101 research outputs found
On the significance in signal search through the sliding window algorithm
The experimental issue of the search for new particles of unknown mass poses
the challenge of exploring a wide interval to look for the usual signatures
represented by excess of events above the background. A side effect of such a
broad range quest is that the traditional significance calculations valid for
signals of known location are no more applicable when such an information is
missing. In this note the specific signal search approach via observation
windows sliding over the range of interest is considered; in the assumptions of
known background and of fixed width of the exploring windows the statistical
implications of such a search scheme are described, with special emphasis on
the correct significance assessment for a claimed discovery.Comment: 10 pages, 6 figures, misprints corrected, an extended version will be
published on NIM
Time and position distributions in large volume spherical scintillation detectors
Large spherical scintillation detectors are playing an increasingly important
role in experimental neutrino physics studies. From the instrumental point of
view the primary signal response of these set-ups is constituted by the time
and amplitude of the anode pulses delivered by each individual phototube
following a particle interaction in the scintillator. In this work, under some
approximate assumptions, we derive a number of analytical formulas able to give
a fairly accurate description of the most important timing features of these
detectors, intended to complement the more complete Monte Carlo studies
normally used for a full modelling approach. The paper is completed with a
mathematical description of the event position distributions which can be
inferred, through some inference algorithm, starting from the primary time
measures of the photomultiplier tubes.Comment: 29 pages, 20 figures, accepted for publication on Nucl. Instr. and
Meth.
recent results on solar neutrinos
G. Bellini, J. Benziger, D. Bick, G. Bonfini, D. Bravo, M. Buizza Avanzini, B. Caccianiga, L. Cadonati, F. Calaprice, C. Carraro, P. Cavalcante, A. Chavarria, D. D'Angelo, S. Davini, A. Derbin, A. Etenko, K. Fomenko, D. Franco, C. Galbiati, S. Gazzana, C. Ghiano, M. Giammarchi, M. Goeger-Neff, A. Goretti, L. Grandi, E. Guardincerri, S. Hardy, Aldo Ianni, Andrea Ianni, A. Kayunov, V. Kobychev, D. Korablev, G. Korga, Y. Koshio, D. Kryn, M. Laubenstein, T. Lewke, E. Litvinovich, B. Loer, F. Lombardi, P. Lombardi, L. Ludhova, I. Machulin, S. Manecki, W. Maneschg, G. Manuzio, Q. Meindl, E. Meroni, L. Miramonti, M. Misiaszek, D. Montanari, P. Mosteiro, V. Muratova, L. Oberauer, M. Obolensky, F. Ortica, K. Otis, M. Pallavicini, L. Papp, L. Perasso, S. Perasso, A. Pocar, R.S. Raghavan, G. Ranucci, A. Razeto, A. Re, A. Romani, N. Rossi, A. Sabelnikov, R. Saldanha, C. Salvo, S. Schonert, H. Simgen, M. Skorokhvatov, O. Smirnov, A. Sotnikov, S. Sukhotin, Y. Suvorov, R. Tartaglia, G. Testera, D. Vignaud, R.B. Vogelaar, F. von Feilitzsch, J. Winter, M. Wojcik, A. Wright, M. Wurm, J. Xu, O. Zaimidoroga, S. Zavatarelli and G. Zuzel (Borexino Collaboration
borexino recent solar and terrestrial neutrino results and description of the sox project
G. Bellini, J. Benziger, D. Bick, G. Bonfini, D. Bravo, M. Buizza Avanzini, B. Caccianiga, L. Cadonati, F. Calaprice, P. Cavalcante, A. Chavarria, A. Chepurnov, D. D'Angelo, S. Davini, A. Derbin, A. Empl, A. Etenko, K. Fomenko, D. Franco, C. Galbiati, S. Gazzana, C. Ghiano, M. Giammarchi, M. Goeger-Neff, A. Goretti, L. Grandi, C: Hagner, E. Hungerford, Aldo Ianni, Andrea Ianni, V. Kobychev, D. Korablev, G. Korga, D. Kryn, M. Laubenstein, T. Lewke, E. Litvinovich, B. Loer, F. Lombardi, P. Lombardi, L. Ludhova, G. Lukyanchenko, I. Machulin, S. Manecki, W. Maneschg, G. Manuzio, Q. Meindl, E. Meroni, L. Miramonti, M. Misiaszek, R. Mollenberg, P. Mosteiro, V. Muratova, L. Oberauer, M. Obolensky, F. Ortica, K. Otis, M. Pallavicini, L. Papp, L. Perasso, S. Perasso, A. Pocar, R.S. Raghavan, G. Ranucci, A. Razeto, A. Re, A. Romani, N. Rossi, R. Saldanha, C. Salvo, S. Schonert, H. Simgen, M. Skorokhvatov, O. Smirnov, A. Sotnikov, S. Sukhotin, Y. Suvorov, R. Tartaglia, G. Testera, D. Vignaud, R.B. Vogelaar, F. von Feilitzsch, J. Winter, M. Wojcik, A. Wright, M. Wurm, J. Xu, O. Zaimidoroga, S. Zavatarelli and G. Zuzel (Borexino Collaboration
Periodogram and likelihood periodicity search in the SNO solar neutrino data
In this work a detailed spectral analysis for periodicity search of the time
series of the 8B solar neutrino flux released by the SNO Collaboration is
presented. The data have been publicly released with truncation of the event
times to the unit of day (1 day binning); they are thus suited to undergo the
traditional Lomb-Scargle analysis for periodicity investigation, as well as an
extension of such a method based on a likelihood approach. The results of the
analysis presented here confirm the absence of modulation signatures in the SNO
data. For completeness, a more refined "1 day binned" likelihood is also
illustrated, which approximates the unbinned likelihood methodology, based upon
the availability of the full time information, adopted by the SNO
collaboration. Finally, this work is completed with two different joint
analyses of the SNO and Super-Kamiokande data, respectively, over the common
and the entire data taking periods. While both analyses reinforce the case of
the constancy of the neutrino flux, the latter in addition provides evidence of
the detection at the 99.7% confidence level of the annual modulation spectral
line due to the Earth's orbit eccentricity around the SunComment: 27 pages, 29 figures. Joint periodicity analysis of the SNO and
Super-Kamiokande data added. Accepted for publication on Phys. Rev.
A Standard Model explanation for the MiniBooNE anomaly
We present the results of a new analysis of the data of the MiniBooNE
experiment taking into account the additional background of photons. MiniBooNE
normalises the rate of photon production to the measured production
rate. We study neutral current (NC) neutrino-induced /photon production
() on carbon nucleus (A=12). Our
conclusion is based on experimental data for photon-nucleus interactions from
the A2 collaboration at the Mainz MAMI accelerator. We work in the
approximation that decays of the intermediate states (non-resonant N,
resonance, higher resonances) unaffected by its production channel, via photon
or Z boson. production scales as A, the surface area of the
nucleus. Meanwhile the photons incoherently created in intermediate states
decays will leave the nucleus, and that cross section will be proportional to
the atomic number of the nucleus. We also took into account the coherent
emission of photons. We show that the new photon background can explain part of
the MiniBooNE low-energy excess, thus significantly lowering the number of
unexplained MiniBooNE electron-like events from to .Comment: Contribution to the proceedings of the 40th ICHEP2020, Prague, Czech
Republic (Virtual Conference), 6 page
PULSE-SHAPE DISCRIMINATION OF LIQUID SCINTILLATORS
In this paper we describe the results of different techniques applied to characterize experimentally the pulse shape discrimination capability of liquid scintillators. A detailed comparison of the results obtained with each method is reported, together with the description of an optimization strategy which can be adopted to obtain the best exploitation of the intrinsic PSD feature of the scintillator samples
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