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SUMMARY:Andreas Mantziris (Imperial College)
DTSTART:20210513T133000Z
DTEND:20210513T143000Z
DTSTAMP:20260423T035930Z
UID:CENTRA/42
DESCRIPTION:Title: <a href="https://researchseminars.org/talk/CENTRA/42/">
 Cosmological implications of electroweak vacuum instability: constraints o
 n the Higgs curvature coupling from inflation</a>\nby Andreas Mantziris (I
 mperial College) as part of CENTRA Seminar\n\n\nAbstract\nSpeaker: Andreas
  Mantziris (Imperial College)\n\nTitle: Cosmological implications of elect
 roweak vacuum instability: constraints on the Higgs curvature coupling fro
 m inflation \n\nAbstract: \nThe current experimentally measured parameters
  of the Standard Model (SM) suggest that our universe lies in a metastable
  electroweak vacuum\, where the Higgs field could decay to a lower vacuum 
 state with catastrophic consequences. Our measurements dictate that such a
 n event has not happened yet\, despite the many different mechanisms that 
 could have triggered it during our past light-cone. Via this observation\,
  we can establish a promising link between cosmology and particle physics 
 and thus constrain important parameters of our theories. The focus of our 
 work has been to explore this possibility by calculating the probability o
 f the false vacuum to decay during the period of inflation and using it to
  constrain the last unknown renormalisable SM parameter $\\xi$\, which cou
 ples the Higgs field with space-time curvature. In our latest study\, we d
 erived lower bounds for the Higgs-curvature coupling from vacuum stability
  in three inflationary models: quadratic and quartic chaotic inflation\, a
 nd Starobinsky-like power-law inflation. In contrast to most previous stud
 ies\, we took the time-dependence of the Hubble rate into account both in 
 the geometry of our past light-cone and in the Higgs effective potential\,
  which is approximated with three-loop renormalisation group improvement s
 upplemented with one-loop curvature corrections. We find that in all three
  models\, the lower bound is $\\xi \\gtrsim 0.051 ... 0.066$ depending on 
 the top quark mass. We also demonstrated that vacuum decay is most likely 
 to happen a few e-foldings before the end of inflation. \n\nRoom: ZOOM vid
 eoconference (contact justin.feng@tecnico.ulisboa.pt for URL)\n
LOCATION:https://researchseminars.org/talk/CENTRA/42/
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