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Bombacigno, F., De Angelis, M., van de Bruck, C., & Giare, W. (2025). Inflation in non-local hybrid metric-Palatini gravity. J. Cosmol. Astropart. Phys., 05(5), 025–30pp.
Abstract: Within the framework of hybrid metric-Palatini gravity, we incorporate non-localities introduced via the inverse of the d'Alembert operators acting on the scalar curvature. We analyze the dynamical structure of the theory and, adopting a scalar-tensor perspective, assess the stability conditions to ensure the absence of ghost instabilities. Focusing on a special class of well-defined hybrid actions where local and non-local contributions are carried by distinct types of curvature we investigate the feasibility of inflation within the resulting Einstein-frame multi-field scenario. We examine how the non-minimal kinetic couplings between the fields, reflecting the non-local structure of the original frame, influence the number of e-folds and the field trajectories. To clarify the physical interpretation of our results, we draw analogies with benchmark single-field inflation scenarios that include spectator fields.
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Lerendegui-Marco, J., Cisterna, G., Hallam, J., Babiano-Suarez, V., Balibrea-Correa, J., Calvo, D., et al. (2025). Imaging neutrons with a position-sensitive monolithic CLYC detector. Nucl. Instrum. Methods Phys. Res. A, 1079, 170594–12pp.
Abstract: In this work, we have developed and characterized a position-sensitive CLYC detector that acts as the neutron imaging layer and y-ray Compton scatterer of the novel dual Gamma-ray and Neutron Vision (GN-Vision) system, which aims at simultaneously obtaining information about the spatial origin of y-ray and neutron sources. We first investigated the performance of two large 50 x 50 mm2 monolithic CLYC crystals, 8 and 13 mm thick respectively, coupled to a pixelated SiPM in terms of energy resolution and neutron-gamma discrimination. The response of two different 95% 6Li-enriched CLYC detectors coupled to an array of 8 x 8 SiPMs was studied in comparison to the results of a conventional photo-multiplier tube. An energy resolution of about 6% with PMT and 8% with SiPMs for the 137Cs peak and a figure of merit of 3-4 for the neutron-gamma discrimination have been obtained. The spatial response of the CLYC-SiPM detector to y-rays and neutrons has also been characterized using charge modulation-based multiplexing techniques based on a diode-coupled charge division circuit. Average resolutions close to 5 mm FWHM with good linearity are obtained in the transverse crystal plane. Last, this work presents the first proof-of-concept experiments of the neutron imaging capability using a neutron pinhole collimator attached to the developed position sensitive CLYC detector.
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Majumdar, A., Papoulias, D. K., Prajapati, H., & Srivastava, R. (2025). Constraining low scale dark hypercharge symmetry at spallation, reactor, and dark matter direct detection experiments. Phys. Rev. D, 111(7), 073006–24pp.
Abstract: Coherent elastic neutrino-nucleus (CEVNS) and elastic neutrino-electron scattering (EVES) data are exploited to constrain “chiral” U(1)X gauged models with light vector mediator mass. These models fall under a distinct class of new symmetries called dark hypercharge symmetries. A key feature is the fact that the Z' boson can couple to all Standard Model fermions at tree level, with the U(1)X charges determined by the requirement of anomaly cancellation. Notably, the charges of leptons and quarks can differ significantly depending on the specific anomaly cancellation solution. As a result, different models exhibit distinct phenomenological signatures and can be constrained through various experiments. In this work, we analyze the recent data from the COHERENT experiment, along with results from dark matter (DM) direct detection experiments such as XENONnT, LUX-ZEPLIN, and PandaX-4T, and place new constraints on three benchmark models. Additionally, we set constraints from a performed analysis of TEXONO data and discuss the prospects of improvement in view of the next-generation DM direct detection DARWIN experiment.
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Bechtle, P. et al, Orero Canet, C., Blanch C., & Irles, A. (2025). A proposal for the LOHENGRIN experiment to search for dark sector particles at the ELSA Accelerator. Eur. Phys. J. C, 85(5), 600–29pp.
Abstract: We present a proposal for a future light dark matter search experiment at the Electron Stretcher Accelerator ELSA in Bonn: Lohengrin. It employs the fixed-target missing momentum based technique for searching for dark-sector particles. The Lohengrin experiment uses a beam of electrons that is extracted from the ELSA accelerator and that is shot onto a thin target to produce mainly Standard Model bremsstrahlung and – in rare occasions – possibly new particles coupling feebly to the electron. A well motivated candidate for such a new particle is the dark photon, a new, possibly massive gauge boson arising from a new gauge interaction in a dark sector and mixing kinetically with the Standard Model photon. The Lohengrin experiment is estimated to reach sensitivity to couplings small enough to explain the relic abundance of dark matter in various models for dark photon masses between approximately 1 MeV and approximately 100 MeV.
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ANTARES Collaboration(Albert, A. et al), Alves, S., Calvo, D., Carretero, V., Gozzini, R., Hernandez-Rey, J. J., et al. (2025). The ANTARES detector: Two decades of neutrino searches in the Mediterranean Sea. Phys. Rep., 1121, 1–46.
Abstract: Interest for studying cosmic neutrinos using deep-sea detectors has increased after the discovery of a diffuse flux of cosmic neutrinos by the IceCube collaboration and the possibility of wider multi-messenger studies with the observations of gravitational waves. The ANTARES detector was the first neutrino telescope in seawater, operating successfully in the Mediterranean Sea for more than a decade and a half. All challenges related to the operation in the deep sea were accurately addressed by the collaboration. Deployment and connection operations became smoother over time; data taking and constant re-calibration of the detector due to the variable environmental conditions were fully automated. A wealth of results on the subject of astroparticle physics, particle physics and multi-messenger astronomy have been obtained, despite the relative modest size of the detector, paving the way to a new generation of larger undersea detectors. This review summarizes the efforts by the ANTARES collaboration that made the possibility to operate neutrino telescopes in seawater a reality and the results obtained in this endeavor.
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