Fri·Oct 10, 2014Friday·October 10, 2014

1. 01*

   Production of inclusive ${\rm Y}$(1S) and ${\rm Y}$(2S) in p-Pb collisions at $\sqrt{{\mathbf{s}}_{\mathrm{NN}}}=5.02$ TeV

   ALICE Collaboration

   We report on the production of inclusive ${\rm Y}$(1S) and ${\rm Y}$(2S) in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV at the LHC. The measurement is performed with the ALICE detector at backward ($-4.46<y_{\mathrm{cms}}<-2.96$) and forward ($2.03<y_{\mathrm{cms}}<3.53$) rapidity down to zero transverse momentum. The production cross sections of the ${\rm Y}$(1S) and ${\rm Y}$(2S) are presented, as well as the nuclear modification factor and the ratio of the forward to backward yields of ${\rm Y}$(1S). A suppression of the inclusive ${\rm Y}$(1S) yield in p-Pb collisions with respect to the yield from pp collisions scaled by the number of binary nucleon-nucleon collisions is observed at forward rapidity but not at backward rapidity. The results are compared to theoretical model calculations including nuclear shadowing or partonic energy loss effects.

   nucl-exPLB(2015)·108 citations
2. 02*

   Giant and pigmy dipole resonances in 4He, 16,22O, and 40Ca from chiral nucleon-nucleon interactions

   S. Bacca🇨🇦 · N. Barnea🇮🇱 · G. Hagen🇺🇸 · M. Miorelli · G. Orlandini🇮🇹 · T. Papenbrock🇺🇸

   We combine the coupled-cluster method and the Lorentz integral transform for the computation of inelastic reactions into the continuum. We show that the bound-state-like equation characterizing the Lorentz integral transform method can be reformulated based on extensions of the coupled-cluster equation-of-motion method, and we discuss strategies for viable numerical solutions. Starting from a chiral nucleon-nucleon interaction at next-to-next-to-next-to-leading order, we compute the giant dipole resonances of 4He, 16,22O and 40Ca, truncating the coupled-cluster equation-of-motion method at the two-particle-two-hole excitation level. Within this scheme, we find a low-lying E1 strength in the neutron-rich 22O nucleus, which compares fairly well with data from [Leistenschneider et al. Phys. Rev. Lett. 86, 5442 (2001)]. We also compute the electric dipole polariziability in 40Ca. Deficiencies of the employed Hamiltonian lead to overbinding, too small charge radii and a too small electric dipole polarizability in 40Ca.

   ↳ nucl-thnucl-exPRC(2014)·91 citations
3. 03*

   Beyond mean-field study of elastic and inelastic electron scattering off nuclei

   J. M. Yao🇯🇵 · M. Bender🇫🇷 · P.-H. Heenen🇧🇪

   Electron scattering provides a powerful tool to determine charge distributions and transition densities of nuclei. This tool will soon be available for short-lived neutron-rich nuclei. [Purpose] Beyond mean-field methods have been successfully applied to the study of excitation spectra of nuclei in the whole nuclear chart. These methods permit to determine energies and transition probabilities starting from an effective in-medium nucleon-nucleon interaction but without other phenomenological ingredients. Such a method has recently been extended to calculate the charge density of nuclei deformed at the mean-field level of approximation [J. M. Yao et al., Phys. Rev. C86, 014310 (2012)]. The aim of this work is to further extend the method to the determination of transition densities between low-lying excited states. [Method] The starting point of our method is a set of Hartree-Fock-Bogoliubov wave functions generated with a constraint on the axial quadrupole moment and using a Skyrme energy density functional. Correlations beyond the mean field are introduced by projecting mean-field wave functions on angular-momentum and particle number and by mixing the symmetry restored wave functions.[Results] We give in this paper detailed formulae derived for the calculation of densities and form factors. These formulae are rather easy to obtain when both initial and final states are $0^{+}$ states but are far from being trivial when one of the states has a finite $J$-value. Illustrative applications to ${}^{24}$Mg and to the even-mass ${}^{58-68}$Ni have permitted to analyse the main features of our method, in particular the effect of deformation on densities and form factors. An illustration calculation of both elastic and inelastic scattering form factors is presented....

   ↳ nucl-thnucl-exPRC(2015)·27 citations
4. 04*

   A digital CDS technique and the performance testing

   Xiao-Yan Liu🇨🇳 · Jing-Bin Lu🇨🇳 · Yan-Ji Yang🇨🇳 · Bo Lu🇨🇳 · Yu-Sa Wang🇨🇳 · Yu-Peng Xu🇨🇳 · Wei-Wei Cui🇨🇳 · Wei Li · Mao-Shun Li🇨🇳 · Juan Wang🇨🇳 · Da-Wei Han🇨🇳 · Tian-Xiang Chen🇨🇳 and 12 other authors

   Readout noise is a critical parameter for characterizing the performance of charge-coupled devices (CCDs), which can be greatly reduced by the correlated double sampling (CDS) circuit. However, conventional CDS circuit inevitably introduces new noises since it consists of several active analog components such as operational amplifiers. This paper proposes a digital CDS circuit technique, which transforms the pre-amplified CCD signal into a train of digital presentations by a high-speed data acquisition card directly without the noisy CDS circuit first, then implement the digital CDS algorithm through numerical method. The readout noise of 3.3 e${}^{-}$ and the energy resolution of 121 eV@5.9keV can be achieved via the digital CDS technique.

   ↳ physics.ins-detnucl-exCPC(2015)·0 citations
5. 05*

   Progress in development of silica aerogel for particle- and nuclear-physics experiments at J-PARC

   Makoto Tabata🇯🇵 · Hideyuki Kawai🇯🇵

   This study presents the advancement in hydrophobic silica aerogel development for use as Cherenkov radiators and muonium production targets. These devices are scheduled for use in several particle- and nuclear-physics experiments that are planned in the near future at the Japan Proton Accelerator Research Complex. Our conventional method to produce aerogel tiles with an intermediate index of refraction of approximately 1.05 is extended so that we can now produce aerogel tiles with lower indices of refraction (i.e., 1.03-1.04) and higher indices of refraction (i.e., 1.075-1.08); each with excellent transparency. A new production method, called pin drying, was optimized to produce larger area aerogels consistently with an ultrahigh index of refraction (>1.10). In addition, for use as a thermal-muonium-emitting material at room temperature, dedicated low-density aerogels were fabricated using the conventional method.

   ↳ physics.ins-dethep-exnucl-exJPS Conf.Proc.(2015)·8 citations
6. 06*

   Positioning the neutron drip line and the r-process paths in the nuclear landscape

   Rui Wang · Lie-Wen Chen🇨🇳

   Exploring nucleon drip lines and astrophysical rapid neutron capture process (r-process) paths in the nuclear landscape is extremely challenging in nuclear physics and astrophysics. While various models predict similar proton drip line, their predictions for neutron drip line and the r-process paths involving heavy neutron-rich nuclei exhibit a significant variation which hampers our accurate understanding of the r-process nucleosynthesis mechanism. Using microscopic density functional theory with a representative set of non-relativistic and relativistic interactions, we demonstrate for the first time that this variation is mainly due to the uncertainty of nuclear matter symmetry energy $E_{\mathrm{sym}}({\rho }_{\mathrm{sc}})$ at the subsaturation cross density ${\rho }_{\mathrm{sc}}=0.11/0.16\times {\rho }_0$ (${\rho }_0$ is saturation density), which reflects the symmetry energy of heavy nuclei. Using the recent accurate constraint on $E_{\mathrm{sym}}({\rho }_{\mathrm{sc}})$ from the binding energy difference of heavy isotope pairs, we obtain quite precise predictions for the location of the neutron drip line, the r-process paths and the number of bound nuclei in the nuclear landscape. Our results have important implications on extrapolating the properties of unknown neutron-rich rare isotopes from the data on known nuclei.

   ↳ nucl-thastro-ph.SRnucl-exPRC(2015)·42 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.