Tue·Feb 5, 2019Tuesday·February 5, 2019

1. 01*

   Measurement of the neutron capture cross-section on argon

   V. Fischer (1)🇺🇸 · L. Pagani (1)🇺🇸 · L. Pickard (1)🇺🇸 · A. Couture (2)🇺🇸 · S. Gardiner (1)🇺🇸 · C. Grant (3)🇺🇸 · J. He (1)🇺🇸 · T. Johnson (1)🇺🇸 · E. Pantic (1)🇺🇸 · C. Prokop (2)🇺🇸 · R. Svoboda (1)🇺🇸 · J. Ullmann (2)🇺🇸 · J. Wang (1) ((1) University of California at Davis, (2) Los Alamos National Laboratory, (3) Boston University)🇨🇳

   The use of argon as a detection and shielding medium for neutrino and dark matter experiments has made the precise knowledge of the cross section for neutron capture on argon an important design and operational parameter. Since previous measurements were averaged over thermal spectra and have significant disagreements, a differential measurement has been performed using a Time-Of-Flight neutron beam and a $\sim$4$\pi$ gamma spectrometer. A fit to the differential cross section from $0.015-0.15$\,eV, assuming a $1/v$ energy dependence, yields ${\sigma }^{2200}=673\pm 26\text{ (stat.)}\pm 59\text{ (sys.)}$\,mb.

   nucl-exhep-exphysics.ins-detPRD(2019)·17 citations
2. 02*

   Has the neutral double hypernucleus ${}_{\Lambda \Lambda }^4$n been observed?

   Sebastian Bleser🇩🇪 · Michael Bölting🇩🇪 · Theodoros Gaitanos🇬🇷 · Josef Pochodzalla🇩🇪 · Falk Schupp🇩🇪 · Marcell Steinen🇩🇪

   The BNL-AGS E906 experiment was the first fully electronic experiment to produce and study double hypernuclei with large statistics. Two dominant structures were observed in the correlated ${\pi }^{-}$--${\pi }^{-}$ momentum matrix at (p${}_{\pi -H}$,p${}_{\pi -L}$) = (133,114) MeV/c and at (114,104) MeV/c. In this work we argue that the interpretation of the structure at (133,114) MeV/c in terms of ${}_{\Lambda }^3$H+${}_{\Lambda }^4$H pairs is questionable. We show, that neither a scenario where the hypernuclei are produced after capture of a stopped ${\Xi }^{-}$ by a ${}^9$Be nucleus nor interactions of energetic ${\Xi }^{-}$ with ${}^9$Be nuclei in the target material can produce a sufficient amount of such twin pairs. We have therefore explored the conjecture of Avraham Gal that decays of the ${}_{\Lambda \Lambda }^4$n may be responsible for the observed structure. Indeed, the inclusion of ${}_{\Lambda \Lambda }^4$n with a two-body ${\pi }^{-}$ branching ratio of 50 % in a statistical multifragmentation model allows to describe the E906 data remarkably well. On the other hand, a bound ${}_{\Lambda }^3$n nucleus would cause a striking structure in the momentum correlation matrix which is clearly inconsistent with the observation of E906.

   nucl-exnucl-thPLB(2019)·10 citations
3. 03*

   Extracting jet transport parameter $\hat{q}$ from a multiphase transport model

   Feng-Chu Zhou🇨🇳 · Guo-Liang Ma🇨🇳 · Yu-Gang Ma🇨🇳

   Within a multi-phase transport model with string melting scenario, jet transport parameter $\hat{q}$ is calculated in Au+Au collisions at $\sqrt{s_{NN}}$= 200 GeV and Pb+Pb collisions at $\sqrt{s_{NN}}$= 2.76 TeV. The $\hat{q}$ increases with the increasing of jet energy for both partonic phase and hadronic phase. The energy and path length dependences of $\hat{q}$ in full heavy-ion evolution are consistent with the expectations of jet quenching. The correlation between jet transport parameter $\hat{q}$ and dijet transverse momentum asymmetry $A_J$ is mainly investigated, which discloses that a larger $\hat{q}$ corresponds to a larger $A_J$. It supports a consistent jet energy loss picture from the two viewpoints of single jet and dijet. It is proposed to measure dijet asymmetry distributions with different jet transport parameter ranges as a new potential method to study jet quenching physics in high energy heavy-ion collisions.

   ↳ hep-phnucl-exnucl-thEPJA(2020)·7 citations
4. 04*

   Nuclear electric dipole moment as a good probe of CP violation

   Nodoka Yamanaka🇫🇷

   The electric dipole moment (EDM) is an excellent probe of new physics beyond the standard model of particle physics. The EDM of light nuclei is particularly interesting due to the high sensitivity to the hadron level CP violation. In this proceedings contribution, we investigate the mechanism of the generation of the EDM for several light nuclei and the prospect for the discovery of new physics.

   ↳ nucl-thhep-exhep-phnucl-exJPS Conf.Proc.(2019)·0 citations
5. 05*

   Propagation of QCD Color through Strongly Interacting Systems

   William K Brooks🇨🇱 · Jorge López🇨🇱

   The propagation of QCD color through atomic nuclei is studied via a new analysis using a geometric model of semi-inclusive deep inelastic scattering. The experimental data were previously published by the HERMES Collaboration and consisted of the multiplicity ratio observable (2007) and the transverse momentum broadening observable (2010). We perform a simultaneous fit of these two observables to estimate (1) the color lifetime of the quark, (2) quark energy loss, (3) the $\hat{q}$ transport coefficient, and (4) the cross section for hadronic interaction with the medium. We present preliminary results for this fit.

   ↳ hep-phhep-exnucl-exnucl-thJPS Conf.Proc.(2019)·0 citations
6. 06*

   Nuclear collective dynamics in the lattice Hamiltonian Vlasov method

   Rui Wang🇨🇳 · Lie-Wen Chen🇨🇳 · Zhen Zhang🇨🇳

   The lattice Hamiltonian method is developed for solving the Vlasov equation with nuclear mean-field based on the Skyrme pseudopotential up to next-to-next-to-next-to leading order. The ground states of nuclei are obtained through varying the total energy with respect to the density distribution of nucleons. Owing to the self-consistent treatment of initial nuclear ground state and the exact energy conservation in the lattice Hamiltonian method, the present framework of solving the Vlasov equation exhibits very stable nuclear ground state evolution. As a first application of the new lattice Hamiltonian Vlasov method, we explore the iso-scalar giant monopole and iso-vector giant dipole modes of finite nuclei. The obtained results are shown to be comparable to that from random-phase approximation and consistent with the experimental data, indicating the capability of the present method in dealing with the long-time near-equilibrium nuclear dynamics.

   ↳ nucl-thastro-ph.SRnucl-exPRC(2019)·24 citations
7. 07*

   QED and Fundamental Symmetries in Positronium Decays

   Steven D. Bass🇵🇱

   We discuss positronium decays with emphasis on tests of fundamental symmetries and the constraints from measurements of other precision observables involving electrons and photons.

   ↳ hep-phnucl-exnucl-thActa Phys.Polon.B(2019)·56 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.