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LHCb Collaboration(Aaij, R. et al), Fernandez Casani, A., Jaimes Elles, S. J., Jashal, B. K., Libralon, S., Martinez-Vidal, F., et al. (2025). Amplitude analysis of the Ξc+ → pK- π+ decay and Ξc+ baryon polarization measurement in semileptonic beauty-hadron decays. Phys. Rev. D, 112(9), 092003–23pp.
Abstract: An amplitude analysis of the Xi(+)(c) -> pK(-) pi(+) decay together with a measurement of the Xi(+)(c) polarization vector in semileptonic beauty-hadron decays is presented. The analysis is performed using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb(-1). An amplitude model is developed and the resonance fractions as well as two- and three-body decay parameters are reported. A sizeable. thornc polarization is found. A large sensitivity of the Xi(c) -> pK(-)pi(+) decay to the polarization is seen, making the amplitude model suitable for Xi(+)(c) polarization measurements in other systems.
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Belocchi, V., Barbaro, M. B., De Pace, A., & Martini, M. (2025). Two-particle two-hole excitations in semi-inclusive neutrino-nucleus scattering. Phys. Rev. D, 112(9), 093002–22pp.
Abstract: A calculation of the two-particle two-hole contribution to the semi-inclusive (nu(mu), μN-) cross section on carbon is performed in the framework of the relativistic Fermi gas model. The process is driven by mesonexchange currents encompassing all contributions involving the exchange of a single pion and the excitation of a Delta resonance. The calculation is validated against the inclusive (nu(mu), mu(-)) response functions already existing in the literature, and then extended for the first time to the semi-inclusive channel. Results are presented both at fixed neutrino energy and folded with the T2K neutrino flux.
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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 decays of the Higgs boson into scalar particles decaying into four or six b quarks using pp collisions at √s=13 TeV with the ATLAS detector. Phys. Rev. D, 112(7), 072005–44pp.
Abstract: A search for exotic decays of the Higgs boson H into new scalar or pseudoscalar particles that subsequently decay into b-quarks is presented. The search considers ZH production with several decay scenarios for the Higgs boson; first to a pair of identical scalars, H -> 2a -> 4b, second to a pair of scalars with different masses (m(a1) < m(a2)), either directly, H -> a(1)a(2) -> 4b, or via a longer decay chain, H -> a(1)a(2) -> 3(a1) -> 6b. The analysis uses proton-proton collision data at root s = 13 TeV collected with the ATLAS detector at the Large Hadron Collider, corresponding to an integrated luminosity of 140 fb(-1). No significant excess above the Standard Model prediction is observed. The search sets upper limits at 95% confidence level on the ratio of the Higgs boson production cross section to the SM prediction times the branching ratio of Higgs bosons decaying into 4b or 6b, between 4% and 25% for sigma(ZH)/sigma(SM) (ZH) x B(H -> 2a -> 4b), between 24% and 38% for sigma(ZH) / sigma(SM) (ZH) x B(H -> a(1) a(2) -> 4b), and between 10% and 20% for sigma(ZH)/sigma(SM)(ZH) x B(H -> a(1)a(2) -> 3(a1) -> 6b), depending on the masses of the scalar particles.
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Herrero-Brocal, A., & Vicente, A. (2026). Minimal Majorana neutrino mass models. J. High Energy Phys., 01(1), 035–25pp.
Abstract: We present an extension of the Casas-Ibarra parametrization that applies to all possible Majorana neutrino mass models. This framework allows us to systematically identify minimal models, defined as those with the smallest number of free parameters. We further analyze the phenomenologically relevant combination of the Yukawa matrix, y dagger y, and show that in certain scenarios it exhibits an unexpected reduction in the number of free parameters, depending on just one real degree of freedom. Finally, the application of our results is illustrated in specific models, which can be tested or falsified due to their definite experimental predictions in heavy neutrino and charged lepton flavor violating decays.
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Ciliberto, G., Balbinot, R., Fabbri, A., & Pavloff, N. (2025). Quantum backreaction in an analog black hole. Phys. Rev. A, 112(6), 063323–17pp.
Abstract: We extend the Gross-Pitaevskii equation to incorporate the effect of quantum fluctuations onto the flow of a weakly interacting Bose-Einstein condensate. Applying this framework to an analog black hole in a quasione-dimensional, transonic flow, we investigate how acoustic Hawking radiation backreacts on the background condensate. Our results point to the emergence of stationary density and velocity undulations in the supersonic region (analogous to the black-hole interior) and enable to evaluate the change in upstream and downstream Mach numbers caused by Hawking radiation. These findings provide new insight into the interplay between quantum fluctuations and analog gravity in Bose-Einstein condensates.
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