| 1. |
- Aprile, E., et al.
(författare)
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Light Dark Matter Search with Ionization Signals in XENON1T
- 2019
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 123:25
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Tidskriftsartikel (refereegranskat)abstract
- We report constraints on light dark matter (DM) models using ionization signals in the XENON1T experiment. We mitigate backgrounds with strong event selections, rather than requiring a scintillation signal, leaving an effective exposure of (22 +/- 3) tonne day. Above similar to 0.4 keV(ee), we observe <1 event/(tonne day keV(ee)), which is more than 1000 times lower than in similar searches with other detectors. Despite observing a higher rate at lower energies, no DM or CEvNS detection may be claimed because we cannot model all of our backgrounds. We thus exclude new regions in the parameter spaces for DM-nucleus scattering for DM masses m(chi) within 3-6 GeV/c(2), DM-electron scattering for m(chi) > 30 MeV/c(2), and absorption of dark photons and axionlike particles for m(chi) within 0.186-1 keV/c(2).
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| 2. |
- Aprile, E., et al.
(författare)
-
Search for Light Dark Matter Interactions Enhanced by the Migdal Effect or Bremsstrahlung in XENON1T
- 2019
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 123:24
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Tidskriftsartikel (refereegranskat)abstract
- Direct dark matter detection experiments based on a liquid xenon target are leading the search for dark matter particles with masses above similar to 5 GeV/c(2), 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/c(2) by looking for electronic recoils induced by the Migdal effect and bremsstrahlung using data from the XENON1T experiment. Besides the approach of detecting both scintillation and ionization signals, we exploit an approach that uses ionization signals only, which allows for a lower detection threshold. This analysis significantly enhances the sensitivity of XENON1T to light dark matter previously beyond its reach.
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| 3. |
- Aprile, E., et al.
(författare)
-
Search for bosonic super-WIMP interactions with the XENON100 experiment
- 2017
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Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:12
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Tidskriftsartikel (refereegranskat)abstract
- We present results of searches for vector and pseudoscalar bosonic super-weakly interacting massive particles (WIMPs), which are dark matter candidates with masses at the keV-scale, with the XENON100 experiment. XENON100 is a dual-phase xenon time projection chamber operated at the Laboratori Nazionali del Gran Sasso. A profile likelihood analysis of data with an exposure of 224.6 live days x34 kg showed no evidence for a signal above the expected background. We thus obtain new and stringent upper limits in the (8-125) keV/c(2) mass range, excluding couplings to electrons with coupling constants of g(ae) > 3 x 10(-13) for pseudo-scalar and alpha'/alpha > 2 x 10(-28) for vector super-WIMPs, respectively. These limits are derived under the assumption that super-WIMPs constitute all of the dark matter in our galaxy.
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| 4. |
- Aprile, E., et al.
(författare)
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The XENON1T dark matter experiment
- 2017
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 77:12
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Tidskriftsartikel (refereegranskat)abstract
- The XENON1T experiment at the Laboratori Nazionali del Gran Sasso (LNGS) is the first WIMP dark matter detector operating with a liquid xenon target mass above the ton-scale. Out of its 3.2t liquid xenon inventory, 2.0t constitute the active target of the dual-phase time projection chamber. The scintillation and ionization signals from particle interactions are detected with low-background photomultipliers. This article describes the XENON1T instrument and its subsystems as well as strategies to achieve an unprecedented low background level. First results on the detector response and the performance of the subsystems are also presented.
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| 5. |
- Aprile, E., et al.
(författare)
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The XENON1T data acquisition system
- 2019
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- The XENON1T liquid xenon time projection chamber is the most sensitive detector built to date for the measurement of direct interactions of weakly interacting massive particles with normal matter. The data acquisition system (DAQ) is constructed from commercial, open source, and custom components to digitize signals from the detector and store them for later analysis. The system achieves an extremely low signal threshold by triggering each channel independently, achieving a single photoelectron acceptance of (93 +/- 3)%, and deferring the global trigger to a later, software stage. The event identification is based on MongoDB database queries and has over 98% efficiency at recognizing interactions at the analysis threshold in the center of the target. A readout bandwidth over 300 MB/s is reached in calibration modes and is further expandable via parallelization. This DAQ system was successfully used during three years of operation of XENON1T.
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| 6. |
- Aprile, E., et al.
(författare)
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Removing krypton from xenon by cryogenic distillation to the ppq level
- 2017
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 77:5
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Tidskriftsartikel (refereegranskat)abstract
- The XENON1T experiment aims for the direct detection of dark matter in a detector filled with 3.3 tons of liquid xenon. In order to achieve the desired sensitivity, the background induced by radioactive decays inside the detector has to be sufficiently low. One major contributor is the beta-emitter Kr-85 which is present in the xenon. For XENON1T a concentration of natural krypton in xenon Kr-nat/Xe < 200 ppq (parts per quadrillion, 1 ppq = 10(-15) mol/mol) is required. In this work, the design, construction and test of a novel cryogenic distillation column using the common McCabe-Thiele approach is described. The system demonstrated a krypton reduction factor of 6.4 . 10(5) with thermodynamic stability at process speeds above 3 kg/h. The resulting concentration of natKr/Xe < 26 ppq is the lowest ever achieved, almost one order of magnitude below the requirements for XENON1T and even sufficient for future dark matter experiments using liquid xenon, such as XENONnT and DARWIN.
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| 7. |
- Aprile, E., et al.
(författare)
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Signal yields of keV electronic recoils and their discrimination from nuclear recoils in liquid xenon
- 2018
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Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 97:9
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Tidskriftsartikel (refereegranskat)abstract
- We report on the response of liquid xenon to low energy electronic recoils below 15 keV from beta decays of tritium at drift fields of 92 V/cm, 154 V/cm and 366 V/cm using the XENON100 detector. A data-to-simulation fitting method based on Markov Chain Monte Carlo is used to extract the photon yields and recombination fluctuations from the experimental data. The photon yields measured at the two lower fields are in agreement with those from literature; additional measurements at a higher field of 366 V/cm are presented. The electronic and nuclear recoil discrimination as well as its dependence on the drift field and photon detection efficiency are investigated at these low energies. The results provide new measurements in the energy region of interest for dark matter searches using liquid xenon.
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| 8. |
- Aprile, E., et al.
(författare)
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Constraining the Spin-Dependent WIMP-Nucleon Cross Sections with XENON1T
- 2019
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 122:14
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Tidskriftsartikel (refereegranskat)abstract
- We report the first experimental results on spin-dependent elastic weakly interacting massive particle (WIMP) nucleon scattering from the XENON1T dark matter search experiment. The analysis uses the full ton year exposure of XENON1T to constrain the spin-dependent proton-only and neutron-only cases. No significant signal excess is observed, and a profile likelihood ratio analysis is used to set exclusion limits on the WIMP-nucleon interactions. This includes the most stringent constraint to date on the WIMP-neutron cross section, with a minimum of 6.3 x 10(-42) cm(2) at 30 GeV/c(2) and 90% confidence level. The results are compared with those from collider searches and used to exclude new parameter space in an isoscalar theory with an axial-vector mediator.
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| 9. |
- Aprile, E., et al.
(författare)
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Dark Matter Search Results from a One Ton-Year Exposure of XENON1T
- 2018
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 121:11
-
Tidskriftsartikel (refereegranskat)abstract
- We report on a search for weakly interacting massive particles (WIMPs) using 278.8 days of data collected with the XENON1T experiment at LNGS. XENON1T utilizes a liquid xenon time projection chamber with a fiducial mass of (1.30 +/- 0.01) ton, resulting in a 1.0 ton yr exposure. The energy region of interest, [1.4; 10.6] keV(ee) ([4.9; 40.9] keV(nr)), exhibits an ultralow electron recoil background rate of [82(-3)(+5) (syst) +/- 3 stat)] events/ton yr keV(ee)). No significant excess over background is found, and a profile likelihood analysis parametrized in spatial and energy dimensions excludes new parameter space for the WIMP-nucleon spin-independent elastic scatter cross section for WIMP masses above 6 GeV/c(2), with a minimum of 4.1 x 10(-47) cm(2) at 30 GeV/c(2) and a 90% confidence level.
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| 10. |
- Aprile, E., et al.
(författare)
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Effective field theory search for high-energy nuclear recoils using the XENON100 dark matter detector
- 2017
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Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:4
-
Tidskriftsartikel (refereegranskat)abstract
- We report on weakly interacting massive particles (WIMPs) search results in the XENON100 detector using a nonrelativistic effective field theory approach. The data from science run II (34 kg x 224.6 live days) were reanalyzed, with an increased recoil energy interval compared to previous analyses, ranging from (6.6-240) keV(nr). The data are found to be compatible with the background-only hypothesis. We present 90% confidence level exclusion limits on the coupling constants of WIMP-nucleon effective operators using a binned profile likelihood method. We also consider the case of inelastic WIMP scattering, where incident WIMPs may up-scatter to a higher mass state, and set exclusion limits on this model as well.
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