Tue·Feb 25, 2020Tuesday·February 25, 2020

1. 01*

   Chiral Magnetic Effects in Nuclear Collisions

   Wei Li🇺🇸 · Gang Wang🇺🇸

   The interplay of quantum anomalies with strong magnetic field and vorticity in chiral systems could lead to novel transport phenomena, such as the chiral magnetic effect (CME), the chiral magnetic wave (CMW) and the chiral vortical effect (CVE). In high-energy nuclear collisions, these chiral effects may survive the expansion of a quark-gluon plasma fireball and be detected in experiments. The experimental searches for the CME, the CMW and the CVE, have aroused extensive interest over the past couple of decades. The main goal of this article is to review latest experimental progress in search for these novel chiral transport phenomena at Relativistic Heavy Ion Collider at BNL and the Large Hadron Collider at CERN. Future programs to help reduce uncertainties and facilitate the interpretation of the data are also discussed.

   nucl-exhep-exhep-phnucl-thAnn.Rev.Nucl.Part.Sci.(2020)·71 citations
2. 02*

   Three-Nucleon Forces: Implementation and Applications to Atomic Nuclei and Dense Matter

   Kai Hebeler🇩🇪

   Recent advances in nuclear structure theory have significantly enlarged the accessible part of the nuclear landscape via ab initio many-body calculations. These developments open new ways for microscopic studies of light, medium-mass and heavy nuclei as well as nuclear matter and represent an important step toward a systematic and comprehensive understanding of atomic nuclei across the nuclear chart. While remarkable agreement has been found between different many-body methods for a given nuclear Hamiltonian, the comparison with experiment and the understanding of theoretical uncertainties are still important open questions. The observed discrepancies to experiment indicate deficiencies in presently used nuclear interactions and operators. Chiral effective field theory (EFT) allows to systematically derive contributions to nucleon-nucleon (NN), three-nucleon (3N) and higher-body interactions including estimates of theoretical uncertainties. While the treatment of NN interactions in many-body calculations is well established, the calculation of 3N interactions and their incorporation in ab initio frameworks is still a frontier. This work reviews in detail recent and current developments on the derivation and implementation of improved 3N interactions and provides a comprehensive introduction to fundamental methods for their practical calculation and representation. We further give an overview of novel and established methods that facilitate the inclusion and treatment of 3N interactions in ab initio nuclear structure frameworks and present a selection of the latest calculations of atomic nuclei as well as nuclear matter based on state-of-the-art nuclear NN and 3N interactions derived within chiral EFT. Finally, we discuss ongoing efforts, open questions and future directions.

   ↳ nucl-thastro-ph.HEnucl-exPhys.Rept.(2021)·182 citations
3. 03*

   Incoherent $\rho$ meson photoproduction in ultraperipheral nuclear collisions at the LHC

   V. Guzey🇷🇺 · E. Kryshen🇷🇺 · M. Zhalov (St. Petersburg, INP)🇷🇺

   Using the Gribov-Glauber model for photon-nucleus scattering and a generalization of the vector meson dominance model for the hadronic structure of the photon, we make predictions for the cross section of incoherent $\rho$ photoproduction in Pb-Pb ultraperipheral collisions (UPCs) in the Large Hadron Collider kinematics. We find that the effect of the inelastic nuclear shadowing is significant and leads to an additional 25% suppression of the incoherent cross section. Comparing our predictions to those of the STARlight Monte Carlo framework, we observe very significant differences.

   ↳ hep-phhep-exnucl-exPRC(2020)·6 citations
4. 04*

   The Collectivity of Heavy Mesons in Proton-Nucleus Collisions

   Cheng Zhang🇨🇳 · Cyrille Marquet🇫🇷 · Guang-You Qin🇨🇳 · Yu Shi🇨🇳 · Lei Wang🇨🇳 · Shu-Yi Wei🇮🇹 · Bo-Wen Xiao🇨🇳

   Using a model based on the Color Glass Condensate framework and the dilute-dense factorization, we systematically study the azimuthal angular correlations between a heavy flavor meson and a light reference particle in proton-nucleus collisions. The obtained second harmonic coefficients (also known as the elliptic flows) for $J/\psi$ and $D^0$ agree with recent experimental data from the LHC. We also provide predictions for the elliptic flows of ${\rm Y}$ and $B$ meson, which can be measured in the near future at the LHC. This work can shed light on the physics origin of the collectivity phenomenon in the collisions of small systems.

   ↳ hep-phnucl-exnucl-thPRD(2020)·37 citations
5. 05*

   Nuclear multipole responses from chiral effective field theory interaction

   B. S. Hu🇨🇳 · Q. Wu🇨🇳 · Q. Yuan · Y. Z. Ma🇨🇳 · X. Q. Yan🇨🇳 · F. R. Xu🇨🇳

   We probe nuclear multipole resonances in the framework of the random-phase approximation by using the interaction obtained from the chiral effective field theory. The three-nucleon force is included in a form of the in-medium two-nucleon interaction which was derived from the chiral three-nucleon force. The isoscalar monopole, isoscalar dipole, isovector dipole and isoscalar quadrupole resonances of the closed-shell ${}^{56,68,78}$Ni have been investigated. The calculations reasonably reproduce the experimental multipole resonances of ${}^{56,68}$Ni, and well describe the pygmy dipole resonance and dipole polarizability measured in ${}^{68}$Ni. The multipole resonances of ${}^{78}$Ni, including pygmy dipole resonance and dipole polarizability, are predicted. The detailed effects of the tensor force and three-body force are analyzed by dissecting the chiral interaction. We find that in general the tensor force effect on electric giant resonances is not as significant as the effect from the three-body force, although the tensor force provides more than half of the binding energy. The effect from three-body force is strong in light nuclei. Particularly, three-body force is crucial for the formation of the pygmy resonance in calculations.

   ↳ nucl-thnucl-exPRC(2020)·8 citations
6. 06*

   Signatures of the vortical quark-gluon plasma in hadron yields

   ExHIC-P Collaboration · Hidetoshi Taya · Aaron Park · Sungtae Cho · Philipp Gubler · Koichi Hattori · Juhee Hong · Xu-Guang Huang · Su Houng Lee · Akihiko Monnai · Akira Ohnishi · Makoto Oka · Di-Lun Yang

   We investigate the hadron production from the vortical quark-gluon plasma created in heavy-ion collisions. Based on the quark-coalescence and statistical hadronization models, we show that total hadron yields summed over the spin components are enhanced by the local vorticity with quadratic dependence. The enhancement factor amounts to be a few percent and may be detectable within current experimental sensitivities. We also show that the effect is stronger for hadrons with larger spin, and thus propose a new signature of the local vorticity, which may be detected by the yield ratio of distinct hadron species having different spins such as $\varphi$ and ${\eta }^{\prime }$. The vorticity dependence of hadron yields seems robust, with consistent predictions in both of the hadron production mechanisms for reasonable values of the vorticity strength estimated for heavy-ion collisions.

   ↳ nucl-thhep-phnucl-exPRC(2020)·14 citations
7. 07*

   Simulation of heat transfer and dissipation in targets used in nuclear astrophysics experiments

   Tanmoy Bar · Chinmay Basu · Mithun Das🇨🇦 · Apurba Kumar Santra · Swarnendu Sen

   This work presents time-dependent numerical calculations of heat generation and dissipation in targets used in high ion-beam current nuclear astrophysics experiments. The simulation is beneficial for choosing the thickness of targets, maximum ion-beam current and design setup for cooling of such targets. It is found that for the very thin target (${}^{27}Al(p,p){,}^{12}C(p,p)$) heat generation inside target is relatively low and a fair amount of high current (few $\mu$A)can be used without any melting issue. But in case of thick targets (${}^{27}Al(p,\gamma ){,}^{12}C(p,\gamma )$) cooling became essential for the survival of reaction target.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.B(2019)·1 citation
8. 08*

   Trees and Forests in Nuclear Physics

   Marco Carnini · Alessandro Pastore🇬🇧

   We present a simple introduction to the decision tree algorithm using some examples from nuclear physics. We show how to improve the accuracy of the classical liquid drop nuclear mass model by performing Feature Engineering with a decision tree. Finally, we apply the method to the Duflo-Zuker model showing that, despite their simplicity, decision trees are capable of improving the description of nuclear masses using a limited number of free parameters.

   ↳ nucl-thcs.LGnucl-exJ.Phys.G(2020)·23 citations
9. 09*

   Measurement of neutron-proton capture in the SNO+ water phase

   The SNO+ Collaboration: M. R. Anderson🇨🇦 · S. Andringa🇵🇹 · M. Askins🇺🇸 · D. J. Auty🇨🇦 · N. Barros🇵🇹 · F. Barão🇵🇹 · R. Bayes🇨🇦 · E.W. Beier🇺🇸 · A. Bialek🇨🇦 · S. D. Biller🇬🇧 · E. Blucher🇺🇸 · R. Bonventre🇺🇸 and 119 other authors

   The SNO+ experiment collected data as a low-threshold water Cherenkov detector from September 2017 to July 2019. Measurements of the 2.2-MeV $\gamma$ produced by neutron capture on hydrogen have been made using an Am-Be calibration source, for which a large fraction of emitted neutrons are produced simultaneously with a 4.4-MeV $\gamma$. Analysis of the delayed coincidence between the 4.4-MeV $\gamma$ and the 2.2-MeV capture $\gamma$ revealed a neutron detection efficiency that is centered around 50% and varies at the level of 1% across the inner region of the detector, which to our knowledge is the highest efficiency achieved among pure water Cherenkov detectors. In addition, the neutron capture time constant was measured and converted to a thermal neutron-proton capture cross section of $336.3_{-1.5}^{+1.2}$ mb.

   ↳ physics.ins-dethep-exnucl-exPRC(2020)·33 citations
10. 10*

    Constraints on the symmetry energy and its associated parameters from nuclei to neutron stars

    Yingxun Zhang🇨🇳 · Min Liu🇨🇳 · Cheng-Jun Xia🇨🇳 · Zhuxia Li🇨🇳 · Subrata Kumar Biswal🇨🇳

    The symmetry energy obtained with the effective Skyrme energy density functional is related to the values of isoscalar effective mass and isovector effective mass, which is also indirectly related to the incompressibility of symmetric nuclear matter. In this work, we analyze the values of symmetry energy and its related nuclear matter parameters in five-dimensional parameter space by describing the heavy ion collision data, such as isospin diffusion data at 35 MeV/u and 50 MeV/u, neutron skin of ${}^{208}$Pb, and tidal deformability and maximum mass of neutron star. We obtain the parameter sets which can describe the isospin diffusion, neutron skin, tidal deformability and maximum mass of neutron star, and give the incompressibility $K_0$=250.23$\pm$20.16 MeV, symmetry energy coefficient $S_0$=31.35$\pm$2.08 MeV, the slope of symmetry energy $L$=59.57$\pm$10.06 MeV, isoscalar effective mass $m_s^{\ast }/m$=0.75$\pm$0.05 and quantity related to effective mass splitting $f_I$=0.005$\pm$0.170. At two times normal density, the symmetry energy we obtained is in 35-55 MeV. To reduce the large uncertainties of $f_I$, more critical works in heavy ion collisions at different beam energies are needed.

    ↳ nucl-thastro-ph.HEnucl-exPRC(2020)·85 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.