2025-08-29 マックス・プランク研究所（MPG）
Dark matter in blue: It is not actually visible, but here astronomers have made the invisible visible. The photo shows the collision of two galaxy clusters. While the “normal” gas (red) clusters in the center, the dark matter (blue) remains unaffected by the collision. The colors were chosen arbitrarily; the researchers deduced the distribution of dark matter from the gravitational profile and visualized it for clarification.
© NASA, ESA, CXC, M. Bradac (University of California, St. Barbara) und S. Allen (Stanford University)
＜関連情報＞
- https://www.mpg.de/25253597/a-new-candidate-for-dark-matter
- https://journals.aps.org/prresearch/abstract/10.1103/fm6h-7r78
- https://link.springer.com/article/10.1007/JHEP08(2025)054
液体シンチレータ検出器における超巨大荷電グラビティノの痕跡 Signatures of supermassive charged gravitinos in liquid scintillator detectors
Adrianna Kruk, Michał Lesiuk, Krzysztof A. Meissner, and Hermann Nicolai
Physical Review Research Published: 13 August, 2025
DOI: https://doi.org/10.1103/fm6h-7r78
Abstract
In a previous work [K. A. Meissner and H. Nicolai, Eur. Phys. J. C 84, 269 (2024)], two of the present authors have suggested possible experimental ways to search for stable supermassive particles with electric charges of (1) in upcoming underground experiments, in particular the new Jiangmen Underground Neutrino Observatory (JUNO) experiment. In this paper, we present a detailed analysis of the specific signature of such gravitino-induced events for the JUNO detector and for upcoming liquid argon detectors like DUNE (Deep Underground Neutrino Experiment). The proposed method of detection relies on the “glow” produced by photons during the passage of such particles through the detector liquid, which would last for about a few to a few hundred microseconds depending on its velocity and the track. The cross sections for electronic excitation of the main component of the scintillator liquid, namely, linear alkylbenzene, by the passing gravitino are evaluated using quantum-chemical methods. The results show that, if such particles exist, the resulting signals would lead to a unique and unmistakable signature, for which we present event simulations as they would be seen by the JUNO or DUNE photomultipliers. Our analysis brings together two very different research areas, namely, fundamental particles physics and the search for a fundamental theory on the one hand, and methods of advanced quantum chemistry on the other.
標準模型の対称性とK(E10) Standard model symmetries and K(E10)
Krzysztof A. Meissner & Hermann Nicolai
Journal of High Energy Physics Published:07 August 2025
DOI:https://doi.org/10.1007/JHEP08(2025)054
Abstract
We clarify and extend our earlier work [1, 2] where it was shown how to amend a scheme originally proposed by M. Gell-Mann to identify the three families of quarks and leptons of the Standard Model with the 48 spin- fermions of N = 8 supergravity that remain after absorption of eight Goldstinos, a scheme that in its original form is dynamically realized at the SU(3) × U(1) stationary point of gauged N = 8 supergravity. We explain how to deform and enlarge this symmetry at the kinematical level to the full Standard Model symmetry group SU(3)c×SU(2)w×U(1)Y, with the correct charge and chiral assignments for all fermions. The framework also leaves room for an extra U(1)B−L symmetry. This symmetry enhancement is achieved by embedding the Standard Model symmetries into (a quotient group of) K(E10), the ‘maximal compact subgroup’ of the maximal rank hyperbolic Kac-Moody symmetry E10, and an infinite prolongation of the SU(8) R-symmetry of N = 8 supergravity. This scheme, which is also supposed to encompass quantum gravity, cannot be realized within the framework of space-time based (quantum) field theory, but requires space-time and related geometrical concepts to be ‘emergent’. We critically review the main hypotheses underlying this construction.
