Guadilla, V. et al, Algora, A., Tain, J. L., Agramunt, J., Jordan, D., Monserrate, M., et al. (2022). Total absorption gamma-ray spectroscopy of the ss decays of Y-96gs,Y-m. Phys. Rev. C, 106(1), 014306–14pp.
Abstract: The ss decays of the ground state (gs) and isomeric state (m) of Y-96 have been studied with the total absorption gamma-ray spectroscopy technique at the Ion Guide Isotope Separator On-Line facility. The separation of the 8(+) isomeric state from the 0(-) ground state was achieved thanks to the purification capabilities of the JYFLTRAP double Penning trap system. The ss-intensity distributions of both decays have been independently determined. In the analyses the deexcitation of the 1581.6 keV level in Zr-96, in which conversion electron emission competes with pair production, has been carefully considered and found to have significant impact on the ss-detector efficiency, influencing the ss-intensity distribution obtained. Our results for Y-96gs (0(-)) confirm the large ground state to ground state ss-intensity probability, although a slightly larger value than reported in previous studies was obtained, amounting to 96.6(-2.1)(+0.3) % of the total ss intensity. Given that the decay of Y-96gs is the second most important contributor to the reactor antineutrino spectrum between 5 and 7 MeV, the impact of the present results on reactor antineutrino summation calculations has been evaluated. In the decay of Y-96m (8(+)), previously undetected ss intensity in transitions to states above 6 MeV has been observed. This shows the importance of total absorption gamma-ray spectroscopy measurements of ss decays with highly fragmented deexcitation patterns. Y-96m (8(+)) is a major contributor to reactor decay heat in uranium-plutonium and thorium-uranium fuels around 10 s after fission pulses, and the newly measured average ss and gamma energies differ significantly from the previous values in evaluated databases. The discrepancy is far above the previously quoted uncertainties. Finally, we also report on the successful implementation of an innovative total absorption gamma-ray spectroscopy analysis of the module-multiplicity gated spectra, as a first proof of principle to distinguish between decaying states with very different spin-parity values.
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de Florian, D., Sassot, R., Epele, M., Hernandez-Pinto, R. J., & Stratmann, M. (2015). Parton-to-pion fragmentation reloaded. Phys. Rev. D, 91(1), 014035–17pp.
Abstract: We present a new, comprehensive global analysis of parton-to-pion fragmentation functions at next-to-leading-order accuracy in QCD. The obtained results are based on the latest experimental information on single-inclusive pion production in electron-positron annihilation, lepton-nucleon deep-inelastic scattering, and proton-proton collisions. An excellent description of all data sets is achieved, and the remaining uncertainties in parton-to-pion fragmentation functions are estimated based on the Hessian method. Extensive comparisons to the results from our previous global analysis are performed.
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Grieger, M., Hensel, T., Agramunt, J., Bemmerer, D., Degering, D., Dillmann, I., et al. (2020). Neutron flux and spectrum in the Dresden Felsenkeller underground facility studied by moderated He-3 counters. Phys. Rev. D, 101(12), 123027–15pp.
Abstract: Ambient neutrons may cause significant background for underground experiments. Therefore, it is necessary to investigate their flux and energy spectrum in order to devise a proper shielding. Here, two sets of altogether ten moderated He-3 neutron counters are used for a detailed study of the ambient neutron background in tunnel IV of the Felsenkeller facility, underground below 45 m of rock in Dresden/Germany. One of the moderators is lined with lead and thus sensitive to neutrons of energies higher than 10 MeV. For each He-3 counter moderator assembly, the energy-dependent neutron sensitivity was calculated with the FLUKA code. The count rates of the ten detectors were then fitted with the MAXED and GRAVEL packages. As a result, both the neutron energy spectrum from 10(-9) to 300 MeV and the flux integrated over the same energy range were determined experimentally. The data show that at a given depth, both the flux and the spectrum vary significantly depending on local conditions. Energy-integrated fluxes of (0.61 +/- 0.05), (1.96 +/- 0.15), and (4.6 +/- 0.4) x 10(-4) cm(-2) s(-1), respectively, are measured for three sites within Felsenkeller tunnel IV which have similar muon flux but different shielding wall configurations. The integrated neutron flux data and the obtained spectra for the three sites are matched reasonably well by FLUKA Monte Carlo calculations that are based on the known muon flux and composition of the measurement room walls.
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Bhattacharya, S., Sil, A., Roshan, R., & Vatsyayan, D. (2022). Symmetry origin of baryon asymmetry, dark matter, and neutrino mass. Phys. Rev. D, 106(7), 075005–10pp.
Abstract: We propose a minimal model based on lepton number symmetry (and violation), to address a common origin of baryon asymmetry, dark matter and neutrino mass generation. The model consists of a vectorlike fermion to constitute the dark sector, three right-handed neutrinos (RHNs) to dictate leptogenesis and neutrino mass, while an additional complex scalar is assumed to be present in the early Universe the decay of which produces both dark matter and RHNs via lepton number violating and lepton number conserving interactions respectively. Interestingly, the presence of the same scalar helps in making the electroweak vacuum stable until the Planck scale. The unnatural largeness and smallness of the parameters required to describe correct experimental limits are attributed to lepton number violation. The allowed parameter space of the model is illustrated via a numerical scan.
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Villanueva-Domingo, P., Villaescusa-Navarro, F., Genel, S., Angles-Alcazar, D., Hernquist, L., Marinacci, F., et al. (2023). Weighing the Milky Way and Andromeda galaxies with artificial intelligence. Phys. Rev. D, 107(10), 103003–8pp.
Abstract: We present new constraints on the masses of the halos hosting the Milky Way and Andromeda galaxies derived using graph neural networks. Our models, trained on 2,000 state-of-the-art hydrodynamic simulations of the CAMELS project, only make use of the positions, velocities and stellar masses of the galaxies belonging to the halos, and are able to perform likelihood-free inference on halo masses while accounting for both cosmological and astrophysical uncertainties. Our constraints are in agreement with estimates from other traditional methods, within our derived posterior standard deviation.
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