αs and gauge coupling unification in flipped SU(5) models with gauge-mediated supersymmetry breaking

We examine gauge coupling unification and prediction for αs(MZ) in minimal flipped SU(5) with gauge-mediated supersymmetry breaking. We include threshold corrections at weak scale, messenger scale and unification scale, and explicitly show that in this model there can be either one-step or two-step gauge coupling unification, depending on unification-scale threshold corrections. The experimental value of αs(MZ) constrains heavy particle masses in one-step unification. In the case of two-step unification, we examine the prediction for αs(MZ) with two-loop, light, messenger and heavy threshold corrections, and find it to be compatible with the updated experimental data.