Flavored quantum Boltzmann equations
We derive from first principles, using nonequilibrium field theory, the quantum Boltzmann equations that describe the dynamics of flavor oscillations, collisions, and a time-dependent mass matrix in the early universe. Working to leading nontrivial order in ratios of relevant time scales, we study in detail a toy model for weak-scale baryogenesis: two scalar species that mix through a slowly varying time-dependent and CP-violating mass matrix, and interact with a thermal bath. This model clearly illustrates how the CP asymmetry arises through coherent flavor oscillations in a nontrivial background. We solve the Boltzmann equations numerically for the density matrices, investigating the impact of collisions in various regimes.
Additional Information© 2010 The American Physical Society. Received 15 February 2010; published 4 May 2010. We acknowledge useful discussions at various stages of this project with Alex Friedland, Bjorn Garbrecht, Boris Kayser, Thomas Konstandin, Emil Mottola, and Petr Vogel. The work of V. C. is supported by the Nuclear Physics Office of the U.S. Department of Energy under Contract No. DE-AC52-06NA25396 and by the LDRD program at Los Alamos National Laboratory. C. L. was supported in part by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231, and in part by the National Science Foundation under Grant No. PHY- 0457315. M. J. R.M and S. T. were supported in part by the U.S. Department of Energy Contract No. DE-FG02- 08ER41531 and by the Wisconsin Alumni Research Foundation. S. T. is kindly supported by the Natural Sciences and Engineering Research Council of Canada. For hospitality during significant portions of this work, we collectively thank the particle and nuclear theory groups at the Berkeley Center for Theoretical Physics and Lawrence Berkeley National Laboratory, the Institute for Nuclear Theory at the University of Washington, the University of Wisconsin–Madison, the California Institute of Technology, and Los Alamos National Laboratory.
Published - Cirigliano2010p10417Phys_Rev_D.pdf