303 research outputs found

    Nuclear Matter in Intense Magnetic Field and Weak Processes

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    We study the effect of magnetic field on the dominant neutrino emission processes in neutron stars.The processes are first calculated for the case when the magnetic field does not exceed the critical value to confine electrons to the lowest Landau state.We then consider the more important case of intense magnetic field to evaluate the direct URCA and the neutronisation processes. In order to estimate the effect we derive the composition of cold nuclear matter at high densities and in beta equilibrium, a situation appropriate for neutron stars. The hadronic interactions are incorporated through the exchange of scalar and vector mesons in the frame work of relativistic mean field theory. In addition the effects of anomalous magnetic moments of nucleons are also considered.Comment: 29 pages (LaTeX) including 7 figure

    On Primordial Magnetic Fields of Electroweak Origin

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    We consider Vachaspati's primordial magnetic field which is generated at the electroweak phase transition. Assuming that either the gradients of the Higgs field or, alternatively, the magnetic field itself are stochastic variables with a normal distribution, we find that the resulting magnetic field has an {\em rms} value in the present-day universe which is fully consistent with what is required for the galactic dynamo mechanism.Comment: 11 pages, Latex, no figures. Preprint NBI-HE-93-3

    Variational Principle in the Algebra of Asymptotic Fields

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    This paper proposes a variational principle for the solutions of quantum field theories in which the ``trial functions'' are chosen from the algebra of asymptotic fields, and illustrates this variational principle in simple cases.Comment: 15 pages, Latex, no figure

    The Color--Flavor Transformation of induced QCD

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    The Zirnbauer's color-flavor transformation is applied to the U(Nc)U(N_c) lattice gauge model, in which the gauge theory is induced by a heavy chiral scalar field sitting on lattice sites. The flavor degrees of freedom can encompass several `generations' of the auxiliary field, and for each generation, remaining indices are associated with the elementary plaquettes touching the lattice site. The effective, color-flavor transformed theory is expressed in terms of gauge singlet matrix fields carried by lattice links. The effective action is analyzed for a hypercubic lattice in arbitrary dimension. We investigate the corresponding d=2 and d=3 dual lattices. The saddle points equations of the model in the large-NcN_c limit are discussed.Comment: 24 pages, 6 figures, to appear in Int. J. Mod. Phys.

    Anomalous Chromomagnetic Moments of Quarks and Large Transverse Energy Jets

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    We consider the jet cross sections for gluons coupling to quarks with an anomalous chromomagnetic moment. We then apply this to the deviation and bounds from QCD found in the CDF and D0 Fermilab data, respectively, to find a range of possible values for the anomalous moments. The quadratic and quartic terms in the anomalous moments can fit to the rise of a deviation with transverse energy. Since previous analyses have been done on the top quark total cross section, here we assume the same moment on all quarks except the top and find the range ∣Îșâ€Č∣≡∣Îș/(2mq)∣=1.0±0.3|\kappa'| \equiv |\kappa/(2 m_q)| = 1.0\pm 0.3 TeV−1^{-1} for the CDF data. Assuming the anomalous moment is present only on a charm or bottom quark which is pair produced results in a range ∣Îșb,câ€Č∣=3.5±1.0|\kappa'_{b,c}| = 3.5 \pm 1.0 TeV−1^{-1}. The magnitudes here are compared with anomalous magnetic moments that could account for RbR_b and found to be in the same general range, as well as not inconsistent with LEP and SLD bounds on ΔΓhad\Delta \Gamma_{\text{had}}.Comment: REVTeX, 11 pages, 2 postscript figure

    Stability and Representation Dependence of the Quantum Skyrmion

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    A constructive realization of Skyrme's conjecture that an effective pion mass ``may arise as a self consistent quantal effect'' based on an ab initio quantum treatment of the Skyrme model is presented. In this quantum mechanical Skyrme model the spectrum of states with I=JI=J, which appears in the collective quantization, terminates without any infinite tower of unphysical states. The termination point depends on the model parameters and the dimension of the SU(2) representation. Representations, in which the nucleon and Δ33\Delta_{33} resonance are the only stable states, exist. The model is developed for both irreducible and reducible representations of general dimension. States with spin larger than 1/2 are shown to be deformed. The representation dependence of the baryon observables is illustrated numerically.Comment: 19 pages, Late

    Lorentz and Galilei Invariance on Lattices

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    We show that the algebraic aspects of Lie symmetries and generalized symmetries in nonrelativistic and relativistic quantum mechanics can be preserved in linear lattice theories. The mathematical tool for symmetry preserving discretizations on regular lattices is the umbral calculus.Comment: 5 page

    Baryons with Two Heavy Quarks as Solitons

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    Using the chiral soliton model and heavy quark symmetry we study baryons containing two heavy quarks. If there exists a stable (under strong interactions) meson consisting of two heavy quarks and two light ones, then we find that there always exists a state of this meson bound to a chiral soliton and to a chiral anti-soliton, corresponding to a two heavy quark baryon and a baryon containing two heavy anti-quarks and five light quarks, or a ``heptaquark".Comment: 7 pages and 2 postscript figures appended, LaTex, UCI-TR 94-3

    Instability of Quark Matter Core in a Compact Newborn Neutron Star With Moderately Strong Magnetic Field

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    It is explicitly shown that if phase transition occurs at the core of a newborn neutron star with moderately strong magnetic field strength, which populates only the electron's Landau levels, then in the ÎČ\beta-equilibrium condition, the quark core is energetically much more unstable than the neutron matter of identical physical condition.Comment: Six pages REVTEX file, one .eps file (included
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