Enhancing sensitivity to neutrino parameters at INO combining muon and hadron information

Abstract

The proposed ICAL experiment at INO aims to identify the neutrino mass hierarchy from observations of atmospheric neutrinos, and help improve the precision on the atmospheric neutrino mixing parameters. While the design of ICAL is primarily optimized to measure muon momentum, it is also capable of measuring the hadron energy in each event. Although the hadron energy is measured with relatively lower resolution, it nevertheless contains crucial information on the event, which may be extracted when taken concomitant with the muon data. We demonstrate that by adding the hadron energy information to the muon energy and muon direction in each event, the sensitivity of ICAL to the neutrino parameters can be improved significantly. Using the realistic detector response for ICAL, we present its enhanced reach for determining the neutrino mass hierarchy, the atmospheric mass squared difference and the mixing angle θ 23 , including its octant. In particular, we show that the analysis that uses hadron energy information can distinguish the normal and inverted mass hierarchies with ∆χ 2 ≈ 9 with 10 years exposure at the 50 kt ICAL, which corresponds to about 40% improvement over the muon-only analysis.

Neutrino physics with non-standard interactions at INO

“…ICAL is also expected to measure the energy deposited in the associated hadron shower. Inclusion of the hadron energy information improves the energy reconstruction of the events and hence in general improves the sensitivity of ICAL [8]. We have not included the hadron energy information in this work.…”

“…[5] and using both the muon energy and angle information as well as hadron energy information in ref. [8]. In this work, we only use the muon energy and angle information and quantify the change in the mass hierarchy sensitivity of ICAL in presence of NSI.…”

“…The sensitivity reach of this experiment for measuring standard neutrino oscillation parameters have been studied extensively in refs. [5][6][7][8][9].…”

India-based neutrino observatory (INO): Physics reach and status report

“…The inclusion of the hadron energy information results [14] in a 3σ hierarchy discrimination being obtainable with 10 years of ICAL exposure, as can be seen from Fig. 8.…”

“…11 with muon information only and with hadron information included [14]. T2K and NOνA have a much better sensitivity to this parameter [14] and it is unlikely that ICAL will have a significant impact on this measurement. CP phase: impact of ICAL ICAL input will also improve the measurement of δ CP itself.…”