4,765 research outputs found
Towards Axion Monodromy Inflation with Warped KK-Modes
We present a particularly simple model of axion monodromy: Our axion is the
lowest-lying KK-mode of the RR-2-form-potential in the standard
Klebanov-Strassler throat. One can think of this inflaton candidate as being
defined by the integral of over the cycle of the throat. It obtains
an exponentially small mass from the IR-region in which the shrinks to
zero size both with respect to the Planck scale and the mass scale of local
modes of the throat. Crucially, the cycle has to be shared between two
throats, such that the second locus where the shrinks is also in a warped
region. Well-known problems like the potentially dangerous back-reaction of
brane/antibrane pairs and explicit supersymmetry breaking are not present in
our scenario. However, the inflaton back-reaction starts to deform the geometry
strongly once the field excursion approaches the Planck scale. We derive the
system of differential equations required to treat this effect quantitatively.
Numerical work is required to decide whether back-reaction makes the model
suitable for realistic inflation. While we have to leave this crucial issue to
future studies, we find it interesting that such a simple and explicit stringy
monodromy model allows an originally sub-Planckian axion to go through many
periods with full quantitative control before back-reaction becomes strong.
Also, the mere existence of our ultra-light throat mode (with double
exponentially suppressed mass) is noteworthy.Comment: 28 pages, 3 figures; v2: references added; v3: Corrected an
underestimate of supergravity back-reaction in Eq. (36); results changed
accordingly; added section 6 which develops the methodology for the 10d
non-linear back-reaction; added reference
Unravelling reaction products of styrene oxide adsorbed on Ag(111) using REMPI-assisted temperature-programmed desorption.
Adsorption of styrene oxide on Ag(111) at 200 K leads to the formation of a stable oxametallacycle by ring-opening of the epoxide. At elevated temperatures, the oxametallacycle reacts and the products desorb from the surface. We employ resonance-enhanced multiphoton ionization time-of-flight mass spectrometry (REMPI-ToF-MS) to identify reaction products after desorption. We assign phenylacetaldehyde as the only product that desorbs at temperatures around 485 K
Surface roughness interpretation of 730 kg days CRESST-II results
The analysis presented in the recent publication of the CRESST-II results
finds a statistically significant excess of registered events over known
background contributions in the acceptance region and attributes the excess to
a possible Dark Matter signal, caused by scattering of relatively light WIMPs.
We propose a mechanism which explains the excess events with ion sputtering
caused by 206Pb recoils and alpha particles from 210Po decay, combined with
realistic surface roughness effects.Comment: 15 pages, 6 figures. v2: corrected quenching factor discussion. v3:
corrected references. v4: added reference
Molecular cloning and expression analysis of MPPa-2, a novel mouse transcript detected in a differential screen of pituitary libraries
We identified a novel isoform transcript, MPP alpha-2, of the mouse Mg(2+)-dependent protein phosphatase (MPP) alpha gene. The amino acid sequence encoded by MPP alpha-2 differs from the previously known MPP alpha-1 sequence only at the carboxyl terminal region. Northern and in situ hybridization analysis revealed differential expression patterns of these two transcripts in the embryo and in the adult organism, suggesting an elaborate regulation of the MPP alpha gene
Farthest points and monotone operators
We apply the theory of monotone operators to study farthest points in closed bounded subsets of real Banach spaces. This new approach reveals the intimate connection between the farthest point mapping and the subdifferential of the farthest distance function. Moreover, we prove that a typical exception set in the Baire category sense is pathwise connected. Stronger results are obtained in Hubert spaces
A Phase Transition between Small and Large Field Models of Inflation
We show that models of inflection point inflation exhibit a phase transition
from a region in parameter space where they are of large field type to a region
where they are of small field type. The phase transition is between a universal
behavior, with respect to the initial condition, at the large field region and
non-universal behavior at the small field region. The order parameter is the
number of e-foldings. We find integer critical exponents at the transition
between the two phases.Comment: 21 pages, 8 figure
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