Dating ancient mosaic glasses by luminescence: The case study of San Pietro in Vaticano

The preliminary results of a study on the dosimetric properties of a set of glass tesserae from the mosaics of the vaults of St. Peter Basilica in Rome (late XVI century) are reported. Main goal of the research was to assess the possibility of dating them by means of luminescence techniques. The samples had already been extensively studied and investigated from historical, artistic and compositional point of view. The period of the making of the mosaic was rather well known, and could be the basis to test the experimental procedures we used for dosimetry. The experiments also aimed at demonstrating the validity of the hypothesis we put forward, i.e. the positive link between presence of micro-crystals and luminescence sensitivity in mosaic glass: to this aim, the samples richer in crystalline inclusions were selected. The role of calcium antimonate and cassiterite was definitely demonstrated. For what concerns their Thermoluminescence (TL) characteristics, a preliminary investigation suggested that the available configuration of the detection systems did not properly fit the wavelength of the emitted TL. Much more promising results have been achieved by the use of Optically Stimulated Luminescence (OSL). For samples with high OSL sensitivity, values of absorbed dose lower that 0.1 Gy were systematically obtained, indicating a recent age, relative to one of the documented restorations that took place during the last century

KEPEMIMPINAN YANG EFEKTIF

vii, 231 hlm.; 21 cm

J/psi pi0 and e+ e- exclusive production in proton-antiproton annihilation

We have measured the non resonant production cross section for the processes p pbar >> J/psi pizero and p pbar >> e+ e- at center of mass energies around 3.5 GeV. We found evidence for a resonance af mass 3525.2 and width <1.1 MeV that we identify with the state hc (1P1) of charmoniu

Study of the angular distribution of the reaction p pbar -> chi c2 -> J/psi gamma -> e+ e- gamma

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Proton electromagnetic form factors in the time like region from 8.9 to 13.0 GeV2

Cross sections for the reaction pp→e+e- have been measured at s=8.9, 12.4, and 13.0 GeV2. The cross sections have been analyzed to obtain the proton electromagnetic form factors in the timelike region

Production of the f2(1520) resonance in antiproton-proton annihilation at sqrt(s)=2980 and 3526 MeV

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Direct search for light gluinos

We present the results for a direct search for light gluinos through the appearance of eta --> 3 pi0 with high transverse momentum in the vacuum tank of the NA48 experiment at CERN. We find one event within a lifetime range of 10^-9 – 10^-3 s and another one between 10^-10 – 10^-9 s. Both events are consistent with the expected background from neutrons in the beam, produced by 450 GeV protons impinging on the Be targets, which interact with the residual air in the tank. From these data we give limits on the production of the hypothetical gg~ bound state, the R0 hadron, and its R0 --> eta gamma~ decay in the R0 mass range between 1 and 5 GeV