Liu, C , Chinese Acad Sci, Inst Theoret Phys, POB 2735, Beijing 100080, Peoples R China
部门归属:
Chinese Acad Sci, Inst Theoret Phys, Beijing 100080, Peoples R China
英文摘要:
It is proposed that supersymmetry (SUSY) may be used to understand fermion mass hierarchies. A family symmetry Z(3L) is introduced, which is the cyclic symmetry among the three generation SU(2) doublets. SUSY breaks at a high energy scale similar to 10(11) GeV. The electroweak energy scale similar to 100 GeV is unnaturally small. No additional global symmetry, like the R-parity, is imposed. The Yukawa couplings and R-parity violating couplings all take their natural values, which are O(10(0) similar to 10(-2)). Under the family symmetry, only the third generation charged fermions get their masses. This family symmetry is broken in the soft SUSY breaking terms, which result in a hierarchical pattern of the fermion masses. It turns out that for the charged leptons, the tau mass is from the Higgs vacuum expectation value (VEV) and the sneutrino VEVs, the muon mass is due to the sneutrino VEVs, and the electron gains its mass due to both Z(3L) and SUSY breaking. The large neutrino mixing are produced with neutralinos playing the partial role of right-handed neutrinos. vertical bar V-e3 vertical bar, which is for v.-v, mixing, is expected to be about 0.1. For the quarks, the third generation masses ate from the Higgs VEVs, the second generation masses are from quantum corrections, and the down quark mass due to the sneutrino VEVs. It explains m(c)/m(s), m(s)/(me), m(d) > m(u), and so on. Other aspects of the model are discussed.
