeV electron synchrotron of the Lebedev Physical Institute, correlated pi+n pairs arising from the reaction gamma + 12C -> N + eta(A-1) -> N + pi+ + n + (A-2) and flying transversely to the photon beam have been observed. When the photon energy exceeds the eta-meson production threshold, a distribution of the pi+n pairs over their total energy is found to have a peak in the subthreshold region of the internal-conversion process eta p -> pi+ n which signals about formation of eta-mesic nuclei.Comment: 6 pages, 6 figures. Talk at CIPANP, May 2000, Quebe

Traženje η-mezičkih jezgri fototvorbenim procesima

We present preliminary results of an experiment performed at the 1–GeV electron synchrotron of the Lebedev Physical Institute. Using the bremsstrahlung photon beam with the end-point energy of 650–850 MeV and the carbon target, correlated π +n pairs with opening angle hθπN i = 180◦ and energies hEπ+ i = 300 MeV, hEni = 100 MeV have been observed. They arise from the process γ + 12C → N + η(A − 1) → N + π +n + (A − 2) and provide evidence for the existence of 11 ηB and 11 ηC η-mesic nuclei.Snopovima kočnog zračenja najviše energije 650 i 850 MeV u Lebedevom fizičkom institutu opažale su se vezane tvorbe parova π +n, koji su nastali procesom γ+12C → N + η(A − 1) → N + π +n + (A − 2). Ti su procesi potvrda postojanja 11 ηB i 11 ηC η-mezičkih jezgri

Effects of dimephosphone on skin survival in conditions of reduced blood circulation

The search for and creation of drugs with dermatoprotective and metabotropic activity is one of the priorities of modern diabetology. Synthetic organophosphorus compounds with no anticholinesterase activity, to which dimephosphone belongs to, deserve great attention in this respec

Traženje η-mezičkih jezgri fototvorbenim procesima

We present preliminary results of an experiment performed at the 1–GeV electron synchrotron of the Lebedev Physical Institute. Using the bremsstrahlung photon beam with the end-point energy of 650–850 MeV and the carbon target, correlated π +n pairs with opening angle hθπN i = 180◦ and energies hEπ+ i = 300 MeV, hEni = 100 MeV have been observed. They arise from the process γ + 12C → N + η(A − 1) → N + π +n + (A − 2) and provide evidence for the existence of 11 ηB and 11 ηC η-mesic nuclei.Snopovima kočnog zračenja najviše energije 650 i 850 MeV u Lebedevom fizičkom institutu opažale su se vezane tvorbe parova π +n, koji su nastali procesom γ+12C → N + η(A − 1) → N + π +n + (A − 2). Ti su procesi potvrda postojanja 11 ηB i 11 ηC η-mezičkih jezgri

Experimental Investigation of the Nature of the Knee in the Primary Cosmic Ray Energy Spectrum with the GAMMA experiment

We present preliminary results obtained by a novel difference method for the study of the nature of the knee in the energy spectrum of the primary cosmic radiation. We have applied this method to data from the GAMMA experiment in Armenia. The analysis provides evidence for the possible existence of a nearby source of primary cosmic rays in the Southern hemisphere.Comment: 17 pages, 5 figure