8,049 research outputs found
Halo-Independent Direct Detection Analyses Without Mass Assumptions
Results from direct detection experiments are typically interpreted by
employing an assumption about the dark matter velocity distribution, with
results presented in the plane. Recently methods which are
independent of the DM halo velocity distribution have been developed which
present results in the plane, but these in turn require an
assumption on the dark matter mass. Here we present an extension of these
halo-independent methods for dark matter direct detection which does not
require a fiducial choice of the dark matter mass. With a change of variables
from to nuclear recoil momentum (), the full halo-independent
content of an experimental result for any dark matter mass can be condensed
into a single plot as a function of a new halo integral variable, which we call
. The entire family of conventional halo-independent
plots for all DM masses are directly found from the single
plot through a simple rescaling of axes. By considering
results in space, one can determine if two experiments are
inconsistent for all masses and all physically possible halos, or for what
range of dark matter masses the results are inconsistent for all halos, without
the necessity of multiple plots for different DM masses.
We conduct a sample analysis comparing the CDMS II Si events to the null
results from LUX, XENON10, and SuperCDMS using our method and discuss how the
mass-independent limits can be strengthened by imposing the physically
reasonable requirement of a finite halo escape velocity.Comment: 23 pages, 8 figures. v2: footnote and references adde
Living deep-water Lophelia and Madrepora corals in Maltese waters (Strait of Sicily, Mediterranean Sea)
The occurrence of living deep-water corals, Lophelia pertusa and Madrepora oculata, from stations 21-42 km
off the southern and south-western coast of Malta is reported. Fragments of living colonies of both species, as well as some
large pieces of Lophelia frameworks were recovered from depths of 390-617 m together with the solitary coral
Desmophyllum dianthus (= cristagalli). The accompanying biota included the barnacle Pachylasma giganteum, the
gastropod Coralliophila richardi, the bivalves Asperarca nodulosa and Spondylus gussonii, and the polychaete Eunice
norvegicus, all of which are frequently associated with deep-water corals. The occurrence of the Lophelia-Madrepora-
Desmophyllum triad, the large pieces of coral frameworks consisting predominantly of live, healthy polyps, and the
associated biota, suggest that coral patches may be present in at least some of the investigated localities, rather than just
fragmented remains or isolated colonies.peer-reviewe
Transplanckian Censorship and Global Cosmic Strings
Large field excursions are required in a number of axion models of inflation.
These models also possess global cosmic strings, around which the axion follows
a path mirroring the inflationary trajectory. Cosmic strings are thus an
interesting theoretical laboratory for the study of transplanckian field
excursions. We describe connections between various effective field theory
models of axion monodromy and study the classical spacetimes around their
supercritical cosmic strings. For small decay constants and large
winding numbers , the EFT is under control and the string cores
undergo topological inflation, which may be either of exponential or power-law
type. We show that the exterior spacetime is nonsingular and equivalent to a
decompactifying cigar geometry, with the radion rolling in a potential
generated by axion flux. Signals are able to circumnavigate infinite straight
strings in finite but exponentially long time, . For
finite loops of supercritical string in asymptotically flat space, we argue
that if topological inflation occurs, then topological censorship implies
transplanckian censorship, or that external observers are forbidden from
threading the loop and observing the full excursion of the axion.Comment: v2: refs added, fig 6 extended. published in JHEP. 28 pages, 7
figure
Photon echo without a free induction decay in a double-Lambda system
We have characterized a novel photon-echo pulse sequence for a
double- type energy level system where the input and rephasing
transitions are different to the applied -pulses. We show that despite
having imperfect -pulses (associated with large coherent emission due to
free induction decay), the noise added is only 0.0190.001 relative to the
shot noise in the spectral mode of the echo. Using this echo pulse sequence in
the `rephased amplified spontaneous emission' (RASE) scheme
\cite{Ledingham2010} will allow for generation of entangled photon pairs that
are in different frequency, temporal, and potentially spatial modes to any
bright driving fields. The coherence and efficiency properties of this sequence
were characterized in a Pr:YSO crystal
Privacy Attitudes among Early Adopters of Emerging Health Technologies.
IntroductionAdvances in health technology such as genome sequencing and wearable sensors now allow for the collection of highly granular personal health data from individuals. It is unclear how people think about privacy in the context of these emerging health technologies. An open question is whether early adopters of these advances conceptualize privacy in different ways than non-early adopters.PurposeThis study sought to understand privacy attitudes of early adopters of emerging health technologies.MethodsTranscripts from in-depth, semi-structured interviews with early adopters of genome sequencing and health devices and apps were analyzed with a focus on participant attitudes and perceptions of privacy. Themes were extracted using inductive content analysis.ResultsAlthough interviewees were willing to share personal data to support scientific advancements, they still expressed concerns, as well as uncertainty about who has access to their data, and for what purpose. In short, they were not dismissive of privacy risks. Key privacy-related findings are organized into four themes as follows: first, personal data privacy; second, control over personal information; third, concerns about discrimination; and fourth, contributing personal data to science.ConclusionEarly adopters of emerging health technologies appear to have more complex and nuanced conceptions of privacy than might be expected based on their adoption of personal health technologies and participation in open science. Early adopters also voiced uncertainty about the privacy implications of their decisions to use new technologies and share their data for research. Though not representative of the general public, studies of early adopters can provide important insights into evolving attitudes toward privacy in the context of emerging health technologies and personal health data research
Capture and Decay of Electroweak WIMPonium
The spectrum of Weakly-Interacting-Massive-Particle (WIMP) dark matter
generically possesses bound states when the WIMP mass becomes sufficiently
large relative to the mass of the electroweak gauge bosons. The presence of
these bound states enhances the annihilation rate via resonances in the
Sommerfeld enhancement, but they can also be produced directly with the
emission of a low-energy photon. In this work we compute the rate for SU(2)
triplet dark matter (the wino) to bind into WIMPonium -- which is possible via
single-photon emission for wino masses above 5 TeV for relative velocity v <
O(10^{-2}) -- and study the subsequent decays of these bound states. We present
results with applications beyond the wino case, e.g. for dark matter inhabiting
a nonabelian dark sector; these include analytic capture and transition rates
for general dark sectors in the limit of vanishing force carrier mass,
efficient numerical routines for calculating positive and negative-energy
eigenstates of a Hamiltonian containing interactions with both massive and
massless force carriers, and a study of the scaling of bound state formation in
the short-range Hulthen potential. In the specific case of the wino, we find
that the rate for bound state formation is suppressed relative to direct
annihilation, and so provides only a small correction to the overall
annihilation rate. The soft photons radiated by the capture process and by
bound state transitions could permit measurement of the dark matter's quantum
numbers; for wino-like dark matter, such photons are rare, but might be
observable by a future ground-based gamma-ray telescope combining large
effective area and a low energy threshold.Comment: 3rd version. An interference sign fixed and changes propagated
through the paper. Topline qualitative conclusions unchange
Non-classical photon streams using rephased amplified spontaneous emission
We present a fully quantum mechanical treatment of optically rephased photon
echoes. These echoes exhibit noise due to amplified spontaneous emission,
however this noise can be seen as a consequence of the entanglement between the
atoms and the output light. With a rephasing pulse one can get an "echo" of the
amplified spontaneous emission, leading to light with nonclassical correlations
at points separated in time, which is of interest in the context of building
wide bandwidth quantum repeaters. We also suggest a wideband version of DLCZ
protocol based on the same ideas.Comment: 5 pages, 4 figures. Added section
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