Statistical methods applied to the search of sterile neutrinos
- PDF / 2,470,863 Bytes
- 22 Pages / 595.276 x 790.866 pts Page_size
- 46 Downloads / 177 Views
Regular Article - Experimental Physics
Statistical methods applied to the search of sterile neutrinos Matteo Agostini1,2,a , Birgit Neumair1,b 1 2
Physik Department E15, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK
Received: 15 January 2020 / Accepted: 23 July 2020 © The Author(s) 2020
Abstract The frequentist statistical methods applied to search for short-baseline neutrino oscillations induced by a sterile neutrino with mass at the eV scale are reviewed and compared. The comparison is performed under limit setting and signal discovery scenarios, considering both when an oscillation would enhance the neutrino interaction rate in the detector and when it would reduce it. The sensitivity of the experiments and the confidence regions extracted for specific data sets change considerably according to which test statistic is used and the assumptions on its probability distribution. A standardized analysis approach based on the most general kind of hypothesis test is proposed.
1 Introduction A vast experimental program has been mounted in the last decade to search for a new elementary particle named sterile neutrino [1]. The sterile neutrino is a particular type of neutrino that does not interact through the weak force. Since Pontecorvo postulated its existence in 1967 [2], the sterile neutrino has become increasingly popular and its existence is nowadays often invoked to explain the mysterious origin of neutrino masses and dark matter [3]. The discovery of sterile neutrinos would hence be a milestone towards the development of new theories beyond the Standard Model, with deep repercussions in particle physics and cosmology. The phenomenology of sterile neutrinos depends on their hypothetical mass value. The main target of the ongoing experimental efforts is sterile neutrinos with a mass of the order of the eV, whose existence has been hinted at by various experiments [4–6] and is still under debate [1,7]. The statistical data treatment for this kind of searches presents various challenges and has not been standardized yet. Currently, different statistical methods are used in the field, each a e-mail:
[email protected] (corresponding author)
b e-mail:
[email protected] (corresponding author)
0123456789().: V,-vol
addressing a different statistical question, and thus providing different results. This situation prevents a direct comparison of the performance of the experiments and of their outcome. In addition, approximations often adopted in the statistical analysis can lead to significantly inaccurate results. In this article we review the statistical methods used in the search for sterile neutrinos at the eV mass scale, expanding the discussion of Refs. [8–10] and performing a comprehensive comparison of the analysis approaches in scenarios with and without a signal. Section 2 describes the phenomenology of eV-mass sterile neutrinos, the signature sought after by th
Data Loading...
