Wed·Jul 15, 2020Wednesday·July 15, 2020

1. 01*

   Multi-nucleon transfer in the interaction of 977 MeV and 1143 MeV ${}^{204}$Hg with ${}^{208}$Pb

   V. V. Desai · A. Pica · W. Loveland · J.S. Barrett · Department of Chemistry · Oregon State University · Corvallis · Oregon 97331 USA · E.A. McCutchan · National Nuclear Data Center · Brookhaven National Laboratory · Upton and 29 other authors

   A previous study of symmetric collisions of massive nuclei has shown that current models of multi-nucleon transfer (MNT) reactions do not adequately describe the transfer product yields. To gain further insight into this problem, we have measured the yields of MNT products in the interaction of 977 (E/A = 4.79 MeV) and 1143 MeV (E/A = 5.60 MeV) ${}^{204}$Hg with ${}^{208}$Pb. We find that the yield of multi-nucleon transfer products are similar in these two reactions and are substantially lower than those observed in the reaction of 1257 MeV (E/A = 6.16 MeV) ${}^{204}$Hg + ${}^{198}$Pt. We compare our measurements with the predictions of the GRAZING-F, di-nuclear systems (DNS) and improved quantum molecular dynamics (ImQMD) models. For the observed isotopes of the elements Au, Hg, Tl, Pb and Bi, the measured values of the MNT cross sections are orders of magnitude larger than the predicted values. Furthermore, the various models predict the formation of nuclides near the N=126 shell, which are not observed.

   nucl-exPRC(2020)·18 citations
2. 02*

   James Chadwick: ahead of his time

   Gerhard Ecker

   James Chadwick is known for his discovery of the neutron. Many of his earlier findings and ideas in the context of weak and strong nuclear forces are much less known. This biographical sketch attempts to highlight the achievements of a scientist who paved the way for contemporary subatomic physics.

   ↳ physics.hist-phhep-exhep-phnucl-ex+10 citations
3. 03*

   Analysis of the ${}^3\mathrm{He}(\alpha ,\gamma {)}^7\mathrm{Be}$ and ${}^3\mathrm{H}(\alpha ,\gamma {)}^7\mathrm{Li}$ astrophysical direct capture reactions in a modified potential-model approach

   E.M. Tursunov · S.A. Turakulov · A.S. Kadyrov

   Astrophysical $S$ factors and reaction rates of the direct radiative capture processes ${}^3\mathrm{He}(\alpha ,\gamma {)}^7\mathrm{Be}$ and ${}^3\mathrm{H}(\alpha ,\gamma {)}^7\mathrm{Li}$, as well as the primordial abundance of the ${}^7\mathrm{Li}$ element, are estimated in the framework of a modified two-body potential model. It is shown that suitable modification of phase-equivalent $\alpha {-}^3\mathrm{He}$ potentials in the $d$ waves can improve the description of the astrophysical $S$ factor for the direct ${}^3\mathrm{He}(\alpha ,\gamma {)}^7\mathrm{Be}$ radiative capture reaction at energies above 0.5 MeV. An estimated ${}^{7}Li/H$ abundance ratio of $(4.89\pm 0.18)\times 10^{-10}$ is in very good agreement with the recent measurement of $(5.0\pm 0.3)\times 10^{-10}$ by the LUNA collaboration.

   ↳ nucl-thastro-ph.COnucl-exNPA(2021)·15 citations
4. 04*

   Insights into nuclear saturation density from parity violating electron scattering

   C. J. Horowitz🇺🇸 · J. Piekarewicz🇺🇸 · Brendan Reed🇺🇸

   The saturation density of nuclear matter ${\rho }_0$ is a fundamental nuclear physics property that is difficult to predict from fundamental principles. The saturation density is closely related to the interior density of a heavy nucleus, such as ${}^{208}$Pb. We use parity violating electron scattering to determine the average interior weak charge and baryon densities in ${}^{208}$Pb. This requires not only measuring the weak radius $R_{\mathrm{wk}}$ but also determining the surface thickness of the weak charge density $a$. We obtain ${\rho }_0=0.150\pm 0.010$ fm${}^{-3}$, where the 7\% error has contributions form the PREX error on the weak radius, an assumed 10\% uncertainty in the surface thickness $a$, and from the extrapolation to infinite nuclear matter. These errors can be improved with the upcoming PREX II results and with a new parity violating electron scattering experiment, at a somewhat higher momentum transfer, to determine $a$.

   ↳ nucl-thnucl-exPRC(2020)·57 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.