Global constraints on heavy neutrino mixing

By Enrique Fernandez-Martinez, J. Hernández-García, J. Lopez-Pavon. 2016

258 citations recorded by the source corpus.

A bstractWe derive general constraints on the mixing of heavy Seesaw neutrinos with the SM fields from a global fit to present flavour and electroweak precision data. We explore and compare both a completely general scenario, where the heavy neutrinos are integrated out without any further assumption, and the more constrained case were only 3 additional heavy states are considered. The latter assumption implies non-trivial correlations in order to reproduce the correct neutrino masses and mixings as observed by oscillation data and thus some qualitative differences can be found with the more general scenario. The relevant processes analyzed in the global fit include searches for Lepton Flavour Violating (LFV) decays, probes of the universality of weak interactions, CKM unitarity bounds and electroweak precision data. In particular, a comparative and detailed study of the present and future sensitivity of the different LFV experiments is performed. We find a mild 1-2σ preference for non-zero heavy neutrino mixing of order 0.03-0.04 in the electron and tau sectors. At the 2σ level we derive bounds on all mixings ranging from 0.1 to 0.01 with the notable exception of the e − μ sector with a more stringent bound of 0.005 from the μ → eγ process.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/468baf7295833e058630464d93c64812257a1a3e

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Nuclear and High Energy Physics

Citations in the corpus

Neutrino Oscillations and Non-standard Interactions (2017, background): “[193] also derives independent bound on κακ ∗ β |α6=β from lepton flavor violation (LFV) processes l− α → l− β γ, but these bounds are valid only for mΨ mW .”
Non-unitarity, sterile neutrinos, and non-standard neutrino interactions (2016, background): “Notice that, for the latter, some of the observables only apply above the electroweak scale [44].”
Deep Underground Neutrino Experiment (DUNE), Far Detector Technical Design Report, Volume II: DUNE Physics (2020, background): “order 10−3 stemming from flavor and electroweak precision observables are added [377, 382], the standard sensitivity is obtained.”
Neutrinoless double beta decay versus other probes of heavy sterile neutrinos (2019, background): “Any mixing between active and sterile neutrinos necessarily induces non-unitarity effects among the active neutrinos visible in CC and NC processes [134–136].”
Lepton Number Violation: Seesaw Models and Their Collider Tests (2017, background): “, [91]), then decays of Ni to on-shell EW bosons, as shown in Figure 16B, can occur with rates comparable to decays via off-shell W∗ R [87].”
Beyond the Standard Model Physics at the HL-LHC and HE-LHC (2018, background): “With 3 ab 1 and after taking into account global constraints on the active-heavy mixing [374] (dot-dashed line in Fig.”