1,016 research outputs found
Recent results and future perspectives of the Borexino experiment
We present the main results achieved by the Borexino experiment on solar neutrino physics. Borexino is a large mass/high radiopurity liquid scintillator detector located under the Gran Sasso mountain (Italy). It has collected high quality data since May 2007. The results presented here refer to the so-called Phase 1 of the experiment which ended in May 2010. Borexino Phase 2 started in October 2011 after an intensive campaign of purification which significantly improved the (already exceptional) quality of the scintillator. The physics potentialities and future
perspectives of this second phase of Borexino will be shortly discussed
Neutrino physics with the Borexino experiment
Borexino is a large mass, high radiopurity detector located under the Gran Sasso Mountain (Italy) and designed to measure in real-time the flux of low energy solar neutrinos. Borexino has been taking data continuously since May 2007. This talk is focused on the main goal of Borexino, the measurement of solar neutrinos produced in the 7Be reaction: I will present the result on the 7Be flux obtained in 2008 after 192 days of data-taking together with a preliminary evaluation of the daynight asymmetry of the signal. I will also discuss the impact on the analysis of the two extensive calibration campaigns performed in 2009. Thanks to these campaigns a new measurement of the 7Be flux will be shortly published with significantly
reduced error. Borexino is also able of measuring the 8B neutrino flux with an unprecedented low threshold of 3MeV (scattered electron kinetic energy): it is the only experiment able of probing the survival probability in the vacuum dominated oscillation regime (with 7Be neutrinos) and in the matter enhanced oscillation regime (with 8B). Finally, I will also present another important result of Borexino, namely the first clear observation of geoneutrinos
GPS-based CERN-LNGS time link for Borexino
We describe the design, the equipment, and the calibration of a new GPS based
time link between CERN and the Borexino experiment at the Gran Sasso Laboratory
in Italy. This system has been installed and operated in Borexino since March
2012, and used for a precise measurement of CNGS muon neutrinos speed in May
2012. The result of the measurement will be reported in a different letter.Comment: 13 pages, 11 figure
Misura dei cambiamenti paesaggistici in ambiente alpino attraverso l’integrazione di dati telerilevati
Dalla met\ue0 del secolo scorso il paesaggio italiano ha subito delle profonde trasformazioni dovute al cambiamento di uso/copertura del suolo con la perdita di prati e pascoli a causa dei naturali processi di successione forestale, con forti ripercussioni sulla conservazione della biodiversit\ue0 (Falcucci et al. 2006).
Gli ecosistemi alpini sono particolarmente sensibili a queste modifiche (Gehrig-Fasel et al. 2007) a causa dell\u2019elevato grado di endemismi fortemente adattati (Billings 1974).
Per attuare delle misure di tipo conservazionistico, quindi \ue8 fondamentale quantificare il cambiamento di copertura del suolo avvenuto negli ultimi decenni ed impostare un monitoraggio a lungo termine delle strutture vegetali per individuare le aree maggiormente sensibili
Exploring the parent population of beamed NLS1s: from the black hole to the jet
The aim of this work is to understand the nature of the parent population of
beamed narrow-line Seyfert 1 galaxies (NLS1s), by studying the physical
properties of three parent candidates samples: steep-spectrum radio-loud NLS1s,
radio-quiet NLS1s and disk-hosted radio-galaxies. In particular, we focused on
the black hole mass and Eddington ratio distribution and on the interactions
between the jet and the narrow-line region.Comment: 6 pages, 2 figures, to appear in Proceedings of High Energy Phenomena
in Relativistic Outflows (HEPRO) V, Workshop Series of the Argentinian
Astronomical Societ
High sensitivity double beta decay study of 116-Cd and 100-Mo with the BOREXINO Counting Test Facility (CAMEO project)
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.Comment: 29 pages, LaTex, 9 eps figure
Unveiling the parent population of beamed narrow-line Seyfert 1s
Narrow-line Seyfert 1 galaxies (NLS1s) are active galactic nuclei (AGN)
recently identified as a new class of -ray sources. The high energy
emission is explained by the presence of a relativistic jet observed at small
angles, just like in the case of blazars. When the latter are observed at
larger angles they appear as radio-galaxies, but an analogue parent population
for beamed NLS1s has not yet been determined. In this work we analyze this
problem by studying the physical properties of three different samples of
parent sources candidates: steep-spectrum radio-loud NLS1s, radio-quiet NLS1s,
and disk-hosted radio-galaxies, along with compact steep-spectrum sources. In
our approach, we first derived black hole mass and Eddington ratio from the
optical spectra, then we investigated the interaction between the jet and the
narrow-line region from the [O III] 4959,5007 lines. Finally,
the radio luminosity function allowed us to compare their jet luminosity and
hence determine the relations between the samples.Comment: 6 pages, no figures. Proceedings of the 28th Texas Symposium, Geneva,
December 13-18, 201
Short distance neutrino Oscillations with BoreXino: SOX
Several anomalies coming from neutrino experiments may be pointing towards new physics: these hints suggest the existence of one (or more) sterile neutrinos. SOX is a short-baseline experiment devoted to shed light on this intriguing hint, by looking for disappearance of ¯νe from a 144Ce-144Pr source with the Borexino apparatus
Assessment of landscape change’s impact on Alpine species distribution using a multi-scale approach
There is a strong relation between biodiversity and traditional land use in Mediterrean areas. In these highly human dominated regions traditional acitvities profoundly shape the landscape with strong consequences on biodiversity pattern. However, in the last few decades the rapid socio-economic change lead to the abandonment of \u201cmarginal\u201d land modifying the landscape structures. Available remote sensing data can provide information about environmental changes, but the occurrence of temporal and spatial gaps (e.g., the limited temporal archive of historical aerial images and the coarser spatial resolution of satellite data) can reduce the applicability of gained information. Considering the importance of the scale-dependency of ecological processes, we propose a multi-temporal and scale approach, combining remote sensed and field data, to monitor changes in vegetation and landscape structures and to evaluate their role in shaping Alpine species distribution. The study area is the Gran Paradiso National Park (NW Italian Alps) and we focused both on 5 altitudinal transects, representative of three altitudinal belts, and on landscape level. At first, from the interpretation of historical aerial photos in sampled areas, we reconstructed the land cover changes occurred during the last decades and we extended this information to the entire Park landscape, through a supervised classification of satellite data. Further, we developed a low-cost procedure of UAV (Unmanned Aerial Vehicle) survey adapted to Alpine environment, integrated with botanical sampling, in order to obtain highresolution land cover maps in test areas to replace the use of aerial photos in supervised classification of satellite data. This multi-scale analysis of landscape change allows us to detail how the environmental patterns affect the Alpine animal species distribution ranging from discrete areas to entire Park area
- …