322 research outputs found

    General Relativistic Mean Field Theory for Rotating Nuclei

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    We formulate a general relativistic mean field theory for rotating nuclei starting from the special relativistic σ−ω\sigma - \omega model Lagrangian. The tetrad formalism is adopted to generalize the model to the accelerated frame.Comment: 13 pages, REVTeX, no figures, submitted to Phys. Rev. Lett., the word `curved' is replaced by `non-inertial' or `accelerated' in several places to clarify the physical situation interested, some references are added, more detail discussions are given with omitting some redundant sentence

    Probing the Higgs Field Using Massive Particles as Sources and Detectors

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    In the Standard Model, all massive elementary particles acquire their masses by coupling to a background Higgs field with a non-zero vacuum expectation value. What is often overlooked is that each massive particle is also a source of the Higgs field. A given particle can in principle shift the mass of a neighboring particle. The mass shift effect goes beyond the usual perturbative Feynman diagram calculations which implicitly assume that the mass of each particle is rigidly fixed. Local mass shifts offer a unique handle on Higgs physics since they do not require the production of on-shell Higgs bosons. We provide theoretical estimates showing that the mass shift effect can be large and measurable, especially near pair threshold, at both the Tevatron and the LHC.Comment: 6 pages, no figures; Version 2 corrects some typographical errors of factors of 2 in equations 14, 17, 18 and 19 (all of the same origin) and mentions a linear collider as an interesting place to test the results of this pape

    Scale-Free model for governing universe dynamics

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    We investigate the effects of scale-free model on cosmology, providing, in this way, a statistical background in the framework of general relativity. In order to discuss properties and time evolution of some relevant universe dynamical parameters (cosmographic parameters), such as H(t)H(t) (Hubble parameter), q(t)q(t) (deceleration parameter), j(t)j(t) (jerk parameter) and s(t)s(t) (snap parameter), which are well re-defined in the framework of scale-free model, we analyze a comparison between WMAP data. Hence the basic purpose of the work is to consider this statistical interpretation of mass distribution of universe, in order to have a mass density ρ\rho dynamics, not inferred from Friedmann equations, via scale factor a(t)a(t). This model, indeed, has been used also to explain a possible origin and a viable explanation of cosmological constant, which assumes a statistical interpretation without the presence of extended theories of gravity; hence the problem of dark energy could be revisited in the context of a classical probability distribution of mass, which is, in particular, for the scale-free model, P(k)∌k−γP(k)\sim k^{-\gamma}, with 2<Îł<32<\gamma<3. The Λ\LambdaCDM model becomes, with these considerations, a consequence of the particular statistics together with the use of general relativity.Comment: 7 pages, 4 figure

    Running Scaling Dimensions in Holographic Renormalization Group Flows

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    Holographic renormalization group flows can be interpreted in terms of effective field theory. Based on such an interpretation, a formula for the running scaling dimensions of gauge-invariant operators along such flows is proposed. The formula is checked for some simple examples from the AdS/CFT correspondence, but can be applied also in non-AdS/non-CFT cases.Comment: 14 pages, 2 figure

    Evidence for Factorization in Three-body B --> D(*) K- K0 Decays

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    Motivated by recent experimental results, we use a factorization approach to study the three-body B --> D(*) K- K0 decay modes. Two mechanisms are proposed for kaon pair production: current-produced (from vacuum) and transition (from B meson). The Bbar0 --> D(*)+ K- K0 decay is governed solely by the current-produced mechanism. As the kaon pair can be produced only by the vector current, the matrix element can be extracted from e+ e- --> K Kbar processes via isospin relations. The decay rates obtained this way are in good agreement with experiment. Both current-produced and transition processes contribute to B- --> D(*)0 K- K0 decays. By using QCD counting rules and the measured B- --> D(*)0 K- K0 decay rates, the measured decay spectra can be understood.Comment: 17 pages, 6 figure

    Studies of the motion and decay of axion walls bounded by strings

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    We discuss the appearance at the QCD phase transition, and the subsequent decay, of axion walls bounded by strings in N=1 axion models. We argue on intuitive grounds that the main decay mechanism is into barely relativistic axions. We present numerical simulations of the decay process. In these simulations, the decay happens immediately, in a time scale of order the light travel time, and the average energy of the radiated axions is ≃7ma \simeq 7 m_a for va/ma≃500v_a/m_a \simeq 500. is found to increase approximately linearly with ln⁥(va/ma)\ln(v_a/m_a). Extrapolation of this behaviour yields ∌60ma \sim 60 m_a in axion models of interest. We find that the contribution to the cosmological energy density of axions from wall decay is of the same order of magnitude as that from vacuum realignment, with however large uncertainties. The velocity dispersion of axions from wall decay is found to be larger, by a factor 10310^3 or so, than that of axions from vacuum realignment and string decay. We discuss the implications of this for the formation and evolution of axion miniclusters and for the direct detection of axion dark matter on Earth. Finally we discuss the cosmology of axion models with N>1N>1 in which the domain wall problem is solved by introducing a small UPQ_{PQ}(1) breaking interaction. We find that in this case the walls decay into gravitational waves.Comment: 37 pages, 10 figures, a minor mistake was corrected, several references and comments were adde

    Chiral 2pi exchange at order four and peripheral NN scattering

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    We calculate the impact of the complete set of two-pion exchange contributions at chiral order four (also known as next-to-next-to-next-to-leading order, N3LO) on peripheral partial waves of nucleon-nucleon scattering. Our calculations are based upon the analytical studies by Kaiser. It turns out that the contribution of order four is substantially smaller than the one of order three, indicating convergence of the chiral expansion. We compare the prediction from chiral pion-exchange with the corresponding one from conventional meson-theory as represented by the Bonn Full Model and find, in general, good agreement. Our calculations provide a sound basis for investigating the issue whether the low-energy constants determined from pi-N lead to reasonable predictions for NN.Comment: 22 pages RevTex including 11 figure

    Temperature and Density Effects on the Nucleon Mass Splitting

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    The finite temperature and finite density dependence of the neutron-proton mass difference is analysed in a purely hadronic framework where the ρ−ω\rho-\omega mixing is crucial for this isospin symmetry breakdown. The problem is handled within Thermo Field Dynamics. The present results, consistent with partial chiral and charge symmetry restoration, improve the experimental data fit for the energy difference between mirror nuclei.Comment: 17 pages, revtex fil

    IR divergences and kinetic equation in de Sitter space. (Poincare patch; Principal series)

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    We explicitly show that the one loop IR correction to the two--point function in de Sitter space scalar QFT does not reduce just to the mass renormalization. The proper interpretation of the loop corrections is via particle creation revealing itself through the generation of the quantum averages ,, and ,whichslowlychangeintime.WeshowthatthisobservationinparticularmeansthatloopcorrectionstocorrelationfunctionsindeSitterspacecannotbeobtainedviaanalyticalcontinuationofthosecalculatedonthesphere.Wefindharmonicsforwhichtheparticlenumber, which slowly change in time. We show that this observation in particular means that loop corrections to correlation functions in de Sitter space can not be obtained via analytical continuation of those calculated on the sphere. We find harmonics for which the particle number dominates over the anomalous expectation values and and . For these harmonics the Dyson--Schwinger equation reduces in the IR limit to the kinetic equation. We solve the latter equation, which allows us to sum up all loop leading IR contributions to the Whiteman function. We perform the calculation for the principle series real scalar fields both in expanding and contracting Poincare patches.Comment: 33 pages, 6 fig; Language was correcte
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