Unparticle Physics

TL;DR

It is found that in the appropriate low-energy limit, unparticle stuff with scale dimension dU looks like a nonintegral number dU of invisible particles, so dramatic evidence for a nontrivial scale invariant sector could show up experimentally in missing energy distributions.

Abstract

I discuss some simple aspects of the low-energy physics of a nontrivial scale invariant sector of an effective field theory -- physics that cannot be described in terms of particles. I argue that it is important to take seriously the possibility that the unparticle stuff described by such a theory might actually exist in our world. I suggest a scenario in which some details of the production of unparticle stuff can be calculated. I find that in the appropriate low energy limit, unparticle stuff with scale dimension $d_{\mathcal{U}}$ looks like a non-integral number $d_{\mathcal{U}}$ of invisible particles. Thus dramatic evidence for a nontrivial scale invariant sector could show up experimentally in missing energy distributions.

Figures (1)

• Figure 1: $d\ln\Gamma/dE_u$ versus $E_u$ in units of $m_t$ with $d_{\mathcal{U}}=j/3$ for $j=4$ to $9$. The dashes get longer as $j$ increases.