University of Oulu

Trzaska, W., Enqvist, T., Jędrzejczak, K., Joutsenvaara, J., Kasztelan, M., Kotavaara, O., Kuusiniemi, P., Loo, K., Orzechowski, J., Puputti, J., Sobkow, A., Słupecki, M., Szabelski, J., Usoskin, I., Ward, T. (2021) New NEMESIS Results. Proceedings of 37th International Cosmic Ray Conference — PoS(ICRC2021), 395, 514.

New NEMESIS results

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Author: Trzaska, W. H.1; Enqvist, T.1; Jedrzejczak, K.2;
Organizations: 1Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland
2Cosmic Ray Laboratory, National Centre for Nuclear Research (NCBJ), 28 Pułku Strzelców Kaniowskich 69, 90-558 Łódz, Poland
3University of Oulu, Kerttu Saalasti Institute, Pajatie 5, 85500 Nivala, Finland
4Institut für Physik (IPH), Johannes Gutenberg-Universität Mainz (JGU), Staudingerweg 7, 55128 Mainz, Germany
5Helsinki Institute of Physics (HIP), P.O. Box 64, 00014 University of Helsinki, Finland
6University of Oulu, Sodankylä Geophysical Observatory, P.O. Box 3000, FIN-99600 Sodankylä, Finland
7Office of Nuclear Energy, DOE 1000 Independence Ave., SW, Washington, D.C., 20585, United States
8TechSource, Santa Fe, NM, United States
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.3 MB)
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Language: English
Published: Sissa, 2021
Publish Date: 2021-11-22


Preliminary results from a 349-day run (live time) with a 565 kg Pb target and a 166-day background measurement are presented. Three minor anomalies were detected in muon-suppressed neutron multiplicity spectra. The multiplicities of these excesses match the outcome of an earlier, similar but independent measurement. The nature of the anomalies remains unclear, but, in principle, they may be a signature of self-annihilation of a Weakly Interacting Massive Particle (WIMP) with a mass around 10 GeV/c². The expected cross section would be around 10⁻⁴² cm² for Spin Dependent and 10⁻⁴⁶ cm² for Spin Independent interactions. Analysis of the event rate, based on the statistical uncertainty, indicates that cross-section limits for Dark Matter (DM) mass range of approximately 3–40 GeV/c² can be investigated with an upgraded NEMESIS setup.

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Series: POS. Proceedings of science
ISSN: 1824-8039
ISSN-E: 1824-8039
ISSN-L: 1824-8039
Issue: 395
Article number: 514
DOI: 10.22323/1.395.0514
Host publication: Proceedings of 37th International Cosmic Ray Conference (ICRC2021)
Conference: International Cosmic Ray Conference
Type of Publication: B3 Article in conference proceedings
Field of Science: 115 Astronomy and space science
Funding: This work has been supported in part by the EU INTERREG for the Baltic Sea programme within the BSUIN project, and by the Polish Ministry of Science and Higher Education (Grant no. 3988/INTERREG BSR/2018/2).
Copyright information: © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0).