89 research outputs found
New Experimental Limit on Photon Hidden-Sector Paraphoton Mixing
We report on the first results of a search for optical-wavelength photons
mixing with hypothetical hidden-sector paraphotons in the mass range between
10^-5 and 10^-2 electron volts for a mixing parameter greater than 10^-7. This
was a generation-regeneration experiment using the "light shining through a
wall" technique in which regenerated photons are searched for downstream of an
optical barrier that separates it from an upstream generation region. The new
limits presented here are approximately three times more sensitive to this
mixing than the best previous measurement. The present results indicate no
evidence for photon-paraphoton mixing for the range of parameters investigated.Comment: 9 pages, 3 figure
Cauchy’s formula on nonempty closed sets and a new notion of Riemann–Liouville fractional integral on time scales
We prove Cauchy’s formula for repeated integration on time scales. The obtained relation gives rise to new notions of fractional integration and differentiation on arbitrary nonempty closed sets.publishe
Absence of linkage between MHC and a gene involved in susceptibility to human schistosomiasis
Probing scalar-pseudoscalar mixing in the CP violating MSSM at high-energy colliders
We study the production processes , and
in the context of the CP violating MSSM. In a given
channel we show that the cross-section for all i (=1,2,3) can be above 0.1 fb
provided M_{H_{2,3}}\la 300 GeV. This should be detectable at a Next Linear
Collider and would provide evidence for scalar-pseudoscalar mixing.Comment: 17 pages, RevTex, 4 ps figures, figure 4 changed, minor modifications
to text, version to appear in PR
SU(5) Unified Theories from Intersecting Branes
We discuss the first string theory examples of three generation
non-supersymmetric SU(5) and {\em flipped} SU(5) GUTS, which break to the
Standard model at low energy, without extra matter and/or gauge group factors.
Our GUT examples are based on IIA orientifolds with D6-branes
intersecting at non-trivial angles. These theories necessarily satisfy RR
tadpoles and are free of NSNS tadpoles as the complex structure moduli are
frozen (even though a dilaton tadpole remains) to discrete values. We identify
appropriately the bifundamental Higgses responsible for electroweak symmetry
breaking. In this way, the neutrino see-saw mechanism get nicely realized in
these constructions. Moreover, as baryon number is not a gauged symmetry gauge
mediated dimension six operators do contribute to proton decay; however proton
lifetime may be safely enhanced by appropriately choosing a high GUT scale. An
accompanying natural doublet-triplet splitting guarantees the suppression of
scalar mediated proton decay modes and the stability of triplet scalar masses
against higher dimensional non-renormalizable operators.Comment: 26 pages, 5 figures; no changes, one comment added in the
introductio
Dynamical relaxation of the CP phases in next-to-minimal supersymmetry
After promoting the phases of the soft masses to dynamical fields
corresponding to Goldstone bosons of spontaneously broken global symmetries in
the supersymmetry breaking sector, the next-to-minimal supersymmetric model is
found to solve the problem and the strong CP problem simultaneously with
an invisible axion. The domain wall problem persists in the form of axionic
domain formation. Relaxation dynamics of the physical CP-violating phases is
determined only by the short-distance physics and their relaxation values are
not necessarily close to the CP-conserving points. Having observable
supersymmetric CP violation and avoiding the axionic domain walls both require
nonminimal flavor structures.Comment: 13 pp, 3 figs, published versio
Supplemental Information 2: TB Mortality and Census Data
Late 19th century epidemics of tuberculosis (TB) in Western Canadian First Nations resulted in peak TB mortality rates more than six times the highest rates recorded in Europe. Using a mathematical modeling approach and historical TB mortality time series, we investigate potential causes of high TB mortality and rapid epidemic decline in First Nations from 1885 to 1940. We explore two potential causes of dramatic epidemic dynamics observed in this setting: first, we explore effects of famine prior to 1900 on both TB and population dynamics. Malnutrition is recognized as an individual-level risk factor for TB progression and mortality; its population-level effects on TB epidemics have not been explored previously. Second, we explore effects of heterogeneity in susceptibility to TB in two ways: modeling heterogeneity in susceptibility to infection, and heterogeneity in risk of developing disease once infected. Our results indicate that models lacking famine-related changes in TB parameters or heterogeneity result in an implausibly poor fit to both the TB mortality time series and census data; the inclusion of these features allows for the characteristic decline and rise in population observed in First Nations during this time period and confers improved fits to TB mortality data
Meta-analysis of genome-wide association studies of asthma in ethnically diverse North American populations.
Asthma is a common disease with a complex risk architecture including both genetic and environmental factors. We performed a meta-analysis of North American genome-wide association studies of asthma in 5,416 individuals with asthma (cases) including individuals of European American, African American or African Caribbean, and Latino ancestry, with replication in an additional 12,649 individuals from the same ethnic groups. We identified five susceptibility loci. Four were at previously reported loci on 17q21, near IL1RL1, TSLP and IL33, but we report for the first time, to our knowledge, that these loci are associated with asthma risk in three ethnic groups. In addition, we identified a new asthma susceptibility locus at PYHIN1, with the association being specific to individuals of African descent (P = 3.9 × 10(-9)). These results suggest that some asthma susceptibility loci are robust to differences in ancestry when sufficiently large samples sizes are investigated, and that ancestry-specific associations also contribute to the complex genetic architecture of asthma
Supersymmetric Dark Matter
There is almost universal agreement among astronomers that most of the mass
in the Universe and most of the mass in the Galactic halo is dark. Many lines
of reasoning suggest that the dark matter consists of some new, as yet
undiscovered, weakly-interacting massive particle (WIMP). There is now a vast
experimental effort being surmounted to detect WIMPS in the halo. The most
promising techniques involve direct detection in low-background laboratory
detectors and indirect detection through observation of energetic neutrinos
from annihilation of WIMPs that have accumulated in the Sun and/or the Earth.
Of the many WIMP candidates, perhaps the best motivated and certainly the most
theoretically developed is the neutralino, the lightest superpartner in many
supersymmetric theories. We review the minimal supersymmetric extension of the
Standard Model and discuss prospects for detection of neutralino dark matter.
We review in detail how to calculate the cosmological abundance of the
neutralino and the event rates for both direct- and indirect-detection schemes,
and we discuss astrophysical and laboratory constraints on supersymmetric
models. We isolate and clarify the uncertainties from particle physics, nuclear
physics, and astrophysics that enter at each step in the calculation. We
briefly review other related dark-matter candidates and detection techniques.Comment: The complete postscript file is available at
ftp://ftp.npac.syr.edu/pub/users/jungman/susyreview/susyreview.ps.Z The TeX
source and figures (plain TeX; macros included) are at
ftp://ftp.npac.syr.edu/pub/users/jungman/susyreview/susyreview.tar.Z Full
paper NOT submitted to lanl archive: table of contents only. To appear in
Physics Report
Physics searches at the LHC
With the LHC up and running, the focus of experimental and theoretical high
energy physics will soon turn to an interpretation of LHC data in terms of the
physics of electroweak symmetry breaking and the TeV scale. We present here a
broad review of models for new TeV-scale physics and their LHC signatures. In
addition, we discuss possible new physics signatures and describe how they can
be linked to specific models of physics beyond the Standard Model. Finally, we
illustrate how the LHC era could culminate in a detailed understanding of the
underlying principles of TeV-scale physics.Comment: 184 pages, 55 figures, 14 tables, hundreds of references; scientific
feedback is welcome and encouraged. v2: text, references and Overview Table
added; feedback still welcom
- …