Thu·Jul 16, 2020Thursday·July 16, 2020

1. 01*

   Anomalous Neutron Yields Confirmed for Ba-Mo and Newly Observed for Ce-Zr from Spontaneous Fission of ${}^{252}$Cf

   B. M. Musangu · A. H. Thibeault · T. H. Richards · E. H. Wang🇺🇸 · J. H. Hamilton🇺🇸 · C. J. Zachary🇺🇸 · J. M. Eldridge🇺🇸 · A. V. Ramayya · Y. X. Luo🇺🇸 · J. O. Rasmussen🇺🇸 · G. M. Ter-Akopian🇷🇺 · Yu. Ts. Oganessian🇷🇺 · S. J. Zhu🇨🇳

   We reinvestigated the neutron multiplicity yields of Ba-Mo, Ce-Zr, Te-Pd, and Nd-Sr from the spontaneous fission of ${}^{252}$Cf; by (i) using both $\gamma$-$\gamma$-$\gamma$-$\gamma$ and $\gamma$-$\gamma$-$\gamma$ coincidence data, (ii) using up to date level scheme structures, and (iii) cross-checking analogous energy transitions in multiple isotopes, we have achieved higher precision than previous analyses. Particular attention was given to the Ba-Mo pairs where our results clearly confirm that the Ba-Mo yield data have a second hot fission mode where 8, 9, 10, and now 11 neutron evaporation channels are observed. These are the first observations of the 11 neutron channel. These 8-11 neutron channels are observed for the first time in the Ce-Zr pairs, but are not observed in other fission pairs. The measured intensities of the second mode in Ba-Mo and Ce-Zr pairs are $\sim$1.5(4)$\%$ and $\sim$1.0(3)$\%$, respectively. These high neutron number evaporation modes can be an indication of hyperdeformation and/or octupole deformation in ${}^{143-145}$Ba and in ${}^{146,148}$Ce at scission to give rise to such high neutron multiplicities.

   nucl-exPRC(2020)·9 citations
2. 02*

   Jet-based measurements of Sivers and Collins asymmetries at the future Electron-Ion Collider

   Miguel Arratia🇺🇸 · Zhong-Bo Kang🇺🇸 · Alexei Prokudin🇺🇸 · Felix Ringer🇺🇸

   We present predictions and projections for hadron-in-jet measurements and electron-jet azimuthal correlations at the future Electron-Ion Collider (EIC). These observables directly probe the three-dimensional (3D) structure of hadrons, in particular, the quark transversity and Sivers parton distributions and the Collins fragmentation functions. We explore the feasibility of these experimental measurements by detector simulations and discuss detector requirements. We conclude that jet observables have the potential to enhance the 3D imaging EIC program.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2020)·64 citations
3. 03*

   Intrinsic radiation background of LaBr${}_3$(Ce) detector via coincidence measurements and simulations

   Hao Cheng🇨🇳 · Bao-Hua Sun🇨🇳 · Li-Hua Zhu🇨🇳 · Tian-Xiao Li🇨🇳 · Guang-Shuai Li🇨🇳 · Cong-Bo Li🇨🇳 · Xiao-Guang Wu🇨🇳 · Yun Zheng🇨🇳

   The LaBr${}_3$(Ce) detector has attracted much attention in recent years for its superior characteristics to other scintillating materials in terms of resolution and efficiency. However, it has relatively high intrinsic radiation background due to the naturally occurring radioisotope in lanthanum, actinium and their daughter nuclei. This limits its applications in low counting rate experiments. In this paper, we identified the radioactive isotopes in the $\varphi 3^{\prime \prime }\times 3^{\prime \prime }$ Saint-Gobain B380 detector by a coincidence measurement using a Clover detector in a low-background shielding system. Moreover, we carried out a Geant4 simulation to the experimental spectra to evaluate the activities of the main internal radiation components. % by means of the $\alpha$, $\gamma$ and $\beta$ decays from the ${}^{138}$La and ${}^{227}$Ac. The activity of radiation background of B380 is determined to be 1.480 (69) Bq/cm${}^3$, the main sources of which include ${}^{138}$La of 1.425 (59) Bq/cm${}^3$, ${}^{211}$Bi of 0.0136 (15) Bq/cm${}^3$, ${}^{219}$Rn of 0.0125 (17) Bq/cm${}^3$, ${}^{223}$Ra of 0.0127 (14) Bq/cm${}^3$, and ${}^{227}$Th of 0.0158 (22) Bq/cm${}^3$.

   ↳ physics.ins-detnucl-exNucl.Sci.Tech.(2020)·5 citations
4. 04*

   Bayesian inference of nuclear symmetry energy from measured and imagined neutron skin thickness in ${}^{116,118,120,122,124,130,132}$Sn, ${}^{208}$Pb, and ${}^{48}$Ca

   Jun Xu🇨🇳 · Wen-Jie Xie🇨🇳 · Bao-An Li🇺🇸

   The neutron skin thickness $\Delta r_{np}$ in heavy nuclei has been known as one of the most sensitive terrestrial probes of the nuclear symmetry energy around $\frac{2}{3}$ of the saturation density ${\rho }_0$ of nuclear matter. Existing neutron skin data mostly from hadronic observables suffer from large uncertainties and their extraction from experiments are often strongly model dependent. While waiting eagerly for the promised model-independent and high-precision neutron skin data for ${}^{208}$Pb and ${}^{48}$Ca from the parity-violating electron scattering experiments (PREX-II and CREX at JLab as well as MREX at MESA), within the Bayesian statistical framework using the Skyrme-Hartree-Fock model we infer the posterior probability distribution functions (PDFs) of the slope parameter $L$ of the nuclear symmetry energy at ${\rho }_0$ from imagined $\Delta r_{np}{(}^{208}$Pb$)=0.15$, 0.20, and 0.30 fm as well as $\Delta r_{np}{(}^{48}$Ca$)=0.12$, 0.15, and 0.25 fm, with different $1\sigma$ error bars. The results are compared with the PDFs of $L$ inferred using the same approach from the available $\Delta r_{np}$ data for Sn isotopes from hadronic probes. They are also compared with results from a recent Bayesian analysis of the radius and tidal deformability data of canonical neutron stars from GW170817 and NICER. The neutron skin data for Sn isotopes gives $L=45.5_{-21.6}^{+26.5}$ MeV surrounding its mean value or $L=53.4_{-29.5}^{+18.6}$ MeV surrounding its maximum {\it a posteriori} value, respectively, with the latter smaller than but consistent with the $L=66_{-20}^{+12}$ MeV from the neutron star data within their 68\% confidence intervals. In order to provide additionally useful information on $L$ extracted from the $\Delta r_{np}$ of Sn isotopes, the experimental error bar of $\Delta r_{np}{(}^{208}$Pb) should be at least smaller than 0.06 fm aimed by some current experiments.

   ↳ nucl-thnucl-exPRC(2020)·56 citations
5. 05*

   A study of charm quark dynamics in quark-gluon plasma with 3+1 D viscous hydrodynamics

   Manu Kurian🇮🇳 · Mayank Singh🇨🇦 · Vinod Chandra🇮🇳 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦

   The drag and diffusion coefficients are studied within the framework of Fokker-Planck dynamics for the case of a charm quark propagating in an expanding quark-gluon plasma. The space-time evolution of the nuclear matter created in the relativistic heavy-ion collision is modelled using MUSIC, a 3+1 D relativistic viscous hydrodynamic approach. The effect of viscous corrections to the heavy quark transport coefficients is explored by considering scattering processes with thermal quarks and gluons in the medium. It is observed that the momentum diffusion of the heavy quarks is sensitive to the shear and bulk viscosity to entropy ratios. The collisional energy loss of the charm quark in the viscous quark-gluon plasma is analyzed.

   ↳ hep-phnucl-exnucl-thPRC(2020)·31 citations
6. 06*

   Azimuthal single- and double-spin asymmetries in semi-inclusive deep-inelastic lepton scattering by transversely polarized protons

   HERMES Collaboration: A. Airapetian🇩🇪 · N. Akopov🇦🇲 · Z. Akopov🇩🇪 · E.C. Aschenauer🇩🇪 · W. Augustyniak🇵🇱 · R. Avakian🇦🇲 · A. Bacchetta🇮🇹 · S. Belostotski🇷🇺 · V. Bryzgalov🇷🇺 · G.P. Capitani🇮🇹 · E. Cisbani🇮🇹 · G. Ciullo🇮🇹 and 62 other authors

   A comprehensive set of azimuthal single-spin and double-spin asymmetries in semi-inclusive leptoproduction of pions, charged kaons, protons, and antiprotons from transversely polarized protons is presented. These asymmetries include the previously published HERMES results on Collins and Sivers asymmetries, the analysis of which has been extended to include protons and antiprotons and also to an extraction in a three-dimensional kinematic binning and enlarged phase space. They are complemented by corresponding results for the remaining four single-spin and four double-spin asymmetries allowed in the one-photon-exchange approximation of the semi-inclusive deep-inelastic scattering process for target-polarization orientation perpendicular to the direction of the incoming lepton beam. Among those results, significant non-vanishing $\cos \varphi -{\varphi }_S$ modulations provide evidence for a sizable worm-gear (II) distribution, $g_{1T}$. Most of the other modulations are found to be consistent with zero with the notable exception of large $\sin {\varphi }_S$ modulations for charged pions and positive kaons.

   ↳ hep-exhep-phnucl-exJHEP(2020)·73 citations
7. 07*

   Comment on "Comparison of optical potential for nucleons and $\Delta$ resonances" by Arie Bodek and Tejin Cai

   U. Mosel🇩🇪

   In \cite{Bodek:2020wbk} Bodek and Cai have tried to extract the potentials for nucleons and $\Delta$ resonances from electron-nucleus inclusive scattering data. They find that the $\Delta$ potential is considerably more attractive than that of the nucleons. This result is at variance with the results of a multitude of analyses of (e,A) and ($\gamma A$) interactions, performed about 35 years ago.

   ↳ nucl-thhep-exnucl-ex4 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.