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1. Electron Scattering Cross-Section Calculations for Atomic and Molecular Iodine

   https://doi.org/10.3390/atoms9040103  

   Ambalampitiya, Harindranath; Hamilton, Kathryn; Zatsarinny, Oleg; Bartschat, Klaus; Turner, Matt; Dzarasova, Anna; Tennyson, Jonathan (December 2021, Atoms)

   Cross sections for electron scattering from atomic and molecular iodine are calculated based on the R-matrix (close-coupling) method. Elastic and electronic excitation cross sections are presented for both I and I2. The dissociative electron attachment and vibrational excitation cross sections of the iodine molecule are obtained using the local complex potential approximation. Ionization cross sections are also computed for I2 using the BEB model. 

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2. Electron Scattering Cross Section Data of Supercritical CO ₂ Clusters

   https://doi.org/10.1109/EIC47619.2020.9158748  

   Haque, Farhina; Wei, Jia; Graber, Lukas; Park, Chanyeop (June 2020, Electrical Insulation Conference)

   null (Ed.)
3. Deep Minima in the Triply Differential Cross Section for Ionization of Atomic Hydrogen by Electron and Positron Impact

   https://doi.org/10.3390/atoms8020026  

   DeMars, C.; Ward, S.; Colgan, J.; Amami, S.; Madison, D. (June 2020, Atoms)

   We investigate ionization of atomic hydrogen by electron- and positron-impact. We apply the Coulomb–Born (CB1) approximation, various modified CB1 approximations, the three body distorted wave (3DW) approximation, and the time-dependent close-coupling (TDCC) method to electron-impact ionization of hydrogen. For electron-impact ionization of hydrogen for an incident energy of approximately 76.45 eV, we obtain a deep minimum in the CB1 triply differential cross section (TDCS). However, the TDCC for 74.45 eV and the 3DW for 74.46 eV gave a dip in the TDCS. For positron-hydrogen ionization (breakup) we apply the CB1 approximation and a modified CB1 approximation. We obtain a deep minimum in the TDCS and a zero in the CB1 transition matrix element for an incident energy of 100 eV with a gun angle of 56.13 ° . Corresponding to a zero in the CB1 transition matrix element, there is a vortex in the velocity field associated with this element. For both electron- and positron-impact ionization of hydrogen the velocity field rotates in the same direction, which is anticlockwise. All calculations are performed for a doubly symmetric geometry; the electron-impact ionization is in-plane and the positron-impact ionization is out-of-plane. 

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4. Cross-section continuity of definitions of angular momentum

   https://doi.org/10.1088/1361-6382/acaa82  

   Chen, Po-Ning; Paraizo, Daniel E; Wald, Robert M; Wang, Mu-Tao; Wang, Ye-Kai; Yau, Shing-Tung (December 2022, Classical and Quantum Gravity)

   Abstract We introduce a notion of ‘cross-section continuity’ as a criterion for the viability of definitions of angular momentum, J , at null infinity: If a sequence of cross-sections, , of null infinity converges uniformly to a cross-section , then the angular momentum, J n , on should converge to the angular momentum, J , on . The Dray–Streubel (DS) definition of angular momentum automatically satisfies this criterion by virtue of the existence of a well defined flux associated with this definition. However, we show that the one-parameter modification of the DS definition proposed by Compere and Nichols—which encompasses numerous other alternative definitions—does not satisfy cross-section continuity. On the other hand, we prove that the Chen–Wang–Yau definition does satisfy the cross-section continuity criterion. 

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5. Gallium neutrino absorption cross section and its uncertainty

   https://doi.org/10.1103/PhysRevC.108.035502  

   Elliott, S R; Gavrin, V N; Haxton, W C; Ibragimova, T V; Rule, E J (September 2023, Physical Review C)

   In the recent Baksan Experiment on Sterile Transitions (BEST), a suppressed rate of neutrino absorption on a gallium target was observed, consistent with earlier results from neutrino source calibrations of the SAGE and GALLEX/GNO solar neutrino experiments. The BEST Collaboration, utilizing a 3.4 MCi 51Cr neutrino source, found observed-to-expected counting rates at two very short baselines of R = 0.791 ± 0.05 and 0.766 ± 0.05, respectively. Among recent neutrino experiments, BEST is notable for the simplicity of both its neutrino spectrum, line neutrinos from an electron-capture source whose intensity can be measured to a estimated precision of 0.23%, and its absorption cross section, where the precisely known rate of electron capture to the gallium ground state, 71Ge(e−, νe ) 71Ga(g.s.), establishes a minimum value. However, the absorption cross section uncertainty is a common systematic in the BEST, SAGE, and GALLEX/GNO neutrino source experiments. Here we update that cross section, considering a variety of electroweak corrections and the role of transitions to excited states, to establish both a central value and reasonable uncertainty, thereby enabling a more accurate assessment of the statistical significance of the gallium anomalies. Results are given for 51Cr and 37Ar sources. The revised neutrino capture rates are used in a reevaluation of the BEST and gallium anomalies. 

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