228 research outputs found
The role of metaphor in shaping the identity and agenda of the United Nations: the imagining of an international community and international threat
This article examines the representation of the United Nations in speeches delivered by its Secretary General. It focuses on the role of metaphor in constructing a common ‘imagining’ of international diplomacy and legitimising an international organisational identity. The SG legitimises the organisation, in part, through the delegitimisation of agents/actions/events constructed as threatening to the international community and to the well-being of mankind. It is a desire to combat the forces of menace or evil which are argued to motivate and determine the organisational agenda. This is predicated upon an international ideology of humanity in which difference is silenced and ‘working towards the common good’ is emphasised. This is exploited to rouse emotions and legitimise institutional power. Polarisation and antithesis are achieved through the employment of metaphors designed to enhance positive and negative evaluations. The article further points to the constitutive, persuasive and edifying power of topic and situationally-motivated metaphors in speech-making
Dark-Photon Search using Data from CRESST-II Phase 2
Identifying the nature and origin of dark matter is one of the major
challenges for modern astro and particle physics. Direct dark-matter searches
aim at an observation of dark-matter particles interacting within detectors.
The focus of several such searches is on interactions with nuclei as provided
e.g. by Weakly Interacting Massive Particles. However, there is a variety of
dark-matter candidates favoring interactions with electrons rather than with
nuclei. One example are dark photons, i.e., long-lived vector particles with a
kinetic mixing to standard-model photons. In this work we present constraints
on this kinetic mixing based on data from CRESST-II Phase 2 corresponding to an
exposure before cuts of 52\,kg-days. These constraints improve the existing
ones for dark-photon masses between 0.3 and 0.7\,keV/c.Comment: submitted EPJ
Results on MeV-scale dark matter from a gram-scale cryogenic calorimeter operated above ground
Models for light dark matter particles with masses below 1 GeV/c are a
natural and well-motivated alternative to so-far unobserved weakly interacting
massive particles. Gram-scale cryogenic calorimeters provide the required
detector performance to detect these particles and extend the direct dark
matter search program of CRESST. A prototype 0.5 g sapphire detector developed
for the -cleus experiment has achieved an energy threshold of
eV, which is one order of magnitude lower than previous
results and independent of the type of particle interaction. The result
presented here is obtained in a setup above ground without significant
shielding against ambient and cosmogenic radiation. Although operated in a
high-background environment, the detector probes a new range of light-mass dark
matter particles previously not accessible by direct searches. We report the
first limit on the spin-independent dark matter particle-nucleon cross section
for masses between 140 MeV/c and 500 MeV/c.Comment: 6 pages, 6 figures, v3: ancillary files added, v4: high energy
spectrum (0.6-12keV) added to ancillary file
A detector module with highly efficient surface-alpha event rejection operated in CRESST-II Phase 2
The cryogenic dark matter experiment CRESST-II aims at the direct detection
of WIMPs via elastic scattering off nuclei in scintillating CaWO crystals.
We present a new, highly improved, detector design installed in the current run
of CRESST-II Phase 2 with an efficient active rejection of surface-alpha
backgrounds. Using CaWO sticks instead of metal clamps to hold the target
crystal, a detector housing with fully-scintillating inner surface could be
realized. The presented detector (TUM40) provides an excellent threshold of
keV and a resolution of keV (at
2.60keV). With significantly reduced background levels, TUM40 sets
stringent limits on the spin-independent WIMP-nucleon scattering cross section
and probes a new region of parameter space for WIMP masses below
3GeV/c. In this paper, we discuss the novel detector design and the
surface-alpha event rejection in detail.Comment: 9 pages, 6 figure
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