Reconstructing Seesaws

TL;DR

This paper investigates the theoretical possibility of reconstructing the heavy singlet sector in supersymmetric type I seesaw models, analyzing different singlet scenarios and their observable implications in lepton flavor violation processes.

Contribution

It demonstrates the potential to reconstruct and differentiate between various singlet configurations in seesaw models using idealized measurements and realistic flavor violation estimates.

Findings

Two-singlet case can be reconstructed with perfect data.

Different singlet scenarios produce distinct observable ratios.

Realistic estimates relate branching ratios in lepton flavor violation.

Abstract

We explore some aspects of "reconstructing" the heavy singlet sector of supersymmetric type I seesaw models, for two, three or four singlets. We work in the limit where one light neutrino is massless. In an ideal world, where selected coefficients of the TeV-scale effective Lagrangian could be measured with arbitrary accuracy, the two-singlet case can be reconstructed, two three or more singlets can be differentiated, and an inverse seesaw with four singlets can be reconstructed. In a more realistic world, we estimate $\ell_\a \to \ell_\b \gamma$ expectations with a "Minimal-Flavour-Violation-like" ansatz, which gives a relation between ratios of the three branching ratios. The two singlet model predicts a discrete set of ratios.