Dressed propagators, fakeon self-energy and peak uncertainty - Zoom talk for HEPC, NICPB, Tallinn

Abstract: After reviewing the properties of purely virtual particles, I discuss their dressed propagators and compare them to the ones of physical particles and ghosts. The three geometric series differ by infinitely many contact terms, which do not admit well-defined sums. The peak region, which is outside the convergence domain, can only be reached in the case of physical particles, thanks to analyticity. In the other cases, nonperturbative effects become important. After introducing the energy resolution ΔE around the peak, I argue that a "peak uncertainty" ΔE≳ΔE_min≃Γ_f/2 around energies E≃m_f expresses the impossibility to approach the fakeon too closely, m_f being the fakeon mass and Γ_f being the fakeon width. The introduction of ΔE is also crucial to explain the observation of unstable long-lived particles, like the muon. Indeed, by the common energy-time uncertainty relation, such particles are also affected by ill-defined sums at ΔE=0, whenever we separate their observation from the observation of their decay products. I study the regime of large Γ_f, which applies to collider physics (and situations like the one of the Z boson), and the regime of small Γ_f, which applies to quantum gravity (and situations like the one of the muon).

Fisica Quantistica per tutti
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Il canale Youtube è sincronizzato con il canale Odysee: https://odysee.com/@QuantumGravity

Pagina Facebook: https://www.facebook.com/FisicaQuantisticaPerTutti

Libri miei:

1. Dalla fisica alla vita - Viaggio nell'infinitamente piccolo e ritorno
https://amzn.to/2V1UCCM (ebook)
https://amzn.to/3jE6ViV (cartaceo)

2. L'involuzione del pensiero scientifico - Come la civiltà perde conoscenza
https://amzn.to/37dZLdC (ebook)
https://amzn.to/3A3aeFr (cartaceo)

Testo universitario (avanzato):

3. Renormalization: https://amzn.to/3dAjwzV

Credits

Progressive Rock by Audionautix is licensed under a Creative Commons Attribution 4.0 license. https://creativecommons.org/licenses/by/4.0/
Artist: http://audionautix.com/