Mon·Oct 10, 2022Monday·October 10, 2022

1. 01*

   Deep underground laboratory measurement of ${}^{13}$C($\alpha$,$n$)${}^{16}$O in the Gamow windows of the $s$- and $i$-processes

   B. Gao🇨🇳 · T.Y. Jiao · Y.T. Li🇨🇳 · H. Chen🇺🇸 · W.P. Lin🇯🇵 · Z. An · L.H. Ru · Z.C. Zhang🇨🇳 · X.D. Tang · X.Y. Wang🇨🇳 · N.T. Zhang · X. Fang and 63 other authors

   The ${}^{13}$C($\alpha$,$n$)${}^{16}$O reaction is the main neutron source for the slow-neutron-capture (s-) process in Asymptotic Giant Branch stars and for the intermediate (i-) process. Direct measurements at astrophysical energies in above-ground laboratories are hindered by the extremely small cross sections and vast cosmic-ray induced background. We performed the first consistent direct measurement in the range of $E_{c.m.}=$0.24 MeV to 1.9 MeV using the accelerators at the China Jinping Underground Laboratory (CJPL) and Sichuan University. Our measurement covers almost the entire i-process Gamow window in which the large uncertainty of the previous experiments has been reduced from 60\% down to 15\%, eliminates the large systematic uncertainty in the extrapolation arising from the inconsistency of existing data sets, and provides a more reliable reaction rate for the studies of the s- and i-processes along with the first direct determination of the alpha strength for the near-threshold state.

   nucl-exPRL(2022)·35 citations
2. 02*

   Towards a unified treatment of $\Delta S=0$ parity violation in low-energy nuclear processes

   Susan Gardner🇺🇸 · Girish Muralidhara🇺🇸

   We revisit the unified treatment of low-energy hadronic parity violation espoused by Desplanques, Donoghue, and Holstein to the end of an ab initio treatment of parity violation in low-energy nuclear processes within the Standard Model. We use our improved effective Hamiltonian and precise non-perturbative assessments of the quark charges of the nucleon within lattice QCD to make new assessments of the parity-violating meson-nucleon coupling constants. Comparing with recent, precise measurements of hadronic parity violation in few-body nuclear reactions, we find improved agreement with these experimental results, though some tensions remain. We thus note the broader problem of comparing low-energy constants from nuclear and few-nucleon systems, considering, too, unresolved theoretical issues in connecting an ab initio, effective Hamiltonian approach to chiral effective theories. We note how future experiments and lattice QCD studies could sharpen the emerging picture, promoting the study of hadronic parity violation as a laboratory for testing ``end-to-end'' theoretical descriptions of weak processes in hadrons and nuclei at low energies.

   ↳ nucl-thhep-phnucl-exPRC(2023)·9 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.