868 research outputs found
Long-range magnetic fields in the ground state of the Standard Model plasma
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
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 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
We perform a comprehensive analysis of the pion-photon transition form factor
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 at large momentum
transfer () region. One should include the contributions beyond the
leading Fock state in small region. In this paper, we construct a
phenomenological expression to estimate the contributions beyond the leading
Fock state based on its asymptotic behavior at . Our present
theoretical results agree well with the experimental data in the whole
region. Then, we extract some useful information of the pionic leading twist-2
distribution amplitude (DA) by comparing our results of
with the CLEO data. By taking best fit, we have the DA moments,
,
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
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
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
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
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
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
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
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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