CP violation in neutrino oscillations and new physics

Abstract

We consider future experiments to detect CP violation in neutrino oscillations and discuss how to test that all asymmetries are indeed described in terms of the single leptonic Jarlskog invariant as predicted in the absence of new physics effects.

LeptonicCPviolation

“…In particular, it has been shown that deviations from the standard picture of LCPV could be established with a modest precision, when considering the uncertainties on the A αβ asymmetries. This has been confirmed for a particular NF setup with detectors at L = 1500 km (Altarelli and Meloni, 2009) and E = 50 GeV.…”

“…At present, these phases are not bounded by the available neutrino oscillation and electroweak data. Although the MUV is a representative scenario of NU in the lepton sector, it has been shown that there is room for considerable new CPV effects even in such a limited framework (Altarelli and Meloni, 2009;Fernandez-Martinez et al, 2007).…”

“…The main question is then how much room do these possible deviations from unitarity leave for the observation of nonstandard CP violation in neutrino oscillations. In order to understand this, one has to write the transition probabilities P αβ and CP asymmetries A αβ ≡ (P αβ − P αβ )/(P αβ +P αβ ) in the MUV framework (Altarelli and Meloni, 2009;Fernandez-Martinez et al, 2007;Goswami and Ota, 2008), which will receive new contributions from η αβ ≡ η αβ e iθ αβ , where θ αβ are the new CP-violating phases.…”

“…On the other hand, the transition probabilities and their corresponding asymmetries for the remaining oscillation channels may be considerably affected by new physics effects. For instance, for µτ oscillations (Altarelli and Meloni, 2009;Fernandez-Martinez et al, 2007) (3.66) where A SM µτ is the CP asymmetry in the standard unitary scenario, which is typically O(10 −3 ), while the new contribution proportional to η τ µ can be as large as ∼ 10 −1 . In Fig.…”

“…Moreover, one should also take into account the experimental accuracy in the determination of the asymmetries, and the impact of the degeneracies discussed in Sec. III.B.3, which can make the task of testing the standard LCPV framework more difficult (Altarelli and Meloni, 2009;Fernandez-Martinez et al, 2007;Goswami and Ota, 2008). In particular, it has been shown that deviations from the standard picture of LCPV could be established with a modest precision, when considering the uncertainties on the A αβ asymmetries.…”