382 research outputs found

    MSSM and Large tanβtan\beta from SUSY Trinification

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    We construct a supersymmetric model based on the semi-simple gauge group SU(3)c×SU(3)L×SU(3)RSU(3)_c \times SU(3)_L \times SU(3)_R with the relation tanβmt/mbtan\beta \simeq m_t/m_b automatically arising from its structure. The model below a scale 1016\sim 10^{16} GeV gives naturally rise just to the minimal supersymmetric standard model and therefore to the presently favored values for sin2θwsin^2 \theta_w and αs\alpha_s without fields in representations higher than the fundamental.Comment: 9 pages, LaTeX, UT-STPD-3-9

    A New Model for Fermion Masses in Supersymmetric Grand Unified Theories

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    We present a simple model for fermion mass matrices and quark mixing in the context of supersymmetric grand unified theories and show its agreement with experiment. Our model realizes the GUT mass relations md=3mem_d=3m_e, ms=mμ/3m_s= m_\mu/3, mb=mτm_b=m_\tau in a new way and is easily consistent with values of mtm_t suggested by MSSM fits to LEP data.Comment: Latex, 8 p., ITP-SB-93-37 (revised version contains minor changes in some wording and citations; no changes in analytic or numerical results.

    A Midwest School District’s Implementation Process Of A New Teacher Evaluation Model

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    The purpose of this study was to test the effectiveness of the implementation of the Marzano Teacher Evaluation Framework (MTEF) in a Midwest school district. The study used quantitative methods to examine the process used to bring about change in the school district’s teacher evaluation model. The researcher examined teacher and administrator perceptions regarding change, professional development, instructional improvement, reliability, and overall satisfaction with ease of use of the MTEF model. The researcher used data collected from one Midwest school district. The school district consisted of twelve elementary schools, four middle schools, and three high schools. A total of 682 teachers and 26 administrators were surveyed. Data was collected by way of an on-line survey. The survey included three sections. The first section contained three demographic questions. The second section consisted of five questions regarding the study’s research constructs: (a) change, (b) professional development, (c) instructional improvement, (d) reliability, and (e) overall satisfaction with the MTEF model’s ease of use. The final section consisted of 19 questions that aligned with the study’s research constructs. For each research construct, there were three to five questions. Data gathered from participants’ responses were analyzed and used to provide recommendations to other school districts and educators around the state and nation as they implement new teacher evaluation models

    A study of the association of HLA DR, DQ, and complement C4 alleles with systemic lupus erythematosus in Iceland

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    To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldOBJECTIVE: To perform an exploratory analysis of the relative contribution of single MHC genes to the pathogenesis of systemic lupus erythematosus (SLE) in a homogenous white population. METHODS: MHC class II alleles and C4 allotypes were determined in 64 SLE patients and in ethnically matched controls. HLA-DR and DQ typing was performed by polymerase chain reaction amplification with sequence specific primers. C4 allotypes were determined by agarose gel electrophoresis. RESULTS: The frequency of C4A*Q0 was significantly higher in patients than in controls (46.9% v 25.3%, p = 0.002). HLA-DRB1, DQA1, and DQB1 alleles in the whole group of SLE patients were not significantly different from those of controls. On the other hand increase in DRB1*03 was observed in the group of patients with C4A*Q0, as compared with patients with other C4A allotypes (p = 0.047). There was no significant correlation between severe and mild disease, as judged by the SLEDAI, and HLADR, DQ alleles and comparing the patients with C4A*Q0 with those with other C4A allotypes there was no significant difference regarding clinical manifestations. CONCLUSION: The results are consistent with the argument that C4A deficiency contributes independently to susceptibility and the pathogenesis of SLE. C4A*Q0 in SLE patients in Iceland shows weaker linkage disequilibrium with DR3 genes than reported in most other white populations and emphasises the role of ethnicity

    Third Generation Effects on Fermion Mass Predictions in Supersymmetric Grand Unified Theories

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    Relations among fermion masses and mixing angles at the scale of grand unification are modified at lower energies by renormalization group running induced by gauge and Yukawa couplings. In supersymmetric theories, the bb quark and τ\tau lepton Yukawa couplings, as well as the tt quark coupling, may cause significant running if tanβ\tan \beta, the ratio of Higgs field expectation values, is large. We present approximate analytic expressions for the scaling factors for fermion masses and CKM matrix elements induced by all three third generation Yukawa couplings. We then determine how running caused by the third generation of fermions affects the predictions arising from three possible forms for the Yukawa coupling matrices at the GUT scale: the Georgi-Jarlskog, Giudice, and Fritzsch textures.Comment: phyzzx, 26 pp., 6 figures not included, e-mailable upon request, JHU-TIPAC-93000

    Family replicated fit of all quark and lepton masses and mixings

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    We review our recent development of family replicated gauge group model, which generates the Large Mixing Angle MSW solution. The model is based on each family of quarks and leptons having its own set of gauge fields, each containing a replica of the Standard Model gauge fields plus a (B-L)-coupled gauge field. A fit of all the seventeen quark-lepton mass and mixing angle observables, using just six new Higgs field vacuum expectation values, agrees with the experimental data order of magnitudewise. However, this model can not predict the baryogenesis in right order, therefore, we discuss further modification of our model and present a preliminary result of baryon number to entropy ratio.Comment: 13 pages, no figure, LaTeX, Talk given at 8th Adriatic Meeting and Central European Symposia on Particle Physics in the New Millennium, 4-14 Sep. 2001, Dubrovnik, Croati

    Hierarchy plus anarchy in quark masses and mixings

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    We introduce a new parameterisation of the effect of unknown corrections from new physics on quark and lepton mass matrices. This parameterisation is used in order to study how the hierarchies of quark masses and mixing angles are modified by random perturbations of the Yukawa matrices. We discuss several examples of flavour relations predicted by different textures, analysing how these relations are influenced by the random perturbations. We also comment on the unlikely possibility that unknown corrections contribute significantly to the hierarchy of masses and mixings.Comment: LaTeX, 18 pages, 16 PS figure

    Scale dependence of the quark masses and mixings: leading order

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    We consider the Renormalization Group Equations (RGE) for the couplings of the Standard Model and its extensions. Using the hierarchy of the quark masses and of the Cabibbo-Kobayashi-Maskawa (CKM) matrix our argument is that a consistent approximation for the RGE should be based on the parameter λ=V^ud0.22\lambda= |\hat{V}_{ud}| \approx0.22. We consider the RGE in the approximation where we neglect all the relative terms of the order λ4\sim\lambda^{4} and higher. Within this approximation we find the exact solution of the evolution equations of the quark Yukawa couplings and of the vacuum expectation value of the Higgs field. Then we derive the evolution of the observables: quark masses, CKM matrix, Jarlskog invariant, Wolfenstein parameters of the CKM matrix and the unitarity triangle. We show that the angles of the unitarity triangle remain constant. This property may restrict the possibility of new symmetries or textures at the grand unification scale.Comment: 15 pages, 4 figures, author of one reference adde

    Test of the Dimopouos-Hall-Raby Ansatz for Fermion Mass Matrices

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    By evolution of fermion mass matrices of the Fritzsch and the Georgi-Jarlskog forms from the supersymmetric grand unified scale, DHR obtained predictions for the quark masses and mixings. Using Monte Carlo methods we test these predictions against the latest determinations of the mixings, the CP-violating parameter epsilon_K and the B_d^0--Bbar_d^0 mixing parameter r_d. The acceptable solutions closely specify the quark masses and mixings, but lie at the edges of allowed regions at 90% confidence level.Comment: 11 pages, 1 figure (not included
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