6,013 research outputs found
Probing Exotic Physics With Cosmic Neutrinos
Traditionally, collider experiments have been the primary tool used in
searching for particle physics beyond the Standard Model. In this talk, I will
discuss alternative approaches for exploring exotic physics scenarios using
high energy and ultra-high energy cosmic neutrinos. Such neutrinos can be used
to study interactions at energies higher, and over baselines longer, than those
accessible to colliders. In this way, neutrino astronomy can provide a window
into fundamental physics which is highly complementary to collider techniques.
I will discuss the role of neutrino astronomy in fundamental physics,
considering the use of such techniques in studying several specific scenarios
including low scale gravity models, Standard Model electroweak instanton
induced interactions, decaying neutrinos and quantum decoherence.Comment: 11 pages, 6 figures; For the proceedings of From Colliders To Cosmic
Rays, Prague, Czech Republic, September 7-13, 200
Inhomogeneity in the Supernova Remnant Distribution as the Origin of the PAMELA Anomaly
Recent measurements of the positron/electron ratio in the cosmic ray (CR)
flux exhibits an apparent anomaly, whereby this ratio increases between 10 and
100 GeV. We show that inhomogeneity of CR sources on a scale of order a kpc,
can naturally explain this anomaly. If the nearest major CR source is about a
kpc away, then low energy electrons ( GeV) can easily reach us. At
higher energies ( GeV), the source electrons cool via synchrotron
and inverse-Compton before reaching Earth. Pairs formed in the local vicinity
through the proton/ISM interactions can reach Earth also at high energies, thus
increasing the positron/electron ratio. A natural origin of source
inhomogeneity is the strong concentration of supernovae in the galactic spiral
arms. Assuming supernova remnants (SNRs) as the sole primary source of CRs, and
taking into account their concentration near the galactic spiral arms, we
consistently recover the observed positron fraction between 1 and 100 GeV.
ATIC's electron excess at GeV is explained, in this picture, as the
contribution of a few known nearby SNRs. The apparent coincident similarity
between the cooling time of electrons at 10 GeV (where the positron/electron
ratio upturn), Myr, and the CRs protons cosmogenic age at the same
energy is predicted by this model
Reproduction, growth and development in two contiguously allopatric rodent species, genus Scotinomys
http://deepblue.lib.umich.edu/bitstream/2027.42/56395/1/MP151.pd
The Interplay Between Collider Searches For Supersymmetric Higgs Bosons and Direct Dark Matter Experiments
In this article, we explore the interplay between searches for supersymmetric
particles and Higgs bosons at hadron colliders (the Tevatron and the LHC) and
direct dark matter searches (such as CDMS, ZEPLIN, XENON, EDELWEISS, CRESST,
WARP and others). We focus on collider searches for heavy MSSM Higgs bosons
(, , ) and how the prospects for these searches are impacted by
direct dark matter limits and vice versa. We find that the prospects of these
two experimental programs are highly interrelated. A positive detection of ,
or at the Tevatron would dramatically enhance the prospects for a
near future direct discovery of neutralino dark matter. Similarly, a positive
direct detection of neutralino dark matter would enhance the prospects of
discovering heavy MSSM Higgs bosons at the Tevatron or the LHC. Combining the
information obtained from both types of experimental searches will enable us to
learn more about the nature of supersymmetry.Comment: 22 pages, 28 figure
Pierre Auger Data, Photons, and Top-Down Cosmic Ray Models
We consider the ultra-high energy cosmic ray (UHECR) spectrum as measured by
the Pierre Auger Observatory. Top-down models for the origin of UHECRs predict
an increasing photon component at energies above about eV. Here we
present a simple prescription to compare the Auger data with a prediction
assuming a pure proton component or a prediction assuming a changing primary
component appropriate for a top-down model. We find that the UHECR spectrum
predicted in top-down models is a good fit to the Auger data. Eventually, Auger
will measure a composition-independent spectrum and will be capable of either
confirming or excluding the quantity of photons predicted in top-down models.Comment: 8 pages, 3 figure
Radiative corrections to the lightest KK states in the T^2/(Z_2\times Z_2') orbifold
We study radiative corrections localized in the fixed points of the orbifold
for the field theory in six dimensions with two dimensions compactified on the
orbifold in a specific realistic model for low energy
physics that solves the proton decay and neutrino mass problem. We calculate
corrections to the masses of the lightest stable KK modes, which could be the
candidates for the dark matter.Comment: 14 pages, 2 figure
Kaluza-Klein Dark Matter, Electrons and Gamma Ray Telescopes
Kaluza-Klein dark matter particles can annihilate efficiently into
electron-positron pairs, providing a discrete feature (a sharp edge) in the
cosmic spectrum at an energy equal to the particle's mass (typically
several hundred GeV to one TeV). Although this feature is probably beyond the
reach of satellite or balloon-based cosmic ray experiments (those that
distinguish the charge and mass of the primary particle), gamma ray telescopes
may provide an alternative detection method. Designed to observe very
high-energy gamma-rays, ACTs also observe the diffuse flux of electron-induced
electromagnetic showers. The GLAST satellite, designed for gamma ray astronomy,
will also observe any high energy showers (several hundred GeV and above) in
its calorimeter. We show that high-significance detections of an
electron-positron feature from Kaluza-Klein dark matter annihilations are
possible with GLAST, and also with ACTs such as HESS, VERITAS or MAGIC.Comment: 10 pages, 2 figure
Should psychiatrists 'Google' their patients?
Since its beginnings in the 1980s the internet has come to shape our everyday lives, but doctors still seem rather afraid of it. This anxiety may be explained by the fact that researchers and regulatory bodies focus less on the way that the internet can be used to enhance clinical work and more on the potential and perceived risks that this technology poses in terms of boundary violations and accidental breaches of confidentiality. Some aspects of the internet’s impact on medicine have been better researched than others, for example, whether email communication, social media and teleconferencing psychotherapy could be used to improve the
delivery of care. However, few authors have considered the specific issue of searching online for information about patients and much of the guidance published by regulatory organisations eludes this issue. In this article we provide clinical examples where the question ‘should I Google the patient?’ may arise and present questions for future research
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