Eur. Phys. J. C (2011) 71: 1611
https://doi.org/10.1140/epjc/s10052-011-1611-8

Regular Article - Theoretical Physics

Global study of electron–quark unparticle interactions

¹ Department of Physics, National Tsing Hua University, Hsinchu, 300, Taiwan
² Division of Quantum Phases & Devices, School of Physics, Konkuk University, Seoul, 143-701, Korea
³ Physics Division, National Center for Theoretical Sciences, Hsinchu, 300, Taiwan
⁴ Institute of Physics, Academia Sinica, Nankang, Taipei, 11529, Taiwan

^* e-mail: cheung@phys.nthu.edu.tw

Received: 21 October 2010
Revised: 22 February 2011
Published online: 8 April 2011

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 and a non-trivial phase factor associated with a time-like unparticle propagator, the energy dependence 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 DØ, 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 .