text: 273,48,1375439934623002625,1324428524,Rikard Enberg,"New paper today on cosmology in the very early universe, with my postdoc and previous PhD student. The paper is about the abrupt phase transition a few picoseconds after the big bang, where the Higgs field switched on and particles stopped being massless. <LINK> You can't have abrupt phase transitions in the Standard Model because the Higgs is too heavy. In theories beyond you can. We look at this in effective field theory and find that with heavy new physics at the TeV scale it can be possible given existing constraints on parameters Why do we want such an abrupt (also called strongly first-order) phase transition? Two reasons: Reason 1. Because then you might be able to explain why there aren't equal amounts of matter and antimatter in the universe. This is called electroweak baryogenesis and requires something very cool called sphalerons. Which you can't have if the transition is too weak. This article by @jonmbutterworth talks a bit about sphalerons. <LINK> Reason 2. Because an abrupt transition is like boiling – bubbles are formed that can make huge amounts of gravitational waves. Which then make up the stochastic gravitational wave background that the space-based GW observatory LISA will search for. @davidjamesweir has done some very cool simulations and movies of such bubbles <LINK> So it's experimentally testable, by an insanely cool experiment (@LISACommunity) that will have three spacecraft in a triangle with sides of 2.5 million km, orbiting the Sun in the same orbit as Earth, with a laser interferometer using of laser beams between these spacecraft. It's also testable by the high luminosity LHC, by looking for pair production of Higgs bosons. If our scenario in <LINK> is correct the cross section is modified in a specific way.",https://arxiv.org/abs/2103.14022,"A first-order Electroweak Phase Transition (EWPT) could explain the observed baryon-antibaryon asymmetry and its dynamics could yield a detectable gravitational wave signature, while the underlying physics would be within the reach of colliders. The Standard Model, however, predicts a crossover transition. We therefore study the EWPT in the Standard Model Effective Field Theory (SMEFT) including dimension-six operators. A first-order EWPT has previously been shown to be possible in the SMEFT. Phenomenology studies have focused on scenarios with a tree-level barrier between minima, which requires a negative Higgs quartic coupling and a new physics scale low enough to raise questions about the validity of the EFT approach. In this work we stress that a first-order EWPT is also possible when the barrier between minima is generated radiatively, the quartic coupling is positive, the scale of new physics is higher, and there is good agreement with experimental bounds. Our calculation is done in a consistent, gauge-invariant way, and we carefully analyze the scaling of parameters necessary to generate a barrier in the potential. We perform a global fit in the relevant parameter space and explicitly find the points with a first-order transition that agree with experimental data. We also briefly discuss the prospects for probing the allowed parameter space using di-Higgs production in colliders. ","A new perspective on the electroweak phase transition in the Standard