Is the magnitude of the Peccei-Quinn scale set by the landscape?

Understand

Rather general considerations of the string theory landscape imply a mild statistical draw towards large soft SUSY breaking terms tempered by the requirement of proper electroweak symmetry breaking where SUSY contributions to the weak scale are not too far from m(weak)~ 100 GeV.

• Such a picture leads to the prediction that m_h~ 125 GeV while most sparticles are beyond current LHC reach.
• Here we explore the possibility that the magnitude of the Peccei-Quinn (PQ) scale f_a is also set by string landscape considerations within the framework of a compelling SUSY axion model.
• First, we examine the case where the PQ symmetry arises as an accidental approximate global symmetry from a more fundamental gravity-safe Z(24)^R symmetry and where the SUSY mu parameter arises from a Kim-Nilles operator.