Revisiting lepton flavor violation in supersymmetric type II seesaw

TL;DR

This paper re-examines lepton flavor violation predictions in supersymmetric type II seesaw models, emphasizing the impact of recent neutrino mixing angle measurements and experimental limits on decay processes.

Contribution

It provides updated correlations between lepton flavor violating decay rates considering recent data and explores how non-universal soft masses can relax experimental constraints.

Findings

Correlation between BR(μ→eγ) and BR(τ→μγ) can be precisely determined after θ13 measurement.

Current MEG limits strongly constrain the sparticle spectrum in minimal models.

Non-universal triplet scalar masses allow lighter sparticles consistent with experimental bounds.

Abstract

In view of the recent measurement of reactor mixing angle $\theta_{13}$ and updated limit on $BR(\mu \to e \gamma)$ by the MEG experiment, we re-examine the charged lepton flavor violations in a framework of supersymmetric type II seesaw mechanism. Supersymmetric type II seesaw predicts strong correlation between $BR(\mu \to e \gamma)$ and $BR(\tau \to \mu \gamma)$ mainly in terms of the neutrino mixing angles. We show that such a correlation can be determined accurately after the measurement of $\theta_{13}$. We compute different factors which can affect this correlation and show that the mSUGRA-like scenarios, in which slepton masses are taken to be universal at the high scale, predicts $3.5 \lesssim BR(\tau \to \mu \gamma)/BR(\mu \to e \gamma) \lesssim 30$ for normal hierarchical neutrino masses. Any experimental indication of deviation from this prediction would rule out the minimal models of supersymmetric type II seesaw. We show that the current MEG limit puts severe constraints on the light sparticle spectrum in mSUGRA model if the seesaw scale lies within $10^{13}$-$10^{15}$ GeV. It is shown that these constraints can be relaxed and relatively light sparticle spectrum can be obtained in a class of models in which the soft mass of triplet scalar is taken to be non-universal at the high scale.