UTAPwiki/セミナー/初期宇宙・相対論速報
Speaker: Katsuki Aoki
Title: Gravitational positivity bounds
Abstract:
Underlying assumptions on ultraviolet completion can impose constraints on its low-energy effective field theories (EFTs). One of the most well-established constraints is called positivity bounds, provided that general assumptions such as Poincare invariance and unitarity are satisfied at all scales. However, it is not straightforward to include gravity in the positivity bounds due to several difficulties associated with the massless spin-2 nature of the graviton. First, I will explain these difficulties and discuss gravitational positivity bounds under technical assumptions. I will then show that the gravitational positivity bound is violated if the Standard Model of particle physics coupled to General Relativity is extrapolated up to $10^16$GeV, implying new physics there or below. If I have time, I will also discuss ideas to find further positivity constraints by considering particles with finite decay widths.
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