Thu·Sep 16, 2021Thursday·September 16, 2021

1. 01*

   First Measurement of the $B(E2;3/2^{-}\to 1/2^{-})$ Transition Strength in ${}^7$Be: Testing Ab Initio Predictions for $A=7$ Nuclei

   S. L. Henderson · T. Ahn🇺🇸 · M. A. Caprio🇺🇸 · P. J. Fasano🇺🇸 · A. Simon🇮🇱 · W. Tan🇨🇳 · P. O'Malley🇺🇸 · J. Allen🇺🇸 · D. W. Bardayan🇺🇸 · D. Blankstein · B. Frentz · M. R. Hall🇺🇸 and 6 other authors

   Electromagnetic observables are able to give insight into collective and emergent features in nuclei, including nuclear clustering. These observables also provide strong constraints for ab initio theory, but comparison of these observables between theory and experiment can be difficult due to the lack of convergence for relevant calculated values, such as $E2$ transition strengths. By comparing the ratios of $E2$ transition strengths for mirror transitions, we find that a wide range of ab initio calculations give robust and consistent predictions for this ratio. To experimentally test the validity of these ab initio predictions, we performed a Coulomb excitation experiment to measure the $B(E2;3/2^{-}\to 1/2^{-})$ transition strength in ${}^7$Be for the first time. A $B(E2;3/2^{-}\to 1/2^{-})$ value of $26(6)(3)e^2{\mathrm{fm}}^4$ was deduced from the measured Coulomb excitation cross section. This result is used with the experimentally known ${}^7$Li $B(E2;3/2^{-}\to 1/2^{-})$ value to provide an experimental ratio to compare with the ab initio predictions. Our experimental value is consistent with the theoretical ratios within $1\sigma$ uncertainty, giving experimental support for the value of these ratios. Further work in both theory and experiment can give insight into the robustness of these ratios and their physical meaning.

   nucl-exnucl-thPRC(2019)·20 citations
2. 02*

   Baryon diffusion near the QCD critical point

   Lipei Du (Ohio State U.)🇺🇸 · Xin An (North Carolina U.)🇺🇸 · Ulrich Heinz (Ohio State U.)🇺🇸

   Fireballs created in relativistic heavy-ion collisions at different beam energies have been argued to follow different trajectories in the QCD phase diagram in which the QCD critical point serves as a landmark. Using a (1+1)-dimensional model setting with transverse homogeneity, we study the complexities introduced by the fact that the evolution history of each fireball cannot be characterized by a single trajectory but rather covers an entire swath of the phase diagram, with the finally emitted hadron spectra integrating over contributions from many different trajectories. Studying the phase diagram trajectories of fluid cells at different space-time rapidities, we explore how baryon diffusion shuffles them around, and how they are affected by critical dynamics near the QCD critical point. We find a striking insensitivity of baryon diffusion to critical effects. Its origins are analyzed and possible implications discussed.

   ↳ nucl-thhep-phnucl-exPoS(2022)·4 citations
3. 03*

   Inclusive electron scattering in the quasielastic region with Korea-IBS-Daegu-SKKU density functional

   Hana Gil🇰🇷 · Chang Ho Hyun🇰🇷 · Kyungsik Kim🇰🇷

   With the framework of KIDS (Korea-IBS-Daegu-SKKU) density functional model, the isoscalar and isovector effective masses of nucleon and the effect of symmetry energy in nuclear medium are investigated in inclusive $(e,e^{\prime })$ reaction in quasielastic region. The effective masses are varied in the range $(0.7\sim 1.0)M$ with free nucleon mass $M$, and the symmetry energy is varied within the uncertainty allowed by nuclear data and neutron star observation. The wave functions of nucleons inside target nucleus are generated by solving Hartree-Fock equation with adjusting equation of state, binding energy and radius of various stable nuclei, and effective mass of nucleon in the KIDS model. With the obtained wave functions, we calculate the differential cross section for the inclusive $(e,e^{\prime })$ reaction and compare the theoretical results with Bates, Saclay, and SLAC experimental data. Our model describes experimental data better at SLAC-type high incident electron energy than those measured from Bates and Saclay. The influence of the effective mass and symmetry energy appears to be precise on the longitudinal cross section.

   ↳ nucl-thnucl-exPRC(2022)·13 citations
4. 04*

   Nuclear giant quadruple resonance within transport approach and its constraint on nucleon effective mass

   Yi-Dan Song🇨🇳 · Rui Wang🇨🇳 · Zhen Zhang🇨🇳 · Yu-Gang Ma🇨🇳

   We study the nuclear iso-scalar giant quadruple resonance~(ISGQR) based on the Boltzmann-Uehling-Uhlenbeck~(BUU) transport equation. The mean-field part of the BUU equation is described by the Skyrme nucleon-nucleon effective interaction, and its collision term, which embodies the two-particle-two-hole ($2$p-$2$h) correlation, is implemented through the stochastic approach. We find that the width of ISGQR for heavy nuclei is exhausted dominated by collisional damping, which is incorporated into the BUU equation through its collision term, and it can be well reproduced through employing a proper in-medium nucleon-nucleon cross section. Based on further Vlasov and BUU calculations with a number of representative Skyrme interactions, the iso-scalar nucleon effective mass at saturation density is extracted respectively as $m_{s,0}^{\ast }/m$ $=$ $0.83\pm 0.04$ and $m_{s,0}^{\ast }/m$ $=$ $0.82\pm 0.03$ from the measured excitation energy $E_x$ of the ISGQR of $\text{isotope}[208]Pb$. The small discrepancy between the two constraints indicates the negligible role of $2$p-$2$h correlation in constraining $m_{s,0}^{\ast }$ with the ISGQR excitation energy.

   ↳ nucl-thnucl-exPRC(2021)·10 citations
5. 05*

   Longitudinal asymmetry in heavy ion collisions at RHIC

   Sanchari Thakur🇮🇳 · Sumit Kumar Saha🇮🇳 · Sk Noor Alam🇮🇳 · Rupa Chatterjee🇮🇳 · Subhasis Chattopadhyay🇮🇳

   The longitudinal asymmetry arises in relativistic heavy ion collisions due to fluctuation in the number of participating nucleons. This asymmetry causes a shift in the center of mass rapidity of the participant zone. The rapidity shift as well as the longitudinal asymmetry have been found to be significant at the top LHC energy for collisions of identical nuclei. We study the longitudinal asymmetry and its effect on charged particle rapidity distribution and anisotropic flow parameters at relatively lower RHIC energies using a model calculation. The rapidity shift is found to be more pronounced for peripheral collisions, smaller systems and also for lower beam energies due to longitudinal asymmetry. A detailed study has been done by associating the average rapidity shift to a polynomial relation where the coefficients of this polynomial characterize the effect of the asymmetry. We show that the rapidity shift may affect observables significantly at RHIC energies.

   ↳ nucl-thnucl-exEPJA(2022)·3 citations
6. 06*

   Measuring Recoiling Nucleons from the Nucleus with the Electron Ion Collider

   F. Hauenstein🇺🇸 · A. Jentsch🇺🇸 · J. R. Pybus🇺🇸 · A. Kiral🇺🇸 · M. D. Baker🇺🇸 · Y. Furletova🇺🇸 · O. Hen🇺🇸 · D. W. Higinbotham🇺🇸 · C. Hyde🇺🇸 · V. Morozov🇺🇸 · D. Romanov🇺🇸 · L.B. Weinstein🇺🇸

   Short range correlated nucleon-nucleon ($NN$) pairs are an important part of the nuclear ground state. They are typically studied by scattering an electron from one nucleon in the pair and detecting its spectator correlated partner ("spectator-nucleon tagging"). The Electron Ion Collider (EIC) should be able to detect these nucleons, since they are boosted to high momentum in the lab frame by the momentum of the ion beam. To determine the feasibility of these studies with the planned EIC detector configuration, we have simulated quasi-elastic scattering for two electron and ion beam energy configurations: 5 GeV $e^{-}$ and 41 GeV/A ions, and 10 GeV $e^{-}$ and 110 GeV/A ions. We show that the knocked-out and recoiling nucleons can be detected over a wide range of initial nucleon momenta. We also show that these measurements can achieve much larger momentum transfers than current fixed target experiments. By detecting both low and high initial-momentum nucleons, the EIC will provide the data that should allow scientists to definitively show if the EMC effect and short-range correlation are connected, and to improve our understanding of color transparency.

   ↳ physics.ins-detnucl-exPRC(2022)·13 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.