Gravity safe, electroweak natural axionic solution to strong CP and SUSY mu problems

TL;DR

This paper proposes a string theory-inspired model with a discrete R-symmetry that naturally solves the strong CP problem and the SUSY mu problem while avoiding gravity-induced symmetry breaking issues.

Contribution

It introduces a gravity-safe, R-symmetry-based model where the PQ symmetry emerges accidentally, addressing key issues in SUSY and axion physics.

Findings

The model suppresses dangerous operators and proton decay.

It provides a natural solution to the strong CP problem.

The mu term is naturally at the weak scale.

Abstract

Particle physics models with Peccei-Quinn (PQ) symmetry breaking as a consequence of supersymmetry (SUSY) breaking are attractive in that they solve the strong CP problem with a SUSY DFSZ-like axion, link the SUSY breaking and PQ breaking intermediate mass scales and can resolve the SUSY mu problem with a naturalness-required weak scale mu term whilst soft SUSY breaking terms inhabit the multi-TeV regime as required by LHC sparticle mass limits and the Higgs mass measurement. On the negative ledger, models based on global symmetries suffer a generic gravity spoliation problem. We present a model based on the discrete R-symmetry Z_{24}^R-- which may emerge from compactification of 10-d Lorentzian spacetime in string theory-- where the mu term and dangerous proton decay and R-parity violating operators are either suppressed or forbidden while a gravity-safe PQ symmetry emerges as an accidental approximate global symmetry leading to a solution to the strong CP problem and a weak-scale/natural value for the mu term.