Mon·May 15, 2017Monday·May 15, 2017

1. 01*

   Linear and non-linear flow mode in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=$ 2.76 TeV

   ALICE Collaboration

   The second and the third order anisotropic flow, $V_2$ and $V_3$, are mostly determined by the corresponding initial spatial anisotropy coefficients, ${\epsilon }_2$ and ${\epsilon }_3$, in the initial density distribution. In addition to their dependence on the same order initial anisotropy coefficient, higher order anisotropic flow, $V_n$ ($n>3$), can also have a significant contribution from lower order initial anisotropy coefficients, which leads to mode-coupling effects. In this Letter we investigate the linear and non-linear modes in higher order anisotropic flow $V_n$ for $n=4$, $5$, $6$ with the ALICE detector at the Large Hadron Collider. The measurements are done for particles in the pseudorapidity range $|\eta |<0.8$ and the transverse momentum range $0.2<p_{\mathrm{T}}<5.0$ GeV/$c$ as a function of collision centrality. The results are compared with theoretical calculations and provide important constraints on the initial conditions, including initial spatial geometry and its fluctuations, as well as the ratio of the shear viscosity to entropy density of the produced system.

   nucl-exhep-exPLB(2017)·99 citations
2. 02*

   Precision mass measurements of ${}^{125-127}$Cd isotopes and isomers approaching the $N=82$ closed shell

   D. Lascar🇨🇦 · R. Klawitter🇨🇦 · C. Babcock🇨🇦 · E. Leistenschneider🇨🇦 · S. R. Stroberg🇨🇦 · B.R. Barquest🇨🇦 · A. Finlay🇨🇦 · M. Foster🇬🇧 · A.T. Gallant🇨🇦 · P. Hunt🇬🇧 · J. Kelly🇺🇸 · B. Kootte🇨🇦 and 15 other authors

   We present the results of precision mass measurements of neutron-rich cadmium isotopes. These nuclei approach the $N=82$ closed neutron shell and are important to nuclear structure as they lie near doubly-magic ${}^{132}$Sn on the chart of nuclides. Of particular note is the clear identification of the ground state mass in ${}^{127}$Cd along with the isomeric state. We show that the ground state identified in a previous mass measurement which dominates the mass value in the Atomic Mass Evaluation is an isomeric state. In addition to ${}^{127/m}$Cd, we present other cadmium masses measured (${}^{125/m}$Cd and ${}^{126}$Cd) in a recent TITAN experiment at TRIUMF. Finally, we compare our measurements to new \emph{ab initio} shell-model calculations and comment on the state of the field in the $N=82$ region.

   nucl-exPRC(2017)·29 citations
3. 03*

   White Paper on Nuclear Data Needs and Capabilities for Basic Science

   F.G. Kondev🇺🇸 · M. Thoennessen🇺🇸 · J. Batchelder🇺🇸 · T. Kawano🇺🇸 · J. Kelley🇺🇸 · E. McCutchan🇺🇸 · M. Smith🇺🇸 · A. Sonzogni🇺🇸 · I. Thompson🇺🇸

   The Workshop on Nuclear Data Needs and Capabilities for Basic Science was held at the University of Notre Dame on 10-11 August 2016. The purpose of this targeted workshop was to assemble and prioritize the needs of the nuclear physics research community for data sets, services and capabilities in areas including nuclear structure, nuclear reactions, nuclear astrophysics, fundamental interactions, neutrino physics and nuclear theory. An overview of nuclear data needs and capabilities identified at this meeting are summarized in the present document.

   nucl-exnucl-th1 citation
4. 04*

   Variational calculation of the ground state of closed-shell nuclei up to $A=40$

   D. Lonardoni🇺🇸 · A. Lovato🇺🇸 · Steven C. Pieper🇺🇸 · R. B. Wiringa🇺🇸

   Variational calculations of ground-state properties of ${}^4$He, ${}^{16}$O, and ${}^{40}$Ca are carried out employing realistic phenomenological two- and three-nucleon potentials. The trial wave function includes two- and three-body correlations acting on a product of single-particle determinants. Expectation values are evaluated with a cluster expansion for the spin-isospin dependent correlations considering up to five-body cluster terms. The optimal wave function is obtained by minimizing the energy expectation value over a set of up to 20 parameters by means of a nonlinear optimization library. We present results for the binding energy, charge radius, one- and two-body densities, single-nucleon momentum distribution, charge form factor, and Coulomb sum rule. We find that the employed three-nucleon interaction becomes repulsive for $A\ge 16$. In ${}^{16}$O the inclusion of such a force provides a better description of the properties of the nucleus. In ${}^{40}$Ca instead, the repulsive behavior of the three-body interaction fails to reproduce experimental data for the charge radius and the charge form factor. We find that the high-momentum region of the momentum distributions, determined by the short-range terms of nuclear correlations, exhibit a universal behavior independent of the particular nucleus. The comparison of the Coulomb sum rules for ${}^4$He, ${}^{16}$O, and ${}^{40}$Ca reported in this work will help elucidate in-medium modifications of the nucleon form factors.

   ↳ nucl-thnucl-exPRC(2017)·86 citations
5. 05*

   Dispersion relations for ${\eta }^{\prime }\to \eta \pi \pi$

   Tobias Isken🇩🇪 · Bastian Kubis🇩🇪 · Sebastian P. Schneider🇩🇪 · Peter Stoffer🇺🇸

   We present a dispersive analysis of the decay amplitude for ${\eta }^{\prime }\to \eta \pi \pi$ that is based on the fundamental principles of analyticity and unitarity. In this framework, final-state interactions are fully taken into account. Our dispersive representation relies only on input for the $\pi \pi$ and $\pi \eta$ scattering phase shifts. Isospin symmetry allows us to describe both the charged and neutral decay channel in terms of the same function. The dispersion relation contains subtraction constants that cannot be fixed by unitarity. We determine these parameters by a fit to Dalitz-plot data from the VES and BES-III experiments. We study the prediction of a low-energy theorem and compare the dispersive fit to variants of chiral perturbation theory.

   ↳ hep-phhep-exnucl-exnucl-thEPJC(2017)·63 citations
6. 06*

   Conserved charge fluctuations using the $D$-measure in heavy-ion collisions

   D. K. Mishra🇮🇳 · P. K. Netrakanti🇮🇳 · P. Garg🇺🇸

   We study the net-charge fluctuations, $D$-measure variable, in high energy heavy-ion collisions in heavy-ion jet interaction generator (HIJING), ultrarelativistic quantum molecular dynamics (UrQMD) and hadron resonance gas (HRG) models for various center-of-mass energies (\sqsn). The effect of kinematic acceptance and resonance decay, in the pseudorapidity acceptance interval ($\Delta \eta$) and lower transverse momentum ($p_T^{min}$) threshold, on fluctuation measures are discussed. A strong dependence of $D$ with the $\Delta \eta$ in HIJING and UrQMD models is observed as opposed to results obtained from the HRG model. The dissipation of fluctuation signal is estimated by fitting the $D$-measure as a function of the $\Delta \eta$. An extrapolated function for higher $\Delta \eta$ values at lower \sqsn is different from the results obtained from models. Particle species dependence of $D$ and the effect of the $p_T^{min}$ selection threshold are discussed in HIJING and HRG models. The comparison of $D$, at midrapidity, of net-charge fluctuations at various \sqsn obtained from the models with the data from the ALICE experiment is discussed. The results from the present work as a function of $\Delta \eta$ and \sqsn will provide a baseline for comparison to experimental measurements.

   ↳ nucl-thhep-phnucl-exPRC(2017)·6 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.