UNIFICATION BOUNDS ON THE POSSIBLE N=2 SUPERSYMMETRY-BREAKING SCALE

In this letter, the possible appearance of N = 2 supersymmetry at a lo w energy scale is investigated in the context of unified theories. Int roducing minor particles for all the gauge and matter multiplets of th e minimal supersymmetric extension of the Standard Model (MSSM), the m easured values of sin(2) theta(W) and alpha(3)(M-Z) indicate that the N = 2 threshold scale M-S2 cannot be lower than similar to 10(14) GeV. If the U(1) normalization coefficient k is treated as a free paramete r, M-S2 can be as low as 10(9) GeV. On the other hand, if mirror quark s and leptons are absent and a non-standard value for k is used, N = 2 supersymmetry breaking could in principle occur at the electroweak sc ale. (C) 1997 Published by Elsevier Science B.V.