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Title: First Direct Observation of Muon Antineutrino Disappearance

Journal Article · · Physical Review Letters
OSTI ID:1040488

This Letter reports the first direct observation of muon antineutrino disappearance. The MINOS experiment has taken data with an accelerator beam optimized for {bar {nu}}{sub {mu}} production, accumulating an exposure of 1.71 x 10{sup 20} protons on target. In the Far Detector, 97 charged current {bar {nu}}{sub {mu}} events are observed. The no-oscillation hypothesis predicts 156 events and is excluded at 6.3{sigma}. The best fit to oscillation yields |{Delta}{bar m}{sup 2}| = [3.36{sub -0.40}{sup +0.46}(stat){+-}0.06(syst)] x 10{sup -3} eV{sup 2}, sin{sup 2}(2{bar {Theta}}) = 0.86{sub -0.12}{sup +0.11}(stat) {+-} 0.01(syst). The MINOS {nu}{sub {mu}} and {bar {nu}}{sub {mu}} measurements are consistent at the 2.0% confidence level, assuming identical underlying oscillation parameters.

Research Organization:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Organization:
USDOE SC OFFICE OF SCIENCE (SC)
DOE Contract Number:
DE-AC02-98CH10886
OSTI ID:
1040488
Report Number(s):
BNL-96229-2011-JA; PRLTAO; R&D Project: PO--022; KA11011020; TRN: US1202466
Journal Information:
Physical Review Letters, Vol. 107, Issue 2; ISSN 0031-9007
Country of Publication:
United States
Language:
English