Antineutrino Oscillations in the Atmospheric Sector

Long-Baseline Neutrino Oscillation Experiments

“…The neutrino flavor composition of the on-axis NuMI beam is as follows: firstly, with the magnetic horn polarity set to focus positive hadrons a neutrino-enhanced beam is produced, giving rise to interactions in the (on-axis) MINOS near detector that are 91.7% ν µ , 7.0% ν µ and 1.3% ν e + ν e ; secondly, with the opposite polarity an antineutrino-enhanced beam is produced, giving near detector interactions that are 40% ν µ , 58% ν µ , 2% ν e + ν e [23]. However, it should be noted that in the antineutrino-enhanced beam the ν µ component comprises about 80% of the interactions below 6 GeV in the region where the oscillation effect is largest.…”

“…from the CHOOZ experiment was known until very recently. Because the CP violating observable, the phase δ, appears always in the product with sin(2θ 12 ) sin(2θ 23 ) sin(2θ 13 ) and θ 23 and θ 12 are known to be large, the size of θ 13 is a major factor in the feasibility of the future CP violation search.…”

Study of antineutrino oscillations using accelerator and atmospheric data in MINOS

“…By assuming thatν µ -CC disappearance is driven by the effective two-flavor model, the best-fit oscillation parameters for considering only statistics yields: Since the value of sin 2 2θ is close to a physical boundary, the confidence contours are corrected by applying the Feldman-Cousins method [135]. This method also allows one to incorporate the systematic effects into the final results [136]. Figure 7.4 shows the surfaces of corrected ∆χ 2 with and without systematic shifts applied.…”

Muon Antineutrino Disappearance in the MINOS Experiment

“…CC-events are recognised by the long muon track, curving in the magnetic field, and NC events typically have only a hadronic shower, from which short tracks can sometimes be found as a background. From [66].…”