Production of a sterile species: Quantum kinetics
Abstract
Production of a sterile species is studied within an effective model of activesterile neutrino mixing in a medium in thermal equilibrium. The quantum kinetic equations for the distribution functions and coherences are obtained from two independent methods: the effective action and the quantum master equation. The decoherence time scale for activesterile oscillations is tau(dec)=2/Gamma(aa), but the evolution of the distribution functions is determined by the two different time scales associated with the damping rates of the quasiparticle modes in the medium: Gamma(1)=Gamma(aa)cos^2theta(m); Gamma(2)=Gamma(aa)sin^2theta(m) where Gamma(aa) is the interaction rate of the active species in the absence of mixing and theta(m) the mixing angle in the medium. These two time scales are widely different away from MikheyevSmirnovWolfenstein resonances and preclude the kinetic description of activesterile production in terms of a simple rate equation. We give the complete set of quantum kinetic equations for the active and sterile populations and coherences and discuss in detail the various approximations. A generalization of the activesterile transition probability in a medium is provided via the quantum master equation. We derive explicitly the usual quantum kinetic equations in terms of the"polarization vector" and show their equivalence to those obtained from the quantum master equation and effectivemore »
 Authors:
 Publication Date:
 Research Org.:
 Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
 Sponsoring Org.:
 Physics Division
 OSTI Identifier:
 934482
 Report Number(s):
 LBNL395E
TRN: US0803801
 DOE Contract Number:
 DEAC0205CH11231
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Physical Review D; Journal Volume: 76; Related Information: Journal Publication Date: 16 October 2007
 Country of Publication:
 United States
 Language:
 English
 Subject:
 72; APPROXIMATIONS; DAMPING; DISTRIBUTION FUNCTIONS; KINETIC EQUATIONS; KINETICS; NEUTRINOS; OSCILLATIONS; POLARIZATION; PROBABILITY; PRODUCTION; THERMAL EQUILIBRIUM
Citation Formats
Ho, Chiu Man, Boyanovsky, D., and Ho, C.M.. Production of a sterile species: Quantum kinetics. United States: N. p., 2007.
Web.
Ho, Chiu Man, Boyanovsky, D., & Ho, C.M.. Production of a sterile species: Quantum kinetics. United States.
Ho, Chiu Man, Boyanovsky, D., and Ho, C.M.. Mon .
"Production of a sterile species: Quantum kinetics". United States.
doi:. https://www.osti.gov/servlets/purl/934482.
@article{osti_934482,
title = {Production of a sterile species: Quantum kinetics},
author = {Ho, Chiu Man and Boyanovsky, D. and Ho, C.M.},
abstractNote = {Production of a sterile species is studied within an effective model of activesterile neutrino mixing in a medium in thermal equilibrium. The quantum kinetic equations for the distribution functions and coherences are obtained from two independent methods: the effective action and the quantum master equation. The decoherence time scale for activesterile oscillations is tau(dec)=2/Gamma(aa), but the evolution of the distribution functions is determined by the two different time scales associated with the damping rates of the quasiparticle modes in the medium: Gamma(1)=Gamma(aa)cos^2theta(m); Gamma(2)=Gamma(aa)sin^2theta(m) where Gamma(aa) is the interaction rate of the active species in the absence of mixing and theta(m) the mixing angle in the medium. These two time scales are widely different away from MikheyevSmirnovWolfenstein resonances and preclude the kinetic description of activesterile production in terms of a simple rate equation. We give the complete set of quantum kinetic equations for the active and sterile populations and coherences and discuss in detail the various approximations. A generalization of the activesterile transition probability in a medium is provided via the quantum master equation. We derive explicitly the usual quantum kinetic equations in terms of the"polarization vector" and show their equivalence to those obtained from the quantum master equation and effective action.},
doi = {},
journal = {Physical Review D},
number = ,
volume = 76,
place = {United States},
year = {Mon Apr 23 00:00:00 EDT 2007},
month = {Mon Apr 23 00:00:00 EDT 2007}
}

Production of a sterile species is studied within an effective model of activesterile neutrino mixing in a medium in thermal equilibrium. The quantum kinetic equations for the distribution functions and coherences are obtained from two independent methods: the effective action and the quantum master equation. The decoherence time scale for activesterile oscillations is {tau}{sub dec}=2/{gamma}{sub aa}, but the evolution of the distribution functions is determined by the two different time scales associated with the damping rates of the quasiparticle modes in the medium: {gamma}{sub 1}={gamma}{sub aa}cos{sup 2}{theta}{sub m}; {gamma}{sub 2}={gamma}{sub aa}sin{sup 2}{theta}{sub m} where {gamma}{sub aa} is the interaction ratemore »

Production of a sterile species via activesterile mixing: An exactly solvable model
The production of a sterile species via activesterile mixing in a thermal medium is studied in an exactly solvable model. The exact time evolution of the sterile distribution function is determined by the dispersion relations and damping rates {gamma}{sub 1,2} for the quasiparticle modes. These depend on {gamma}tilde={gamma}{sub aa}/2{delta}E, with {gamma}{sub aa} the interaction rate of the active species in absence of mixing and {delta}E the oscillation frequency in the medium without damping. {gamma}tilde <<1, {gamma}tilde >>1 describe the weak and strong damping limits, respectively. For {gamma}tilde <<1, {gamma}{sub 1}={gamma}{sub aa}cos{sup 2}{theta}{sub m}; {gamma}{sub 2}={gamma}{sub aa}sin{sup 2}{theta}{sub m} where {theta}{submore » 
Radiative neutrino mass matrix for three active plus one sterile species
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