Mass Hierarchy Determination for $\theta_{13}=0$ and Atmospheric Neutrinos

Understand

We examine the possibility of determining the neutrino mass hierarchy in the limit \theta_{13} = 0 using atmospheric neutrinos as the source.

• In this limit, in which \theta_{13} driven matter effects are absent, independent measurements of \Delta_{31} and \Delta_{32} can, in principle, lead to hierarchy determination.
• Since the difference between these two is \Delta_{21}, one needs an experimental arrangement where \Delta_{21} L/E \gtrsim 1 can be achieved.
• This condition can be satisfied by atmospheric neutrinos since they have a large range of energies and baselines.