868 research outputs found

    Long-range magnetic fields in the ground state of the Standard Model plasma

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    In thermal equilibrium the ground state of the plasma of Standard Model particles is determined by temperature and exactly conserved combinations of baryon and lepton numbers. We show that at non-zero values of the global charges a translation invariant and homogeneous state of the plasma becomes unstable and the system transits into a new state, containing a large-scale magnetic field. The origin of this effect is the parity-breaking character of weak interactions and chiral anomaly. This situation can occur in the early Universe and may play an important role in its subsequent evolution.Comment: 6 pages. Comments are welcom

    On the induced gauge invariant mass

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    We derive a general expression for the gauge invariant mass (m_G) for an Abelian gauge field, as induced by vacuum polarization, in 1+1 dimensions. From its relation to the chiral anomaly, we show that m_G has to satisfy a certain quantization condition. This quantization can be, on the other hand, explicitly verified by using the exact general expression for the gauge invariant mass in terms of the fermion propagator. This result is applied to some explicit examples, exploring the possibility of having interesting physical situations where the value of mGm_G departs from its canonical value. We also study the possibility of generalizing the results to the 2+1 dimensional case at finite temperature, showing that there are indeed situations where a finite and non-vanishing gauge invariant mass is induced.Comment: 18 pages, Latex, 3 figures (pstex

    A Comprehensive Analysis on the Pion-Photon Transition Form Factor Beyond the Leading Fock State

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    We perform a comprehensive analysis of the pion-photon transition form factor Fπγ(Q2)F_{\pi \gamma}(Q^2) involving the transverse momentum corrections with the present CLEO experimental data, in which the contributions beyond the leading Fock state have been taken into consideration. As is well-known, the leading Fock-state contribution dominates of Fπγ(Q2)F_{\pi \gamma}(Q^2) at large momentum transfer (Q2Q^2) region. One should include the contributions beyond the leading Fock state in small Q2Q^2 region. In this paper, we construct a phenomenological expression to estimate the contributions beyond the leading Fock state based on its asymptotic behavior at Q20Q^2\to0. Our present theoretical results agree well with the experimental data in the whole Q2Q^2 region. Then, we extract some useful information of the pionic leading twist-2 distribution amplitude (DA) by comparing our results of Fπγ(Q2)F_{\pi \gamma}(Q^2) with the CLEO data. By taking best fit, we have the DA moments, a2(μ02)=0.0020.054+0.063a_2(\mu_0^2)=0.002^{+0.063}_{-0.054}, a4(μ02)=0.0220.012+0.026a_4(\mu_0^2)=-0.022_{-0.012}^{+0.026} and all of higher moments, which are closed to the asymptotic-like behavior of the pion wavefunction.Comment: 25 pages, 7 figures. Typo error correcte

    Elementary Derivation of the Chiral Anomaly

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    An elementary derivation of the chiral gauge anomaly in all even dimensions is given in terms of noncommutative traces of pseudo-differential operators.Comment: Minor errors and misprints corrected, a reference added. AmsTex file, 12 output pages. If you do not have preloaded AmsTex you have to \input amstex.te

    Dipole binding in a cosmic string background due to quantum anomalies

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    We propose quantum dynamics for the dipole moving in cosmic string background and show that the classical scale symmetry of a particle moving in cosmic string background is still restored even in the presence of dipole moment of the particle. However, we show that the classical scale symmetry is broken due to inequivalent quantization of the the non-relativistic system. The consequence of this quantum anomaly is the formation of bound state in the interval \xi\in(-1,1). The inequivalent quantization is characterized by a 1-parameter family of self-adjoint extension parameter \Sigma. We show that within the interval \xi\in(-1,1), cosmic string with zero radius can bind the dipole and the dipole does not fall into the singularity.Comment: Accepted for publication in Phys. Rev.

    Conference on Early Mars: Geologic and Hydrologic Evolution, Physical and Chemical Environments, and the Implications for Life

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    Topics considered include: Geology alteration and life in an extreme environment; developing a chemical code to identify magnetic biominerals; effect of impacts on early Martin geologic evolution; spectroscopic identification of minerals in Hematite-bearing soils and sediments; exopaleontology and the search for a Fossil record on Mars; geochemical evolution of the crust of Mars; geological evolution of the early earth;solar-wind-induced erosion of the Mars atmosphere. Also included geological evolution of the crust of Mars

    Higher Dimensional Schwinger-like Anomalous Effective Action

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    We construct explicit form of the anomalous effective action, in arbitrary even dimension, for Abelian vector and axial gauge fields coupled to Dirac fermions. It turns out to be a surprisingly simple extension of 2D Schwinger model effective action.Comment: 7 pages, no figures, ReVTeX, to appear in Phys.Rev.

    Inequality and Procedural Justice in Social Dilemmas

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    This study investigates the influence of resource inequality and the fairness of the allocation procedure of unequal resources on cooperative behavior in social dilemmas. We propose a simple formal behavioral model that incorporates conflicting selfish and social motivations. This model allows us to predict how inequality influences cooperative behavior. Allocation of resources is manipulated by three treatments that vary in terms of procedural justice: allocating resources randomly, based on merit, and based on ascription. As predicted, procedural justice influences cooperation significantly. Moreover, gender is found to be an important factor interacting with the association between procedural justice and cooperative behavior.

    A New Look at the Axial Anomaly in Lattice QED with Wilson Fermions

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    By carrying out a systematic expansion of Feynman integrals in the lattice spacing, we show that the axial anomaly in the U(1) lattice gauge theory with Wilson fermions, as determined in one-loop order from an irrelevant lattice operator in the Ward identity, must necessarily be identical to that computed from the dimensionally regulated continuum Feynman integrals for the triangle diagrams.Comment: 1 figure, LaTeX, 18 page

    Induced fermionic current in toroidally compactified spacetimes with applications to cylindrical and toroidal nanotubes

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    The vacuum expectation value of the fermionic current is evaluated for a massive spinor field in spacetimes with an arbitrary number of toroidally compactified spatial dimensions in presence of a constant gauge field. By using the Abel-Plana type summation formula and the zeta function technique we present the fermionic current in two different forms. Non-trivial topology of the background spacetime leads to the Aharonov-Bohm effect on the fermionic current induced by the gauge field. The current is a periodic function of the magnetic flux with the period equal to the flux quantum. In the absence of the gauge field it vanishes for special cases of untwisted and twisted fields. Applications of the general formulae to Kaluz-Klein type models and to cylindrical and toroidal carbon nanotubes are given. In the absence of magnetic flux the total fermionic current in carbon nanotubes vanishes, due to the cancellation of contributions from two different sublattices of the graphene hexagonal lattice.Comment: 18 pages, 5 figures, explicit regularization procedure adde
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