skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Predictive fermion mass matrix [ital Ansaetze] in nonsupersymmetric SO(10) grand unification

Journal Article · · Physical Review, D (Particles Fields); (United States)
;  [1]
  1. Institute of Theoretical Science, University of Oregon, Eugene, Oregon 97403-5203 (United States)

We investigate the status of predictive fermion mass [ital Ansaetze] in nonsupersymmetric SO(10) grand unification which make use of the grand unification scale conditions [ital m][sub [ital e]]=[ital m][sub [ital d]]/3, [ital m][sub [mu]]=3[ital m][sub [ital s]], and [vert bar][ital V][sub [ital c][ital b]][vert bar]= [radical][ital m][sub [ital c]]/[ital m][sub b]in nonsupersymmetric SO(10) grand unification. The gauge symmetry below an intermediate symmetry-breaking scale [ital M][sub [ital I]] is assumed to be that of the standard model with either one or two Higgs doublets. We find in both cases that a maximum of 5 standard model parameters may be predicted within 1[sigma] experimental ranges. The standard model scenario predicts the low energy [vert bar][ital V][sub [ital c][ital b]][vert bar] to be in a range which includes its experimental midvalue 0.044 and which for a large top mass can extend to lower values than the range resulting in the supersymmetric case. In the two Higgs standard model case, we identify the regions of parameter space for which unification of the bottom quark and [tau] lepton Yukawa couplings is possible at grand unification scale. In fact, we find that unification of the top, bottom, and [tau] Yukawa couplings is possible with the running [ital b]-quark mass within the 1[sigma] preferred range [ital m][sub [ital b]]=4.25[plus minus]0.1 GeV provided [alpha][sub 3[ital c]]([ital M][sub [ital Z]]) is near the low end of its allowed range. In this case, one may make 6 predictions which include [vert bar][ital V][sub [ital c][ital b]][vert bar] within its 90% confidence limits. However unless the running mass [ital m][sub [ital b]][gt]4.4 GeV, third generation Yukawa coupling unification requires the top mass to be greater than 180 GeV. We compare these nonsupersymmetric cases to the case of the minimal supersymmetric standard model embedded in the SO(10) grand unified group.

DOE Contract Number:
FG06-85ER40224
OSTI ID:
7142938
Journal Information:
Physical Review, D (Particles Fields); (United States), Vol. 50:5; ISSN 0556-2821
Country of Publication:
United States
Language:
English