Sensitivity to neutrino mixing parameters with atmospheric neutrinos

We have analyzed the atmospheric neutrino data to study the octant of θ23 and the precision of the oscillation parameters for a large iron calorimeter detector. The iron calorimeter being a tracking detector has the ability to measure the energy and the direction of the muon with high resolution. From bending of the track in the magnetic field it can also distinguish its charge. We have generated events by Nuance and then considered only the muons (directly measurable quantities) produced in charge current interactions in our analysis. This encounters the main problem of wide resolutions of energy and baseline. The energy-angle correlated two-dimensional resolution functions are used to migrate the energy and the zenith angle of the neutrino to those of the muon. A new type of binning has been introduced to get better reflection of the oscillation pattern in χ2 analysis. Then the marginalization of the χ2 over all parameters has been carried out for neutrinos and antineutrinos separately. We find that the measurement of θ13 is possible at a significant precision with atmospheric neutrinos. The precisions of Δm322 and sin2θ23 are found ∼8% and 38%, respectively, at 90% C.L. The discrimination of the octant as well as the deviation from maximal mixing of atmospheric neutrinos is also possible for some combinations of (θ23,θ13). We also discuss the impact of the events at near horizon on the precision studies.