Triple neutral gauge boson couplings in noncommutative Standard Model

It has been shown recently that the triple neutral gauge boson couplings are not uniquely determined in noncommutative extension of the Standard Model (NCSM). Depending on specific schemes used, the couplings are different and may even be zero. To distinguish different realizations of the NCSM, additional information either from theoretical or experimental considerations is needed. In this Letter we show that these couplings can be uniquely determined from considerations of unification of electroweak and strong interactions. Using SU(5) as the underlying theory and integrating out the heavy degrees of freedom, we obtain unique non-zero new triple gammagammagamma, gammagammaZ, gammaZZ, ZZZ, gammaGG, ZGG and GGG couplings at the leading order in the NCSM. We also briefly discuss experimental implications. (C) 2002 Elsevier Science B.V. All rights reserved.