1,535 research outputs found

    The Gauge Hierarchy Problem and Higher Dimensional Gauge Theories

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    We report on an attempt to solve the gauge hierarchy problem in the framework of higher dimensional gauge theories. Both classical Higgs mass and quadratically divergent quantum correction to the mass are argued to vanish. Hence the hierarchy problem in its original sense is solved. The remaining finite mass correction is shown to depend crucially on the choice of boundary condition for matter fields, and a way to fix it dynamically is presented. We also point out that on the simply-connected space S2S^2 even the finite mass correction vanishes.Comment: LaTeX2e. 12 pages, 3 Postscript figures; Added references, some comment

    Measurement of the mass of the τ lepton

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    The mass of the τ lepton has been measured at the Beijing Electron-Positron Collider using the Beijing Spectrometer. A search near threshold for e^+e^-→τ^+τ^- was performed. Candidate events were identified by requiring that one τ decay via τ→eνν¯, and the other via τ→μνν¯. The mass value, obtained from a fit to the energy dependence of the τ^+τ^- cross section, is m_τ=1776.9_(-0.5)^(+0.4)±0.2 MeV

    A model of CP Violation from Extra Dimension

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    We construct a realistic model of CP violation in which CP is broken in the process of dimensional reduction and orbifold compactification from a five dimensional theories with SU(3)×SU(3)×SU(3)SU(3)\times SU(3) \times SU(3) gauge symmetry. CP violation is a result of the Hosotani type gauge configuration in the higher dimension.Comment: 5 page

    The Origin of Spontaneous Symmetry Breaking in Theories with Large Extra Dimensions

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    We suggest that the electroweak Higgs particles can be identified with extra-dimensional components of the gauge fields, which after compactification on a certain topologically non-trivial background become tachyonic and condense. If the tachyonic mass is a tree level effect, the natural scale of the gauge symmetry breaking is set by the inverse radius of the internal space, which, in case of the electroweak symmetry, must be around ∼1/\sim 1/TeV. We discuss the possibility of a vanishing tree level mass for the Higgs. In such a scenario the tachyonic mass can be induced by quantum loops and can be naturally smaller than the compactification scale. We give an example in which this possibility can be realized. Starting from an Einstein--Yang--Mills theory coupled to fermions in 10-dimensions, we are able to reproduce the spectrum of the Standard Model like chiral fermions and Higgs type scalars in 4-dimensions upon compactifying on CP1×CP2{\mathbb{C}}P^1\times {\mathbb{C}}P^2. The existence of a monopole solution on CP1{\mathbb{C}}P^1 and a self dual U(1) instanton on CP2{\mathbb{C}}P^2 are essential in obtaining chiral fermions as well as tachyonic or massless scalars in 4-dimensions. We give a simple rule which helps us to identify the presence of tachyons on the monopole background on S2S^2.Comment: 33 pages. Version accepted for publication in Phys.Rev.

    Study of nuclear correlation effects via 12C(p,n)12N(g.s.,1+) at 296 MeV

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    We report measurements of the cross section and a complete set of polarization observables for the Gamow--Teller 12C(p⃗,n⃗)12N(g.s.,1+){}^{12}{\rm C}(\vec{p},\vec{n}){}^{12}{\rm N}({\rm g.s.},1^+) reaction at a bombarding energy of 296 MeV. The data are compared with distorted wave impulse approximation calculations employing transition form factors normalized to reproduce the observed beta-decay ftft value. The cross section is significantly under-predicted by the calculations at momentum transfers q≳q \gtrsim 0.5 fm−1{\rm fm^{-1}}. The discrepancy is partly resolved by considering the non-locality of the nuclear mean field. However, the calculations still under-predict the cross section at large momentum transfers of qq ≃\simeq 1.6 fm−1{\rm fm^{-1}}. We also performed calculations employing random phase approximation response functions and found that the observed enhancement can be attributed in part to pionic correlations in nuclei.Comment: 5 figures, submitted to Phys. Lett.

    A proteomic analysis of the functional effects of fatty acids in NIH 3T3 fibroblasts

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    Previous studies have demonstrated that long chain fatty acids influence fibroblast function at sub-lethal concentrations. This study is the first to assess the effects of oleic, linoleic or palmitic acids on protein expression of fibroblasts, as determined by standard proteomic techniques. The fatty acids were not cytotoxic at the concentration used in this work as assessed by membrane integrity, DNA fragmentation and the MTT assay but significantly increased cell proliferation. Subsequently, a proteomic analysis was performed using two dimensional difference gel electrophoresis (2D-DIGE) and MS based identification. Cells treated with 50 ÎźM oleic, linoleic or palmitic acid for 24 h were associated with 24, 22, 16 spots differentially expressed, respectively. Among the identified proteins, Îą-enolase and far upstream element binding protein 1 (FBP-1) are of importance due to their function in fibroblast-associated diseases. However, modulation of Îą-enolase and FBP-1 expression by fatty acids was not validated by the Western blot technique

    Complete set of polarization transfer coefficients for the 3He(p,n){}^{3}{\rm He}(p,n) reaction at 346 MeV and 0 degrees

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    We report measurements of the cross-section and a complete set of polarization transfer coefficients for the 3He(p,n){}^{3}{\rm He}(p,n) reaction at a bombarding energy TpT_p = 346 MeV and a reaction angle θlab\theta_{\rm lab} = 0∘0^{\circ}. The data are compared with the corresponding free nucleon-nucleon values on the basis of the predominance of quasi-elastic scattering processes. Significant discrepancies have been observed in the polarization transfer DLL(0∘)D_{LL}(0^{\circ}), which are presumably the result of the three-proton TT = 3/2 resonance. The spin--parity of the resonance is estimated to be 1/2−1/2^-, and the distribution is consistent with previous results obtained for the same reaction at TpT_p = 48.8 MeV.Comment: 4 figures, Accepted for publication in Physical Review

    The Classic: Integration of Deoxyribonucleic Acid Specific for Rous Sarcoma Virus after Infection of Permissive and Nonpermissive Hosts: (RNA tumor viruses/reassociation kinetics/duck cells)

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    A relatively simple but stringent technique was developed to detect the integration of virus-specific DNA into the genomes of higher organisms. In both permissive (duck) and nonpermissive (mammalian) cells which normally contain no nucleotide sequences specific for Rous sarcoma virus, transformation by the virus results in the appearance of DNA specific for Rous sarcoma virus covalently integrated into strands of host-cell DNA containing reiterated sequences. Early after infection of mouse or duck cells by Rous sarcoma virus, unintegrated DNA specific for the virus can be demonstrated
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