A Novel Probe of Supersymmetry in Light of Nanohertz Gravitational Waves

Understand

A new era of exploring the early Universe may have begun with the recent strong evidence for the stochastic gravitational wave (GW) background from the data reported by NANOGrav, EPTA, PPTA, and CPTA.

• Inspired by this, we propose a new potential source of stochastic GWs in the minimal supersymmetric standard model (MSSM), which could be the theory at a very high energy scale.
• This source is the "axion" field in the Higgs multiplets when the Higgs field takes a large value along the D-flat direction in the early Universe, for example, during inflation.
• The axion motion triggers the instability of the standard model ${\rm U}(1)$ and/or ${\rm SU}(3)$ gauge fields, producing stochastic GWs during the inflation.