PROBING FOR ULTRAHEAVY QUANTA AT LHC

Experiments at the LHC are sensitive to the presence or absence of mat ter quanta at mass scales far beyond the scales they can probe directl y. The production of Z boson pairs by gluon-gluon fusion is greatly en hanced if there are ultraheavy quanta that carry SU(3)(Color) and get their mass from electroweak symmetry breaking. For example, a fourth g eneration quark doublet with an arbitrarily heavy mass would induce a large excess in the ZZ yield that could be detected at the LHC with on ly similar or equal to 10% of the design luminosity.