174 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
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
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
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
Observation of the radiative kaon decay K- --> mu-pi0gammanu
Using data collected with the ISTRA+ spectrometer during the 2001 run of the
U-70 proton synchrotron in Protvino, we report the first observation of the
radiative kaon decay K- -->mu-pi0gammanu. We find Br(Kmu3g)/Br(Kmu3) for two
regions 5<Eg<30 and 30<Eg<60 MeV consistent with theoretical predictions. The
measured angular distribution asymmetry for the first region,
0.093+/-0.141, is two standard deviations away from the theoretical
prediction of 0.354. The measured asymmetry in the T-odd variable is
-0.03+/-0.13.Comment: 15 pages, 8 figurs, submitted to Yadernaya Fizik
Measurement of the charged-pion polarisability
The COMPASS collaboration at CERN has investigated pion Compton scattering,
, at centre-of-mass energy below 3.5 pion
masses. The process is embedded in the reaction
, which is initiated by
190\,GeV pions impinging on a nickel target. The exchange of quasi-real photons
is selected by isolating the sharp Coulomb peak observed at smallest momentum
transfers, \,(GeV/). From a sample of 63\,000 events the
pion electric polarisability is determined to be $\alpha_\pi\ =\ (\,2.0\ \pm\
0.6_{\mbox{\scriptsize stat}}\ \pm\ 0.7_{\mbox{\scriptsize syst}}\,) \times
10^{-4}\,\mbox{fm}^3\alpha_\pi=-\beta_\pi$, which
relates the electric and magnetic dipole polarisabilities. It is the most
precise measurement of this fundamental low-energy parameter of strong
interaction, that has been addressed since long by various methods with
conflicting outcomes. While this result is in tension with previous dedicated
measurements, it is found in agreement with the expectation from chiral
perturbation theory. An additional measurement replacing pions by muons, for
which the cross-section behavior is unambigiously known, was performed for an
independent estimate of the systematic uncertainty.Comment: Published version: 9 pages, 3 figures, 1 tabl
- …