D. Indumathi

Question of hierarchy: Matter effects with atmospheric neutrinos and antineutrinos

It is by now established that neutrinos mix, have (different) nonzero masses, and therefore oscillate. The oscillation parameters themselves, however, are not all well-known. An open problem is that of the neutrino mass hierarchy. We study the possibility of determining the neutrino mass hierarchy with atmospheric neutrinos using an iron calorimeter detector capable of charge identification such as the proposed monolith and ical/ino detectors. We find that such detectors are sensitive to the sign of the mass-squared difference, {delta}{sub 32}=m{sub 3}{sup 2}-m{sub 2}{sup 2}, provided the as-yet unknown mixing angle between the first and third generations, {theta}{sub 13}, is greater than 6 deg. (sin{sup 2}2{theta}{sub 13}>0.04). A result with a significance greater than 90% CL requires large exposures (more than 500 kton-years) as well as good energy and angular resolution of the detected muons (better than 15%), especially for small {theta}{sub 13}. Hence obtaining definitive results with such a detector is difficult, unless {theta}{sub 13} turns out to be large. In contrast, such detectors can establish a clear oscillation pattern in atmospheric neutrinos in about 150 kton-years, therefore determining the absolute value of {delta}{sub 32} and sin{sup 2}2{theta}{sub 23} to within 10%.

Hadron energy response of the Iron Calorimeter detector at the India-based Neutrino Observatory

The results of a Monte Carlo simulation study of the hadron energy response for the magnetized Iron CALorimeter detector, ICAL, proposed to be located at the India-based Neutrino Observatory (INO) is presented. Using a GEANT4 modeling of the detector ICAL, interactions of atmospheric neutrinos with target nuclei are simulated. The detector response to hadrons propagating through it is investigated using the hadron hit multiplicity in the active detector elements. The detector response to charged pions of fixed energy is studied first, followed by the average response to the hadrons produced in atmospheric neutrino interactions using events simulated with the NUANCE event generator. The shape of the hit distribution is observed to fit the Vavilov distribution, which reduces to a Gaussian at high energies. In terms of the parameters of this distribution, we present the hadron energy resolution as a function of hadron energy, and the calibration of hadron energy as a function of the hit multiplicity. The energy resolution for hadrons is found to be in the range 85% (for 1 GeV) – 36% (for 15 GeV).

Neutrino oscillation probabilities: Sensitivity to parameters

We study in detail the sensitivity of neutrino oscillation probabilities to the fundamental neutrino parameters and their possible determination through experiments. The first part of the paper is devoted to the broad theme of isolating regions in the neutrino (and antineutrino) energy and propagation length that are sensitive to the oscillation parameters. Such a study is relevant to neutrinos both from the Earths atmosphere or from a neutrino factory. For completeness we discuss the sensitivity, however small, to the parameters involved in a three-generation framework, and to the Earth matter density profile. We then study processes relevant to atmospheric neutrinos which are sensitive to and allow precision measurements of the mixing angle

Effect of tau neutrino contribution to muon signals at neutrino factories

{\ensuremath{\theta}}_{23}

India-based Neutrino Observatory (INO)

and mass-squared difference

Working Group Report: Quantum Chromodynamics

{\ensuremath{\delta}}_{32}

Neutrinos from stellar collapse: Effects of flavor mixing

apart from the mixing angle

Spin dependent gluon densities from largeP T photon and dimuon production

{\ensuremath{\theta}}_{13}

Simulation studies of hadron energy resolution as a function of iron plate thickness at INO-ICAL

. Crucial to this analysis is charge identification; detectors having this capability can isolate these matter effects. In particular, we address the issue of using matter effects to determine whether the mixing angle

J/

{\ensuremath{\theta}}_{23}