...Lee,preprintDK,DKHEP

The numerical value of $\tau_{\nu_e}$ corresponds to toroid dipole moment of Majorana neutrino and is obtained summing over all contributions in eq. (16) of [5].

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... neutrino 

Recall that both the Vavilov-Cherenkov and transition radiations are not depend on the nature of a moving source [13]

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.... 

The transition radiation induced by the neutrino magnetic moment disappeares in the massless limit since $\mu_\nu\sim m_\nu$.

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