Constraints on Unparticle Interactions from Particle and Antiparticle Oscillations

Abstract

We study unparticle effects on particle and antiparticle osillations in meson-antimeson, and muonium-antimuonium systems. Unlike usual tree level contributions to meson oscillations from heavy particle exchange with small ${\Gamma }_{12}$, the unparticle may have sizeable contributions to both $M_{12}$ and ${\Gamma }_{12}$ due to fractional dimension $d_{\text{U}}$ of the unparticle. We find that very stringent constraints on the unparticle and particle interactions can be obtained. If unparticle effect dominates the contributions (which may happen in $D^0-{\bar{D}}^0$ mixing) to meson mixing parameters $x$ and $y$, we find that $x/y=\cot (\pi d_{\text{U}})$. Interesting constraints on unparticle and particle interactions can also be obtained using muonion and antimuonion oscillation data. We also comment on unparticle effects on CP violation in meson oscillations.

Comments: 14 pages, 4 figures