669 research outputs found
The Cosmic Ray Antiproton Background for AMS-02
The AMS-02 experiment is measuring the cosmic ray antiproton flux with high
precision. The interpretation of the upcoming data requires a thorough
understanding of the secondary antiproton background. In this work, we employ
newly available data of the NA49 experiment at CERN, in order to recalculate
the antiproton source term arising from cosmic ray spallations on the
interstellar matter. We systematically account for the production of
antiprotons via hyperon decay and discuss the possible impact of isospin
effects on antineutron production. A detailed comparison of our calculation
with the existing literature as well as with Monte Carlo based evaluations of
the antiproton source term is provided. Our most important result is an updated
prediction for the secondary antiproton flux which includes a realistic
assessment of the particle physics uncertainties at all energies.Comment: 24 pages, 10 figures, source term and secondary flux available in the
ancillary file
Aligned Natural Inflation: Monodromies of two Axions
Natural (axionic) inflation can accommodate sizeable primordial tensor modes
but suffers from the necessity of trans-Planckian variations of the inflaton
field. This problem can be solved via the mechanism of aligned axions
arXiv:hep-ph/0409138, where the aligned axion spirals down in the potential of
other axions. We elaborate on the mechanism in view of the recently reported
observations of the BICEP2 collaboration arXiv:1403.3985.Comment: 11 pages, 3 figures, v2: typos corrected, references added, v3:
references added, matches published versio
Modulated Natural Inflation
We discuss some model-independent implications of embedding (aligned) axionic
inflation in string theory. As a consequence of string theoretic duality
symmetries the pure cosine potentials of natural inflation are replaced by
modular functions. This leads to "wiggles" in the inflationary potential that
modify the predictions with respect to CMB-observations. In particular, the
scalar power spectrum deviates from the standard power law form. As a
by-product one can show that trans-Planckian excursions of the aligned
effective axion are compatible with the weak gravity conjecture.Comment: 8 pages, 6 figure
Natural Inflation and Low Energy Supersymmetry
Natural (axionic) inflation provides a well-motivated and predictive scheme
for the description of the early universe. It leads to sizeable primordial
tensor modes and thus a high mass scale of the inflationary potential. Naively
this seems to be at odds with low (TeV) scale supersymmetry, especially when
embedded in superstring theory. We show that low scale supersymmetry is
compatible with natural (high scale) inflation. The mechanism requires the
presence of two axions that are provided through the moduli of string theory.Comment: 15 pages, 4 figure
The Hilbert basis method for D-flat directions and the superpotential
We discuss, using the Hilbert basis method, how to efficiently construct a
complete basis for D-flat directions in supersymmetric Abelian and non-Abelian
gauge theories. We extend the method to discrete (R and non-R) symmetries. This
facilitates the construction of a basis of all superpotential terms in a theory
with given symmetries.Comment: 11 pages; a related mathematica code can be found at
http://einrichtungen.ph.tum.de/T30e/codes/NonAbelianHilbert
Elastic Superhydrophobic and Photocatalytic Active Films Used as Blood Repellent Dressing
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