2018/03/13 by Tobias Stirner, G. Sigl, Günter Sigl +2 · 33 citations
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Commutator #Flavor #Kinetic energy #Lie algebra #Mathematical physics #Neutrino #Neutrino Physics Research #Neutrino oscillation #Operator (biology) #Order (exchange) #Oscillation (cell signaling) #Particle physics #Particle physics theoretical and experimental studies #Physics #Quantum mechanics #astro-ph.HE #hep-ph
paper · pdf · doi:10.1088/1475-7516/2018/05/016
published in Journal of Cosmology and Astroparticle Physics 2018(05), 016 (Institute of Physics)
arxiv created 2018/03/13 · openalex publication_date 2018/05/04 · arxiv updated 2018/05/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Neutrino production, absorption, transport, and flavor evolution in astrophysical environments is described by a kinetic equation D ϱ=− i [ H ,ϱ]+𝒞[ϱ]. Its basic elements are generalized occupation numbers ϱ, matrices in flavor space, that depend on time t , space x , and momentum p . The commutator expression encodes flavor conversion in terms of a matrix H of oscillation frequencies, whereas 𝒞[ϱ] represents source and sink terms as well as collisions. The Liouville operator on the left hand side involves linear derivatives in t , x and p . The simplified expression D =∂ t + ⋅∂ x for ultra-relativistic neutrinos was recently questioned in that flavor-dependent velocities should appear instead of the unit vector . Moreover, a new damping term was postulated as a result. We here derive the full flavor-dependent velocity structure of the Liouville term although it appears to cause only higher-order corrections. Moreover, we argue that on the scale of the neutrino oscillation length, the kinetic equation can be seen as a first-order wave equation.