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Muon-induced background in a next-generation dark matter experiment based on liquid xenon

by Viktor Pěč, Vitaly A. Kudryavtsev

Submission summary

Authors (as registered SciPost users): Viktor Pěč
Submission information
Preprint Link: scipost_202210_00041v2  (pdf)
Date accepted: 2023-04-28
Date submitted: 2022-11-14 15:25
Submitted by: Pěč, Viktor
Submitted to: SciPost Physics Proceedings
Proceedings issue: 14th International Conference on Identification of Dark Matter (IDM2022)
Ontological classification
Academic field: Physics
  • High-Energy Physics - Experiment
Approach: Experimental


We have investigated the implication of laboratory depth on the muon induced background in a future dark matter experiment capable of reaching the so-called neutrino floor. Our simulation study focuses on a xenon-based detector with 71 tonnes of active mass, surrounded by additional veto systems including an instrumented water shield. Two locations at the Boulby Underground Laboratory (UK) at depths of 2850 m.w.e. and 3575 m.w.e. served as a case study. Our results show that less than one event of cosmogenic background is likely to survive standard analysis cuts for 10 years of operation at either location. The largest background component that we identified comes from delayed neutron emission from N-17 which is produced from F-19 in the fluoropolymer components of the experiment. Our results confirm that a dark matter search with sensitivity to the neutrino floor is viable (from the point of view of cosmogenic backgrounds) in underground laboratories at these levels of rock overburden.

Author comments upon resubmission

We have read through the report and changed the manuscript accordingly, see the list of changes.

We did not act upon the requested change 1. We prefer not to name any specific potential experiment as the study was aimed to be more generic. We belief that the important qualities of the simplified design model are stated in the abstract. The motivation for the chosen design is described in section 2.1.

List of changes

i. added "(fog)" after 2 mentions of "neutrino floor" in the abstract. (Re. request 2)

ii. added 2 sentences in the Conclusion section (Re. request 3):
"We have looked at simulations in different rock materials (NaCl, polyhalite, CaCO$_3$) and also with different cavern sizes and we observed that the background does not change significantly for the given detector design. Therefore we conclude that the results are applicable to other sites of similar depth to our case study of the Boulby mine."
Right after
"From the point of view of cosmogenic background, the depth of about 3\,k\mwe\ or deeper is sufficient for a next generation dark matter experiment based on liquid xenon."

iii. removed "(NR)" in section 3. (Re. request 4)

iv. deleted text in red on the front page (Re. request 5)

v. adde a sentence in section 3 (Re. request 6) after
"We chose thresholds of 100\,keV, 200\,keV and 200\,MeV in the skin, liquid scintillator and water tank, respectively, to trigger veto signals.":
"These thresholds were inspired by our previous experience with LZ, detector modelling and the existing water Cherenkov experiments, mainly the previously used energy thresholds with consideration of the photo-coverage."

Current status:
Accepted in target Journal

Editorial decision: For Journal SciPost Physics Proceedings: Publish
(status: Editorial decision fixed and (if required) accepted by authors)

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