  The massive Schwinger model in bosonic representation is quantized on the
light front using the Dirac--Bergmann method. The non-perturbative theta-
vacuum in terms of coherent states of the gauge-field zero mode is derived and
found to coincide with the massless case. On the other hand, the mass term
becomes highly non-linear due to the constrained zero mode of the scalar field.
A non-trivial mixing between the normal-mode and zero-mode sectors of the model
is crucial for the correct calculation of the theta-dependence of the leading
order mass correction to the chiral condensate.

High Energy Physics - Theory