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Search Results: 1 - 10 of 189893 matches for " G. Pagliaroli "
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Using supernova neutrinos to monitor the collapse, to search for gravity waves and to probe neutrino masses
F. Vissani,G. Pagliaroli,F. Rossi-Torres
Physics , 2010, DOI: 10.1142/S0218271811019888
Abstract: We discuss the importance of observing supernova neutrinos. By analyzing the SN1987A observations of Kamiokande-II, IMB and Baksan, we show that they provide a 2.5{\sigma} support to the standard scenario for the explosion. We discuss in this context the use of neutrinos as trigger for the search of the gravity wave impulsive emission. We derive a bound on the neutrino mass using the SN1987A data and argue, using simulated data, that a future galactic supernova could probe the sub-eV region.
Spectrum of Supernova Neutrinos in Ultra-pure Scintillators
C. Lujan-Peschard,G. Pagliaroli,F. Vissani
Physics , 2014, DOI: 10.1088/1475-7516/2014/07/051
Abstract: There is a great interest in measuring the non-electronic component of neutrinos from core collapse supernovae by observing, for the first time, also neutral-current reactions. In order to assess the physics potential of the ultra-pure scintillators in this respect, we study the entire expected energy spectrum in the Borexino, KamLAND and SNO+ detectors. We examine the various sources of uncertainties in the expectations, and in particular, those due to specific detector features and to the relevant cross sections. We discuss the possibility to identify the different neutrino flavors, and we quantify the effect of confusion, due to other components of the energy spectrum, overlapped with the neutral-current reactions of interest.
Which is the flavor of cosmic neutrinos seen by IceCube?
A. Palladino,G. Pagliaroli,F. L. Villante,F. Vissani
Physics , 2015, DOI: 10.1103/PhysRevLett.114.171101
Abstract: We analyze the high-energy neutrino events observed by IceCube, aiming to probe the initial flavor of cosmic neutrinos. We study the track-to-shower ratio of the subset with energy above 60 TeV, where the signal is expected to dominate and show that different production mechanisms give rise to different predictions even accounting for the uncertainties due to neutrino oscillations. We include for the first time the passing muons observed by IceCube in the analysis. They corroborate the hypotheses that cosmic neutrinos have been seen and their flavor matches expectations.
What is the issue with SN1987A neutrinos?
F. Vissani,M. L. Costantini,W. Fulgione,A. Ianni,G. Pagliaroli
Physics , 2010,
Abstract: What did we learn out of SN1987A neutrino observations? What do we still need for a full understanding? We select important issues debated in the literature on SN1987A. We focus the discussion mostly on the relevance of certain data features; on the role of detailed statistical analyses of the data; on the astrophysics of the neutrino emission process; on the effects of oscillations and of neutrino masses. We attempt to clearly identify those issues that are still open.
A step toward CNO solar neutrinos detection in liquid scintillators
F. L. Villante,A. Ianni,F. Lombardi,G. Pagliaroli,F. Vissani
Physics , 2011, DOI: 10.1016/j.physletb.2011.05.068
Abstract: The detection of CNO solar neutrinos in ultrapure liquid scintillator detectors is limited by the background produced by Bismuth-210 nuclei that undergo beta-decay to Polonium-210 with a lifetime equal to about 7 days. Polonium-210 nuclei are unstable and decay with a lifetime equal to about 200 days emitting alpha particles that can be also detected. In this letter, we show that the Bi-210 background can be determined by looking at the time evolution of alpha-decay rate of Po-210, provided that alpha particle detection efficiency is stable over the data acquisition period and external sources of Po-210 are negligible. A sufficient accuracy can be obtained in a relatively short time. As an example, if the initial Po-210 event rate is 2000 cpd/100 ton or lower, a Borexino-like detector could start discerning CNO neutrino signal from Bi-210 background in about 1 yr.
The diffuse supernova neutrino background: Expectations and uncertainties derived from SN1987A
Francesco Vissani,Giulia Pagliaroli
Physics , 2011, DOI: 10.1051/0004-6361/201016109
Abstract: Context: The detection of the diffuse supernova neutrino background may be imminent, but theoretical predictions are affected by substantial uncertainties. AIMS. We calculate the signal and its uncertainty with the present configuration of Super-Kamiokande and consider the possibility of lowering the threshold by means of gadolinium loading. Methods: We model neutrino emission following the analysis of SN1987A by Pagliaroli and collaborators 2009 and use the number of expected events in the neutrino detector as a free parameter of the fit. The best-fit value of this parameter and its error are evaluated by means of standard maximum likelihood procedures, taking into account properly the correlations. Results: The uncertainties in the astrophysics of the emission dominates the total uncertainty in the expected signal rate, which conservatively ranges from 0.3 to 0.9 events per year and from 1.1 to 2.9 with gadolinium.
On the Goals of Neutrino Astronomy
Francesco Vissani,Giulia Pagliaroli,Francesco Lorenzo Villante
Physics , 2009, DOI: 10.1393/ncc/i2009-10474-8
Abstract: What do we mean by neutrino astronomy? Which information is it able to provide us and which is its potential? To address these questions, we discuss three among the most relevant sources of neutrinos: the Sun; the core collapse supernovae; the supernova remnants. For each of these astronomical objects, we describe the state of the art, we present the expectations and we outline the most actual problems from the point of view of neutrino astronomy.
The fraction of muon tracks in cosmic neutrinos
Francesco Vissani,Giulia Pagliaroli,Francesco L. Villante
Physics , 2013, DOI: 10.1088/1475-7516/2013/09/017
Abstract: The study of the distintive signatures of the ultra high energy events recently seen by IceCube can allow to single the neutrino origin out. The detection of tau neutrinos would be a clear way to prove that they come from cosmic distances, but at the highest energies currently seen, about 1 PeV, an experimental characterization of tau events is difficult. The study of the fraction of the muon tracks seems more promising. In fact, for any initial composition, because of the occurrence of flavor oscillations and despite their uncertainties, the fraction of muon tracks in the cosmic neutrinos is smaller than the one of atmospheric neutrinos, even hypothesizing an arbitrarily large contribution from charmed mesons. A good understanding of the detection efficiencies and the optimization of the analysis cuts, along with a reasonable increase in the statistics, should provide us with a significant test of the cosmic origin of these events.
Searching for prompt signatures of nearby core-collapse supernovae by a joint analysis of neutrino and gravitational-wave data
I. Leonor,L. Cadonati,E. Coccia,S. D'Antonio,A. Di Credico,V. Fafone,R. Frey,W. Fulgione,E. Katsavounidis,C. D. Ott,G. Pagliaroli,K. Scholberg,E. Thrane,F. Vissani
Physics , 2010, DOI: 10.1088/0264-9381/27/8/084019
Abstract: We discuss the science motivations and prospects for a joint analysis of gravitational-wave (GW) and low-energy neutrino data to search for prompt signals from nearby supernovae (SNe). Both gravitational-wave and low-energy neutrinos are expected to be produced in the innermost region of a core-collapse supernova, and a search for coincident signals would probe the processes which power a supernova explosion. It is estimated that the current generation of neutrino and gravitational-wave detectors would be sensitive to Galactic core-collapse supernovae, and would also be able to detect electromagnetically dark SNe. A joint GW-neutrino search would enable improvements to searches by way of lower detection thresholds, larger distance range, better live-time coverage by a network of GW and neutrino detectors, and increased significance of candidate detections. A close collaboration between the GW and neutrino communities for such a search will thus go far toward realizing a much sought-after astrophysics goal of detecting the next nearby supernova.
Counting muons to probe the neutrino mass spectrum
Lujan-Peschard, Carolina;Pagliaroli, Giulia;Vissani, Francesco
High Energy Physics - Phenomenology , 2013,
Abstract: The experimental evidence that \theta_{13} is large opens new opportunities to identify the neutrino mass spectrum. We outline a possibility to investigate this issue by means of conventional technology. The ideal setup turns out to be long baseline experiment: the muon neutrino beam, with 10^{20} protons on target, has an average energy of 6 (8) GeV; the neutrinos, after propagating 6000 (8000) km, are observed by a muon detector of 1 Mton and with a muon energy threshold of 2 GeV. The expected number of muon events is about 1000, and the difference between the two neutrino spectra is sizeable, about 30%. This allows the identification of the mass spectrum just counting muon tracks. The signal events are well characterized experimentally by their time and direction of arrival, and 2/3 of them are in a region with little atmospheric neutrino background, namely, between 4 GeV and 10 GeV. The distances from CERN to Baikal Lake and from Fermilab to KM3NET, or ANTARES, fit in the ideal range.
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