Supersymmetric mass spectra and the seesaw type-I scale

TL;DR

This paper investigates how supersymmetric mass spectra can reveal the presence of a type-I seesaw mechanism at high scales, using a combined LHC+ILC analysis to distinguish between models.

Contribution

It introduces a method to identify the seesaw scale through SUSY mass measurements, highlighting the importance of smuon and selectron mass splittings.

Findings

Large seesaw scales can produce detectable mass splittings.

Accurate measurements are crucial for distinguishing models.

Hints of the seesaw mechanism may appear for scales above 10^{14} GeV.

Abstract

We calculate supersymmetric mass spectra with cMSSM boundary conditions and a type-I seesaw mechanism added to explain current neutrino data. Using published, estimated errors on SUSY mass observables for a combined LHC+ILC analysis, we perform a theoretical $\chi^2$ analysis to identify parameter regions where pure cMSSM and cMSSM plus seesaw type-I might be distinguishable with LHC+ILC data. The most important observables are determined to be the (left) smuon and selectron masses and the splitting between them, respectively. Splitting in the (left) smuon and selectrons is tiny in most of cMSSM parameter space, but can be quite sizeable for large values of the seesaw scale, $m_{SS}$. Thus, for very roughly $m_{SS} \ge 10^{14}$ GeV hints for type-I seesaw might appear in SUSY mass measurements. Since our numerical results depend sensitively on forecasted error bars, we discuss in some detail the accuracies, which need to be achieved, before a realistic analysis searching for signs of type-I seesaw in SUSY spectra can be carried out.