"Fast neutrino-flavor swap in high-energy astrophysical environments"

Masamichi Zaizen and Hiroki Nagakura
arXiv:2311.13842

These animations show the time evolution of survival probability in a colliding neutrino beam model in Fig.1 and 2. They illustrate that neutrinos undergo a complete flavor swap \( P_{ee} = 0 \) after their colliding (creating ELN crossing) at the center of the domain. Also, the EXZS (ELN-XLN Zero Surface), where neutrinos stay at a flavor equipartition \( P_{ee} = 0.5 \), moves toward the positive \(z\)-direction in the case of \( \alpha \neq 1 \) with time.

Animation of Fig.1

Left: Flavor asymmetry \( \alpha = 1.0 \) Right: \( \alpha = 0.5 \)
Horizontal: Spatial domain Vertical: Survival probability
Red color corresponds to electron neutrinos going to the right direction, while blue corresponds to the anti-partners going to the left.

Animation of Fig.2

Left: Flavor asymmetry \( \alpha = 1.0 \) Right: \( \alpha = 0.5 \)
Top: Real space \( z \) Bottom: Spatial domain \( \lambda \) scaled by the interval between the leading parts of injected neutrinos
In the scaled domain, the location of EXZS is stationary. Note that after the leading parts escape the box, the visualization fails to capture the whole structures because the EXZS get out of the box.