arXiv subjects
Publications and source records attributed to Masaki Yasue.
Two-loop radiative mechanism, when combined with an U(1)_{L'} symmetry generated by L_e-L_μ-L_τ(=L'), is shown to provide an estimate of Δm^2_{\odot}/Δm^2_{atm} $\sim$ εm_e/m_τ, where εmeasures the U(1)_{L'}-breaking. Since Δm^2_{atm} $\sim 3.5x10^{-3} eV^2, we find that Δm^2_{\odot} $\sim$ εx10^{-6} eV^2, which will fall into the allowed region of the LOW solution to the solar neutrino problem for ε$\sim$ 0.1.
Responding to the recent claim that the origin of moduli space may be unstable in "magnetic" supersymmetric quantum chromodynamics (SQCD) with N_f <= 3N_c/2 (N_c>2) for N_f flavors and N_c colors of quarks, we explore the possibility of finding nonperturbative physics for "electric" SQCD. We present a recently discussed effective superpotential for "electric" SQCD with N_c+2 <= N_f <= 3N_c/2 (N_c>2) that generates chiral symmetry breaking with a residual nonabelian symmetry of SU(N_c)_{L+R}xSU(N_f-N_c)_Lx SU(N_f-N_c)_R. Holomorphic decoupling property is shown to be respected. For massive N_f-N_c quarks, our superpotential with instanton effect taken into account produces a consistent vacuum structure for SQCD with N_f=N_c compatible with the holomorphic decoupling.
In SU(3)_L x U(1)_N gauge models for electroweak interactions, we discuss how to implement a radiative mechanism of generating Majorana neutrino masses by considering the property that the Higgs scalar, which has a coupling to a charged lepton (\ell)-neutrino (ν) pair, is naturally included. The mechanism is shown to work in models with a heavy charged lepton, ω^+, in a lepton triplet (ν, \ell, ω^+) and with a heavy neutral lepton, N, in (ν, \ell, N). A minimal model with \ell and \ell^c in (ν, \ell, \ell^c) together with a sextet Higgs scalar suffers from a fine-tuning problem to suppress tree-level neutrino masses.
By the use of an effective superpotential in supersymmetric quantum chromodynamics (SQCD) with N_f flavors and N_c colors of quarks for N_f>=N_c+2, the influence of soft supersymmetry (SUSY) breakings is examined to clarify dynamics of chiral symmetry breakings near the SUSY limit. In case that SQCD triggers spontaneous chiral symmetry breakings, it is possible to show that our superpotential dynamically favors the successive formation of condensates, leaving either SU(N_f-N_c) or SU(N_f-N_c+1) unbroken as a chiral nonabelian symmetry.
A mechanism of radiatively generating neutrino masses is implemented in an SU(2)_L x U(1)_Y x SU(2)'_L x U(1)'_Y model, where the first and second families respect SU(2)_L x U(1)_Y while SU(2)'_L x U(1)'_Y is specific for the third family. The fourth neutrino, nu_s, that has a U(1)_Y x U(1)'_Y coupling joins in the model to induce neutrino mixings by additional interactions with e and mu. The phenomenologically consistent oscillation of nu_s - nu_e requires a dominated coupling of nu_s to e.
Properties of extra weak bosons are discussed in a gauge model based on SU(2)_LXU(1)_YXSU(2)'_L. The physics of SU(2)'_L respects the duality in the Higgs and confining phases, where massive gauge bosons in the Higgs phase are equivalently represented by composite vector bosons in the confining phase below the scale of SU(2)'_L . interactions for SU(2)'_L-singlet composites induced in the confining phase can be generated by nonlinear interactions of the four Fermi type respecting SU(2)_LXU(1)_Y, which create quarks, q_i^A (A=r,g,b; i=1,2), leptons, l_i, vector bosons, V_mu^(a) (a=1,2,3) and the Higgs scalar, phi, made by scalar subconstituents, c^{0,A}, and spinor subconstituents, w_i,as q.l=cw, V=(w-{bar}w)_{J=1} and phi=(w-{bar}w)_{J=0} . The physics described by these composites is equivalent to the one by SU(2)_LXU(1)_YXSU(2)'_L below the confining scale.