Radiative natural supersymmetry emergent from the string landscape

TL;DR

This paper proposes that in a multiverse framework, statistical and anthropic considerations naturally favor radiative natural supersymmetry models, aligning with current experimental data and predicting testable collider signatures.

Contribution

It introduces a multiverse-based statistical approach that favors radiative natural SUSY models over other SUSY scenarios, explaining the observed Higgs and superparticle masses.

Findings

Statistical selection favors large soft SUSY breaking terms.

Anthropic principle constrains the weak scale close to observed value.

Predicted spectra are testable at future colliders.

Abstract

In string theory with flux compactifications, anthropic selection for structure formation from a discretuum of vacuum energy values provides at present our only understanding of the tiny yet positive value of the cosmological constant. We apply similar reasoning to a toy model of the multiverse restricted to vacua with the MSSM as the low energy effective theory. Here, one expects a statistical selection favoring large soft SUSY breaking terms leading to a derived value of the weak scale in each pocket universe (with appropriate electroweak symmetry breaking) which differs from the weak scale as measured in our universe. In contrast, the SUSY preserving \mu parameter is selected uniformly on a log scale as is consistent with the distribution of SM fermion masses: this favors smaller values of \mu. An anthropic selection of the weak scale to within a factor of a few of our measured value -- in order to produce complex nuclei as we know them (atomic principle) -- provides statistical predictions for Higgs and sparticle masses in accord with LHC measurements. The statistical selection then more often leads to (radiatively-driven) {\it natural} SUSY models over the Standard Model or finely-tuned SUSY models such as mSUGRA/CMSSM, split, mini-split, spread, high scale or PeV SUSY. The predicted Higgs and superparticle spectra might be testable at HL-LHC via higgsino pair production but is certainly testable at higher energy hadron colliders with \sqrt{s}~ 30-100 TeV.