Unparticle Physics with Jets

TL;DR

This paper demonstrates that, through effective field theory and resummation of Sudakov logarithms, the spectral densities of quark and gluon fields in QCD resemble those of unparticles, suggesting unparticles are less exotic than previously thought.

Contribution

The study shows that QCD spectral densities can mimic unparticle behavior, challenging the notion of unparticles as fundamentally exotic entities.

Findings

QCD spectral densities resemble unparticle spectral densities after resummation.

Hidden QCD-like sectors can produce unparticle-like signatures.

Unparticles may be less exotic than initially believed.

Abstract

Using methods of effective field theory, we show that after resummation of Sudakov logarithms the spectral densities of interacting quark and gluon fields in ordinary quantum field theories such as QCD are virtually indistinguishable from those of "unparticles" of a hypothetical conformal sector coupled to the Standard Model, recently studied by Georgi. Unparticles are therefore less exotic that originally thought. Models in which a hidden sector weakly coupled to the Standard Model contains a QCD-like theory, which confines at some scale much below the characteristic energy of a given process, can give rise to signatures closely resembling those from unparticles.