Weak properties of the tau lepton via a spin-0 unparticle

TL;DR

This paper investigates how a spin-0 unparticle could significantly influence the weak and electromagnetic properties of the tau lepton, potentially exceeding standard model predictions within current experimental bounds.

Contribution

It introduces a calculation of unparticle effects on fermion properties, providing estimates for tau lepton properties considering recent experimental constraints.

Findings

Unparticle contributions to tau electromagnetic properties can surpass SM predictions.

Weak property contributions are larger than SM but below current experimental limits.

Potential implications for bottom and top quark properties are discussed.

Abstract

We consider a spin-0 unparticle and calculate its contribution to the weak properties of a fermion, which in the proper limit reduce to previously reported results for the electromagnetic properties. We then obtain an estimate for the electromagnetic and weak properties of the tau lepton. For the unparticle parameters, we consider the most recent bounds from the lepton flavor violating decay tau -> 3 mu, the muon anomalous magnetic moment, and the data for monojet production plus missing transverse energy at the LHC. In the most promising promising scenario, it is found that the unparticle contributions to the tau electromagnetic properties can be larger than the contributions predicted by the standard model (SM) and some of its extensions, such as the SeeSaw model and extensions of the minimal supersymmetric standard model (MSSM) with a mirror fourth generation and vectorlike multiplets. As for the contributions to the weak properties, they are larger than the SM contributions but are much smaller than the current experimental limits. We also discuss the case of the electromagnetic and weak properties of the bottom and top quarks.