2007/06/30 by Yi Liao, Ji-Yuan Liu · 10 citations
Physics and Astronomy · #Dark Matter and Cosmic Phenomena #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ex #hep-ph
paper · pdf · doi:10.1103/physrevlett.99.191804
published as Phys.Rev.Lett.99:191804,2007 · v1: 10 pages, no figure, 1 table; v2: Proofread version for PRL. Main changes: (1) Shortened considerably to meet the length limit by cutting some calculational details. (2) Introduction paragraphs hopefully improved. (3) Minor rewording in the text and title. There are no changes to numerical results and conclusions
arxiv created 2007/11/03 · openalex publication_date 2007/11/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Unparticles as suggested by Georgi are identities that are not constrained by dispersion relations but are governed by their scaling dimension d. Their coupling to particles can result in macroscopic interactions between matter that are generally an inverse nonintegral power of distance. This is totally different from known macroscopic forces. We use the precisely measured long-ranged spin-spin interaction of electrons to constrain unparticle couplings to the electron. For 1<d<1.5 the axial vector unparticle coupling is excluded, and for 1<d<1.3 the pseudoscalar and vector couplings are also ruled out. These bounds and the ones for other ranges of d exceed or are complementary to those obtained previously from exotic positronium decays.