2026/04/20 by Damiano F. G. Fiorillo, Georg G. Raffelt
Physics and Astronomy · #hep-ph #astro-ph.CO #astro-ph.HE
Flavor instabilities develop in neutrino plasmas through the emission of flavomons, the quanta of flavor waves. Matter gradients can sweep flavomons across the unstable wave-number range, halting their amplification. This effect is parametrically small for fast modes, where it was first identified, but we show that it strongly alters neutrino-mass-induced instabilities below the supernova shock, while leaving those outside largely unaffected. The role of these instabilities can therefore be established only through a global treatment beyond local dispersion relations. Using the WKB approximation, we derive the covariant evolution equation for the flavomon amplitude along geometrical-optics rays, enabling a global treatment of instability growth and seeding.