Does zero temperature decide on the nature of the electroweak phase transition?

Taking on a new perspective of the electroweak phase transition, we investigate in detail the role played by the depth of the electroweak minimum (“vacuum energy difference”). we find a strong correlation between the vacuum energy difference and the strength of the phase transition. this correlation only breaks down if a negative eigen-value develops upon thermal corrections in the squared scalar mass matrix in the broken vacuum before the critical temperature. as a result the scalar fields slide across field space toward the symmetric vacuum, often causing a significantly weakened phase transition. phenomenological constraints are found to strongly disfavour such sliding scalar scenarios. for several popular models, we suggest numerical bounds that guarantee a strong first order electroweak phase transition. the zero temperature phenomenology can then be studied in these parameter regions without the need for any finite temperature calculations. for almost all non-supersymmetric models with phenomenologically viable parameter points, we find a strong phase transition is guaranteed if the vacuum energy difference is greater than −8.8 × 107 gev4. for the gnmssm, we guarantee a strong phase transition for phenomenologically viable parameter points if the vacuum energy difference is greater than −6.9×107 gev4. alternatively, we capture more of the parameter space exhibiting a strong phase transition if we impose a simultaneous bound on the vacuum energy difference and the singlet mass.