On the measurement of leptonic CP violation

Abstract

We show that the simultaneous determination of the leptonic CP-odd phase $\delta$ and the angle $\theta_{13}$ from the subleading transitions $\nu_e\to\nu_\mu$ and ${\bar\nu}_e\to{\bar\nu}_\mu$ results generically, at fixed neutrino energy and baseline, in two degenerate solutions. In light of this, we refine a previous analysis of the sensitivity to leptonic CP violation at a neutrino factory, in the LMA-MSW scenario, by exploring the full range of $\delta$ and $\theta_{13}$. Furthermore, we take into account the expected uncertainties on the solar and atmospheric oscillation parameters and in the average Earth matter density along the neutrino path. An intermediate baseline of O(3000) km is still the best option to tackle CP violation, although a combination of two baselines turns out to be very important in resolving degeneracies.Comment: 19 pages, 14 figures, uses epsfi

Systematic exploration of the neutrino factory parameter space including errors and correlations

“…This method was for example used in [29]. It is, however, important to keep in mind that such an approach relies on the validity of the linear approximation of the functional dependence of x i on λ.…”

“…In connection with measurements of δ CP it has been recognized that the correlation of the CP phase δ CP with the mixing angle θ 13 could possibly hide the effect of CP violation [29]. The implications of this correlation on the expected precision of measurements of of θ 13 have not been discussed.…”

Interim Design Report

“…For a more detailed discussion of these possible optimisation strategies see reference [100]. The optimisation of the Neutrino Factory has been studied in great detail, for instance, in references [101][102][103][104][105][106][107][108][109][110]. Here we will give a brief summary of the considerations which led to the IDS-NF baseline setup.…”

Resolving the octant degeneracy by neutrino oscillation experiments

“…There are 3 types of such degeneracy, octant [6], intrinsic [7] and sign ∆m 2 [8] degeneracy. Here we focus only on the octant degeneracy, which is decoupled from the other ones with a good approximation in our experimental set up.…”