Mon·Jun 14, 2021Monday·June 14, 2021

1. 01*

   Measurement of material isotopics and atom number ratio with alpha-particle spectroscopy for the NIFFTE fission Time Projection Chamber actinide target

   M. Monterial🇺🇸 · K.T. Schmitt🇺🇸 · C. Prokop🇺🇸 · E. Leal-Cidoncha🇺🇸 · M. Anastasiou🇺🇸 · N.S. Bowden🇺🇸 · J. Bundgaard🇺🇸 · R.J. Casperson🇺🇸 · D.A. Cebra🇺🇸 · T. Classen🇺🇸 · D.H. Dongwi🇺🇸 · N. Fotiades🇺🇸 and 28 other authors

   We present the results of a measurement of isotopic concentrations and atomic number ratio of a double-sided actinide target with alpha-spectroscopy and mass spectrometry. The double-sided actinide target, with primarily Pu-239 on one side and U-235 on the other, was used in the fission Time Projection Chamber (fissionTPC) for a measurement of the neutron-induced fission cross-section ratio between the two isotopes. The measured atomic number ratio is intended to provide an absolute normalization of the measured fission cross-section ratio. The Pu-239/U-235 atom number ratio was measured with a combination of mass spectrometry and alpha-spectroscopy with a planar silicon detector with uncertainties of less than 1%.

   nucl-exphysics.ins-detNucl.Instrum.Meth.A(2022)·3 citations
2. 02*

   Dispersion-theoretical analysis of the electromagnetic form factors of the nucleon: Past, present and future

   Yong-Hui Lin🇩🇪 · Hans-Werner Hammer🇩🇪 · Ulf-G. Meißner🇩🇪

   We review the dispersion-theoretical analysis of the electromagnetic form factors of the nucleon. We emphasize in particular the role of unitarity and analyticity in the construction of the isoscalar and isovector spectral functions. We present new results on the extraction of the nucleon radii, the electric and magnetic form factors and the extraction of $\omega$-meson couplings. All this is supplemented by a detailed calculation of the theoretical uncertainties, using bootstrap and Bayesian methods to pin down the statistical errors, while systematic errors are determined from variations of the spectral functions. We also discuss the physics of the time-like form factors and point out further issues to be addressed in this framework.

   ↳ hep-phhep-exhep-latnucl-ex+1EPJA(2021)·74 citations
3. 03*

   inclusiveAI: A machine learning representation of the $F_2$ structure function over all charted $Q^2$ and $x$ range

   S. Brown🇺🇸 · G. Niculescu🇺🇸 · I. Niculescu🇺🇸

   Structure function data provide insight into the nucleon quark distribution. They are relatively straightforward to extract from the world's vast, and growing, amount of inclusive lepto-production data. In turn, structure functions can be used to model the physical processes needed for planning and optimizing future experiments. In this paper a machine learning algorithm capable of predicting, using a unique set of parameters, the $F_2$ structure function, for four-momentum transfer $0.055\le Q^2\le 800.0$ GeV${}^2$ and for Bjorken $x$ from $2.8\times 10^{-5}$ to the pion threshold is presented. The model was trained and reproduces the hydrogen and the deuterium data at the 7~\% level, comparable with the average uncertainty of the experimental data. Extending the model to other nuclei or expanding the kinematic range are straightforward. The model is at least ten times faster than existing structure functions parameterizations, making it an ideal candidate for event generators and systematic studies.

   ↳ hep-phnucl-exPRC(2021)·2 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.