Prospects for the detection of Dark Matter with Long-lived Mediators in the Sun using the Southern Wide-field Gamma-ray Observatory - Paper proceedings

Sep 8, 2026

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Search for dark matter advances with next-generation gamma-ray observatories, enabling deeper probing of elusive particles. This work studies hidden-sector scenarios where dark matter annihilates into long-lived mediators that escape the solar environment before decaying into gamma rays. Using SWGO instrument response functions, the analysis evaluates updated sensitivities for dark matter capture in the Sun and estimates spin-dependent reach down to ~10−46 cm² for masses below ~5 TeV, improving indirect constraints by over an order of magnitude.

LanguageEnglish

CategoryResearch & Report

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Pages3

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Summary

Preliminary results with updated SWGO IRFs

Beyond Ref. [1]

Acknowledgments

References

Prospects for the detection of Dark Matter with Long-lived Mediators in the Sun using the Southern Wide-field Gamma-ray Observatory Micael Andrade,􀀰,∗ Juan Fagiani, Clarissa Siqueira, 􀀱 Vitor de Souza􀀰 and Aion Viana􀀰 for the SWGO collaboration† 􀀰 Instituto de Física de São Carlos -USP, Av. Trab. São Carlense, 400, São Carlos, Brazil 􀀱 Observatório Nacional, R. Gen. José Cristino, 77, Rio de Janeiro, Brazil E-mail: [micaelandrade@ifsc.usp.br](micaelandrade@ifsc.usp.br) , [juanvitorfagiani@gmail.com](juanvitorfagiani@gmail.com) , [csiqueira@ifsc.usp.br](csiqueira@ifsc.usp.br) , [vitor@ifsc.usp.br](vitor@ifsc.usp.br) , [aion.viana@ifsc.usp.br](aion.viana@ifsc.usp.br) The search for dark matter is advancing into a new era with the development of next-generation gamma-ray observatories, which will significantly enhance detection capabilities. These instruments will extend the limits of detection, offering new opportunities to investigate one of the most elusive components of the universe. Among them, the Southern Wide-field Gamma-ray Observatory, SWGO, stands out for its potential to detect gamma-ray signals originating from dark matter particles trapped within the Sun. This work focuses on hidden sector models, particularly secluded scenarios, where dark matter particles annihilate into long-lived mediators. Unlike standard annihilation channels occurring deep within the Sun’s core, in these scenarios, dark matter annihilates into these mediators that escape the dense solar environment before decaying into detectable gamma rays. The detection of these decay products by SWGO could provide valuable insights into dark matter interactions. Our analysis indicates that SWGO will reach a high level of sensitivity, probing spin-dependent cross-sections as low as 10−46 cm² for dark matter masses below ≈ 5 TeV. This represents a substantial improvement over current detection capabilities, improving current indirect detection constraints by over an order of magnitude. Such advancements will not only strengthen the search for dark matter but also contribute to a deeper understanding of its fundamental properties. 39th International Cosmic Ray Conference (ICRC2025) 15–24 July 2025 Geneva, Switzerland ∗ Speaker †For the complete list of the SWGO Collaboration and acknowledgments, please visit: [https://www.swgo.org/](https://www.swgo.org/)[ ](https://www.swgo.org/)SWGOWiki/lib/exe/fetch.php?media=wiki:the_swgo_collaboration_icrc25.pdf © 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) . [https://pos.sissa.it/](https://pos.sissa.it/) PoS(ICRC2025)464 Summary This proceeding is based entirely on the results presented in Ref. [1] . For a detailed description of the methodology, analysis, and conclusions, we refer the reader to that work. Preliminary results with updated SWGO IRFs Beyond the results presented in Ref. [1], we have updated the sensitivities to dark matter capture in the Sun incorporating the most recent Southern Wide-field Gamma-ray Observatory (SWGO) instrument response functions (IRFs), which became available after the publication of that work. We are now using IRFs derived from the reference layout of SWGO [2], which consists of an array of 3763 independent Water Cherenkov Detectors (WCDs) distributed in a 3-zone configuration with fill factors of 70%, 4%, and 1.7%, decreasing from the center. We are also showing the performance of the first phase of SWGO, called SWGO-A, corresponding to a 385 WCD-unit segment of the inner array, with a fill factor of 65%, arranged in seven independent clusters of 55 tanks. In addition to the changes in the SWGO IRFs, the main methodological changes to the performance analysis are: (i) we now employ the IRFs for each sky position, and not an average value, as it was the case before; (ii) the exposure is computed according to the actual selected site l

FAQs

What dark matter scenario is analyzed in this work?

The study focuses on hidden-sector models, especially secluded scenarios where dark matter annihilates into long-lived mediators. These mediators escape the Sun before decaying into detectable gamma rays.

How does this proceeding update the sensitivity estimates compared with Ref. [1]?

It updates SWGO sensitivities by incorporating the latest instrument response functions (IRFs). Methodologically, it uses IRFs per sky position rather than an average and computes exposure for the actual site location in Pampa La Bola, Chile.

What sensitivity improvement does SWGO achieve for spin-dependent interactions?

The analysis indicates SWGO can reach spin-dependent cross-sections as low as ~10−46 cm² for dark matter masses below ~5 TeV. This corresponds to more than an order-of-magnitude improvement over current indirect detection constraints.

Sep 8, 2026

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