BOUND ON BAG CONSTANT AND NIELSEN-OLESEN UNSTABLE MODE IN QCD

A specific state of QCD is put forward as an ansatz for the true vacuum (outside bag state). This state is obtained by, in addition to a constant color magnetic field, exciting only the Nielsen-Olesen unstable mode. The simplest ansatz achieving a genuine decrease of the energy density turns out to give fields varying as a θ{symbol}3 function. The energy density is estimated using a semiclassical approximation for the Nielsen-Olesen unstable modes. A lower bound for the MIT bag constant is produced which is saturated phenomenologically. It requires, in terms of the QCD scale parameter, Λ {less-than or approximate} 0.42 GeV. © 1979.