Adams et al .
( 1997b ) have noted that according to our current understanding of the unification of fundamental interactions , there should have been phase transitions associated with spontaneous symmetry breaking during the inflationary era .
This may have resulted in the breaking of scale-invariance of the primordial density perturbation for brief periods .
A possible such feature was identified in the power spectrum of galaxy clustering in the APM survey at the scale k \sim 0.1 h { Mpc } ^ { -1 } and it was shown that the secondary acoustic peaks in the power spectrum of the CMB anisotropy should consequently be suppressed .
We demonstrate that this prediction is confirmed by the recent Boomerang and Maxima observations , which favour a step-like spectral feature in the range k \sim ( 0.06 - 0.6 ) h { Mpc } ^ { -1 } , independently of the similar previous indication from the APM data .
Such a spectral break enables an excellent fit to both APM and CMB data with a baryon density consistent with the BBN value .
It also allows the possibility of a matter-dominated universe with zero cosmological constant , which we show can now account for even the evolution of the abundance of rich clusters .