Phenomenology of future neutrino experiments with large Theta(13)

TL;DR

The paper discusses how the unexpectedly large neutrino mixing angle θ13 impacts future experiments, making mass hierarchy determination easier but complicating CP violation measurements, and emphasizes the need for new experimental strategies.

Contribution

It provides a phenomenological analysis of the implications of large θ13 for neutrino experiments, highlighting the challenges and opportunities in measuring CP violation and mass hierarchy.

Findings

Large θ13 simplifies neutrino mass hierarchy determination.

Large θ13 complicates the measurement of CP violation.

New experimental approaches are needed to reliably measure CP phase.

Abstract

The question "how small is the lepton mixing angle \theta_{13}?" had a convincing answer in a surprisingly short time, \theta_{13} \simeq 9^{\circ}, a large value comparable to the Chooz limit. It defines a new epoch in the program of determining the lepton mixing parameters, opening the door to search for lepton CP violation of the Kobayashi-Maskawa-type. I discuss influences of the large value of \theta_{13} to search for CP violation and determination of the neutrino mass hierarchy, the remaining unknowns in the standard three-flavor mixing scheme of neutrinos. I emphasize the following two points: (1) Large \theta_{13} makes determination of the mass hierarchy easier. It stimulates to invent new ideas and necessitates quantitative reexamination of practical ways to explore it. (2) However, large \theta_{13} does not quite make CP measurement easier so that we do need a "guaranteeing machine" to measure CP phase \delta.