FULLY PACKED LOOP MODEL ON THE HONEYCOMB LATTICE

We investigate the O(n) model on the honeycomb lattice, using its loop representation in the limit of full packing. The universal properties , which we calculate by means of finite-size scaling and transfer-matr ix techniques, are different from the branches of O(n) critical behavi or known thus far. The conformal anomaly of the model varies between - 1 and 2 in the interval 0 less-than-or-equal-to n less-than-or-equal-t o 2. The universality class of the model is characterized as a superpo sition of a low-temperature O(n) phase, and a solid-on-solid model at a temperature independent of n.