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Published online: 7 May 2008 | doi:10.1038/nchina.2008.104

Meson mixing: Unparticles unravelled

Tim Reid

Introduction

© (2008) CERN

High-energy particle accelerators such as the Large Hadron Collider opening at CERN this year could provide evidence for some cutting-edge theories. Xueqian Li and Zhengtao Wei at Nankai University in Tianjin¹ have predicted that particles called D mesons are ideal for testing the new idea of unparticles.

Unparticle physics states that matter cannot be explained in terms of particles because it requires components that are scale invariant — objects or laws that do not change if their length or energy are scaled up or down by a common factor. Usually scale invariance is broken because quantum theories place limits on the space–time continuum, but at very high energies scale invariance is recovered.

The researchers predicted the mixing interactions of B mesons and D mesons with their own antiparticles. They found that B-meson mixing was almost fully explained by the Standard Model, but D-meson mixing required large contributions from the new unparticle physics. In particular, the exchange of unparticles induces a 'flavour' change in D-meson quarks.

If new experiments observe D-meson mixing, they may prove the need for unparticle theory. Furthermore, the new physics could be improved to explain any measured data that is beyond the scope of the Standard Model.

The authors of this work are from:
Department of Physics, Nankai University, Tianjin, China.

Reference

1. Li, X. Q. & Wei, Z. T. Unparticle physics effects on D⁰-D⁰ mixing. Phys. Lett. B 651, 380–383 (2007). | Article | ChemPort |