| 1. |
- Aprile, E., et al.
(författare)
-
Effective Field Theory and Inelastic Dark Matter Results from XENON1T
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In this work we expand on the XENON1T nuclear recoil searches and study the individual signals of Dark Matter interactions from operators up to dimension-eight in a Chiral Effective Field Theory (ChEFT) as well as a model of inelastic Dark Matter using data from the two science runs of the detector totalling 1 tonne*year exposure. For these analyses we extended the region of interest from [4.9, 40.9]keVnr to [4.9, 54.4]keVnr to enhance our sensitivity for signals that peak at nonzero energies. We show that the data is consistent with a background only hypothesis, with small excesses in the models which peak between 20 and 50keVnr, obtaining a maximum local discovery significance of 1.7 for the VVs ChEFT model for a WIMP mass of 70GeV/c2, and 1.8 for an iDM particle of 50GeV/c2 with a mass splitting of 100keV/c2. For each model we report 90% confidence level upper limits. We also report limits on three benchmark models of WIMP interaction using ChEFT for which we investigate the effect of isospin breaking interactions, reporting up to 6 orders of magnitude weaker limits with respect to the isospin conserving case driven by cancellations in the expected rate.
|
|
| 2. |
|
|
| 3. |
- Shebanits, Oleg, 1984-, et al.
(författare)
-
On Ion Drifts and Neutral Winds in Titan’s Thermosphere
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Saturn’s largest moon Titan hosts an atmosphere with complex organic chemistry initiated partly in the ionosphere. The nightside chemistry may be influenced by the ion transport from the dayside ionosphere. In turn, ion transport (ion drifts) may be affected by the neutral winds, which cannot be measured directly by Cassini. In this study we derive the ion drifts along the spacecraft trajectories based on analysis of in-situ measurements of electron and ion fluxes, mean masses of positive and negative ions and the magnetic field. Data from Titan flybys TA to T100 (Oct 2005 - Apr 2014) is included in this study, 55 flybys are below 1400 km and 48 are below 1200 km altitude. Based on the measurements, three regions of the ionosphere were defined by altitude: 1) above 1600 km, ions are ?×?-drifting (frozen into the magnetic field), 2) 1100-1600 km, dynamo-region, ions drift partly in opposite directions (perpendicular to B) and 3) below 1100 km (upper limit depends on convection electric field strength), ions are following neutrals.
|
|
| 4. |
- Zhou Hagström, Nanna, 1993-, et al.
(författare)
-
Megahertz-rate Ultrafast X-ray Scattering and Holographic Imaging at the European XFEL
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The advent of X-ray free-electron lasers (XFELs) has revolutionized fundamental science, from atomic to condensed matter physics, from chemistry to biology, giving researchers access to X-rays with unprecedented brightness, coherence, and pulse duration. All XFEL facilities built until recently provided X-ray pulses at a relatively low repetition rate, with limited data statistics. Here, we present the results from the first megahertz repetition rate X-ray scattering experiments at the Spectroscopy and Coherent Scattering (SCS) instrument of the European XFEL. We illustrate the experimental capabilities that the SCS instrument offers, resulting from the operation at MHz repetition rates and the availability of the novel DSSC 2D imaging detector. Time-resolved magnetic X-ray scattering and holographic imaging experiments in solid state samples were chosen as representative examples, providing an ideal test-bed for operation at megahertz rates. Nevertheless, our results are relevant and applicable to any other non-destructive XFEL experiments in the soft X-ray range.
|
|
