Mon·Sep 23, 2019Monday·September 23, 2019

1. 01*

   First direct measurement of isotopic fission-fragment yields of ${}^{239}$U

   D. Ramos🇫🇷 · M. Caamano🇪🇸 · A. Lemasson🇫🇷 · M. Rejmund🇫🇷 · L. Audouin🇫🇷 · H. Alvarez-Pol🇪🇸 · J.D. Frankland🇫🇷 · B. Fernandez-Dominguez🇪🇸 · E. Galiana-Baldo🇪🇸 · J. Piot🇫🇷 · D. Ackermann🇫🇷 · S. Biswas🇫🇷 and 16 other authors

   A direct and complete measurement of isotopic fission-fragment yields of ${}^{239}$U has been performed for the first time. The ${}^{239}$U fissioning system was produced with an average excitation energy of 8.3 MeV in one-neutron transfer reactions between a ${}^{238}$U beam and a ${}^9$Be target at Coulomb barrier energies. The fission fragments were detected and isotopically identified using the VAMOS++ spectrometer at the GANIL facility. This measurement allows to directly evaluate the fission models at excitation energies of fast neutrons, relevant for next-generation nuclear reactors. The present data, in agreement with model calculations, do not support the recently reported anomaly in the fission-fragment yields of ${}^{239}$U and confirm the persistence of spherical shell effects in the Sn region at excitation energies exceeding the fission barrier by few MeV.

   nucl-exPRL(2019)·22 citations
2. 02*

   Beam-energy dependence of the azimuthal anisotropic flow from RHIC

   Niseem Magdy🇺🇸

   Recent STAR measurements of the anisotropic flow coefficients (v${}_n$) are presented for Au+Au collisions spanning the beam energy range $\sqrt{s_{NN}}=7.7-200$ GeV. The measurements indicate dependences on the harmonic number ($n$), transverse momentum ($p_T$), pseudorapidity ($\eta$), collision centrality and beam energy ($\sqrt{s_{NN}}$) which could serve as important constraints to test different initial-state models and to aid precision extraction of the temperature dependence of the specific shear viscosity.

   nucl-ex9 citations
3. 03*

   Reevaluating Reactor Antineutrino Anomalies with Updated Flux Predictions

   Jeffrey Berryman🇺🇸 · Patrick Huber🇺🇸

   Hints for the existence of a sterile neutrino at nuclear reactors are reexamined using two updated predictions for the fluxes of antineutrinos produced in fissions. These new predictions diverge in their preference for the rate deficit anomaly, relative to previous analyses, but the anomaly in the ratios of measured antineutrino spectra persists. We comment on upcoming experiments and their ability to probe the preferred region of the sterile-neutrino parameter space in the electron neutrino disappearance channel.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2020)·39 citations
4. 04*

   Light Nuclei Production in Au+Au Collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5-200 GeV from JAM model

   Hui Liu🇨🇳 · Dingwei Zhang🇨🇳 · Shu He🇨🇳 · Kai-jia Sun🇺🇸 · Ning Yu🇨🇳 · Xiaofeng Luo🇨🇳

   Light nuclei production is sensitive to the baryon density fluctuations and can be used to probe the QCD phase transition in relativistic heavy-ion collisions. In this work, we studied the production of proton, deuteron, triton in central Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5, 7.7, 11.5, 14.5, 19.6, 27, 39, 54.4, 62.4 and 200 GeV from a transport model (JAM). Based on the coalescence production of light nuclei, we calculated the energy dependence of rapidity density $dN/dy$ and particle ratios ($d/p$, $t/p$, and $t/d$). More importantly, the yield ratio $N_t\times N_p/N_d^2$, which is sensitive to the neutron density fluctuations, shows a flat energy dependence and cannot describe the non-monotonic trend observed by the STAR experiment. Based on the nucleon coalescence, this work can provide constraint and reference to search for the QCD critical point and/or first order phase transition with light nuclei production in future heavy-ion collision experiments.

   ↳ nucl-thhep-phnucl-exPLB(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.