1202.0953 (H. Minakata et al.)

Neutrino Velocity and Neutrino Oscillations    [PDF]

H. Minakata, A. Yu. Smirnov

We study distances of propagation and the group velocities of the muon
neutrinos in the presence of mixing and oscillations assuming that Lorentz
invariance holds. Oscillations lead to distortion of the $\nu_\mu-$ wave packet
which, in turn, changes the group velocity and the distance $\nu_\mu$ travels.
We find that the change of the distance, $d_{osc}$, is proportional to the
length of the wave packet, $\sigma_x$, and the oscillation phase, $\phi_p$,
acquired by neutrinos in the $\pi-$ and $K-$ meson decay tunnel where neutrino
wave packet is formed: $d_{osc} \propto \sigma \phi_p$. Although the distance
$d_{osc}$ may effectively correspond to the superluminal motion, the OPERA
result can not be explained. For OPERA we obtain $d_{osc} \sim - 10^{-5}$ cm
using $\Delta m^2 = 2.5 \times 10^{-3}$ eV$^2$. We analyze various
possibilities to increase $d_{osc}$ and discuss experimental setups in which
$d_{osc}$ (corresponding to the superluminal motion) can reach an observable
value $\sim 1$ m.

View original: http://arxiv.org/abs/1202.0953