SCREENING OF HEAVY SCALARS BEYOND THE STANDARD MODEL

Spontaneously broken gauge models generically present large radiative corrections when the masses of the scalars are larger than the symmetry-breaking scale(s). This is not necessary, however, and we determine, based on the symmetry and renormalization properties of the theory, the most general conditions under which scalar radiative effects are screened. Barring fine tuning, the properties of the Goldstone sector determine whether this type of screening is present or not, and this can be decided in most cases by inspection (given the pattern of symmetry breaking). We consider several examples. In particular we show that in left-right symmetric models the two requirements that all scalars be significantly heavier than the gauge bosons is inconsistent with screening; this implies either the presence of large radiative corrections produced by the heavy scalars, or the presence of scalars with masses similar to that of the (heaviest) gauge bosons in these models.