Note on the pseudo-Nambu-Goldstone Boson of Meta-stable SUSY Violation

TL;DR

This paper discusses a light pseudo-Nambu-Goldstone boson arising from meta-stable SUSY models, examining its experimental and astrophysical constraints, and implications for hidden sector gauge groups and symmetry breaking scales.

Contribution

It identifies the astrophysical constraints on the PNGB and explores their implications for the structure of meta-stable SUSY models and hidden sector gauge groups.

Findings

Current experiments do not constrain the PNGB decay rates.

Astrophysical data from red giants impose significant constraints.

Models with large hidden gauge groups are ruled out or require a high-scale symmetry breaking.

Abstract

Many models of meta-stable supersymmetry (SUSY) breaking lead to a very light scalar pseudo-Nambu Goldstone boson (PNGB), P, associated with spontaneous breakdown of a baryon number like symmetry in the hidden sector. Current particle physics data provide no useful constraints on the existence of P. For example, the predicted decay rates for both K --> pi + P, b--> s + P and Upsilon --> photon + P are many orders of magnitude below the present experimental bounds. We also consider astrophysical implications of the PNGB and find a significant constraint from its effect on the evolution of red giants. This constraint either rules out models with a hidden sector gauge group larger than SU(4), or requires a new intermediate scale, of order at most 10^{10} GeV, at which the hidden sector baryon number is explicitly broken.