Gravitational waves from phase transition in a supersymmetric left-right model

A bstract We investigate the cosmological phase transition dynamics in a supersymmetric left-right symmetric model based on the gauge group SU(3) C × SU(2) L × SU(2) R × U(1) B−L that addresses the strong CP problem through extended parity symmetry and doublet-doublet splitting. We compute the finite temperature effective potential including one-loop Coleman-Weinberg corrections, thermal contributions, and daisy resummation to determine whether the SU(2) R × U(1) B − L → U(1) Y symmetry breaking transition can produce observable gravitational waves. For phenomenologically viable parameters satisfying current LHC constraints, we find that the phase transition is strongly first-order with nucleation temperature T n ~ 0.5 v R , transition strength parameter α ~ 0.01 – 0.3, and inverse duration β / H ~ 100. The resulting stochastic gravitational wave background peaks at frequencies f ~ 0.1 – 1 Hz with amplitude h 2 Ω GW ~ 10 −14 – 10 −12 . We find that there is a parameter region where the gravitational wave spectrum overlaps with DECIGO/BBO sensitivity curves, providing a potentially observable signature connecting the theoretical solution to the strong CP problem with gravitational wave experiments.