Physics – High Energy Physics – High Energy Physics - Phenomenology
Scientific paper
2005-08-29
Phys.Rev. D72 (2005) 085016
Physics
High Energy Physics
High Energy Physics - Phenomenology
31 pages 2 figures. Version to appear in Phys. Rev. D
Scientific paper
10.1103/PhysRevD.72.085016
Neutrino oscillations in the early Universe prior to the epoch of primordial nucleosynthesis is studied by implementing real time non-equilibrium field theory methods. We focus on two flavors of Dirac neutrinos, however, the formulation is general. We obtain the equations of motion for neutrino wavepackets of either chirality and helicity in the plasma allowing for CP asymmetry. Contributions non-local in space-time to the self-energy dominate over the asymmetry for $T \gtrsim 3-5 \mathrm{MeV}$ if the lepton and neutrino asymmetries are of the same order as the baryon asymmetry. We find a new contribution which cannot be interpreted as the usual effective potential. The mixing angles and dispersion relations in the medium depend on \emph{helicity}. We find that resonant transitions are possible in the temperature range $ 10 \lesssim T \ll 100 \mathrm{MeV} $. Near a resonance in the mixing angle, the oscillation time scale in the medium as compared to the vacuum is \emph{slowed-down} substantially for small vacuum mixing angle. The time scale of oscillations \emph{speeds-up} for off resonance high energy neutrinos for which the mixing angle becomes vanishingly small. The equations of motion reduce to the familiar oscillation formulae for negative helicity ultrarelativistic neutrinos, but include consistently both the \emph{mixing angle and the oscillation frequencies in the medium}. These equations of motion also allow to study the dynamics of right handed as well as positive helicity neutrinos.
Boyanovsky Daniel
de Vega Hector J.
Ho Chang-Ming
No associations
LandOfFree
Neutrino Oscillations in the Early Universe: A Real Time Formulation does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Neutrino Oscillations in the Early Universe: A Real Time Formulation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Neutrino Oscillations in the Early Universe: A Real Time Formulation will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-405003