3,461 research outputs found
A Simple UV-Completion of QED in 5D
We construct a Lifshitz-like version of five-dimensional (5D) QED which is UV
- completed and reduces at low energies to ordinary 5D QED. The UV quantum
behaviour of this theory is very smooth. In particular, the gauge coupling
constant is finite at all energy scales and at all orders in perturbation
theory. We study the IR properties of this theory, when compactified on a
circle, and compare the one-loop energy dependence of the coupling in the
Lifshitz theory with that coming from the standard 5D QED effective field
theory. The range of validity of the 5D effective field theory is found to
agree with the more conservative version of Naive Dimensional Analysis.Comment: 24 pages, 7 figures; v2: Minor improvements, matches journal versio
Effect of sodium hyluronate added to topical corticosteroids in chronic rhinosinusitis with nasal polyposis
Available medical treatments for chronic rhinosinusitis (CRS) with nasal polyposis (CRSwNP) comprise systemic and topical therapies. Although topical corticosteroids are effective in the treatment of CRS, they are not completely devoid of adverse effects. Thus, care has to be taken when long-term treatments are prescribed. There is recent evidence that sodium hyaluronate (SH), the major component of many extracellular matrices, promotes tissue healing, including activation and moderation of the inflammatory responses, cell proliferation, migration, and angiogenesis
Multiloop divergences in the closed bosonic string theory
The structure of the divergences in the multiloop vacuum diagrams for the closed bosonic strings in the framework of the Polyakov covariant formalism is discussed. It is found, by an explicit computation, that all the divergences in the theory may be interpreted as due to tadpole diagrams in which the dilaton goes into the vacuum
Sommerfeld enhancement from Goldstone pseudo-scalar exchange
We point out that the exchange of a Goldstone pseudo-scalar can provide an
enhancement in the dark matter annihilation rate capable of explaining the
excess flux seen in high energy cosmic ray data. The mechanism of enhancement
involves the coupling of s and d waves through the tensor force that is very
strong and, in fact, singular at short distances. The results indicate that
large enhancements require some amount of fine tuning. We also discuss the
enhancement due to other singular attractive potentials, such as WIMP models
with a permanent electric dipole.Comment: 14 pages, 4 figures, v2 includes contact informatio
Factorization and Unitarity in Superstring Theory
The overall coefficient of the two-loop 4-particle amplitude in superstring
theory is determined by making use of the factorization and unitarity. To
accomplish this we computed in detail all the relevant tree and one-loop
amplitudes involved and determined their overall coefficients in a consistent
way.Comment: LaTex file, 19 pages, 4 figures; v2, minor corrections and figures
corrected; v3, minor corrections with the English, to be published in JHE
Factorization of the Two Loop Four-Particle Amplitude in Superstring Theory Revisited
We study in detail the factorization of the newly obtained two-loop
four-particle amplitude in superstring theory. In particular some missing
factors from the scalar correlators are obtained correctly, in comparing with a
previous study of the factorization in two-loop superstring theory. Some
details for the calculation of the factorization of the kinematic factor are
also presented.Comment: 11 pages, 1 figure; v2, minor corrections and references update
Edge Tunneling of Vortices in Superconducting Thin Films
We investigate the phenomenon of the decay of a supercurrent due to the
zero-temperature quantum tunneling of vortices from the edge in a thin
superconducting film in the absence of an external magnetic field. An explicit
formula is derived for the tunneling rate of vortices, which are subject to the
Magnus force induced by the supercurrent, through the Coulomb-like potential
barrier binding them to the film's edge. Our approach ensues from the
non-relativistic version of a Schwinger-type calculation for the decay of the
2D vacuum previously employed for describing vortex-antivortex pair-nucleation
in the bulk of the sample. In the dissipation-dominated limit, our explicit
edge-tunneling formula yields numerical estimates which are compared with those
obtained for bulk-nucleation to show that both mechanisms are possible for the
decay of a supercurrent.Comment: REVTeX file, 15 pages, 1 Postscript figure; to appear in Phys.Rev.
Multiloop divergences in the closed bosonic string theory
The structure of the divergences in the multiloop vacuum diagrams for the closed bosonic strings in the framework of the Polyakov covariant formalism is discussed. It is found, by an explicit computation, that all the divergences in the theory may be interpreted as due to tadpole diagrams in which the dilaton goes into the vacuum
String Form Factors
We compute the cross section for scattering of light string probes by
randomly excited closed strings. For high energy probes, the cross section
factorizes and can be used to define effective form factors for the excited
targets. These form factors are well defined without the need for infinite
subtractions and contain information about the shape and size of typical
strings. For highly excited strings the elastic form factor can be written in
terms of the `plasma dispersion function', which describes charge screening in
high temperature plasmas.Comment: 18 pages, 3 figures. Typos corrected, 1 footnote (in Section 4) and 1
reference adde
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