text: 414,82,1394264179993808907,369569444,Takahiro TERADA (寺田 隆広),"Our new paper on ""Massless Preheating and Electroweak Vacuum Metastability"" <LINK> Precise measurements of Standard Model parameters suggest that the electroweak vacuum is metastable. We need to ensure the (meta)stability throughout cosmological history. Quantum fluctuations of the Higgs field during cosmic inflation and parametric/tachyonic instability after that might destabilize the electroweak vacuum. We can stabilize the Higgs by introducing an effective mass term in the form of Higgs-inflaton and/or gravitational couplings. However, the stability during and after inflation is typically in a trade-off relation. It is important to study the condition that ensures stability throughout these epochs. <LINK> In our work, we focus on (quasi) scale-invariant models with quartic potentials and non-minimal gravitational couplings. (Why scale invariance? 1. It can explain the flatness of the inflaton potential consistently with observations. 2. It might explain the hierarchy problem.) <LINK> Naively, scale invariance implies unimpeded growth of resonance and hence unavoidable destabilization of the vacuum, which is a cosmological catastrophe. However, we find this is not the case taking into account the perturbative Higgs decay and backreaction of produced particles. <LINK> We find nontrivial and dynamical interplays between the effects of quartic and curvature couplings, which can partially cancel each other in some cases. We finally find disjoint ""islands of (meta)stability"" in the couplings parameter space. <LINK>",http://arxiv.org/abs/2105.06939,"Current measurements of Standard Model parameters suggest that the electroweak vacuum is metastable. This metastability has important cosmological implications, because large fluctuations in the Higgs field could trigger vacuum decay in the early universe. For the false vacuum to survive, interactions which stabilize the Higgs during inflation -- e.g., inflaton-Higgs interactions or non-minimal couplings to gravity -- are typically necessary. However, the post-inflationary preheating dynamics of these same interactions could also trigger vacuum decay, thereby recreating the problem we sought to avoid. This dynamics is often assumed catastrophic for models exhibiting scale invariance since these generically allow for unimpeded growth of fluctuations. In this paper, we examine the dynamics of such ""massless preheating"" scenarios and show that the competing threats to metastability can nonetheless be balanced to ensure viability. We find that fully accounting for both the backreaction from particle production and the effects of perturbative decays reveals a large number of disjoint ""islands of (meta)stability"" over the parameter space of couplings. Ultimately, the interplay among Higgs-stabilizing interactions plays a significant role, leading to a sequence of dynamical phases that effectively extend the metastable regions to large Higgs-curvature couplings. ",Massless Preheating and Electroweak Vacuum Metastability,6,"['Our new paper on ""Massless Preheating and Electroweak Vacuum Metastability"" <LINK>\nPrecise measurements of Standard Model parameters suggest that the electroweak vacuum is metastable. We need to ensure the (meta)stability throughout cosmological history.', 'Quantum fluctuations of the Higgs field during cosmic inflation and parametric/tachyonic instability after that might destabilize the electroweak vacuum. We can stabilize the Higgs by introducing an effective mass term in the form of Higgs-inflaton and/or gravitational couplings.', 'However, the stability during and after inflation is typically in a trade-off relation. It is important to study the condition that ensures stability throughout these epochs. https://t.co/yXRKN1rELr', 'In our work, we focus on (quasi) scale-invariant models with quartic potentials and non-minimal gravitational couplings.  (Why scale invariance?  1. It can explain the flatness of the inflaton potential consistently with observations.  2. It might explain the hierarchy problem.) https://t.co/PX66DX1WKU', 'Naively, scale invariance implies unimpeded growth of resonance and hence unavoidable destabilization of the vacuum, which is a cosmological catastrophe. However, we find this is not the case taking into account the perturbative Higgs decay and backreaction of produced particles. https://t.co/onEH7axRcP', 'We find nontrivial and dynamical interplays between the effects of quartic and curvature couplings, which can partially cancel each other in some cases. We finally find disjoint ""islands of (meta)stability"" in the couplings parameter space. https://t.co/7SnuXWK6NK']",21,05,1537