3,194 research outputs found

    Quantum effects from a purely geometrical relativity theory

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    A purely geometrical relativity theory results from a construction that produces from three-dimensional space a happy unification of Kaluza's five-dimensional theory and Weyl's conformal theory. The theory can provide geometrical explanations for the following observed phenomena, among others: (a) lifetimes of elementary particles of lengths inversely proportional to their rest masses; (b) the equality of charge magnitude among all charged particles interacting at an event; (c) the propensity of electrons in atoms to be seen in discretely spaced orbits; and (d) `quantum jumps' between those orbits. This suggests the possibility that the theory can provide a deterministic underpinning of quantum mechanics like that provided to thermodynamics by the molecular theory of gases.Comment: 7 pages, LaTeX jpconf.cls (Institute of Physics Publishing), 6 Encapsulated PostScript figures (Fig. 6 is 1.8M uncompressed); Presented at VI Mexican School on Gravitation and Mathematical Physics "Approaches to Quantum Gravity

    Testing the Dirac equation

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    The dynamical equations which are basic for the description of the dynamics of quantum felds in arbitrary space--time geometries, can be derived from the requirements of a unique deterministic evolution of the quantum fields, the superposition principle, a finite propagation speed, and probability conservation. We suggest and describe observations and experiments which are able to test the unique deterministic evolution and analyze given experimental data from which restrictions of anomalous terms violating this basic principle can be concluded. One important point is, that such anomalous terms are predicted from loop gravity as well as from string theories. Most accurate data can be obtained from future astrophysical observations. Also, laboratory tests like spectroscopy give constraints on the anomalous terms.Comment: 11 pages. to appear in: C. L\"ammerzahl, C.W.F. Everitt, and F.W. Hehl (eds.): Gyros, Clocks, Interferometers...: Testing Relativistic Gravity in Space, Lecture Notes in Physics 562, Springer 200

    Finite Temperature and Density Effect on Symmetry Breaking by Wilson Loops

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    A finite temperature and density effect of Wilson loop elements on non-simply connected space is investigated in the model suggested by Hosotani. Using one-loop calculations it is shown that the value of an "order parameter" does not shift as the temperature grows. We find that finite density effect is of much importance for restoration of symmetry.Comment: 11pages, no figur

    A Geometric Approach to CP Violation: Applications to the MCPMFV SUSY Model

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    We analyze the constraints imposed by experimental upper limits on electric dipole moments (EDMs) within the Maximally CP- and Minimally Flavour-Violating (MCPMFV) version of the MSSM. Since the MCPMFV scenario has 6 non-standard CP-violating phases, in addition to the CP-odd QCD vacuum phase \theta_QCD, cancellations may occur among the CP-violating contributions to the three measured EDMs, those of the Thallium, neutron and Mercury, leaving open the possibility of relatively large values of the other CP-violating observables. We develop a novel geometric method that uses the small-phase approximation as a starting point, takes the existing EDM constraints into account, and enables us to find maximal values of other CP-violating observables, such as the EDMs of the Deuteron and muon, the CP-violating asymmetry in b --> s \gamma decay, and the B_s mixing phase. We apply this geometric method to provide upper limits on these observables within specific benchmark supersymmetric scenarios, including extensions that allow for a non-zero \theta_QCD.Comment: 34 pages, 16 eps figures, to appear in JHE

    A distinct tospovirus causing necrotic streak on Alstroemeria sp. in Colombia

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    A tospovirus causing necrotic streaks on leaves was isolated from Alstroemeria sp. in Colombia. Infected samples reacted positively with tomato spotted wilt virus (TSWV) antiserum during preliminary serological tests. Further analysis revealed a close serological relationship to tomato chlorotic spot virus (TCSV) and groundnut ringspot virus (GRSV). A major part of the S-RNA segment, encompassing the nucleocapsid (N) protein gene, the 5′ untranslated region and a part of the intergenic region 3′ of the N gene, was cloned and sequenced. The deduced N protein sequence showed highest amino acid identity (82%) to that of TCSV, indicating that the virus represents a new tospovirus species, for which the name Alstroemeria necrotic streak virus (ANSV) is coined. Phylogenetic analysis based on the N protein sequence revealed that this Alstroemeria-infecting tospovirus clustered with tospoviruses from the American continent. Frankliniella occidentalis was identified as potential vector species for ANSV

    Pathogenic challenge reveals immune trade-off in mussels exposed to reduced seawater pH and increased temperature

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    Mussels tolerant to seawater pH's that are projected to occur by 2300 due to ocean acidification.•Exposure to pH 6.50 reduced mussel immune response, yet in the absence of a pathogen.•Subsequent pathogenic challenge led to a reversal of immune suppression at pH 6.50.•Study highlights the importance of undertaking multiple stressor exposures.•Shows a need to consider physiological trade-offs and measure responses functionall

    Cosmic optical activity in the spacetime of a scalar-tensor screwed cosmic string

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    Measurements of radio emission from distant galaxies and quasars verify that the polarization vectors of these radiations are not randomly oriented as naturally expected. This peculiar phenomenon suggests that the spacetime intervening between the source and observer may be exhibiting some sort of optical activity, the origin of which is not known. In the present paper we provide a plausible explanation to this phenomenon by investigating the r\^ole played by a Chern-Simons-like term in the background of an ordinary or superconducting screwed cosmic string in a scalar-tensor gravity. We discuss the possibility that the excess in polarization of the light from radio-galaxies and quasars can be understood as if the electromagnetic waves emitted by these cosmic objects interact with a scalar-tensor screwed cosmic string through a Chern-Simons coupling. We use current astronomical data to constrain possible values for the coupling constant of this theory, and show that it turns out to be: λ1026\lambda \sim 10^{-26} eV, which is two orders of magnitude larger than in string-inspired theories.Comment: Revised version, to appear in Phys. Rev.

    Heavy quark flavour dependence of multiparticle production in QCD jets

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    After inserting the heavy quark mass dependence into QCD partonic evolution equations, we determine the mean charged hadron multiplicity and second multiplicity correlators of jets produced in high energy collisions. We thereby extend the so-called dead cone effect to the phenomenology of multiparticle production in QCD jets and find that the average multiplicity of heavy-quark initiated jets decreases significantly as compared to the massless case, even taking into account the weak decay products of the leading primary quark. We emphasize the relevance of our study as a complementary check of bb-tagging techniques at hadron colliders like the Tevatron and the LHC.Comment: Version revised, accepted for publication in JHEP, 21 pages and 7 figure

    A stopped Delta-Matter Source in Heavy Ion Collisions at 10 GeV/n

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    We predict the formation of highly dense baryon-rich resonance matter in Au+Au collisions at AGS energies. The final pion yields show observable signs for resonance matter. The Delta(1232) resonance is predicted to be the dominant source for pions of small transverse momenta. Rescattering effects -- consecutive excitation and deexcitation of Deltas -- lead to a long apparent lifetime (> 10 fm/c) and rather large volumina (several 100 fm^3) of the Delta-matter state. Heavier baryon resonances prove to be crucial for reaction dynamics and particle production at AGS.Comment: 17 pages, 5 postscript figures, uses psfig.sty and revtex.st
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