Updated fit to three neutrino mixing: status of leptonic CP violation

Abstract

We present a global analysis of solar, atmospheric, reactor and accelerator neutrino data in the framework of three-neutrino oscillations based on data available in summer 2014. We provide the allowed ranges of the six oscillation parameters and show that their determination is stable with respect to uncertainties related to reactor neutrino and solar neutrino flux predictions. We find that the maximal possible value of the Jarlskog invariant in the lepton sector is $0.0329 \pm 0.0009$ ($\pm 0.0027$) at the $1\sigma$ ($3\sigma$) level and we use leptonic unitarity triangles to illustrate the ability of global oscillation data to obtain information on CP violation. We discuss "tendencies and tensions" of the global fit related to the octant of $\theta_{23}$ as well as the CP violating phase $\delta_\mathrm{CP}$. The favored values of $\delta_\mathrm{CP}$ are around $3\pi/2$ while values around $\pi/2$ are disfavored at about $\Delta\chi^2 \simeq 6$. We comment on the non-trivial task to assign a confidence level to this $\Delta\chi^2$ value by performing a Monte Carlo study of T2K data.Comment: 28 pages, 10 figures, 1 table. Typos corrected. Updated results of the global fit will be available at http://www.nu-fit.org

Dark matter and lepton flavour violation in a hybrid neutrino mass model

“…However, future LFV searches will be able to probe the interesting region λ ≈ O(1) and δm 41 = (m N 4 − m N 1 )/m N 1 ≈ 0.01 − 0.1. Compared to the strong dependence Br(µ → eγ) ∝ δm 2 41 , the relic abundance is relatively weakly affected by δm 41 , with a suppression of the abundance for δm 41 0.1 due to enhanced co-annihilation. In addition, the current limit on Br(τ → µγ) cannot give a further constraint since from eq.…”

“…Roughly speaking, for TeV scale m φ and λ ∼ 1, the loop-induced transition Br(τ → µγ) is slightly below the current bound, while Br(µ → eγ) violates the current limit for ∆m 41 10 GeV.…”

“…We neglect small asymmetries in uncertainties and differences between the HN and IH cases as present in the recent global fits [40,41].…”

“…As mentioned above, . Therefore, the physical range for θ 41 ranges from 0 to π, which is the same as α 41 . In this work, we restrain ourselves on the region of θ 41 ∈ (0, π/2).…”

Linking leptonic CP violation to quark unitarity triangle

“…is given in terms of φ 2 (α) by using eq. (2.36): [44][45][46]. Now we predict δ PMNS in terms of the CP violating phase of the quarks by using eq.…”