228 research outputs found
MSSM and Large from SUSY Trinification
We construct a supersymmetric model based on the semi-simple gauge group
with the relation automatically arising from its structure. The model below a scale
GeV gives naturally rise just to the minimal supersymmetric
standard model and therefore to the presently favored values for and 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
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 , , in a new way and is easily consistent with values of
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 study of the association of HLA DR, DQ, and complement C4 alleles with systemic lupus erythematosus in Iceland
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
Loss of heterozygosity at chromosome 11 in breast cancer: association of prognostic factors with genetic alterations.
We examined DNA from 116 female and four male breast cancer patients for loss of heterozygosity (LOH). DNA was analysed by polymerase chain reaction using ten microsatellite markers on chromosome 11. Three distinct regions of LOH were identified: 11p15.5, 11q13 and 11q22-qter with a LOH frequency of 19, 23 and 37-43% respectively. The marker D11S969 showing the highest frequency of LOH (43%) is located at the 11q24.1-q25 region. No previous molecular genetic studies have shown frequent LOH at the region telomeric to q23 on chromosome 11. Southern analysis revealed that LOH at 11q13 was due to amplification, whereas LOH at 11q22qter was due to deletion. LOH at 11p15.5 was associated with paucity of hormone receptor proteins, high S-phase and positive node status. An association was found between LOH at 11q13 and positive node status. LOH at the 11q22-qter region correlated with a high S-phase fraction. A significant association was found between LOH at 11p15 and chromosome regions 17q21 (the BRCA1 region) and 3p
Third Generation Effects on Fermion Mass Predictions in Supersymmetric Grand Unified Theories
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
quark and lepton Yukawa couplings, as well as the quark coupling,
may cause significant running if , 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
Predictions for Constrained Minimal Supersymmetry with Bottom-Tau Mass Unification
We examine the Constrained Minimal Supersymmetric Standard Model (CMSSM) with
an additional requirement of strict b - tau unification in the region of small
tan(beta). We find that the parameter space becomes completely limited below
about 1 TeV by physical constraints alone, without a fine-tuning constraint. We
study the resulting phenomenological consequences, and point out several ways
of falsifying the adopted b - tau unification assumption. We also comment on
the effect of a constraint from the non-observation of proton decay.Comment: Michigan preprint UM-TH-94-03, LaTeX, 18 pages with inline figures
(figures included in uuencoded file). Complete PS file also available by
anonymous FTP to williams.physics.lsa.umich.edu in
/pub/preprints/UM-TH-94-03.ps.Z or by e-mailing reques
Hierarchy plus anarchy in quark masses and mixings
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
Test of the Dimopouos-Hall-Raby Ansatz for Fermion Mass Matrices
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
Family replicated fit of all quark and lepton masses and mixings
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
Grand unification in the minimal left-right symmetric extension of the standard model
The simplest minimal left-right symmetric extension of the standard model is
studied in the high energy limit, and some consequences of the grand
unification hypothesis are explored assuming that the parity breaking scale is
the only relevant energy between the electro-weak scale and the unification
point. While the model is shown to be compatible with the observed neutrino
phenomenology, the parity breaking scale and the heavy boson masses are
predicted to be above 10^7 TeV, quite far from the reach of nowadays
experiments. Below that scale only an almost sterile right handed neutrino is
allowed with a mass M \approx 100 TeV
- …