Unification bounds on the possible N = 2 supersymmetry-breaking scale

In this letter, the possible appearance of N = 2 supersymmetry at a low energy scale is investigated in the context of unified theories. Introducing mirror particles for all the gauge and matter multiplets of the minimal supersymmetric extension of the Standard Model (MSSM), the measured values of sin2θW and α3(MZ) indicate that the N = 2 threshold scale MS2 cannot be lower than ∼ 1014 GeV. If the U(1) normalization coefficient k is treated as a free parameter, MS2 can be as low as 109 GeV. On the other hand, if mirror quarks and leptons are absent and a non-standard value for k is used, N = 2 supersymmetry breaking could in principle occur at the electroweak scale.