Thermodynamics of a Two-Step Electroweak Phase Transition.

New field content beyond that of the standard model of particle physics can alter the thermal history of electroweak symmetry breaking in the early Universe. In particular, the symmetry breaking may have occurred through a sequence of successive phase transitions. We study the thermodynamics of such a scenario in a real triplet extension of the standard model, using nonperturbative lattice simulations. Two-step electroweak phase transition is found to occur in a narrow region of allowed parameter space with the second transition always being first order. The first transition into the phase of nonvanishing triplet vacuum expectation value is first order in a non-negligible portion of the two-step parameter space. A comparison with two-loop perturbative calculation is provided and significant discrepancies with the nonperturbative results are identified.

Nonperturbative Analysis of the Electroweak Phase Transition in the Two Higgs Doublet Model.

We perform a nonperturbative study of the electroweak phase transition (EWPT) in the two Higgs doublet model (2HDM) by deriving a dimensionally reduced high-temperature effective theory for the model, and matching to known results for the phase diagram of the effective theory. We find regions of the parameter space where the theory exhibits a first-order phase transition. In particular, our findings are consistent with previous perturbative results suggesting that the primary signature of a first-order EWPT in the 2HDM is m_{A_{0}}>m_{H_{0}}+m_{Z}.

Childhood predictors of future psychiatric morbidity in offspring of mothers with psychotic disorder: results from the Helsinki High-Risk Study.

BACKGROUND: The Helsinki High-Risk Study monitors women treated for schizophrenia-spectrum disorders in Helsinki mental hospitals before 1975, their offspring, and controls. AIMS: To compare the development of high-risk and control group children, and investigate which factors predicted future psychiatric disorders. METHOD: We examined information from childhood and school health record cards of 159 high-risk and 99 control group offspring. Logistic regression was used to assess whether developmental abnormalities predicted later mental disorders. RESULTS: Compared with controls, children in the high-risk group had more emotional symptoms before school age, attentional problems and social inhibition at school age, and neurological soft signs throughout. In this group pre-school social adjustment problems (OR=9.7, 95% CI 1.8-51.8) or severe neurological symptoms (Fisher's test, P=0.006) predicted future schizophrenia-spectrum disorder. Social adjustment problems and emotional symptoms during school age predicted future non-psychotic psychiatric disorders. CONCLUSIONS: Our study supports the validity of neurological, emotional, social and behavioural markers as vulnerability indicators of psychotic and other mental disorders, particularly among children genetically at high risk of psychosis.