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Poster Summaries Part G: 1 – Solar Neutrino Physics; 2 – The HOURS Software Package

March 15, 2013

Here are the two last poster summaries:

1 – Vito Antonelli: Solar Neutrino Physics

Ten years after the ‘‘annus mirabilis’’ 2002, we revise the main results 
of solar neutrino physics and discuss the main open questions and the way 
in which they will be addressed. After the solution of the long standing 
solar neutrino puzzle, different solar neutrino experiments and KamLAND 
went on producing data which made possible a more and more accurate 
determination of the oscillation parameters and of the medium and high 
energy part of the solar neutrino spectrum. Meanwhile, we could finally 
start attaching the study of the low energy part of the spectrum and 
Borexino measured the ^7Be monochromatic line and the important pep 
component and put a limit on the CNO neutrino flux. The mass and mixing 
pattern emerging from all these data and from the parallel 
phenomenological analyses and the comparison with the solar models offer 
a generally coherent picture which is confirmed by the recent discovery 
of a non zero mixing between the first and the third generations. 
However, some points still need to be clarified. Some anomalies seem 
to emerge in the low energy part of ^8B spectrum, in the so called vacuum 
to matter transition region, where SNO and Borexino show a partial 
deficit with respect to the theoretical predictions. This observation 
stimulated a flourishing of studies of possible non standard interactions 
and it clearly indicates the need of a more detailed analysis of this 
region. 

This is one of the main task of present and future experiments: Borexino, 
SNO+ and different other experiments planned for the future. They will 
try also to measure the lower energy components of the pp cycle (better 
determination of pep and possibly measurement of pp neutrinos) and to 
combine these data with the study of the CNO neutrinos, with the hope to 
discriminate between high Z and low Z solar models and solve the 
‘‘metallicity’’ problem. Main future hopes rely on multipurpose 
experiments with high detector masses and designed to reach very high 
radiopurity levels. We discuss different future experiments, which will 
use liquid scintillators of different kinds: organic scintillators  and 
new techniques (like in the LENA and LENS cases), noble gases (CLEAN/DEAP, 
XMASS, DARWIN).      

Image


2 – Apostolos Tsingotis: HOU Reconstruction & Simulation (HOURS): A simulation and reconstruction package for neutrino telescopy

[A. G. Tsirigotis (submitter), G. Bourlis, A. Leisos, D. Lenis, S. E. Tzamarias]

The Hellenic Open University Reconstruction & Simulation (HOURS) software package has been developed in order to study in detail the response of underwater neutrino telescopes. This package provides the tools for performing studies to estimate the detector sensitivity to several astrophysical neutrino sources and atmospheric neutrino oscillation parameters. It contains physics event generators, neutrino interaction simulation, Cherenkov emmision from the produced charged particles, detector response simulation, filter-triggering algorithms and reconstruction analysis code.

HOURS is one of the main physics analysis packages used extensively in evaluating architectures and technologies proposed during the design study and preparatory phase of KM3NeT [1]. HOURS results are in good agreement with other simulation efforts within the KM3NeT collaboration. We report on the structure and performance of the HOURS package. We also report on results, using HOURS, concerning the evaluation of the performance of a Mediterranean neutrino telescope to discover/observe astrophysical neutrino sources, and on results concerning the detection efficiency of low energy atmospheric neutrinos for neutrino oscillation studies.

The observation of point-like sources of neutrinos would bring unique new insights on the nature of cosmic accelerators and resolve the enigma of the origin of cosmic rays. Observations by gamma ray telescopes have revealed many astrophysical objects, in which high-energy processes at and beyond the TeV level take place. However, measurements with gamma rays alone cannot clearly distinguish whether the accelerated particles are leptons or hadrons. Only the observation of neutrinos from a source can unambiguously establish the hadronic nature of that source. One such source, that has been extensively studied, is the Supernova remnant RXJ1713. It is visible 75% of the time by a Meditarranean neutrino telescope and has been found to be active in low (Fermi-LAT) and high (HESS) energy gamma rays. Assuming that the high energy gamma rays are of hadronic origin, the neutrino flux (reference flux) can be predicted by phenomenological models [2].

Image

The Figure shows the discovery potential (5sigma, 50% probability), in units of the reference flux, vs the number of observation years with KM3NeT of RXJ1713. The points correspond to various analysis techniques. The best technique gives ~5 years for discovery of the reference flux.

References:

[1] KM3NeT Technical Design Report (2010), ISBN 978-90-6488-033-9 ; http://www.km3net.org

[2] S.R. Kelner, et al., Phys. Rev. D74, 034018 (2006)Simulation Package for Neutrino Telescopes

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