Probing inelastic dark matter at large mass splittings requires heavy target nuclei, an extended recoil-energy range, and the high-velocity tail of the dark-matter distribution. We exploit these features with the RES-NOVA prototype detector, featuring a PbWO4 cryogenic calorimeter, produced from archaeological Pb and operated at the deep-underground laboratory of Gran Sasso of INFN (Italy), analyzing a 32.4 g day exposure over 2.5 keV - 1 MeV under both the Standard Halo Model (SHM) and a Large Magellanic Cloud (LMC)-motivated velocity distribution. We extend direct-detection constraints beyond the 330 keV reach of established technologies (e.g. Xe-based TPCs), probing splittings up to 510 (780) keV in the SHM (LMC) benchmark, while future exposures will probe new regions of the parameter space.
Abstract We report on the operation of a 13 g PbWO $$_4$$ 4 crystal, grown from archaeological Pb and operated as a cryogenic calorimeter in an underground environment. Read out with a Ge thermistor, the detector achieves a low energy threshold and, for the first time, enables the derivation of a dark matter exclusion limit using PbWO $$_4$$ 4 as target material, for both spin-dependent interactions on neutrons and spin-independent interactions. Although limited in mass and not representative of the final RES–NOVA detector design, this prototype demonstrates effective control of mechanical vibrations and low-energy noise in a cryogenic system, which is a key requirement for rare-event searches. The experiment therefore provides a proof of principle for the RES–NOVA detection concept, validating the use of archaeological Pb-based PbWO $$_4$$ 4 crystals, low-background operation, and robust data-analysis procedures. These results establish a solid technological and methodological foundation for future RES–NOVA detectors employing larger target masses and advanced thermal readout technologies.
Sodium iodide (NaI) is a widely used scintillator in direct dark matter searches. In particular, NaI-based cryogenic scintillating calorimeters have emerged as promising candidates, like in the COSINUS experiment, for testing the annually modulating signal reported by DAMA/LIBRA. In this study, we investigate defect formation within NaI crystals and its impact on the dark matter detection signal. Using molecular dynamics simulations and density functional theory techniques, we simulate a DM particle collision on an NaI crystal, focusing on the possible defects formation and their structural and electronic properties. Our analysis includes a detailed study of the electronic states associated with the interstitial atoms and vacancies, the energetic cost of defect formation, and the anisotropic threshold displacement energy. Finally, we highlight the potential to exploit dark matter-induced defects as a novel detection channel, enabled by the introduction of new states within the electronic band gap.
Aqueous Zn//MnO2 batteries hold significant promise for safe and cost-effective large-scale energy storage, yet their practical deployment is hindered by rapid performance degradation. Here, we identify bilateral ionic crosstalk, a previously overlooked failure mechanism driven by active ion, as a root cause of electrode degradation. We demonstrate that excess Zn2+ migrating from the anode induces irreversible phase transitions at the MnO2 cathode, forming electrochemically inert Znx(MnO2)y phase (ZMO sclerosis). Concurrently, dissolved Mn2+ from the cathode exacerbates corrosion and dendrite growth on the Zn anode. To mitigate this crosstalk, we design a hierarchical fluorinated polymer separator (HFPS). Such HFPS enables selective cation coordination and guides ion transport, achieving simultaneous regulation of Zn2+ and Mn2+ fluxes. This targeted regulation effectively mitigates ionic crosstalk and stabilizes both electrodes. Batteries employing the HFPS exhibit exceptional cycling stability, retaining 97% capacity after 1,000 cycles at 0.5 A g-1 with stable operation exceeding 500 h. This performance represents a 54% lifespan enhancement over state-of-the-art aqueous counterparts. Our work provides a fundamental mechanistic understanding of active-ion-induced failure and establishes ion flux regulation as a universal design strategy for durable aqueous zinc-ion batteries.
