HIP NEWS June 9th 2014
DEPARTMENT OF PHYSICS / HIP JOINT COLLOQUIA / SEMINARS
Monday 9 June 2014 at 14.15 in A315
Ioan Ghisoiu (Bern)
Three-loop Debye mass and effective coupling in thermal QCD
Abstract: QCD at finite temperature is afflicted with infrared divergences that can be cured in part in the framework of a dimensionally reduced effective theory, Electrostatic QCD. We determine the three-loop effective parameters of this theory as matching coefficients to full QCD.
Tuesday 10 June 2014 at 10.15 in A315
Aleksi Kurkela (CERN)
Bottom-up thermalization in heavy-ion collisions
Abstract: It is a commonly held belief that weak coupling dynamics are in contradiction with the apparently fast thermalization observed in heavy-ion collisions at RHIC and at the LHC. This belief is based on solely parametric estimates and naturalness arguments in the “Bottom-up?? picture of thermalization of Baier, Mueller, Schiff, and Son. In my talk, I will discuss elevating this parametric picture into a numerical one through simulations in an effective kinetic theory. I discus how the numerical factors play an important role and show that the Bottom-Up scenario results in rapid thermalization at realistic couplings.
Wednesday 11 June 2014 at 14:15 in A315
Matti Herranen (NBI,Copenhagen)
Nonequilibrium QFT approach to leptogenesis
The observed baryon asymmetry of the Universe may have been produced dynamically in the very early Universe by a baryogenesis process. Baryogenesis via leptogenesis is among the most prominent candidates for a successfull baryogenesis scenario. For reliable calculations of the baryon asymmetry first principle methods of nonequilibrium quantum field theory are required. We construct a transport theory of leptogenesis based on the Schwinger-Keldysh or Closed Time Path (CTP) formalism of nonequilibrium QFT. The resulting kinetic equations incorporate finite density medium effects and quantum coherence effects and therefore provide a generalization to standard (quantum) Boltzmann equations. We find that the finite density corrections from loop integrals typically lead to an enhancement of the asymmetry. In the resonant regime with nearly degenerate right-handed neutrino masses, our results confirm the general structure of the resonant enhancement of CP-violation, however, novel terms related to flavour oscillations can be important in the dynamics.
I. Ghisoiu 7.6. – 11.6. (AV)
M. Herranen 9.6. – 11.6. (SR)
M. Hindmarsh 22.4. – 15.6. (KR)
A. Kurkela 9.6. – 12.6. (KR)
R. Malik 12.6. – 18.6. (AT)