152,597 research outputs found
String Representation for the 't Hooft Loop Average in the Abelian Higgs Model
Making use of the duality transformation, we derive in the Londons' limit of
the Abelian Higgs Model string representation for the 't Hooft loop average
defined on the string world-sheet, which yields the values of two coefficient
functions parametrizing the bilocal correlator of the dual field strength
tensors. The asymptotic behaviours of these functions agree with the ones
obtained within the Method of Vacuum Correlators in QCD in the lowest order of
perturbation theory. We demonstrate that the bilocal approximation to the
Method of Vacuum Correlators is an exact result in the Londons' limit, i.e. all
the higher cumulants in this limit vanish. We also show that at large
distances, apart from the integration over metrics, the obtained string
effective theory (which in this case reduces to the nonlinear massive axionic
sigma model) coincides with the low-energy limit of the dual version of 4D
compact QED, the so-called Universal Confining String Theory. We derive string
tension of the Nambu-Goto term and the coupling constant of the rigidity term
for the obtained string effective theory and demonstrate that the latter one is
always negative, which means the stability of strings, while the positiveness
of the former is confirmed by the present lattice data. These data enable us to
find the Higgs boson charge and the vacuum expectation value of the Higgs
field, which model QCD best of all. We also study dynamics of the weight factor
of the obtained string representation for the 't Hooft average in the loop
space. In conclusion, we obtain string representation for the partition
function of the correlators of an arbitrary number of Higgs currents, by virtue
of which we rederive the structure of the bilocal correlator of the dual field
strength tensors, which yields the surface term in the string effective action.Comment: 11 pages, LaTeX, no figures, references are adde
Gamma-ray bursts and the relevance of rotation-induced neutrino sterilization
A la Pontecorvo when one defines electroweak flavour states of neutrinos as a
linear superposition of mass eigenstates one ignores the associated spin. If,
however, there is a significant rotation between the neutrino source, and the
detector, a negative helicity state emitted by the former acquires a non-zero
probability amplitude to be perceived as a positive helicity state by the
latter. Both of these states are still in the left-Weyl sector of the Lorentz
group. The electroweak interaction cross sections for such helicity-flipped
states are suppressed by a factor of , where is the
expectation value of the neutrino mass, and is the associated energy.
Thus, if the detecting process is based on electroweak interactions, and the
neutrino source is a highly rotating object, the rotation-induced helicity flip
becomes very significant in interpreting the data. The effect immediately
generalizes to anti-neutrinos. Motivated by these observations we present a
generalization of the Pontecorvo formalism and discuss its relevance in the
context of recent data obtained by the IceCube neutrino telescope.Comment: 4 page
Three-Species Diffusion-Limited Reaction with Continuous Density-Decay Exponents
We introduce a model of three-species two-particle diffusion-limited
reactions A+B -> A or B, B+C -> B or C, and C+A -> C or A, with three
persistence parameters (survival probabilities in reaction) of the hopping
particle. We consider isotropic and anisotropic diffusion (hopping with a
drift) in 1d. We find that the particle density decays as a power-law for
certain choices of the persistence parameter values. In the anisotropic case,
on one symmetric line in the parameter space, the decay exponent is
monotonically varying between the values close to 1/3 and 1/2. On another, less
symmetric line, the exponent is constant. For most parameter values, the
density does not follow a power-law. We also calculated various characteristic
exponents for the distance of nearest particles and domain structure. Our
results support the recently proposed possibility that 1d diffusion-limited
reactions with a drift do not fall within a limited number of distinct
universality classes.Comment: 12 pages in plain LaTeX and four Postscript files with figure
Double charmonium production at B-factories within light cone formalism
This paper is devoted to the study of the processes e^+e^- \to J/\Psi \eta_c,
J/\Psi \eta_c', \psi' \eta_c, \psi' \eta_c' within light cone formalism. It is
shown that if one disregards the contribution of higher fock states, the
twist-3 distribution amplitudes needed in the calculation can be unambiguously
determined from the twist-2 distribution amplitudes and equations of motion.
Using models of the twist-2 distribution amplitudes the cross sections of the
processes under study have been calculated. The results of the calculation are
in agreement with Belle and BaBar experiments. It is also shown that
relativistic and radiative corrections to the cross sections play crucial role
in the achievement of the agreement between the theory and experiments. The
comparison of the results of this paper with the results obtained in other
papers has been carried out. In particular, it is shown that the results of
papers where relativistic and radiative corrections were calculated within
NRQCD are overestimated by a factor of ~1.5.Comment: 14 pages, 1 figur
Dark matter and dark gauge fields
Following the unexpected theoretical discovery of a mass dimension one
fermionic quantum field of spin one half, we now present first results on two
_local_ versions. The Dirac and Majorana fields of the standard model of
particle physics are supplemented by their natural counterparts in the dark
matter sector. The possibility that a mass dimension transmuting symmetry may
underlie a new standard model of particle physics is briefly suggested.Comment: This manuscript combines a plenary talk (by DVA) and an invited talk
(by DS) at "Dark 2007 - Sixth International Heidelberg Conference on Dark
Matter in Astro and Particle Physics (Sydney, Australia, 24th-28th September
2007)." 11 pages. v2: minor typos correcte
Light Gravitinos at Colliders and Implications for Cosmology
Light gravitinos, with mass in the eV to MeV range, are well-motivated in
particle physics, but their status as dark-matter candidates is muddled by
early-Universe uncertainties. We investigate how upcoming data from colliders
may clarify this picture. Light gravitinos are produced primarily in the decays
of the next-to-lightest supersymmetric particle, resulting in spectacular
signals, including di-photons, delayed and non-pointing photons, kinked charged
tracks, and heavy metastable charged particles. We find that the Tevatron with
20/fb and the 7 TeV LHC with 1/fb may both see evidence for hundreds of
light-gravitino events. Remarkably, this collider data is also well suited to
distinguish between currently viable light-gravitino scenarios, with striking
implications for structure formation, inflation, and other early-Universe
cosmology.Comment: 12 pages, 6 figures. To be submitted to Phys. Rev. D
Chiral symmetry breaking in a uniform external magnetic field II. Symmetry restoration at high temperatures and chemical potentials
Chiral symmetry is dynamically broken in quenched, ladder QED at weak gauge
couplings when an external magnetic field is present. In this paper, we show
that chiral symmetry is restored above a critical chemical potential and the
corresponding phase transition is of first order. In contrast, the chiral
symmetry restoration at high temperatures (and at zero chemical potential) is a
second order phase transition.Comment: Latex; 12 pages; 8 postscript figures include
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The Business Boost from Marriage Equality: Evidence from the Health and Marriage Equality in Massachusetts Survey
This brief draws on two sources of data, a survey and state-collected tax revenue data, and finds that marriages have had a positive economic effect on Massachusetts -- likely providing a boost of over $100 million to the state economy. Same-sex couples' weddings injected significant spending into the Massachusetts economy and brought out-of-state guests to the state, whose spending also added to the economic boost
Search for Free Fractional Electric Charge Elementary Particles
We have carried out a direct search in bulk matter for free fractional
electric charge elementary particles using the largest mass single sample ever
studied - about 17.4 mg of silicone oil. The search used an improved and highly
automated Millikan oil drop technique. No evidence for fractional charge
particles was found. The concentration of particles with fractional charge more
than 0.16e (e being the magnitude of the electron charge) from the nearest
integer charge is less than particles per nucleon with 95%
confidence.Comment: 10 pages,LaTeX, 4 PS figures, submitted to PR
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