SO(10) unification in noncommutative geometry revisited

We investigate the SO(10) unification model in a Lie-algebraic formulation of noncommutative geometry. The SO(10) symmetry is broken by a 45-Higgs and the Majorana mass term for the right neutrinos (126-Higgs) to the standard model structure group. We study the case where the fermion masses are as g eneral as possible, which leads to two 10-multiplets, four 120-multiplets a nd two additional 126-multiplets of Higgs fields. This Higgs structure diff ers considerably from the two Higgs multiplets 16 X 16* and 16(c) X 16* use d by Chamseddine and Frohlich. We find the usual tree level predictions of noncommutative geometry: m(W) = 1/2 m(t), sin(2) theta(W) = 3/8 and g(2) = g(3) as well as m(H) less than or equal to m(t).