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Full-Text Articles in Physics
X17 Boson And The ³H(P, E⁺E⁻) ⁴He And ³He(N,E⁺E⁻) ⁴He Processes: A Theoretical Analysis, M. Viviani, E. Filandri, C. Gustavino, A. Kievsky, L. E. Marcucci, Rocco Schiavilla
X17 Boson And The ³H(P, E⁺E⁻) ⁴He And ³He(N,E⁺E⁻) ⁴He Processes: A Theoretical Analysis, M. Viviani, E. Filandri, C. Gustavino, A. Kievsky, L. E. Marcucci, Rocco Schiavilla
Physics Faculty Publications
The present work deals with e+−e− pair production in the four-nucleon system. We first analyze the process as a purely electromagnetic one in the context of a state-of-the-art approach to nuclear strong-interaction dynamics and nuclear electromagnetic currents, derived from chiral effective field theory (χEFT). Next, we examine how the exchange of a hypothetical low-mass boson would impact the cross section for such a process. We consider several possibilities, that this boson is either a scalar, pseudoscalar, vector, or axial particle. The ab initio calculations use exact hyperspherical-harmonics methods to describe the bound state and low-energy spectrum of …
Magnetic Structure And Radiative Captures Of Few-Nucleon Systems: Status And Prospects, Laura Elisa Marcucci, Rocco Schiavilla, Alex Gnech, Michele Viviani
Magnetic Structure And Radiative Captures Of Few-Nucleon Systems: Status And Prospects, Laura Elisa Marcucci, Rocco Schiavilla, Alex Gnech, Michele Viviani
Physics Faculty Publications
We review the main ingredients for an ab-initio study of few-nucleon reactions of astrophysical interest within the chiral effective field theory approach, with particular attention to radiative captures relevant for Big Bang Nucleosynthesis and stellar evolution. We conclude with an outlook for ongoing and future work.
Quantum Monte Carlo Calculations Of Weak Transitions In A=6-10 Nuclei, S. Pastore, A. Baroni, S. Gandolfi, R. Schiavilla, R. B. Wiringa
Quantum Monte Carlo Calculations Of Weak Transitions In A=6-10 Nuclei, S. Pastore, A. Baroni, S. Gandolfi, R. Schiavilla, R. B. Wiringa
Physics Faculty Publications
Ab initio calculations of the Gamow-Teller (GT) matrix elements in the β decays of 6He and 10C and electron captures in 7Be are carried out using both variational and Green's function Monte Carlo wave functions obtained from the Argonne v18 two-nucleon and Illinois-7 three-nucleon interactions, and axial many-body currents derived from either meson-exchange phenomenology or chiral effective field theory. The agreement with experimental data is excellent for the electron captures in 7Be, while theory overestimates the 6He and 10C data by ~2% and ~10%, respectively. We show that for these systems correlations in the nuclear …