  On 2010 MINOS experiment was showing an hint of possible different mass
splitting and mixing angles for neutrinos and anti-neutrinos, suggesting a
charge-parity-time (CPT) violation in the lepton sector; last year 2012 a
second result from MINOS showed a reduced discrepancy between the two set of
parameters, nearly compatible with no CPT violation. We proposed an experiment
for more precise estimation of neutrino oscillation parameters being useful not
only for a complete discrimination for CPT scenarios, but also for mass
hierarchy and theta 13 determination, and mostly for the first oscillated
detection of tau and antitau neutrinos. We show an experiment, (the longest
baseline neutrino oscillation test available by crossing most of Earth
diameter, a NeuWorld), that may improve the oscillation measurement and
disentangle at best any hypothetical CPT violation while testing tau appearance
at the same time of the muon disappearance correlated. The experiment use a
neutrino beam crossing the Earth, within an OPERA-like experiment from CERN (or
Fermilab), in the direction of the IceCube DeepCore detector at the South Pole.
Such a tuned beaming and its detection may lead to a strong signature of
neutrino muon-tau mixing (nearly one anti tau or two tau a day, with 10 sigma
in a year), even for an one per-cent OPERA-like NeuWorld experiment.
