Matter effects in upward-going muons and sterile neutrino oscillations

M Ambrosio,G Sirri,A Habig,F Cei,L Patrizii,R Antolini,F Ronga,E Scapparone,A Grillo,R Bellotti,P Spinelli,M Calicchio,A Margiotta,C Lane,C Bemporad,P Fusco,J Reynoldson,P Pistilli,M Sitta,R Webb,O Erriquez,V Patera,D Martello,P Bernardini,O Palamara,N Giglietto,M Grassi,S Mufson,C Forti,C Bloise,P Lipari,C Favuzzi,P Monacelli,K Scholberg,M Vakili,H Dekhissi,R Pazzi,H Kim,R Nolty,I Katsavounidis,E Iarocci,R Steinberg,M Brigida,V Bisi,M Spurio,S Coutu,G Mancarella,L Perrone,M Monteno,G Osteria,C Gustavino,G Giacomelli,S Bussino,K Hanson,F Cafagna,S Kyriazopoulou,G Auriemma,A Sciubba,E Kearns,C Bower,F Maaroufi,A Baldini,M Carboni,F Loparco,G Mandrioli,V Popa,S Cecchini,S Mikheyev,E Katsavounidis,M Sioli,D Bakari,M Giorgini,P Serra,E Lamanna,V Togo,R Caruso,S Petrera,C Satriano,F Guarino,M Spinetti,A Marini,G Battistoni,R Heinz,V Chiarella,T Montaruli,Y Becherini,D Campana,L Gray,H Bilokon,A Surdo,J Musser,M J Longo ,D G Michael ,B C Choudhary ,C W Peck ,Laura Stephanie Miller ,G Tarlé ,N P Longley ,J E Derkaoui ,A Di Credico ,A Marzari‐Chiesa ,M N Mazziotta ,T Giannini ,C J Orth ,M De Vincenzi ,I De Mitri ,G De Cataldo ,L Sulak ,D Nicolò ,B Barish ,D Levin ,G C Barbarino ,Abdeslem Rrhioua ,C De Marzo ,A Rainò ,C W Walter ,J L Stone

doi:10.1016/s0370-2693(01)00992-3

Abstract

The angular distribution of upward-going muons produced by atmospheric neutrinos in the rock below the MACRO detector show anomalies in good agreement with two flavor neutrino-mu ==> neutrino-tau oscillations with maximum mixing and Delta m**2 around 0.0024 eV**2. Exploiting the dependence of magnitude of the matter effect on oscillation channel, and using a set of 809 upward-going muons observed in MACRO, we show that the two flavor neutrino-mu ==> neutrino-sterile oscillation is disfavored with 99% C.L. with respect to neutrino-mu ==> neutrino-tau.

Highlights

Neutrino oscillations [1] were first suggested by B
Where m2 = m21 − m22, L, E (GeV), θ is the mixing angle and L is the path length between the neutrino production point and the location at which the neutrino flavor is measured. This simple relation should be modified when a neutrino propagates through matter and when there is a difference in the interactions of the two neutrino flavors with matter [2]
In MACRO, neutrino oscillation is observed in three different event topologies, having different characteristic ranges of parent neutrino energies

Summary

27 September 2001

Webb o a Dipartimento di Fisica dell’Università di Bari and INFN, 70126 Bari, Italy b Dipartimento di Fisica dell’Università di Bologna and INFN, 40126 Bologna, Italy c Physics Department, Boston University, Boston, MA 02215, USA d California Institute of Technology, Pasadena, CA 91125, USA e Department of Physics, Drexel University, Philadelphia, PA 19104, USA f Laboratori Nazionali di Frascati dell’INFN, 00044 Frascati, Roma, Italy g Laboratori Nazionali del Gran Sasso dell’INFN, 67010 Assergi, L’Aquila, Italy h Departments of Physics and of Astronomy, Indiana University, Bloomington, IN 47405, USA i Dipartimento di Fisica dell’Università dell’Aquila and INFN, 67100 L’Aquila, Italy j Dipartimento di Fisica dell’Università di Lecce and INFN, 73100 Lecce, Italy k Department of Physics, University of Michigan, Ann Arbor, MI 48109, USA l Dipartimento di Fisica dell’Università di Napoli and INFN, 80125 Napoli, Italy m Dipartimento di Fisica dell’Università di Pisa and INFN, 56010 Pisa, Italy.

Introduction

Data analysis

Findings

Two flavors sterile neutrino oscillations and tau neutrino oscillations