Tue·Apr 11, 2017Tuesday·April 11, 2017

1. 01*

   How tightly is nuclear symmetry energy constrained by unitary Fermi gas?

   Nai-Bo Zhang🇨🇳 · Bao-Jun Cai🇺🇸 · Bao-An Li🇺🇸 · William G. Newton🇺🇸 · Jun Xu🇨🇳

   We examine critically how tightly the density dependence of nuclear symmetry energy \esym is constrained by the universal equation of state (EOS) of the unitary Fermi gas $E_{\mathrm{UG}}(\rho )$ considering currently known uncertainties of higher order parameters describing the density dependence of the Equation of State of isospin-asymmetric nuclear matter. We found that $E_{\mathrm{UG}}(\rho )$ does provide a useful lower boundary for the \esym. However, it does not tightly constrain the correlation between the magnitude $E_{\mathrm{sym}}({\rho }_0)$ and slope $L$ unless the curvature $K_{\mathrm{sym}}$ of the symmetry energy at saturation density ${\rho }_0$ is more precisely known. The large uncertainty in the skewness parameters affects the $E_{\mathrm{sym}}({\rho }_0)$ versus $L$ correlation by the same almost as significantly as the uncertainty in $K_{\mathrm{sym}}$.

   ↳ nucl-thnucl-exNucl.Sci.Tech.(2017)·59 citations
2. 02*

   Pseudorapidity profile of transverse momentum fluctuations in heavy ion collisions

   Sandeep Chatterjee🇵🇱 · Piotr Bozek🇵🇱

   We investigate pseudorapidity correlations of the average transverse flow of particles emitted in relativistic heavy-ion collisions. We employ 3+1 dimensional viscous relativistic hydrodynamics with initial conditions from the quark Glauber Monte Carlo model to confront the recent measurements on the pseudorapidity correlations of the transverse momentum fluctuations in Pb+Pb collisions at $\sqrt{s_{NN}}=2760$GeV. We find good agreement between the model predictions and data. Further, we study two other observables build with the covariance of the average transverse momentum in different rapidity bins. These observables have better stability under various systematics, thus allowing for a robust comparison between data and model. The transverse flow-transverse flow correlation coefficient is directly related to correlations of the underlying collective flow at different pseudorapidities. The 3-bin measure of $p_T$ factorization breaking in pseudorapidity gives an estimate of possible decorrelation of the average transverse flow in the longitudinal direction.

   ↳ nucl-thhep-phnucl-exPRC(2017)·18 citations
3. 03*

   Beam energy scan theory: Status and open questions

   H. Petersen🇩🇪

   The goal of heavy ion reactions at low beam energies is to explore the QCD phase diagram at high net baryon chemical potential. To relate experimental observations with a first order phase transition or a critical endpoint, dynamical approaches for the theoretical description have to be developed. In this summary of the corresponding plenary talk, the status of the dynamical modeling including the most recent advances is presented. The remaining challenges are highlighted and promising experimental measurements are pointed out.

   ↳ nucl-thhep-phnucl-exNPA(2017)·11 citations
4. 04*

   Saturation with chiral interactions and consequences for finite nuclei

   J. Simonis🇩🇪 · S. R. Stroberg🇨🇦 · K. Hebeler🇩🇪 · J. D. Holt🇨🇦 · A. Schwenk🇩🇪

   We explore the impact of nuclear matter saturation on the properties and systematics of finite nuclei across the nuclear chart. Using the ab initio in-medium similarity renormalization group (IM-SRG), we study ground-state energies and charge radii of closed-shell nuclei from ${}^4$He to ${}^{78}$Ni, based on a set of low-resolution two- and three-nucleon interactions that predict realistic saturation properties. We first investigate in detail the convergence properties of these Hamiltonians with respect to model-space truncations for both two- and three-body interactions. We find one particular interaction that reproduces well the ground-state energies of all closed-shell nuclei studied. As expected from their saturation points relative to this interaction, the other Hamiltonians underbind nuclei, but lead to a remarkably similar systematics of ground-state energies. Extending our calculations to complete isotopic chains in the $sd$ and $pf$ shells with the valence-space IM-SRG, the same interaction reproduces not only experimental ground states but two-neutron-separation energies and first excited $2^{+}$ states. We also calculate radii with the valence-space IM-SRG for the first time. Since this particular interaction saturates at too high density, charge radii are still too small compared with experiment. Except for this underprediction, the radii systematics is, however, well reproduced. Our results highlight the importance of nuclear matter as a theoretical benchmark for the development of next-generation chiral interactions.

   ↳ nucl-thnucl-exPRC(2017)·233 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.