NUFACT2014, XVIth International Workshop on Neutrino Factories and Future Neutrino Beam Facilities

Enhancing the reach of INO-ICAL using correlated muon and hadron information

Not scheduled

15m

Western Infirmary Lecture Theatre (University of Glasgow)

Description

The magnetized iron calorimeter (ICAL) at the India-based neutrino observatory (INO) aims at distinguishing the neutrino mass hierarchy as well as determining the atmospheric neutrino parameters with a fine precision. The ICAL can detect muons with good reconstruction efficiency and momentum ($E_\mu$, $\cos \theta_\mu$) resolution. It is also capable of measuring the hadron energy $E'_{had} = E_\nu - E_\mu$, by calibrating the hadron shower hits. For a given neutrino event, the correlation between $E'_{had}$ and $E_\mu$ is an important property, which may be used for improving the oscillation parameter estimation. We take care of this correlation by bining the events in the three observables ($E_\mu$, $\cos \theta_\mu$, $E'_{had}$). A $\chi^2$ analysis is performed after incorporating the ICAL muon and hadron response, obtained from GEANT4 simulation. We find that, with an exposure of 500 kt - year, the ICAL can rule out the wrong hierarchy with a $\Delta \chi^2~\approx~9.5$, which marks an enhancement of about 40\% compared with the muon-only analysis. The inclusion of hadron information also improves the precision bounds on $|\Delta m^2_{32}|$, $\theta_{23}$ and its octant. We show that 10 years of ICAL exposure would be able to measure $\sin^2 \theta_{23}$ and $|\Delta m^2_{32}|$ to a relative 1$\sigma$ precision of 12\% and 2.9\% respectively.