We present the XMM-Newton Medium sensitivity Survey (XMS), including a total of 318 X-ray sources found among the serendipitous content of 25 XMM-Newton target fields. The XMS comprises four largely ...overlapping source samples selected at soft (0.5-2 keV), intermediate (0.5-4.5 keV), hard (2-10 keV) and ultra-hard (4.5-7.5 keV) bands, the first three of them being flux-limited. We report on the optical identification of the XMS samples, complete to 85-95%. At the intermediate flux levels sampled by the XMS we find that the X-ray sky is largely dominated by Active Galactic Nuclei. The fraction of stars in soft X-ray selected samples is below 10%, and only a few per cent for hard selected samples. We find that the fraction of optically obscured objects in the AGN population stays constant at around 15-20% for soft and intermediate band selected X-ray sources, over 2 decades of flux. The fraction of obscured objects amongst the AGN population is larger (~35-45%) in the hard or ultra-hard selected samples, and constant across a similarly wide flux range. The distribution in X-ray-to-optical flux ratio is a strong function of the selection band, with a larger fraction of sources with high values in hard selected samples. Sources with X-ray-to-optical flux ratios in excess of 10 are dominated by obscured AGN, but with a significant contribution from unobscured AGN.
Current Status of the BOREXINO experiment Galbiati, Cristiano; Balata, M.; de Bari, A. ...
Nuclear physics. Section B, Proceedings supplement,
2005, Letnik:
143
Journal Article
The status of the BOREXINO experiment is presented. The physics potential of the experiment is reviewed.
Eur.Phys.J.C19:43-55,2001 The unique features (super-low background and large sensitive volume) of the
CTF and BOREXINO set ups are used in the CAMEO project for a high sensitivity
study of 100-Mo ...and 116-Cd neutrinoless double beta decay. Pilot measurements
with 116-Cd and Monte Carlo simulations show that the sensitivity of the CAMEO
experiment (in terms of the half-life limit for neutrinoless double beta decay)
is (3-5) 10^24 yr with a 1 kg source of 100-Mo (116-Cd, 82-Se, and 150-Nd) and
about 10^26 yr with 65 kg of enriched 116-CdWO_4 crystals placed in the liquid
scintillator of the CTF. The last value corresponds to a limit on the neutrino
mass of less than 0.06 eV. Similarly with 1000 kg of 116-CdWO_4 crystals
located in the BOREXINO apparatus the neutrino mass limit can be pushed down to
m_nu<0.02 eV.
In the exciting arena of the solar neutrino research a new actor is expected to come soon in the game: Borexino. This massive, calorimetric, liquid scintillation detector, in advanced phase of ...installation in the underground Gran Sasso Laboratory, will be focused towards one of the fundamental issues of this field, i.e. the direct determination of the flux of the neutrinos produced in the
7
Be electron capture reaction in the Sun. As a pilot program for the full detector, the Counting Test Facility operated for two years at Gran Sasso, provided the convicing evidence that the fundamental technological challenge of the experiment, the achievement in the scintillator of unprecedented radiopurity levels, can be accomplished successfully, thus opening the way to the realization of the experiment.
The unique features (super-low background and large sensitive volume) of the CTF and BOREXINO set ups are used in the CAMEO project for a high sensitivity study of 100-Mo and 116-Cd neutrinoless ...double beta decay. Pilot measurements with 116-Cd and Monte Carlo simulations show that the sensitivity of the CAMEO experiment (in terms of the half-life limit for neutrinoless double beta decay) is (3-5) 10^24 yr with a 1 kg source of 100-Mo (116-Cd, 82-Se, and 150-Nd) and about 10^26 yr with 65 kg of enriched 116-CdWO_4 crystals placed in the liquid scintillator of the CTF. The last value corresponds to a limit on the neutrino mass of less than 0.06 eV. Similarly with 1000 kg of 116-CdWO_4 crystals located in the BOREXINO apparatus the neutrino mass limit can be pushed down to m_nu<0.02 eV.
E687 has been a highly successful experiment on charm physics at Fermilab collecting approximately 100,000 fully reconstructed charm events. Still recently, after seven years since last data taking, ...E687 has produced world class physics results, the latest of which will be summarized in this article.
An overview of Fermilab experiment FOCUS and of its physics goals will be presented. During the 96–97 fixed target run at Fermilab we collected more than 6.3 billion events with the expectation of in ...excess of 1 million fully reconstructed charmed particles. Preliminary results on charmed meson decays will be reported.
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Collection : Bibliothèque des meilleurs romans étrangers
Contient une table des ...matières
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