489 research outputs found
Self-limited growth of nanocrystals in structural heterogeneous phosphosilicate melts during cooling:An invited talk
AdS/QCD Phenomenological Models from a Back-Reacted Geometry
We construct a fully back-reacted holographic dual of a four-dimensional
field theory which exhibits chiral symmetry breaking. Two possible models are
considered by studying the effects of a five-dimensional field, dual to the
operator. One model has smooth geometry at all radii and the other
dynamically generates a cutoff at finite radius. Both of these models satisfy
Einstein's field equations. The second model has only three free parameters, as
in QCD, and we show that this gives phenomenologically consistent results. We
also discuss the possibility that in order to obtain linear confinement from a
back-reacted model it may be necessary to consider the condensate of a
dimension two operator.Comment: 13 pages, 4 figures, Replaced with minor correction
Spin- and charge-density oscillations in spin chains and quantum wires
We analyze the spin- and charge-density oscillations near impurities in spin
chains and quantum wires. These so-called Friedel oscillations give detailed
information about the impurity and also about the interactions in the system.
The temperature dependence of these oscillations explicitly shows the
renormalization of backscattering and conductivity, which we analyze for a
number of different impurity models. We are also able to analyze screening
effects in one dimension. The relation to the Kondo effect and experimental
consequences are discussed.Comment: Final published version. 15 pages in revtex format including 22
epsf-embedded figures. The latest version in PDF format is available from
http://fy.chalmers.se/~eggert/papers/density-osc.pd
Muon anomalous magnetic moment in the standard model with two Higgs doublets
The muon anomalous magnetic moment is investigated in the standard model with
two Higgs doublets (S2HDM) motivated from spontaneous CP violation. Thus all
the effective Yukawa couplings become complex. As a consequence of the non-zero
phase in the couplings, the one loop contribution from the neutral scalar
bosons could be positive and negative relying on the CP phases. The
interference between one and two loop diagrams can be constructive in a large
parameter space of CP-phases. This will result in a significant contribution to
muon anomalous magnetic moment even in the flavor conserving process with a
heavy neutral scalar boson ( 200 GeV) once the effective muon Yukawa
coupling is large (). In general, the one loop contributions
from lepton flavor changing scalar interactions become more important. In
particular, when all contributions are positive in a reasonable parameter space
of CP phases, the recently reported 2.6 sigma experiment vs. theory deviation
can be easily explained even for a heavy scalar boson with a relative small
Yukawa coupling in the S2HDM.Comment: 8 pages, RevTex file, 5 figures, published version Phys. Rev. D 54
(2001) 11501
Low energy fast events from radon progenies at the surface of a CsI(Tl) scintillator
In searches for rare phenomena such as elastic scattering of dark matter
particles or neutrinoless double beta decay, alpha decays of Rn222 progenies
attached to the surfaces of the detection material have been identified as a
serious source of background. In measurements with CsI(Tl) scintillator
crystals, we demonstrate that alpha decays of surface contaminants produce fast
signals with a characteristic mean-time distribution that is distinct from
those of neutron- and gamma-induced events.Comment: 9 pages, 8 figure
Rapid increase of scrub typhus incidence in Guangzhou, southern China, 2006-2014
Background: In the last decade, scrub typhus (ST) has been emerging or re-emerging in some areas of Asia, including Guangzhou, one of the most affected endemic areas of ST in China. Methods: Based on the data on all cases reported in Guangzhou from 2006 to 2014, we characterized the epidemiological features, and identified environmental determinants for the spatial distribution of ST using a panel negative binomial model. Results: A total of 4821 scrub typhus cases were reported in Guangzhou during 2006-2014. The annual incidence increased noticeably and the increase was relatively high and rapid in rural townships and among elderly females. The majority of cases (86.8%) occurred during May-October, and farmers constituted the majority of the cases, accounting for 33.9% in urban and 61.6% in rural areas. The number of housekeeper patients had a rapid increment in both rural and urban areas during the study period. Atmospheric pressure and relative humidity with lags of 1 or 2 months, distributions of broadleaved forest and rural township were identified as determinants for the spatiotemporal distribution of scrub typhus. Conclusion: Our results indicate that surveillance and public education need to be focused on the elderly farmers in rural areas covered with broadleaf forest in southern China
Measurements of decays into Vector- Tensor final states
Decays of the into vector plus tensor meson final states have been
studied with 14 million events collected with the BESII detector.
Branching fractions of \psi(2S) \rt \omega f_{2}(1270), ,
and are
determined. They improve upon previous BESI results and confirm the violation
of the "12%" rule for decays to VT channels with higher precision.Comment: 7 pages, 7 figures and 2 table
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