Thermal Unparticles: A New Form of Energy Density in the Universe

1. Thermal Unparticles: A New Form of Energy Density in the Universe Nankai University Hu xuepeng Shao-Long Chen (Taiwan, Natl. Taiwan U.) , Xiao-Gang He (Taiwan, Natl. Taiwan U. & Nankai U.) , Xue-Peng Hu, Yi Liao (Nankai U.) . arXiv:0710.5129 

2. 1. Original idea due to Georgi • Unparticle physics Phys.Rev.Lett.98:221601,2007 （hep-ph/0703260） • Another Odd Thing About Unparticle Physics • Phys.Lett.B650:275-278,2007 （0704.2457[hep-ph]）

3. The very high energy theory contains the fields of the standard model and the fields(Banks-Zaks fields) of a theory with a nontrivial IR fixed point.

4. The most important properties of unparticle • 1 Scale invar. -->the state density of unparticle • 2 the propagator of unparticle is

5. There has been a burst of activities since the seminal work of Georgi on various aspects of unparticle physics: • FCNC Effects – Precision B physics • collider effects – LHC era • precision QED tests – Any new idea must pass! • unitarity issue of gauge boson scattering • theoretical issues: interpretation of unparticles in terms of particles • cosmology and astrophysics • and so on

6. 2. The thermodynamics of unparticle • The thermodynamics of a gas of bosonic particles with mass μ is determined by the partition function: • where accounts for degrees offreedom like spin.

7. we can interpret ( 1 ) in terms of a continuous collection of particles with the help of a spectral function :

8. partition function for unparticles is

10. 3. unparticle in expanding universe

12. 3.1 minimal decoupling temperature

14. 3.2 deof nparticle vs.BBN

15. Thanks!