Degenerate Neutrinos and Supersymmetric Inflation

A moderate extension of the minimal supersymmetric standard model which includes a U(1)_(B-L) gauge group (B and L being the baryon and lepton number) and a Peccei-Quinn symmetry, U(1)_PQ, is presented. The hybrid inflationary scenario is automatic and `natural' in this model. The mu problem of the minimal supersymmetric standard model is solved by coupling the electroweak higgses to fields which break U(1)_PQ. Baryon number conservation and, thus, proton stability are automatic consequences of a R-symmetry. Neutrinos are assumed to acquire degenerate masses of about 1.5 eV by coupling to SU(2)_L triplet superfields, thereby providing the hot dark matter of the universe. The inflaton decays into these triplets which, via their subsequent decay, produce a primordial lepton asymmetry later converted into the observed baryon asymmetry of the universe. The gravitino and baryogenesis constraints can be satisfied with `natural' values (of order 10^{-3}) of the relevant coupling constants.Comment: 13 pages, Revtex, minor correction

Supersymmetry and Inflation

A variant of hybrid inflation which is applicable in a wide class of supersymmetric grand unified models and reproduces the observed temperature perturbations of cosmic background radiation with natural values of the parameters is presented. The theory is consistent with the unification of the minimal supersymmetric standard model gauge couplings as measured at LEP. The termination of inflation is smooth and does not produce any topological defects. Numerical investigation of the cosmological evolution of the system shows that for almost all initial values of the fields we do get an adequate amount of inflation. Finally, the "reheating" process following inflation and the production of the baryon asymmetry of the universe via a primordial lepton asymmetry are briefly discussed and some important implications for right handed neutrino Majorana masses are investigated.Comment: 5 pages LaTeX 1 eps figure. Talk presented at SUSY 96,Maryland,May 1996. Published in Nuclear Physics B(Proc.Suppl.) 52A(1997)242-24

MSSM from SUSY Trinification

We construct a $SU(3)^3$ supersymmetric gauge theory with a common gauge coupling g. Spontaneous breaking of this gauge group at a scale $M_X=1.3\times10^{16}$GeV gives naturally rise exactly to the Minimal Supersymmetric Standard Model $(MSSM)$ and consequently to the experimentally favored values of $sin^2\theta_w$ and $\alpha_s$.The gauge hierarchy problem is naturally solved by a missing-partner-type mechanism which works to all orders in the superpotential. The baryon asymmetry can be generated in spite of the (essential) stability of the proton. The solar neutrino puzzle is solved by the MSW mechanism. The LSP is a natural "cold" dark matter candidate and "hot" dark matter might consist of $\tau$-neutrinos. This model could be thought of as an effective $4d$ theory emerging from a more fundamental theory at a scale $M_c=M_P/\sqrt{8\pi}$ where $a_G\equiv{g^2\over{4\pi}}$ happens to be equal to unity.Comment: 10 pages, LaTeX,UT-STPD-2-9

Tropomyosin antibody: the specific localization of tropomyosin in nonmuscle cells

An antibody against purified chicken skeletal muscle tropomyosin is used in indirect immunofluorescence to visualize the localization of tropomyosin in a variety of nonmuscle cells. The antibody produces a fluorescent pattern which is very similar to that obtained with an actin-specific antibody. This pattern is composed of fluorescent fibers which are shown to be coincident with the fibers seen with phase-contrast optics. High resolution epifluorescent microscopy reveals that fibers stained with the actin antibody show a continuous fluorescence, while fibers reacted with the tropomyosin antibody show a periodic fluorescence. Measurements indicate that the lengths of the fluorescent segments are variable with an average of 1.2 μm while the spacing between segments is approximately 0.4 μm

Neutrino Masses and Mixing from Supersymmetric Inflation

A supersymmetric model based on a left-right symmetric gauge group is proposed where hybrid inflation, baryogenesis and neutrino oscillations are linked.This scheme, supplemented by a familiar ansatz for the neutrino Dirac masses and mixing of the two heaviest families and with the MSW resolution of the solar neutrino puzzle, implies that $m_{\nu_{\tau}}$ lies between 1 and 9 eV. The mixing angle $\theta_{\mu \tau}$ is predicted to lie in a narrow range which will be partially tested by the Chorus/Nomad experiment.Comment: 6 pages, 2 postscript figures, uses spocl.sty To be published in the proceedings of COSMO-97,International Workshop on Particle Physics and the Early Universe,15-19 September 1997, Ambleside,Lake District,Englan

How to remedy the eta-problem of SUSY GUT hybrid inflation via vector backreaction

It is shown that, in supergravity models of inflation where the gauge kinetic function of a gauge field is modulated by the inflaton, we can obtain a new inflationary attractor solution, in which the roll-over of the inflaton suffers additional impedance due to the vector field backreaction. As a result, directions of the scalar potential which, due to strong Kaehler corrections, become too steep and curved to normally support slow-roll inflation can now naturally do so. This solves the infamous eta-problem of inflation in supergravity and also keeps the spectral index of the curvature perturbation mildly red despite eta of order unity. This mechanism is applied to a model of hybrid inflation in supergravity with a generic Kaehler potential. The spectral index of the curvature perturbation is found to be 0.97 - 0.98, in excellent agreement with data. The gauge field can act as vector curvaton generating statistical anisotropy in the curvature perturbation. However, this anisotropy could be possibly observable only if the gauge coupling constant is unnaturally small.Comment: 10 pages, talk given at the International Workshop on Grand Unified Theories (GUT2012), Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto, Japan, March 15-17, 2012 (to appear in the proceedings

Actin, α-actinin, and tropomyosin interaction in the structural organization of actin filaments in nonmuscle cells

During the spreading of a population of rat embryo cells, approximately 40% of the cells develop a strikingly regular network which precedes the formation of the straight actin filament bundles seen in the fully spread out cells. Immunofluorescence studies with antibodies specific for the skeletal muscle structural proteins actin, α-actinin, and tropomyosin indicate that this network is composed of foci containing actin and α-actinin, connected by tropomyosin-associated actin filaments. Actin filaments, having both tropomyosin and α-actinin associated with them, are also seen to extend from the vertices of this network to the edges of the cell. These results demonstrate a specific interaction of α-actinin and tropomyosin with actin filaments during the assembly and organization of the actin filament bundles of tissue culture cells. The three-dimensional network they form may be regarded as the structural precursor and the vertices of this network as the organization centers of the ultimately formed actin filament bundles of the fully spread out cells