“…is expected to hold [1], where t 21 is the transition amplitude on an isolated atom. Recently there was much discussion on possible laboratory observations of neutrino electro-magnetic conversion, for instance, using the high-quality resonant cavity converters [6,7,8]. In these experiments one deals with transition form factor at the photon virtuality as small as q 2 ∼ (10 −6 eV ) 2 .…”