New universality class in three dimensions?: the antiferromagnetic RP2 model

We present the results of a Monte Carlo simulation of the RP2 model in three dimensions with negative coupling. We observe a second order phase transition between the disordered phase and an antiferromagnetic, unfrustrated, ordered one. We measure, with a finite size scaling analysis, the thermal exponent, obtaining ν = 0.784(8). We have found two magnetic-type relevant operators whose related η exponents are 0.038(2) and 1.338(8) respectively.