Bulletin of the American Physical Society
2020 Fall Meeting of the APS Division of Nuclear Physics
Volume 65, Number 12
Thursday–Sunday, October 29–November 1 2020; Time Zone: Central Time, USA
Session DK: Mini-Symposium: Short Range Correlations I |
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Chair: Wim Cosyn, FIU |
Friday, October 30, 2020 8:30AM - 9:06AM |
DK.00001: Probing the Isospin Dependence of Short-range Correlations in A=3 Nuclei Invited Speaker: Shujie Li The nucleon-nucleon correlations at short ranges generate high-momentum nucleons in nuclei. Previous exclusive scattering experiments observed the neutron-proton pair (isospin singlet) dominance in high-momentum nucleons. This np dominance causes a scaling behavior inclusive cross sections at the xbj>1 quasielastic tail. At Jefferson Lab Hall A we checked this np dominance of SRC via the electron scattering on A=3 nuclei system. The 3H to 3He inclusive cross section at xbj>1 were measured at 0.4 < Q2 < 3 GeV^2 in two experiments ( E12-11-112 and E12-14-011). Absolute cross sections were extracted. The fraction of np pairs among high momentum nucleons in the A=3 system was determined from the 3H to 3He cross section ratio at xbj > 1. [Preview Abstract] |
Friday, October 30, 2020 9:06AM - 9:18AM |
DK.00002: Probing high momentum neutrons in light nuclei Holly Szumila-Vance Short-ranged correlated (SRC) nucleon-nucleon ($NN$) pairs account for approximately 20\% of all nucleons in nuclei and about 75\% of the nuclear kinetic energy. SRC $NN$ pairs have high relative momentum and smaller center of mass momentum (relative to the Fermi momentum). High-momentum electron-scattering studies have taught us that almost all high-momentum nucleons belong to SRC pairs and that these pairs are predominantly $pn$ pairs. Here, we extract SRC momentum-dependent characteristics in light nuclei, specifically $^3$He, $^4$He, and $^{12}$C, from 4.4 GeV Jefferson Lab CLAS data. We use the large acceptance of the CLAS detector and the identification of neutrons in the Electromagnetic Calorimeter to measure the distribution and fraction of $np$ pairs at high missing momentum. This is the first measurement of SRC nucleons in $^3$He, a particularly interesting nucleus as it is the lightest asymmetric bound system, and the majority nucleons are protons. This talk will discuss the new results and will provide a brief overview of an approved CLAS12 experiment that will measure short range correlations over a large kinematic range for many different nuclei. [Preview Abstract] |
Friday, October 30, 2020 9:18AM - 9:30AM |
DK.00003: Tagged measurements of Short-Range Correlation at the EIC Florian Hauenstein Understanding the modification of quarks in nucleons within nuclei (EMC effect) is a longstanding open question in nuclear physics. Recent experimental results from electron scattering at Jefferson Lab strengthen the correlation between the EMC effect and nucleon-nucleon short-range correlated pairs (SRC) within nuclei. That means that the EMC effect is probably driven by the high-momentum highly-virtual nucleons of the SRC pairs. This connection can be tested experimentally by measuring electron deep inelastic scattering (DIS) from a nucleon and detecting its correlated SRC partner nucleon (tagging). The Electron-Ion-Collider (EIC) is an ideal machine for tagging measurements due to unique capability of measuring recoil nucleons compared to fixed-target experiments. The design of the EIC detectors allows for a full acceptance for forward-going protons, neutrons and nuclear fragments in addition to the scattered electron. In my talk, I will present results from simulation studies of tagged short-range correlations in Quasi-elastic and DIS kinematics at the EIC. The results will show the requirements for detectors and beam energies for tagged SRC physics at the EIC as well as achievable statistics. [Preview Abstract] |
Friday, October 30, 2020 9:30AM - 9:42AM |
DK.00004: Prospects for Studies of Short-Range Correlations in Nuclei at the Future Electron-Ion Collider Alexander Jentsch Quantum Chromodynamics (QCD) provides the framework for understanding the strong nuclear force. However, due to the nature of nuclear dynamics, our understanding of the dynamical forces between nucleons in a nucleus is as-of-yet incomplete. The EMC effect describes the suppression of the ratio of the structure function, $F_{2}$, between a heavy nucleus and a deuteron for x \textgreater .3. Short-range correlations (SRCs) were proposed as one possible explanation of the EMC Effect, making the study of SRCs valuable for understanding QCD. SRCs are best studied in e$+$A collisions, either using a fixed target, or an e$+$A collider. In January 2020, CD-0 was approved for an Electron-Ion Collider (EIC) at Brookhaven National Laboratory. The EIC will enable collisions of electrons with a wide range of nuclei at a range of center of mass energies, enabling detailed study of SRCs. In this talk, I describe a new study of SRCs using the novel e$+$A MC event generator, BeAGLE. In particular, we use BeAGLE to study the sensitivity of observables to high internal nucleon momentum via incoherent diffractive J/Psi vector meson production. By tagging the spectator nucleon from the deuteron breakup in full EIC detector simulations in the far-forward region ($\Theta $ \textless 2$^{\mathrm{o}})$ access to the SRCs in the deuteron is assessed. [Preview Abstract] |
Friday, October 30, 2020 9:42AM - 9:54AM |
DK.00005: Study of Short-Range Correlations in exotic nuclei at $\rm R ^3 B$ Meytal Duer Most of the knowledge we have about Short-Range Correlated (SRC) pairs comes from electron-induced quasi-free scattering (QFS) experiments, which cannot be performed with short-lived nuclei today. To overcome this limitation, proton-induced QFS in inverse kinematics was proposed. This method has been successfully applied in the recent years to probe the structure of very isospin-asymmetric nuclei. Our recent experiment at JINR (Russia) showed for the first time that SRC pairs are accessible in inverse kinematics using $^{12}\rm C$ beam at high energy and a liquid hydrogen target. This showcases a new ability to study SRC in short-lived exotic nuclei at the setup for Reactions with Relativistic Radioactive Beams ($\rm R^3B$) at GSI and in the future at FAIR (Germany). We plan a first experiment with a neutron-rich nucleus at $\rm R^3B$, scattering a $^{16}\rm C$ beam off a liquid hydrogen target in inverse kinematics at energies up to 1.25 GeV/u, and perform a fully exclusive kinematical measurement. A successful experiment will be the first step into a new era of SRC measurements with hadronic probes along isotopic chains. Studying SRC in such exotic nuclear environment will open the possibility to get insight into the interaction of cold dense nuclear matter as neutron-stars. [Preview Abstract] |
Friday, October 30, 2020 9:54AM - 10:06AM |
DK.00006: SRC scaling below the inclusive limit Igor Korover Short Range Correlated (SRC) pairs are temporary fluctuations of two strongly interacting nucleons in close proximity. SRC pairing shifts nucleons from low-momentum nuclear shell model states to high-momentum states with momenta greater than the nuclear Fermi momentum ($k_F$). This high-momentum tail has a similar shape for all nuclei (scaling). One can isolate SRC contributions by measuring inclusive electron scattering cross sections in select kinematic regions, eg. large $Q^2$ and $x_B > x_B^{thr}\approx 1.4$. For these kinematics the scattering is off nucleons with momentum above $k_F$, Meson Exchange Current (MEC) effect as well as inelastic contributions are largely suppressed. The relative abundance of SRC pairs in a nucleus relative to deuterium approximately equals to the ratio of their inclusive (e,e’) cross-sections in the selected quasi-elastic kinematics presented above. We extended these ratios to much lower $x_B$ by “tagging” the inclusive scattering to identify scattering from nucleons in SRC pairs. We did this by detecting the associated knocked-out proton and requiring that the missing momentum (which is related to the initial momentum of the knocked-out proton) be greater than the Fermi momentum. By using the large acceptance Jefferson Lab CLAS spectrometer. [Preview Abstract] |
Friday, October 30, 2020 10:06AM - 10:18AM |
DK.00007: New Short-Range Correlation ratio measurements of Boron-10 and Boron-11 at JLab Casey Morean The strongly repulsive core of the nucleon-nucleon potential leads to short-range two-nucleon configurations with high relative momenta. Measurements of these Short-Range Correlations (SRCs) have been made in Hall C at JLab in the 6 GeV era using quasi-elastic electron scattering. Six GeV results suggest a correlation between SRC pairs and the EMC effect, warranting further investigation. With the upgrade of JLab to 11 GeV, two new nuclear targets: boron-10 and boron-11 have been studied during the commissioning of the super high momentum spectrometer in Hall C. The preliminary cross-sections and preliminary SRC ratios of boron-10 and boron-11 will be presented and discussed. [Preview Abstract] |
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