DOES A COSMOLOGICAL CONSTANT INCREASE THE EFFECT OF GRAVITATIONAL LENSING ON THE COSMIC MICROWAVE BACKGROUND

We consider flat universes with nonzero cosmological constant (LAMBDA) and study the temperature anisotropies caused by microwave photons af fected by gravitational lensing. We study the lensing effect produced by linear density fluctuations present from recombination to now. The result is that, for the cold dark matter (CDM) model, the dispersion o f the gravitational deflections decreases with LAMBDA. Considering tha t scenario with two values of OMEGA0 (OMEGA0 = 0.2, 1), we calculate t he effect of bending on measurements of small-scale experiments findin g that the enhancement of the temperature anisotropies measured in a f lat universe with LAMBDA not-equal 0 is slightly lower than the one me asured in a flat universe with zero cosmological constant.