Journal Club

Seminar Room

If you want to propose a paper, you can contact Supratim Das Bakshi (sdb AT

Tuesday 16th of May, 2023

Title: Long live the continuum

Presented by: Manuel Pérez-Victoria

Abstract: Unstable particles decay sooner or later, so they are not described by asymptotic one-particle states and they should not be included as independent states in unitarity relations such as the optical theorem. The same applies to any countable collection of particles with common decay channels. However, I will show that the behaviour of unparticle stuff, that is, a continuous collection of particles with different masses, is pretty different: its decay rate decreases as time goes by and it has a finite probability of surviving for ever. The corresponding asymptotic states must be taken into account to comply with unitarity. I will also discuss compressed spectra and the transition from the discrete to the continuous case.