| 1. |
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| 2. |
- Aalbers, Jelle, et al.
(författare)
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Solar neutrino detection sensitivity in DARWIN via electron scattering
- 2020
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 80:12
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Tidskriftsartikel (refereegranskat)abstract
- We detail the sensitivity of the proposed liquid xenon DARWIN observatory to solar neutrinos via elastic electron scattering. We find that DARWIN will have the potential to measure the fluxes of five solar neutrino components: pp, 7Be, 13N, 15O and pep. The precision of the 13N, 15O and pep components is hindered by the double-beta decay of 136Xe and, thus, would benefit from a depleted target. A high-statistics observation of pp neutrinos would allow us to infer the values of the electroweak mixing angle, sin2 theta w, and the electron-type neutrino survival probability, Pee, in the electron recoil energy region from a few keV up to 200 keV for the first time, with relative precision of 5% and 4%, respectively, with 10 live years of data and a 30 tonne fiducial volume. An observation of pp and 7Be neutrinos would constrain the neutrino-inferred solar luminosity down to 0.2%. A combination of all flux measurements would distinguish between the high- (GS98) and low-metallicity (AGS09) solar models with 2.1-2.5 sigma significance, independent of external measurements from other experiments or a measurement of 8B neutrinos through coherent elastic neutrino-nucleus scattering in DARWIN. Finally, we demonstrate that with a depleted target DARWIN may be sensitive to the neutrino capture process of 131Xe.
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| 3. |
- 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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| 4. |
- 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 .- 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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| 5. |
- 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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| 6. |
- Aprile, E., et al.
(författare)
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Energy resolution and linearity of XENON1T in the MeV energy range
- 2020
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 80:8
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Tidskriftsartikel (refereegranskat)abstract
- Xenon dual-phase time projection chambers designed to search for weakly interacting massive particles have so far shown a relative energy resolutionwhich degrades with energy above similar to 200 keV due to the saturation effects. This has limited their sensitivity in the search for rare events like the neutrinoless double-beta decay of Xe-136 at its Q value, Q(beta beta) similar or equal to 2.46 MeV. For the XENON1T dual-phase time projection chamber, we demonstrate that the relative energy resolution at 1 sigma/mu is as low as (0.80 +/- 0.02)% in its one-ton fiducial mass, and for single-site interactions at Q(beta beta). We also present a new signal correction method to rectify the saturation effects of the signal readout system, resulting in more accurate position reconstruction and indirectly improving the energy resolution. The very good result achieved in XENON1T opens up new windows for the xenon dual-phase dark matter detectors to simultaneously search for other rare events.
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| 7. |
- Aprile, E., et al.
(författare)
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Excess electronic recoil events in XENON1T
- 2020
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 102:7
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Tidskriftsartikel (refereegranskat)abstract
- We report results from searches for new physics with low-energy electronic recoil data recorded with the XENONIT detector. With an exposure of 0.65 tonne-years and an unprecedentedly low background rate of 76 +/- 2(stat) events/(tonne x year x keV) between 1 and 30 keV, the data enable one of the most sensitive searches for solar axions, an enhanced neutrino magnetic moment using solar neutrinos, 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 three-dimensional 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 x 10(-12), g(ae)g(an)(eff) < 4.8 x 10(-18), and g(ae)g(a gamma) < 7.7 x 10(-22) GeV-1, and excludes either g(ae) = 0 or g(ae)g(a gamma) = g(ae)ge(an)(eff), = 0. The neutrino magnetic moment signal is similarly favored over background at 3.2 sigma, and a confidence interval of mu(nu) is an element of (1.4, 2.9) x 10(-11) mu(B) (90% C.L.) is reported. Both results are in strong tension with stellar constraints. The excess can also be explained by beta decays of tritium at 3.2 sigma significance with a corresponding tritium concentration in xenon of (6.2 +/- 2.0) x 10(-25) mol/mol. Such a trace amount can neither be confirmed nor excluded with current knowledge of its production and reduction mechanisms. The significances of the solar axion and neutrino magnetic moment hypotheses arc decreased to 2.0 sigma and 0.9 sigma, respectively, if an unconstrained tritium component is included in the fitting. With respect to bosonic dark matter, the excess favors a monoenergetic peak at (2.3 +/- 0.2) keV (68% C.L.) with a 3.0 sigma global (4.0 sigma local) significance over background. This analysis sets the most restrictive direct constraints to date on pseudoscalar and vector bosonic dark matter for most masses between 1 and 210 keV/c(2). We also consider the possibility that Ar-37 may be present in the detector, yielding a 2.82 keV peak from electron capture. Contrary to tritium, the Ar-37 concentration can be tightly constrained and is found to be negligible.
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| 8. |
- Aprile, E., et al.
(författare)
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First Results on the Scalar WIMP-Pion Coupling, Using the XENON1T Experiment
- 2019
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 122:7
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Tidskriftsartikel (refereegranskat)abstract
- We present first results on the scalar coupling of weakly interacting massive particles (WIMPs) to pions from 1 t yr of exposure with the XENON1T experiment. This interaction is generated when the WIMP couples to a virtual pion exchanged between the nucleons in a nucleus. In contrast to most nonrelativistic operators, these pion-exchange currents can be coherently enhanced by the total number of nucleons and therefore may dominate in scenarios where spin-independent WIMP-nucleon interactions are suppressed. Moreover, for natural values of the couplings, they dominate over the spin-dependent channel due to their coherence in the nucleus. Using the signal model of this new WIMP-pion channel, no significant excess is found, leading to an upper limit cross section of 6.4 x 10(-46) cm(2) (90% confidence level) at 30 GeV/c(2) WIMP mass.
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| 9. |
- Aprile, E., et al.
(författare)
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Observation of two-neutrino double electron capture in 124Xe with XENON1T
- 2019
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 568:7753, s. 532-535
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Tidskriftsartikel (refereegranskat)abstract
- Two-neutrino double electron capture (2νECEC) is a second-order weak-interaction process with a predicted half-life that surpasses the age of the Universe by many orders of magnitude. Until now, indications of 2νECEC decays have only been seen for two isotopes, 78Kr and 130Ba, and instruments with very low background levels are needed to detect them directly with high statistical significance. The 2νECEC half-life is an important observable for nuclear structure models and its measurement represents a meaningful step in the search for neutrinoless double electron capture—the detection of which would establish the Majorana nature of the neutrino and would give access to the absolute neutrino mass. Here we report the direct observation of 2νECEC in 124Xe with the XENON1T dark-matter detector. The significance of the signal is 4.4 standard deviations and the corresponding half-life of 1.8 × 1022 years (statistical uncertainty, 0.5 × 1022 years; systematic uncertainty, 0.1 × 1022 years) is the longest measured directly so far. This study demonstrates that the low background and large target mass of xenon-based dark-matter detectors make them well suited for measuring rare processes and highlights the broad physics reach of larger next-generation experiments.
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| 10. |
- Aprile, E., et al.
(författare)
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Projected WIMP sensitivity of the XENONnT dark matter experiment
- 2020
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Ingår i: Journal of Cosmology and Astroparticle Physics. - : IOP Publishing. - 1475-7516. ; :11
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Tidskriftsartikel (refereegranskat)abstract
- XENONnT is a dark matter direct detection experiment, utilizing 5.9 t of instrumented liquid xenon, located at the INFN Laboratori Nazionali del Gran Sasso. In this work, we predict the experimental background and project the sensitivity of XENONnT to the detection of weakly interacting massive particles (WIMPs). The expected average differential background rate in the energy region of interest, corresponding to (1, 13) keV and (4, 50) keV for electronic and nuclear recoils, amounts to 12.3 +/- 0.6 (keV t y)(-1) and (2.2 +/- 0.5) x 10(-3 )(keV t y)(-1), respectively, in a 4t fiducial mass. We compute unified confidence intervals using the profile construction method, in order to ensure proper coverage. With the exposure goal of 20 t y, the expected sensitivity to spin-independent WIMP-nucleon interactions reaches a cross-section of 1.4 x 10(-48) cm(2) for a 50 GeV/c(2) mass WIMP at 90% confidence level, more than one order of magnitude beyond the current best limit, set by XENON1T. In addition, we show that for a 50 GeV/c(2) WIMP with cross-sections above 2.6 x 10(-48) cm(2) (5.0 x 10(-48) cm(2)) the median XENONnT discovery significance exceeds 3 sigma (5 sigma). The expected sensitivity to the spin-dependent WIMP coupling to neutrons (protons) reaches 2.2 x 10(-43) cm(2) (6.0 x 10(-42) cm(2)).
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