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1. A closer look in the mirror: reflections on the matter/dark matter coincidence

   https://doi.org/10.1007/JHEP06(2024)052  

   Bodas, Arushi; Buen-Abad, Manuel A; Hook, Anson; Sundrum, Raman (June 2024, Journal of High Energy Physics)

   A<sc>bstract</sc> We argue that the striking similarity between the cosmic abundances of baryons and dark matter, despite their very different astrophysical behavior, strongly motivates the scenario in which dark matter resides within a rich dark sector parallel in structure to that of the standard model. The near cosmic coincidence is then explained by an approximateℤ₂exchange symmetry between the two sectors, where dark matter consists of stable dark neutrons, with matter and dark matter asymmetries arising via parallel WIMP baryogenesis mechanisms. Taking a top-down perspective, we point out that an adequateℤ₂symmetry necessitates solving the electroweak hierarchy problem in each sector, without our committing to a specific implementation. A higher-dimensional realization in the far UV is presented, in which the hierarchical couplings of the two sectors and the requisiteℤ₂-breaking structure arise naturally from extra-dimensional localization and gauge symmetries. We trace the cosmic history, paying attention to potential pitfalls not fully considered in previous literature. Residualℤ₂-breaking can very plausibly give rise to the asymmetric reheating of the two sectors, needed to keep the cosmological abundance of relativistic dark particles below tight bounds. We show that, despite the need to keep inter-sector couplings highly suppressed after asymmetric reheating, there can naturally be order-one couplings mediated by TeV scale particles which can allow experimental probes of the dark sector at high energy colliders. Massive mediators can also induce dark matter direct detection signals, but likely at or below the neutrino floor. 

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2. The XENON1T dark matter experiment

   https://doi.org/10.1140/epjc/s10052-017-5326-3  

   Aprile, E.; Aalbers, J.; Agostini, F.; Alfonsi, M.; Amaro, F. D.; Anthony, M.; Antunes, B.; Arneodo, F.; Balata, M.; Barrow, P.; et al (December 2017, The European Physical Journal C)
3. Organic matter in the ocean

   https://doi.org/10.1016/B978-0-323-99762-1.00054-1  

   Boiteau, Rene M; McParland, Erin L (January 2025, Elsevier)
4. The XENONnT dark matter experiment

   https://doi.org/10.1140/epjc/s10052-024-12982-5  

   XENON_Collaboration; Aprile, E.; Aalbers, J.; Abe, K.; Ahmed_Maouloud, S.; Althueser, L.; Andrieu, B.; Angelino, E.; Angevaare, J_R; Antochi, V_C; et al (August 2024, The European Physical Journal C)

   Abstract The multi-staged XENON program at INFN Laboratori Nazionali del Gran Sasso aims to detect dark matter with two-phase liquid xenon time projection chambers of increasing size and sensitivity. The XENONnT experiment is the latest detector in the program, planned to be an upgrade of its predecessor XENON1T. It features an active target of 5.9 tonnes of cryogenic liquid xenon (8.5 tonnes total mass in cryostat). The experiment is expected to extend the sensitivity to WIMP dark matter by more than an order of magnitude compared to XENON1T, thanks to the larger active mass and the significantly reduced background, improved by novel systems such as a radon removal plant and a neutron veto. This article describes the XENONnT experiment and its sub-systems in detail and reports on the detector performance during the first science run. 

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5. The Effects of Linear Matter Power Spectrum Enhancement on Dark Matter Substructure

   https://doi.org/10.3847/1538-4357/ae073b  

   Nadler, Ethan O; Gluscevic, Vera; Benson, Andrew (October 2025, The Astrophysical Journal)

   Abstract We present cosmological dark matter (DM)–only zoom-in simulations of a Milky Way analog originating from enhanced linear matter power spectraP(k) relative to the standard cold, collisionless DM (CDM) cosmology. We consider a Gaussian power excess inP(k) followed by a cutoff in select cases; this behavior could arise from early-Universe physics that alters the primordial matter power spectrum or DM physics in the radiation-dominated epoch. We find that enhanced initial conditions (ICs) lead to qualitative differences in substructure relative to CDM. In particular, the subhalo mass function (SHMF) resulting from ICs with both an enhancement and a cutoff is amplified at high masses and suppressed at low masses, indicating that DM substructure is sensitive to features inP(k). Critically, the amplitude and shape of the SHMF enhancement depend on the wavenumber of theP(k) excess and the presence or absence of a cutoff on smaller scales. These alterations to the SHMF are mainly imprinted at infall rather than during tidal evolution. Additionally, subhalos are found systematically closer to the host center, and their concentrations are increased in scenarios withP(k) enhancement. Our work thus reveals effects that must be captured to enableP(k) reconstruction using DM substructure. 

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