The decay of an autoionising state (As) is considered in the presence of a resonance electromagnetic field (EMF) connecting the AS with some other level. It is shown that if the EMF is switched on suddenly the process of decay can be characterised by two constants which depend on frequency, intensity and polarisation of the EMF. One of these constants is always more or of about the order of the field-free autoionising width of the AS. However, if the EMF parameters obey some conditions the other decay constant can be much smaller than the field-free AS width. In this case the lifetime of the AS in the EMF as a whole can be much larger than the field-free lifetime of the AS, this means that there is a partial stabilisation of the AS. An increase in the AS lifetime is connected with a destructive interference between the autoionising and ionising transitions. However, there are always some 'non-interfering' transitions due to which stabilisation can never be absolute. The long living part of the AS population is shown to be rather small. If the EMF is switched on adiabatically there is only a simple one-exponential decay with only the characteristic decay time and there is no field-induced stabilisation.

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There exist several classes of theories beyond the Standard Model which contain massive spin-1 color octets, generically called "colorons". Indeed we argue that colorons inevitably appear in the spectrum whenever new colored particles feel an additional confining force. Colorons are distinctive at hadron colliders as this is the only environment in which they can be resonantly produced. In the simplest models we show that the coloron naturally decays to multijets via secondary resonances, which can be consistent with all existing bounds, even for colorons as light as a few hundred GeV. We perform representative case studies and show that a search in the four-jet channel at the Tevatron has strong signal significance, while the LHC faces formidable challenges for such a search.