Search results for "FOS"
showing 10 items of 15075 documents
Search for inelastic scattering of WIMP dark matter in XENON1T
2021
We report the results of a search for the inelastic scattering of weakly interacting massive particles (WIMPs) in the XENON1T dark matter experiment. Scattering off $^{129}$Xe is the most sensitive probe of inelastic WIMP interactions, with a signature of a 39.6 keV de-excitation photon detected simultaneously with the nuclear recoil. Using an exposure of 0.89 tonne-years, we find no evidence of inelastic WIMP scattering with a significance of more than 2$\sigma$. A profile-likelihood ratio analysis is used to set upper limits on the cross-section of WIMP-nucleus interactions. We exclude new parameter space for WIMPs heavier than 100 GeV/c${}^2$, with the strongest upper limit of $3.3 \time…
Search for Light Dark Matter Interactions Enhanced by the Migdal Effect or Bremsstrahlung in XENON1T.
2019
Direct dark matter detection experiments based on a liquid xenon target are leading the search for dark matter particles with masses above ∼5 GeV/c2, but have limited sensitivity to lighter masses because of the small momentum transfer in dark matter-nucleus elastic scattering. However, there is an irreducible contribution from inelastic processes accompanying the elastic scattering, which leads to the excitation and ionization of the recoiling atom (the Migdal effect) or the emission of a bremsstrahlung photon. In this Letter, we report on a probe of low-mass dark matter with masses down to about 85 MeV/c2 by looking for electronic recoils induced by the Migdal effect and bremsstrahlung us…
XENON1T Dark Matter Data Analysis: Signal Reconstruction, Calibration and Event Selection
2019
The XENON1T experiment at the Laboratori Nazionali del Gran Sasso is the most sensitive direct detection experiment for dark matter in the form of weakly interacting particles (WIMPs) with masses above $6\,$GeV/$c^2$ scattering off nuclei. The detector employs a dual-phase time projection chamber with 2.0 metric tons of liquid xenon in the target. A one metric $\mathrm{ton}\times\mathrm{year}$ exposure of science data was collected between October 2016 and February 2018. This article reports on the performance of the detector during this period and describes details of the data analysis that led to the most stringent exclusion limits on various WIMP-nucleon interaction models to date. In pa…
Excess electronic recoil events in XENON1T
2020
We report results from searches for new physics with low-energy electronic recoil data recorded with the XENON1T detector. With an exposure of 0.65 t-y and an unprecedentedly low background rate of $76\pm2$ events/(t y keV) between 1 and 30 keV, the data enables sensitive searches for solar axions, an enhanced neutrino magnetic moment, and bosonic dark matter. An excess over known backgrounds is observed at low energies and most prominent between 2 and 3 keV. The solar axion model has a 3.4$\sigma$ significance, and a 3D 90% confidence surface is reported for axion couplings to electrons, photons, and nucleons. This surface is inscribed in the cuboid defined by $g_{ae}<3.8 \times 10^{-12}$,…
Production cross section and decay study of $^{243}$Es and $^{249}$Md
2019
In the study of the odd-$Z$, even-$N$ nuclei $^{243}$Es and $^{249}$Md, performed at the University of Jyv\"askyl\"a, the fusion-evaporation reactions $^{197}$Au($^{48}$Ca,2$n$)$^{243}$Es and $^{203}$Tl($^{48}$Ca,2$n$)$^{249}$Md have been used for the first time. Fusion-evaporation residues were selected and detected using the RITU gas-filled separator coupled with the focal-plane spectrometer GREAT. For $^{243}$Es, the recoil decay correlation analysis yielded a half-life of $24 \pm 3$s, and a maximum production cross section of $37 \pm 10$ nb. In the same way, a half-life of $26 \pm 1$ s, an $\alpha$ branching ratio of 75 $\pm$ 5%, and a maximum production cross section of 300 $\pm$ 80 nb…
Managing the gap – policy and practice of parents in child care and education
2017
Nurture and play for foster families with young children : Foster-parents’ reflections on attachment-focused group intervention
2022
An insecure attachment history puts foster children at risk for many kinds of difficulties, which may include psychopathology. Nurture and Play (NaP) for foster families–intervention for children aged one to five years of age aims to help the new attachment relationship between foster parents and their young children develop in a secure direction. The aim of this study is to gain deeper understanding on how foster parents use their mentalization skills to reflect the different meanings of the NaP for foster families–intervention. A stimulated recall method was chosen to correspond to these research targets. It was revealed that parents’ reflections were evidently focused on the child, the i…
Zaangażowanie ojców zastępczych w realizację rodzicielskiej działalności w rodzinnych domach dziecka
2019
Przedmiotem rozważań niniejszego artykułu uczyniono zaangażowanie ojców zastępczych w realizację rodzicielskiej działalności w rodzinnych domach dziecka. Problem badawczy sformułowano w następującym pytaniu: Jaki jest poziom zaangażowania ojców zastępczych w realizację rodzicielskiej działalności, zarówno w wymiarze globalnym, jak i parcjalnym? W badaniach wzięło udział 55 ojców zastępczych z 55 rodzinnych domów dziecka. Zastosowanym narzędziem badawczym była Skala Zaangażowania Ojca Zastępczego w Opiekę i Wychowanie Dziecka. Opracowanie statystyczne zgromadzonego materiału pozwoliło udzielić następującej odpowiedzi: poziom zaangażowania ojców zastępczych w realizację rodzicielskiej działal…
Long-term changes in pigmentation of arctic Daphnia provide potential for reconstructing aquatic UV exposure
2016
Abstract Despite the biologically damaging impacts of solar ultraviolet radiation (UV) in nature, little is known about its natural variability, forcing mechanisms, and long-term effects on ecosystems and organisms. Arctic zooplankton, for example the aquatic keystone genus Daphnia (Crustacea, Cladocera) responds to biologically damaging UV by utilizing photoprotective strategies, including pigmentation. We examined the preservation and content of UV-screening pigments in fossil Daphnia remains (ephippia) in two arctic lake sediment cores from Cornwallis Island (Lake R1), Canada, and Spitsbergen (Lake Fugledammen), Svalbard. The aims were to document changes in the degree of UV-protective p…