Mon·Jul 11, 2022Monday·July 11, 2022

1. 01*

   First Measurement of the EMC Effect in ${}^{10}$B and ${}^{11}$B

   A. Karki🇺🇸 · D. Biswas🇺🇸 · F. A. Gonzalez🇺🇸 · W. Henry🇺🇸 · C. Morean🇺🇸 · A. Nadeeshani🇺🇸 · A. Sun🇺🇸 · D. Abrams🇺🇸 · Z. Ahmed🇨🇦 · B. Aljawrneh🇺🇸 · S. Alsalmi🇺🇸 · R. Ambrose🇨🇦 and 85 other authors

   The nuclear dependence of the inclusive inelastic electron scattering cross section (the EMC effect) has been measured for the first time in ${}^{10}$B and ${}^{11}$B. Previous measurements of the EMC effect in $A\le 12$ nuclei showed an unexpected nuclear dependence; ${}^{10}$B and ${}^{11}$B were measured to explore the EMC effect in this region in more detail. Results are presented for ${}^9$Be, ${}^{10}$B, ${}^{11}$B, and ${}^{12}$C at an incident beam energy of 10.6~GeV. The EMC effect in the boron isotopes was found to be similar to that for ${}^9$Be and ${}^{12}$C, yielding almost no nuclear dependence in the EMC effect in the range $A=4-12$. This represents important, new data supporting the hypothesis that the EMC effect depends primarily on the local nuclear environment due to the cluster structure of these nuclei.

   nucl-exPRC(2023)·14 citations
2. 02*

   Principal Component Analysis of Azimuthal Flow in Intermediate-Energy Heavy-Ion Reactions

   Bao-An Li🇺🇸 · Jake Richter🇺🇸

   Principal Component Analysis (PCA) via Singular Value Decomposition (SVD) of large datasets is an adaptive exploratory method to uncover natural patterns underlying the data. Several recent applications of the PCA-SVD to event-by-event single-particle azimuthal angle distribution matrices in ultra-relativistic heavy-ion collisions at RHIC-LHC energies indicate that the sine and cosine functions chosen {\it a priori} in the traditional Fourier analysis are naturally the most optimal basis for azimuthal flow studies according to the data itself. We perform PCA-SVD analyses of mid-central Au+Au collisions at $E_{\mathrm{beam}}/A$=1.23 GeV simulated using an isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) transport model to address the following two questions: (1) if the principal components of the covariance matrix of nucleon azimuthal angle distributions in heavy-ion reactions around 1 GeV/nucleon are naturally sine and/or cosine functions and (2) what if any advantages the PCA-SVD may have over the traditional flow analysis using the Fourier expansion for studying the EOS of dense nuclear matter. We find that (1) in none of our analyses the principal components come out naturally as sine and/or cosine functions, (2) while both the eigenvectors and eigenvalues of the covariance matrix are appreciably EOS dependent, the PCA-SVD has no apparent advantage over the traditional Fourier analysis for studying the EOS of dense nuclear matter using the azimuthal collective flow in heavy-ion collisions.

   ↳ nucl-thnucl-exNPA(2023)·3 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.