Mon·Apr 27, 2020Monday·April 27, 2020

1. 01*

   Novel observation of isospin structure of short-range correlations in calcium isotopes

   D. Nguyen🇺🇸 · Z. Ye🇺🇸 · P. Aguilera🇨🇱 · Z. Ahmed🇺🇸 · H. Albataineh🇺🇸 · K. Allada🇺🇸 · B. Anderson🇺🇸 · D. Anez🇨🇦 · K. Aniol🇺🇸 · J. Annand🇬🇧 · J. Arrington🇺🇸 · T. Averett🇺🇸 and 92 other authors

   Short Range Correlations (SRCs) have been identified as being responsible for the high momentum tail of the nucleon momentum distribution, n(k). Hard, short-range interactions of nucleon pairs generate the high momentum tail and imprint a universal character on n(k) for all nuclei at large momentum. Triple coincidence experiments have shown a strong dominance of np pairs, but these measurements involve large final state interactions. This paper presents the results from Jefferson Lab experiment E08014 which measured inclusive electron scattering cross-section from Ca isotopes. By comparing the inclusive cross section from 48Ca to 40Ca in a kinematic region dominated by SRCs we provide a new way to study the isospin structure of SRCs.

   nucl-exPRC(2020)·26 citations
2. 02*

   First Precision Measurement of the Parity Violating Asymmetry in Cold Neutron Capture on ${}^3$He

   n3He Collaboration: M.T. Gericke (9)🇨🇦 · S. Baeßler (6,7)🇺🇸 · L. Barrón-Palos (4)🇲🇽 · N. Birge (3)🇺🇸 · J.D. Bowman (7)🇺🇸 · C. Britton Jr. (7) · J. Calarco (8)🇺🇸 · V. Cianciolo (7)🇺🇸 · C.E. Coppola (3)🇺🇸 · C.B. Crawford (2)🇺🇸 · D. Ezell (7)🇺🇸 · N. Fomin (3)🇺🇸 and 16 other authors

   We report the first precision measurement of the parity-violating asymmetry in the direction of proton emission with respect to the neutron spin, in the reaction ${}^3\mathrm{He}(\mathrm{n},\mathrm{p}{)}^3\mathrm{H}$, using the capture of polarized cold neutrons in an unpolarized active ${}^3\mathrm{He}$ target. The asymmetry is a result of the weak interaction between nucleons, which remains one of the most poorly understood aspects of electro-weak theory. The measurement provides an important benchmark for modern effective field theory (EFT) calculations. Measurements like this are necessary to determine the spin-isospin structure of the hadronic weak interaction. Our asymmetry result is $A_{PV}=\left(1.58\pm 0.97(\mathrm{stat})\pm 0.24(\mathrm{sys})\right)\times 10^{-8}$, which has the smallest uncertainty of any parity-violating asymmetry measurement so far.

   nucl-exPRL(2020)·22 citations
3. 03*

   Longitudinal dependence of B and D meson nuclear modifications in heavy-ion collisions at RHIC and the LHC

   Caio A. G. Prado🇨🇳 · Wen-Jing Xing🇨🇳 · Shanshan Cao🇺🇸 · Guang-You Qin🇨🇳 · Xin-Nian Wang🇨🇳

   It is widely acknowledged that heavy flavor probes are sensitive to the properties of the quark-gluon plasma and are often considered an important tool for the plasma tomography studies. Forward rapidity observables can provide further insight on the dynamics of the medium due to the interplay between the medium size and the differences in the production spectra of heavy quark probes. In this proceedings we present the nuclear modification factor $R_{\text{AA}}$'s for B and D mesons, as well as heavy flavor leptons, in the rapidity range $-4.0<y<4.0$ obtained from relativistic Langevin equation with gluon radiation coupled with a (3+1)-dimensional viscous hydrodynamics medium background. We present comparison with experimental data at mid-rapidity as well as predictions for different rapidity ranges.

   ↳ nucl-thhep-phnucl-exNPA(2021)·1 citation
4. 04*

   Tensile behavior of dual-phase titanium alloys under high-intensity proton beam exposure: radiation-induced omega phase transformation in Ti-6Al-4V

   Taku Ishida · Eiichi Wakai · Shunsuke Makimura · Andrew M. Casella · Danny J. Edwards · Ramprashad Prabhakaran · David J. Senor · Kavin Ammigan · Sujit Bidhar · Patrick G. Hurh · Frederique Pellemoine · Christopher J. Densham and 8 other authors

   A high-intensity proton beam exposure with 181 MeV energy has been conducted at Brookhaven Linac Isotope Producer facility on various material specimens for accelerator targetry applications, including titanium alloys as a beam window material. The radiation damage level of the analyzed capsule was 0.25 dpa at beam center region with an irradiation temperature around 120 degree C. Tensile tests showed increased hardness and a large decrease in ductility for the dual alpha+beta-phase Ti-6Al-4V Grade-5 and Grade-23 extra low interstitial alloys, with the near alpha-phase Ti-3Al-2.5V Grade-9 alloy still exhibiting uniform elongation of a few % after irradiation. Transmission Electron Microscope analyses on Ti-6Al-4V indicated clear evidence of a high-density of defect clusters with size less than 2 nm in each alpha-phase grain. The beta-phase grains did not contain any visible defects such as loops or black dots, while the diffraction patterns clearly indicated omega-phase precipitation in an advanced formation stage. The radiation-induced omega-phase transformation in the beta-phase could lead to greater loss of ductility in Ti-6Al-4V alloys in comparison with Ti-3Al-2.5V alloy with less beta-phase.

   ↳ physics.ins-dethep-exnucl-exJ.Nucl.Mater.(2020)·11 citations
5. 05*

   Beam energy dependence of cumulants of the net-baryon, net-charge and deuteron multiplicity distributions in Au+Au collisions at $\sqrt{s_{NN}}=3.0-5.0$ GeV

   Yunxiao Ye🇨🇳 · Yongjia Wang🇨🇳 · Qingfeng Li🇨🇳 · Dinghui Lu🇨🇳 · Fuqiang Wang🇺🇸

   Within the ultra-relativistic quantum molecular dynamics (UrQMD) model, in which the Lorentz-covariant treatment of nuclear mean-field potential is considered, the fluctuations of net-baryon, net-charge and deuterons multiplicity distributions in Au+Au head-on collisions at $\sqrt{s_{NN}}=3.0-5.0$ GeV are calculated. The results show that the nuclear mean-field potential can significantly enhance the magnitude of baryon number fluctuations in narrow rapidity windows, and this enhancement rapidly weakens with increasing beam energy. However, for proton and net-charge number fluctuations, the mean-field effects are less noticeable than that for baryon number. In addition, for net-charge number fluctuations, the negative binomial distribution agrees well with the calculated results at mid-pseudorapidity window. Finally, the event-by-event fluctuations of deuteron number in the coalescence production picture are calculated as well, it is found that its cumulant ratios decrease linearly with increasing the average multiplicity of deuterons per event, i.e., increase with increasing beam energy.

   ↳ nucl-thhep-phnucl-exPRC(2020)·10 citations
6. 06*

   Status of the Compressed Baryonic Matter experiment at FAIR

   Peter Senger (for the CBM Collaboration)🇩🇪

   The Compressed Baryonic Matter (CBM) experiment will investigate high-energy heavy-ion collisions at the international Facility for Antiproton and Ion Research (FAIR), which is under construction in Darmstadt, Germany. The CBM research program is focused on the exploration of QCD matter at neutron star core densities, such as study of the equation-of-state and the search for phase transitions. Key experimental observables include (multi-) strange (anti-) particles, electron-positron pairs and dimuons, particle correlations and fluctuations, and hyper-nuclei. In order to measure these diagnostic probes multi-differentially with unprecedented precision, the CBM detector and data acquisition systems are designed to run at reaction rates up to 10 MHz. This requires the development of fast and radiation hard detectors and readout electronics for track reconstruction, electron and muon identification, time-of-flight determination, and event characterization. The data are read-out by ultra-fast, radiation-tolerant, and free-streaming front-end electronics, and then transferred via radiation-hard data aggregation units and high-speed optical connections to a high-performance computing center. A fast and highly parallelized software will perform online track reconstruction, particle identification, and event analysis. The components of the CBM experimental setup will be discussed, and results of physics performance studies will be presented.

   ↳ physics.ins-detnucl-exIJMPE(2020)·7 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.