185 research outputs found
State-Insensitive Trapping of Alkaline-Earth Atoms in a Nanofiber-Based Optical Dipole Trap
Neutral atoms trapped in the evanescent optical potentials of nanotapered
optical fibers are a promising platform for developing quantum technologies and
exploring fundamental science, such as quantum networks and quantum
electrodynamics. Building on the successful advancements with trapped alkali
atoms, here we demonstrate a state-insensitive optical dipole trap for
strontium-88, an alkaline-earth atom, using the evanescent fields of a
nanotapered optical fiber. Leveraging the low laser-cooling temperatures of
K readily achievable with strontium, we demonstrate trapping in
record low trap depths corresponding to K. Further, employing a
double magic wavelength trapping scheme, we realize state-insensitive trapping
on the kilohertz-wide 5s^{2}\;^{1}\!S_{0}-5s5p\;^{3}\!P_{1,|m|=1} cooling
transition, which we verify by performing near-surface high-resolution
spectroscopy of the atomic transition. This allows us to experimentally find
and verify the state insensitivity of the trap nearby a theoretically predicted
magic wavelength of 435.827(25) nm. Given the non-magnetic ground state and low
collisional scattering length of strontium-88, this work also lays the
foundation for developing versatile and robust matter-wave atomtronic circuits
over nanophotonic waveguides.Comment: 14 pages, 15 figure
Experimental study of direct photon emission in K- --> pi- pi0 gamma decay using ISTRA+ detector
The branching ratio in the charged-pion kinetic energy region of 55 to 90 MeV
for the direct photon emission in the K- --> pi- pi0 gamma decay has been
measured using in-flight decays detected with the ISTRA+ setup operating in the
25 GeV/c negative secondary beam of the U-70 PS. The value
Br(DE)=[0.37+-0.39(stat)+-0.10(syst)]*10^(-5) obtained from the analysis of 930
completely reconstructed events is consistent with the average value of two
stopped-kaon experiments, but it differs by 2.5 standard deviations from the
average value of three in-flight-kaon experiments. The result is also compared
with recent theoretical predictions.Comment: 13 pages, 8 figure
Geometric Calibration and Radiometric Correction of LiDAR Data and Their Impact on the Quality of Derived Products
LiDAR (Light Detection And Ranging) systems are capable of providing 3D positional and spectral information (in the utilized spectrum range) of the mapped surface. Due to systematic errors in the system parameters and measurements, LiDAR systems require geometric calibration and radiometric correction of the intensity data in order to maximize the benefit from the collected positional and spectral information. This paper presents a practical approach for the geometric calibration of LiDAR systems and radiometric correction of collected intensity data while investigating their impact on the quality of the derived products. The proposed approach includes the use of a quasi-rigorous geometric calibration and the radar equation for the radiometric correction of intensity data. The proposed quasi-rigorous calibration procedure requires time-tagged point cloud and trajectory position data, which are available to most of the data users. The paper presents a methodology for evaluating the impact of the geometric calibration on the relative and absolute accuracy of the LiDAR point cloud. Furthermore, the impact of the geometric calibration and radiometric correction on land cover classification accuracy is investigated. The feasibility of the proposed methods and their impact on the derived products are demonstrated through experimental results using real data
Measurement of the decay form factors in the OKA experiment
A precise measurement of the vector and axial-vector form factors difference
in the decay is presented.
About 95K events of are selected in
the OKA experiment. The result is .
Both errors are smaller than in the previous measurements.Comment: 9 pages, 8 figure
Процедуры расследования авиационных происшествий
The article discusses current issues of the investigation of aircraft accidents. On the basis of regulatory documents it presents the scheme of the procedure of investigation of aircraft accidents based on the JCAO requirements and recommendations.Рассматриваются актуальные вопросы расследования авиационных происшествий. На основе регламентирующих документов представлена схема порядка проведения расследования авиационных происшествий, в основе которого лежат требования и рекомендации ИКАО
Collins and Sivers asymmetries in muonproduction of pions and kaons off transversely polarised proton
Measurements of the Collins and Sivers asymmetries for charged pions and
charged and neutral kaons produced in semi-inclusive deep-inelastic scattering
of high energy muons off transversely polarised protons are presented. The
results were obtained using all the available COMPASS proton data, which were
taken in the years 2007 and 2010. The Collins asymmetries exhibit in the
valence region a non-zero signal for pions and there are hints of non-zero
signal also for kaons. The Sivers asymmetries are found to be positive for
positive pions and kaons and compatible with zero otherwise.Comment: 15 pages, 13 figures and 1 tabl
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