Global Study of Electron-Quark Unparticle Interactions

TL;DR

This paper conducts a comprehensive analysis of electron-quark interactions mediated by unparticles, considering their unique theoretical features and energy dependence, using diverse high-energy experimental data to constrain unparticle parameters.

Contribution

It provides the first global fit of spin-1 unparticle effects across multiple high-energy experiments, incorporating non-trivial phase factors and energy scaling in the analysis.

Findings

Hadronic data at LEPII shows a 3-4 sigma preference for new physics.

No overall preference for unparticle effects when all data are combined.

Established improved 95% CL limits on the unparticle energy scale .

Abstract

We perform a global fit on parity-conserving electron-quark interactions via spin-1 unparticle exchange. Besides the peculiar features of unparticle exchange due to non-integral values for the scaling dimension d_U and a non-trivial phase factor exp (-id_U \pi) associated with a time-like unparticle propagator, the energy dependence s^{-2 + d_U} of the unparticle contributions in the scattering amplitudes are also taken into account. The high energy data sets taken into consideration in our analysis are from (1) deep inelastic scattering at high Q^2 from ZEUS and H1, (2) Drell-Yan production at Run II of CDF and DO, and (3) e^+e^- --> hadrons at LEPII. The hadronic data at LEPII by itself indicated a 3-4 sigma preference of new physics over the Standard Model. However, when all data sets are combined, no preference for unparticle effects can be given. We thus deduce an improved 95% confidence level limit on the unparticle energy scale \Lambda_\U.