Thu·Aug 30, 2018Thursday·August 30, 2018

1. 01*

   Antinuclei in Heavy-Ion Collisions

   Jinhui Chen🇨🇳 · Declan Keane🇺🇸 · Yugang Ma🇨🇳 · Aihong Tang🇺🇸 · Zhangbu Xu🇺🇸

   We review progress in the study of antinuclei, starting from Dirac's equation and the discovery of the positron in cosmic-ray events. The development of proton accelerators led to the discovery of antiprotons, followed by the first antideuterons, demonstrating that antinucleons bind into antinuclei. With the development of heavy-ion programs at the Brookhaven AGS and CERN SPS, it was demonstrated that central collisions of heavy nuclei offer a fertile ground for research and discoveries in the area of antinuclei. In this review, we emphasize recent observations at Brookhaven's Relativistic Heavy Ion Collider and at CERN's Large Hadron Collider, namely, the antihypertriton and the antihelium-4, as well as measurements of the mass difference between light nuclei and antinuclei, and the interaction between antiprotons. Physics implications of the new observations and different production mechanisms are discussed. We also consider implications for related fields, such as hypernuclear physics and space-based cosmic-ray experiments.

   nucl-exhep-phnucl-thPhys.Rept.(2018)·160 citations
2. 02*

   Novel physics opportunities at the HESR-Collider with PANDA at FAIR

   Leonid Frankfurt🇮🇱 · Mark Strikman🇺🇸 · Alexei Larionov🇩🇪 · Andreas Lehrach🇩🇪 · Rudolf Maier🇩🇪 · Hendrik van Hees🇩🇪 · Christian Spieles🇩🇪 · Volodymyr Vovchenko🇩🇪 · Horst Stoecker🇩🇪

   Exciting new scientific opportunities are presented for the PANDA detector at the High Energy Storage Ring in the redefined $\bar{\text{p}}\text{p}(A)$ collider mode, HESR-C, at the Facility for Antiproton and Ion Research (FAIR) in Europe. The high luminosity, $L\sim 10^{31}$ cm${}^{-2}$ s${}^{-1}$, and a wide range of intermediate and high energies, $\sqrt{s_{\text{NN}}}$ up to 30 GeV for $\bar{\text{p}}\text{p}(A)$ collisions will allow to explore a wide range of exciting topics in QCD, including the study of the production of excited open charm and bottom states, nuclear bound states containing heavy (anti)quarks, the interplay of hard and soft physics in the dilepton production, and the exploration of the regime where gluons -- but not quarks -- experience strong interaction.

   ↳ hep-phhep-exnucl-exnucl-th4 citations
3. 03*

   Two-neutron correlations in a Borromean ${}^{20}\mathrm{C}+n+n$ system: Sensitivity of unbound subsystems

   Jagjit Singh🇯🇵 · W. Horiuchi🇯🇵 · L. Fortunato🇮🇹 · A. Vitturi🇮🇹

   The structure of ${}^{22}$C plays a vital role in the new physics at subshell closure of $N=16$ in the neutron-rich region. We study the two-neutron correlations in the ground state of the weakly-bound Borromean nucleus ${}^{22}$C sitting at the edge of the neutron-drip line and its sensitivity to $\mathrm{core}$-$n$ potential. For the present study, we employ a three-body ($\mathrm{core}+n+n$) structure model designed for describing the Borromean system by explicit coupling of unbound continuum states of the subsystem ($\mathrm{core}+n$). We use a density-independent contact-delta interaction to describe the neutron-neutron interaction and its strength is varied to fix the binding energy. Along with the ground-state properties of ${}^{22}$C, we investigate its electric-dipole and monopole responses, discussing the contribution of various configurations. Our results indicate more configuration mixing as compared to the previous studies in the ground state of ${}^{22}$C. However, they strongly depend upon the choice of the ${}^{20}\mathrm{C}$-$n$ potential as well as the binding energy of ${}^{22}$C, which call for new precise measurements for the low-lying continuum structure of the binary system (${}^{20}\mathrm{C}+n$) and the mass of ${}^{22}$C. These measurements will be essential to understand the Borromean three-body system ${}^{22}$C with more accuracy.

   ↳ nucl-thnucl-exFew Body Syst.(2019)·13 citations
4. 04*

   Weak sensitivity of three-body ($d,p$) reactions to $np$ force models

   A. Deltuva🇱🇹

   Adiabatic distorted-wave approximation (ADWA) study of three-body $(d,p)$ transfer reactions [G.W. Bailey, N.K. Timofeyuk, and J.A. Tostevin, Phys. Rev. Lett. 117, 162502 (2016)] reported strong sensitivity of cross sections to the neutron-proton $(np)$ interaction model when the nucleon-nucleus optical potential is nonlocal. The verification of this unusual finding using more reliable methods is aimed for in the present work. A rigorous Faddeev-type three-body scattering theory is applied to the study of $(d,p)$ transfer reactions. The equations for transition operators are solved in the momentum-space partial-wave framework. Differential cross sections for ${}^{26}$Al$(d,p{)}^{27}$Al reactions are calculated using nonlocal nuclear optical potentials and a number of realistic $np$ potentials. Only a weak dependence on the $np$ force model is observed, typically one order of magnitude lower than in the previous ADWA study. The shape of the angular distribution of the experimental data is well reproduced. Cross sections of $(d,p)$ transfer reactions calculated using a rigorous three-body method show little sensitivity to the $np$ interaction model. This indicates a failure of the ADWA in the context of nonlocal potentials. Some evident shortcomings of the ADWA are pointed out.

   ↳ nucl-thnucl-exPRC(2018)·9 citations
5. 05*

   Elliptic flow in ultra-relativistic collisions with polarized deuterons

   Piotr Bozek🇵🇱 · Wojciech Broniowski🇵🇱

   Predictions are made for elliptic flow in collisions of polarized deuterons with a heavy nucleus. It is shown that the eccentricity of the initial fireball, evaluated with respect to the deuteron polarization axis perpendicular to the beam direction, has a substantial magnitude for collisions of highest multiplicity. Within the Glauber approach we obtain $\sim 7\%$ for the deuteron states with spin projection 0, and $\sim -3\%$ for spin projection $\pm 1$. We propose to measure the elliptic flow coefficient as the second order harmonic coefficient in the azimuthal distribution of produced charged hadrons with respect to the fixed polarization axis. Collective expansion yields a value of the order of $1\%$ for this quantity, as compared to zero in the absence of polarization and/or collectivity. Such a vivid rotational symmetry breaking could be measured with the current experimental accuracy of the relativistic heavy-ion experiments. The effect has a fundamental significance for understanding the nature of dynamics in small systems, as its experimental confirmation would prove the presence of the shape-flow transmutation mechanism, typical of hydrodynamic expansion or rescattering in the later stages of the fireball evolution.

   ↳ nucl-thhep-phnucl-exPRL(2018)·17 citations
6. 06*

   The isospin and neutron-to-proton excess dependence of short-range correlations

   Jan Ryckebusch🇧🇪 · Wim Cosyn🇧🇪 · Sam Stevens🇧🇪 · Corneel Casert🇧🇪 · Jannes Nys🇧🇪

   We provide a systematic study of the isospin composition and neutron-to-proton $\left(\frac{N}{Z}\right)$ ratio dependence of nuclear short-range correlations (SRC) across the nuclear mass table. We use the low-order correlation operator approximation (LCA) to compute the SRC contribution to the single-nucleon momentum distributions for 14 different nuclei from $A=4$ to $A=208$. Ten asymmetric nuclei are included for which the neutrons outnumber the protons by a factor of up to 1.54. The computed momentum distributions are used to extract the pair composition of the SRC. We find that there is a comprehensive picture for the isospin composition of SRC and their evolution with nucleon momentum. We also compute the non-relativistic kinetic energy of neutrons and protons and its evolution with nuclear mass $A$ and $\frac{N}{Z}$. Confirming the conclusions from alternate studies it is shown that the minority species (protons) become increasingly more short-range correlated as the neutron-to-proton ratio increases. We forge connections between measured nucleon-knockout quantities sensitive to SRC and single-nucleon momentum distributions. It is shown that the LCA can account for the observed trends in the data, like the fact that in neutron-rich nuclei the protons are responsible for an unexpectedly large fraction of the high-momentum components.

   ↳ nucl-thnucl-exPLB(2019)·27 citations
7. 07*

   Probing the gluon TMDs with quarkonia

   Jean-Philippe Lansberg🇫🇷 · Cristian Pisano🇮🇹 · Florent Scarpa🇫🇷 · Marc Schlegel🇺🇸

   We briefly review how quarkonium hadroproduction can be used to access the polarised and unpolarised gluon TMDs.

   ↳ hep-phhep-exnucl-exnucl-thPoS(2018)·2 citations
8. 08*

   Theoretical analysis of double parton scatterings in quarkonium production in proton-proton collisions at the LHC

   Nodoka Yamanaka🇫🇷 · Jean-Philippe Lansberg🇫🇷 · Hua-Sheng Shao🇫🇷 · Yu-Jie Zhang🇨🇳

   The production process of quarkonia in proton-proton (pp) collision is a very good probe of the parton structure of the proton. Recent experimental data of the production of J/psi+vector boson or quarkonium pairs at the LHC and Tevatron suggest the relevance of double parton scatterings (DPS). We discuss here the single parton scattering (SPS) contribution to the J/psi +Z, J/psi +W, and J/psi +J/psi productions in hadron collisions. By revisiting the computations of the SPS contributions to the J/psi+Z and J/psi +W productions, we demonstrate that the ATLAS data in fact show evidence for DPS.

   ↳ hep-phhep-exnucl-exnucl-thPoS(2018)·0 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.