736 research outputs found
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Characterisation of the UV environment of the Beagle 2 landing site
A study of the UV environment of the Beagle 2 landing site has been carried out. An instrument to measure the UV flux is present on the lander, and this work serves to aid in the interpretation of expected data
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Surface Profiling of Natural Dust Devils
We present results from the first high-resolution near-surface profiles conducted on dust devil wind fields. These results are integrated with extensive geologic mapping to understand the factors that influence vortex generation and erosive efficacy
CP Studies of the Higgs Sector
The CP structure of the Higgs sector will be of great interest to future
colliders. The measurement of the CP properties of candidate Higgs particles
will be essential in order to distinguish models of electroweak symmetry
breaking, and to discover or place limits on CP-violation in the Higgs sector.
In this report we briefly summarize various methods of determining the CP
properties of Higgs bosons at different colliders and identify areas where more
study is required. We also provide an example of a synergy between the LHC, an
e+e- Linear Collider and a Photon Collider, for the examination of CP-violation
in a Two-Higgs-Doublet-Model.Comment: A contribution to the LHC / LC Study Group document; 9 pages, 2
figure
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Impact pressures generated by spherical particle hypervelocity impact on Yorkshire Sandstone
Hypervelocity impact tests were carried out at 4.8 km/s using the Open University's All Axis Light Gas Gun (AALGG) in the Planetary and Space Sciences Research Institute (PSSRI)'s Hypervelocity Impact Laboratory. A first estimate of the peak loading pressures was made using preliminary hydrocode simulations, supported by calculations. Following a review of existing published quartz and sandstone data, our previously published plate impact data were combined with high pressure quartz data to produce a synthetic Hugoniot. This will form the basis of future hydrocode modelling, as a linear Us-Up relationship does not adequately represent the behaviour of sandstone over the pressure range of interest, as indicated by experimental data on Coconino sandstone. This work is a precursor to investigating the biological effects of shock on microorganisms in sandstone targets. This paper also contains the first presentation of results of ultra high speed imaging of hypervelocity impact at the Open University. © 2007 American Institute of Physics
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A miniature UV-VIS spectrometer for the surface of Mars
A miniature spectrometer is in the process of development for a future Mars mission, to measure the UV-VIS spectrum encountered at the martian surface. With an intended mass of ~100 g, the spectrometer is planned as part of the ESA ExoMars mission
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A close encounter with a terrestrial dust devil
We report on an extremely well characterised encounter with a terrestrial dust devil, and its comparison with martian dust devils
Simulating hard photon production with WHIZARD
One of the important goals of the proposed future collider
experiments is the search for dark matter particles using different
experimental approaches. The most general search approach is based on the
mono-photon signature, which is expected when production of the invisible final
state is accompanied by a hard photon from initial state radiation. Analysis of
the energy spectrum and angular distributions of those photons can shed light
on the nature of dark matter and its interactions. Therefore, it is crucial to
be able to simulate the signal and background samples in a uniform framework,
to avoid possible systematic biases. The WHIZARD program is a flexible tool,
which is widely used by collaborations for simulation of many
different "new physics" scenarios. We propose the procedure of merging the
matrix element calculations with the lepton ISR structure function implemented
in WHIZARD. It allows us to reliably simulate the mono-photon events, including
the two main Standard Model background processes: radiative neutrino pair
production and radiative Bhabha scattering. We demonstrate that cross sections
and kinematic distributions of mono-photon in neutrino pair-production events
agree with corresponding predictions of the KKMC, a Monte Carlo generator
providing perturbative predictions for SM and QED processes, which has been
widely used in the analysis of LEP data.Comment: 17 pages, 8 figures, 6 tables, 2 example steering file
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Exomars entry and descent science
The entry, descent and landing of ExoMars offer a rare (once-per-mission) opportunity to perform in situ investigation of the martian environment over a wide altitude range. We present an initial assessment of the atmospheric science that can be performed using sensors of the Entry, Descent and Landing System (EDLS), over and above the expected engineering information. This is intended to help fulfill the concept of an Atmospheric Parameters Package (APP), as mentioned in the ExoMars draft Science Management Plan [ESA, 2005].
Mars' atmosphere is highly variable in time and space, due to phenomena including inertio-gravity waves, thermal tide effects, dust, solar wind conditions, and diurnal, seasonal and topographic effects. Atmospheric profile measurements, drawing on heritage from the Huygens Atmospheric Structure Instrument (HASI), which encountered Titan's atmosphere
in 2005 [1], should allow us to address questions of the martian atmosphere's structure, dynamics and variability
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