Search for New Physics in Electronic Recoil Data from XENONnT

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Search for New Physics in Electronic Recoil Data from XENONnT

E. Aprile et al. (XENON Collaboration)

Phys. Rev. Lett. 129, 161805 – Published 13 October 2022

See Research News: Potential Dark Matter Signal Gives Way to New Limits

Abstract

We report on a blinded analysis of low-energy electronic recoil data from the first science run of the XENONnT dark matter experiment. Novel subsystems and the increased 5.9 ton liquid xenon target reduced the background in the (1, 30) keV search region to $(15.8 \pm 1.3) events / (ton \times year \times keV)$ , the lowest ever achieved in a dark matter detector and $\sim 5$ times lower than in XENON1T. With an exposure of 1.16 ton-years, we observe no excess above background and set stringent new limits on solar axions, an enhanced neutrino magnetic moment, and bosonic dark matter.

Received 29 July 2022
Accepted 21 September 2022

DOI:https://doi.org/10.1103/PhysRevLett.129.161805

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

Published by the American Physical Society

Physics Subject Headings (PhySH)

Particle dark matter

Axions

Dark matter detectors

Particles & FieldsGravitation, Cosmology & Astrophysics

Research News

Potential Dark Matter Signal Gives Way to New Limits

Published 13 October 2022

Results from two leading dark matter experiments—XENONnT and PandaX-4T—rule out an enigmatic signal detected in 2020 and set new constraints on dark matter particle candidates consisting of light fermions, respectively.

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Authors & Affiliations

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Search for Light Fermionic Dark Matter Absorption on Electrons in PandaX-4T

Dan Zhang et al. (PandaX Collaboration)

Phys. Rev. Lett. 129, 161804 (2022)

Article Text

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References

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Issue

Vol. 129, Iss. 16 — 14 October 2022

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Images

Figure 1
Efficiencies in reconstructed energy and the solar axion signal in true (red solid) and reconstructed energy (red dashed). The purple curve represents the detection efficiency dominated by the threefold S1 coincidence requirement. The black curve is the total efficiency, which is a combination of the detection and event-selection efficiencies. The discontinuity at 10 keV is caused by the still-blinded WIMP search region. The bands indicate the $1 σ$ uncertainty. The black dashed line shows the 1 keV energy threshold of this search. The red solid and dashed lines represent the solar axion signal model before and after accounting for energy smearing and efficiency loss.
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Figure 2
Calibration data and models at low energy. Both ${}^{220}{Rn}$ and ${}^{37}{Ar}$ data are fit using unbinned maximum likelihoods. The ${}^{220}{Rn}$ data fit is performed in the energy interval (1, 140) keV, with the low-energy region showing the efficiency near the energy threshold. The ${}^{37}{Ar}$ data validate the energy reconstruction and skew-Gaussian smearing model.
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Figure 3
Science data (black dots) in the cS1-cS2 space, overlaid on ${}^{220}{Rn}$ data (2D histogram). The WIMP search region (orange) is still blinded and not used in this search. Regions (gray shaded) far away from the ER band are excluded to avoid anomalous backgrounds. Iso-energy lines are represented by the gray dashed lines.
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Figure 4
Fit to SR0 data using the background model $B_{0}$ . The fit result of $B_{0}$ is the red line. The subdominant AC background is not shown.
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Figure 5
Data and best-fit $B_{0}$ model below 30 keV. No significant excess above the background was found. The bump at $\sim 10 keV$ is from the LL shell of ${}^{124}{Xe}$ $2 ν ECEC$ [44], while the discontinuity at 10 keV is caused by the blinded WIMP search region; see Figs. 1 and 3. A finer binning than in Fig. 4 is used to show the event rate change near the threshold.
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Figure 6
90% C.L. upper limit on different new physics models. Constraints on the axion-electron $g_{ae}$ and axion-photon $g_{a γ}$ couplings from a search for solar axions are shown in (a). Constraints on solar neutrinos with an enhanced magnetic moment (b), ALP DM (c), and dark photon DM (d) are shown together with the $1 σ$ (green) and $2 σ$ (yellow) sensitivity bands estimated with the background-only fit. Constraints between $(39, 44) keV / c^{2}$ are excluded in (c) and (d) due to the unconstrained ${}^{83 m}{Kr}$ background. Selected limits from other experiments [47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61] and astrophysical observations [62, 63, 64, 65, 66] are also shown.
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