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ATLAS Collaboration(Aad, G. et al), Aikot, A., Amos, K. R., Bouchhar, N., Cabrera Urban, S., Cantero, J., et al. (2025). Search for Higgs boson decays into a Z boson and a light hadronically decaying resonance in pp at √s=13 TeV with the ATLAS detector. Phys. Lett. B, 868, 139671–24pp.
Abstract: A search for decays of the Higgs boson into a Z boson and a light resonance, with a mass of 0.5-3.5 GeV, is performed using the full 140 fb(-1) dataset of 13 TeV proton-proton collisions recorded by the ATLAS detector during LHC Run 2. Leptonic decays of the Z boson and hadronic decays of the light resonance are considered. The resonance can be interpreted as a J/psi or eta(c) meson, an axion-like particle, or a light pseudoscalar predicted in two-Higgs-doublet models. Due to its low mass, this resonance is produced with a high Lorentz boost in the laboratory frame and therefore reconstructed as a single small-radius jet of hadrons. A neural network is used to correct the Monte Carlo simulation of the total expected background using data from sideband regions. Two additional neural networks are used to distinguish signal from background, enhancing the purity of the signal region. A binned profile-likelihood fit is performed on the final-state invariant mass distribution. No significant excess of events relative to the expected background is observed, and upper limits at 95% confidence level are set on the Higgs boson's branching fraction to a Z boson and a light resonance. The exclusion limit is similar to 10% for the lower masses, and increases for higher masses. Upper limits on the effective coupling C-ZH(eff)/A of an axion-like particle to a Higgs boson and.. boson are also set at 95% confidence level, and range from 0.9 to 2 TeV-1.
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Barbagallo, G., Cerdeira, J. L. V., Gomez-Fayren, C., Meessen, P., & Ortin, T. (2025). On the generalized Komar charge of Kaluza-Klein theories and higher-form symmetries. SciPost Phys. Core, 8(4), 077–14pp.
Abstract: The generalized Komar (d -2)-form charge can be modified by the addition of any other on-shell closed (conserved) (d-2)-form charge. We show that, with Kaluza-Klein boundary conditions, one has to add a charge related to the higher-form symmetry identified in Ref. [10] to the naive Komar charge of pure 5-dimensional gravity to obtain a conserved charge whose integral at spatial infinity gives the mass. The new term also contains the contribution of the Kaluza-Klein monopole charge leading to electric-magnetic duality invariance.
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ANTARES Collaboration(Albert, A. et al), Alves, S., Calvo, D., Carretero, V., Gozzini, R., Hernandez-Rey, J. J., et al. (2026). Search for magnetic monopoles with the complete ANTARES dataset. J. High Energy Astrophys., 50, 100500–8pp.
Abstract: This study presents a search for magnetic monopoles using the full ANTARES dataset collected over 14 years (2008-2022). The interaction of monopoles with matter was modeled according to the Kazama, Yang and Goldhaber cross-section, and dedicated reconstruction strategies were applied to probe velocities both above and below the Cherenkov threshold. No signal consistent with monopoles was found. We derive 90% C.L. upper limits on the flux of relativistic monopoles at the level of 10-18 cm-2 s-1 sr-1, improving upon previous ANTARES results and confirming those obtained by IceCube and other neutrino telescopes. These results constitute the final contribution of ANTARES to the search for magnetic monopoles.
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Liu, X. Z., Yang, Y. H., Gessner, M., Smerzi, A., Li, W. D., Yang, X., et al. (2025). Photonic Metrology with Hierarchic Quantum Frequentist Bounds. Adv. Photon. Res., , 7pp.
Abstract: Quantum metrology establishes fundamental precision limits for parameter estimation, yet standard Quantum Cram & eacute;r-Rao Bound (QCRB) becomes insufficient in the finite-data regime. In this article, the QCRB is systematically tighten using a hybrid classical-quantum framework by incorporating generalized unbiasedness constraints through test observables. These frequentist bounds form a hierarchy converging asymptotically to the QCRB as more measurements are performed. These hierarchical frequentist bounds are validated for single-qubit phase estimation on a photonic platform.
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Amerio, A., Hooper, D., & Linden, T. (2025). Millisecond pulsars in globular clusters and implications for the galactic center gamma-ray excess. J. Cosmol. Astropart. Phys., 10(10), 106–34pp.
Abstract: We study the gamma-ray emission from millisecond pulsars within the Milky Way's globular cluster system in order to measure the luminosity function of this source population. We find that these pulsars have a mean luminosity of (L gamma) ti (1-8) x 1033 erg/s (integrated between 0.1 and 100 GeV) and a log-normal width of sigma L ti 1.4-2.8. If the Galactic Center Gamma-Ray Excess were produced by pulsars with similar characteristics, Fermi would have already detected N ti 17-37 of these sources, whereas only three such pulsar candidates have been identified. We conclude that the excess gamma-ray emission can originate from pulsars only if they are significantly less bright, on average, than those observed within globular clusters or in the Galactic Plane. This poses a serious challenge for pulsar interpretations of the Galactic Center Gamma-Ray Excess.
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