Tue·Jan 26, 2016Tuesday·January 26, 2016

1. 01*

   Progress on nuclear modifications of structure functions

   S. Kumano (KEK/J-PARC)🇯🇵

   We report progress on nuclear structure functions, especially on their nuclear modifications and a new tensor structure function for the deuteron. To understand nuclear structure functions is an important step toward describing nuclei and QCD matters from low to high densities and from low to high energies in terms of fundamental quark and gluon degrees of freedom beyond conventional hadron and nuclear physics. It is also practically important for understanding new phenomena in high-energy heavy-ion collisions at RHIC and LHC. Furthermore, since systematic errors of current neutrino-oscillation experiments are dominated by uncertainties of neutrino-nucleus interactions, such studies are valuable for finding new physics beyond current framework. Next, a new tensor-polarized structure function $b_1$ is discussed for the deuteron. There was a measurement by HERMES; however, its data are inconsistent with the conventional convolution estimate based on the standard deuteron model with D-state admixture. This fact suggests that a new hadronic phenomenon should exist in the tensor-polarized deuteron at high energies, and it will be experimentally investigated at JLab from the end of 2010's.

   ↳ hep-phhep-exnucl-exnucl-thEPJ Web Conf.(2016)·0 citations
2. 02*

   Time-dependent Hartree-Fock calculations for multinucleon transfer and quasifission processes in the ${}^{64}$Ni+${}^{238}$U reaction

   Kazuyuki Sekizawa🇯🇵 · Kazuhiro Yabana🇯🇵

   Background: Multinucleon transfer (MNT) and quasifission (QF) processes are dominant processes in low-energy collisions of two heavy nuclei. They are expected to be useful to produce neutron-rich unstable nuclei. Nuclear dynamics leading to these processes depends sensitively on nuclear properties such as deformation and shell structure. Purpose: We elucidate reaction mechanisms of MNT and QF processes involving heavy deformed nuclei, making detailed comparisons between microscopic time-dependent Hartree-Fock (TDHF) calculations and measurements for the ${}^{64}$Ni+${}^{238}$U reaction. Methods: Three-dimensional Skyrme-TDHF calculations are performed. Particle-number projection method is used to evaluate MNT cross sections from the TDHF wave function after collision. Results: Fragment masses, total kinetic energy (TKE), scattering angle, contact time, and MNT cross sections are investigated for the ${}^{64}$Ni+${}^{238}$U reaction. They show reasonable agreements with measurements. At small impact parameters, collision dynamics depends sensitively on the orientation of deformed ${}^{238}$U. In tip (side) collisions, we find a larger (smaller) TKE and a shorter (longer) contact time. In tip collisions, we find a strong influence of quantum shells around ${}^{208}$Pb. Conclusions: It is confirmed that the TDHF calculations reasonably describe both MNT and QF processes in the ${}^{64}$Ni+${}^{238}$U reaction. Analyses of this system indicates the significance of the nuclear structure effects such as deformation and quantum shells in nuclear reaction dynamics at low energies.

   ↳ nucl-thnucl-exPRC(2016)·146 citations
3. 03*

   An improvement of isochronous mass spectrometry: Velocity measurements using two time-of-flight detectors

   P. Shuai🇨🇳 · X. Xu🇨🇳 · Y. H. Zhang🇨🇳 · H. S. Xu🇨🇳 · Yu. A. Litvinov🇨🇳 · M. Wang🇨🇳 · X. L. Tu🇨🇳 · K. Blaum🇩🇪 · X. H. Zhou🇨🇳 · Y. J. Yuan🇨🇳 · X. L. Yan🇨🇳 · X. C. Chen🇨🇳 and 6 other authors

   Isochronous mass spectrometry (IMS) in storage rings is a powerful tool for mass measurements of exotic nuclei with very short half-lives down to several tens of microseconds, using a multicomponent secondary beam separated in-flight without cooling. However, the inevitable momentum spread of secondary ions limits the precision of nuclear masses determined by using IMS. Therefore, the momentum measurement in addition to the revolution period of stored ions is crucial to reduce the influence of the momentum spread on the standard deviation of the revolution period, which would lead to a much improved mass resolving power of IMS. One of the proposals to upgrade IMS is that the velocity of secondary ions could be directly measured by using two time-of-flight (double TOF) detectors installed in a straight section of a storage ring. In this paper, we outline the principle of IMS with double TOF detectors and the method to correct the momentum spread of stored ions.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.B(2016)·19 citations
4. 04*

   Neutron Capture Nucleosynthesis

   Miklos Kiss

   Heavy elements (beyond iron) are formed in neutron capture nucleosynthesis processes. We have proposed a simple unified model to investigate the neutron capture nucleosynthesis in arbitrary neutron density environment. We have also investigated what neutron density is required to reproduce the measured abundance of nuclei assuming equilibrium processes. We found both of these that the medium neutron density has a particularly important role at neutron capture nucleosynthesis. About these results most of the nuclei can formed at medium neutron capture density environment e.g. in some kind of AGB stars. Besides these observations our model is capable to use educational purpose.

   ↳ astro-ph.SRastro-ph.HEnucl-exProceedings of the international conferen…·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.