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Bara, S. et al, Algora, A., & Nacher, E. (2025). New upper limits for β-delayed fission probabilities of 230,232Fr and 230,232,234Ac. Phys. Rev. C, 111(6), 065803–11pp.
Abstract: The process of /3-delayed fission (/3DF) of 230,232Fr and 230,232,234Ac was studied in an experiment performed at the ISOLDE facility at CERN. As no fission fragments were observed for any of the nuclei investigated, upper limits for their /3DF probability (P/3DF) were determined. The experimental results were compared with theoretical calculations that were first benchmarked on 178,180Tl P/3DF experimental values. The P/3DF values were calculated using the code TALYS to which /3-strength functions obtained from the D1M Gogny parametrization and from the Skyrme functional SKO' were given as input together with fission paths obtained with BSkG3 and BSk14 models. Sensitivity studies of different /3-strength functions, and fission paths scaling on the P/3DF values were conducted, suggesting a stronger dependence of the P/3DF on the fission paths rather than on the /3-strength function used.
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Kostelecky, V. A., McNulty, W. P., Passemar, E., & Sherrill, N. (2025). Flavor-changing Lorentz and CPT violation in muonic atoms. Phys. Lett. B, 868, 139755–6pp.
Abstract: Flavor-changing signatures of Lorentz and CPT violation involving muon-electron conversions in muonic atoms are studied using effective field theory. Constraints on coefficients for Lorentz violation at parts in 10-12 GeV-1 for flavor-changing electromagnetic muon decays and parts in 10-13 GeV-2 for flavor-changing 4-point quark-lepton interactions are extracted using existing data from the SINDRUM II experiment at the Paul Scherrer Institute. Estimates are provided for sensitivities attainable in the forthcoming experiments Mu2e at Fermilab and COMET at the Japan Proton Accelerator Complex.
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Suzuki, H. et al, Algora, A., Rubio, B., Victoria, J. A., Tain, J. L., Tolosa, A., et al. (2025). Discovery of 98Sn Produced by the Projectile Fragmentation of a 345-MeV/Nucleon 124Xe Beam. Prog. Theor. Exp. Phys., 2025(5), 053D02–11pp.
Abstract: We present the discovery of a new isotope of 98Sn beyond the double-magic N = Z = 50 nucleus 100Sn. 98Sn was identified among the projectile-fragmentation products of a 124Xe beam at 345 MeV/nucleon at the RI Beam Factory, RIKEN, Japan. Additionally, we have confirmed the production of 96In and 94Cd, previously reported as new isotopes at RIKEN. These highly proton-rich nuclei were separated and identified using the large-acceptance two-stage separator BigRIPS. Furthermore, we have determined the cross sections of 98Sn and its neighboring nuclei. These experimental values were compared to the semi-empirical cross-section formula EPAX3.1a, resulting in a reduction of the predicted cross sections by roughly a factor of 5.
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Bolton, P. D., Fajfer, S., Kamenik, J. F., & Novoa-Brunet, M. (2025). Impact of new invisible particles on B-* K(*)Emiss observables. Phys. Rev. D, 112(3), 035010–14pp.
Abstract: Motivated by a recent Belle II measurement that suggests an excess in the rare decay B-* KEmiss, and building upon our recent differential decay rate likelihood analysis of the existing experimental information, we investigate possible new physics (NP) scenarios in which light invisible states participate in flavor-changing b-* s transitions. In particular, we consider the total and differential B-* K*Emiss decay rates and K* polarization effects in each NP scenario preferred by the B-* KEmiss measurement. We show that future measurements of these B-* K*Emiss observables will offer decisive discrimination among the different NP explanations. Our results highlight the strong complementarity of the rare semi-invisible b-hadron decay observables, and underline the importance of analysing their momentum transfer spectra when probing extensions of the Standard Model that feature new light degrees of freedom.
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Broussard, L. J. et al, & Bas i Beneito, A. (2025). Baryon number violation: from nuclear matrix elements to BSM physics. J. Phys. G, 52(8), 083001–28pp.
Abstract: Processes that violate baryon number, most notably proton decay and nn(sic) transitions, are promising probes of physics beyond the Standard Model (BSM) needed to understand the lack of antimatter in the Universe. To interpret current and forthcoming experimental limits, theory input from nuclear matrix elements to UV complete models enters. Thus, an interplay of experiment, effective field theory, lattice QCD, and BSM model building is required to develop strategies to accurately extract information from current and future data and maximize the impact and sensitivity of next-generation experiments. Here, we briefly summarize the main results and discussions from the workshop 'INT-25-91W: Baryon Number Violation: From Nuclear Matrix Elements to BSM Physics,' held at the Institute for Nuclear Theory, University of Washington, Seattle, WA, 13-17 January 2025.
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