Neutrino quantum kinetics in three flavors

Shashank Shalgar; Irene Tamborra

Paper

Neutrino quantum kinetics in three flavors

Abstract

The impact of neutrino flavor conversion on the supernova mechanism is yet to be fully understood. We present multi-energy and multi-angle solutions of the neutrino quantum kinetic equations in three flavors, without employing any attenuation term for the neutrino self-interaction strength and taking into account neutrino advection and non-forward collisions with the background medium. Flavor evolution is explored within a spherically symmetric shell surrounding the region of neutrino decoupling in the interior of a core-collapse supernova, relying on the output of a spherically symmetric core-collapse supernova model with a progenitor mass of

. We select two representative post-bounce times:

s (no angular crossings are present and flavor conversion is triggered by slow collective effects) and

s (angular crossings trigger fast flavor instabilities). We find that flavor equipartition is achieved for the late post-bounce time (

s), where the (anti)neutrino emission properties among different flavors tend to approach each other. In this case,

tends to

and a similar trend holds for neutrinos. However, flavor equipartition does not occur for our early post-bounce time (

s). Accounting for weak-magnetism corrections, crossings in the

and

lepton number angular distributions arise; however, such crossings have a magnitude smaller than the one occurring in the electron sector and negligibly affect flavor evolution. Because of flavor conversion, the neutrino heating rate increases up to

with respect to the case where flavor conversion is neglected.