Eur. Phys. J. C (2013) 73: 2439
https://doi.org/10.1140/epjc/s10052-013-2439-1

Regular Article - Theoretical Physics

Counting muons to probe the neutrino mass spectrum

¹ INFN, Laboratori Nazionali del Gran Sasso, Assergi (AQ), Italy
² Departamento de Fisica, DCeI, Universidad de Guanajuato, León, Guanajuato, México
³ Gran Sasso Science Institute (INFN), L’Aquila, Italy

^* e-mail: vissani@lngs.infn.it

Received: 12 February 2013
Revised: 3 May 2013
Published online: 15 May 2013

Abstract

The experimental evidence that θ 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 set-up turns out to be long baseline experiment: the muon neutrino beam, with 10²⁰ 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.