The OPERA neutrino experiment is designed to perform the first observa- tion of neutrino oscillations in direct appearance mode in the νμ → ντ channel, via the detection of the τ-leptons created in charged current ντ interactions. The detector, located in the underground Gran Sasso Laboratory, consists of an emulsion/lead target with an average mass of about 1.2 kt, complemented by electronic detectors. It is exposed to the CERN Neutrinos to Gran Sasso beam, with a baseline of 730 km and a mean energy of 17 GeV. The observation of the first ντ candidate event and the analysis of the 2008-2009 neutrino sample have been reported in previous publications. This work describes sub- stantial improvements in the analysis and in the evaluation of the detection efficiencies and backgrounds using new simulation tools. The analysis is extended to a sub-sample of 2010 and 2011 data, resulting from an electronic detector-based pre-selection, in which an additional ντ candidate has been observed. The significance of the two events in terms of a νμ → ντ oscillation signal is of 2.40σ.
New results on νμ→ντ appearance with the OPERA experiment in the CNGS beam / DE LELLIS, Giovanni; Lauria, Adele; Montesi, MARIA CRISTINA; DI CRESCENZO, Antonia. - In: JOURNAL OF HIGH ENERGY PHYSICS. - ISSN 1126-6708. - 11:(2013), pp. 36-68. [10.1007/JHEP11(2013)036]
New results on νμ→ντ appearance with the OPERA experiment in the CNGS beam
DE LELLIS, GIOVANNI;LAURIA, ADELE;MONTESI, MARIA CRISTINA;DI CRESCENZO, ANTONIA
2013
Abstract
The OPERA neutrino experiment is designed to perform the first observa- tion of neutrino oscillations in direct appearance mode in the νμ → ντ channel, via the detection of the τ-leptons created in charged current ντ interactions. The detector, located in the underground Gran Sasso Laboratory, consists of an emulsion/lead target with an average mass of about 1.2 kt, complemented by electronic detectors. It is exposed to the CERN Neutrinos to Gran Sasso beam, with a baseline of 730 km and a mean energy of 17 GeV. The observation of the first ντ candidate event and the analysis of the 2008-2009 neutrino sample have been reported in previous publications. This work describes sub- stantial improvements in the analysis and in the evaluation of the detection efficiencies and backgrounds using new simulation tools. The analysis is extended to a sub-sample of 2010 and 2011 data, resulting from an electronic detector-based pre-selection, in which an additional ντ candidate has been observed. The significance of the two events in terms of a νμ → ντ oscillation signal is of 2.40σ.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.