Wed·Mar 18, 2020Wednesday·March 18, 2020

1. 01*

   Measurement of deuteron carbon vector analyzing powers in the kinetic energy range 170-380 MeV

   JEDI Collaboration: F. Müller (1,2)🇩🇪 · M. Zurek (2)🇩🇪 · Z. Bagdasarian (2)🇩🇪 · L. Barion (3)🇮🇹 · M. Berz (4)🇺🇸 · I. Ciepal (5)🇵🇱 · G. Ciullo (3)🇮🇹 · S. Dymov (2,6)🇩🇪 · D. Eversmann (1)🇩🇪 · M. Gaisser (1)🇩🇪 · R. Gebel (2)🇩🇪 · K. Grigoryev (1,2)🇩🇪 and 48 other authors

   A measurement of vector analyzing powers in elastic deuteron-carbon scattering has been performed at the Cooler Synchrotron COSY of Forschungszentrum Jülich, Germany. Seven kinetic beam energies between 170 and 380 MeV have been used. A vector-polarized beam from a polarized deuteron source was injected, accelerated to the final desired energy and stored in COSY. A thin needle-shaped diamond strip was used as a carbon target, onto which the beam was slowly steered. Elastically scattered deuterons were identified in the forward direction using various layers of scintillators and straw tubes. Where data exist in the literature (at 200 and 270 MeV), excellent agreement of the angular shape was found. The beam polarization of the presented data was deduced by fitting the absolute scale of the analyzing power to these references. Our results extend the world data set and are necessary for polarimetry of future electric dipole moment searches at storage rings. They will as well serve as an input for theoretical description of polarized hadron-hadron scattering.

   nucl-exhep-exEPJA(2020)·9 citations
2. 02*

   Ultraperipheral nuclear interactions

   I.M. Dremin🇷🇺

   Large-distance ultraperipheral collisions of two relativistic ions are considered. The clouds of photons surrounding the ions are responsible for their distant electromagnetic interaction. The perturbative approach and the method of equivalent photons are described. It is shown that the total cross section of these collisions increases rapidly with increasing energy and is especially large for heavy ions. Some experimental data and their comparison with theoretical approaches are described. Further proposals are discussed.

   ↳ hep-phhep-exnucl-exnucl-thPhys.Usp.(2020)·7 citations
3. 03*

   Revisiting the $\Omega (2012)$ as a hadronic molecule and its strong decays

   Jun-Xu Lu🇨🇳 · Chun-Hua Zeng🇨🇳 · En Wang🇨🇳 · Ju-Jun Xie🇨🇳 · Li-Sheng Geng🇨🇳

   Recently, the Belle collaboration measured the ratios of the branching fractions of the newly observed $\Omega (2012)$ excited state. They did not observe significant signals for the $\Omega (2012)\to \bar{K}{\Xi }^{\ast }(1530)\to \bar{K}\pi \Xi$ decay, and reported an upper limit for the ratio of the three body decay to the two body decay mode of $\Omega (2012)\to \bar{K}\Xi$. In this work, we revisit the newly observed $\Omega (2012)$ from the molecular perspective where this resonance appears to be a dynamically generated state with spin-parity $3/2^{-}$ from the coupled channels interactions of the $\bar{K}{\Xi }^{\ast }(1530)$ and $\eta \Omega$ in $s$-wave and $\bar{K}\Xi$ in $d$-wave. With the model parameters for the $d$-wave interaction, we show that the ratio of these decay fractions reported recently by the Belle collaboration can be easily accommodated.

   ↳ hep-phhep-exnucl-exnucl-thEPJC(2020)·39 citations
4. 04*

   Quantal diffusion approach for multinucleon transfer processes in the ${}^{58,64}$Ni+${}^{208}$Pb reactions: Toward the production of unknown neutron-rich nuclei

   Kazuyuki Sekizawa🇯🇵 · Sakir Ayik🇺🇸

   Background: In recent years, substantial efforts have been made for the study of multinucleon transfer reactions at energies around the Coulomb barrier both experimentally and theoretically, aiming at the production of unknown neutron-rich heavy nuclei. It is crucial to provide reliable theoretical predictions based on microscopic theories with sufficient predictive power. Purpose: This paper aims to clarify the applicability of the quantal diffusion approach based on the stochastic mean-field (SMF) theory for multinucleon transfer processes. Isotope production cross sections are evaluated for the reactions of ${}^{64}$Ni+${}^{208}$Pb at $E_{c.m.}$=268 MeV and ${}^{58}$Ni+${}^{208}$Pb at $E_{c.m.}$=270 MeV and are compared with available experimental data. Methods: Three-dimensional time-dependent Hartree-Fock (TDHF) calculations are carried out for a range of initial orbital angular momenta with Skyrme SLy4d functional. Quantal diffusion equations, derived based on the SMF theory, for variances and covariance of neutron and proton numbers of reaction products are solved, with microscopic drift and diffusion coefficients obtained from the time evolution of occupied single-particle orbitals in TDHF. Secondary deexcitation processes, both particle evaporation and fission, are simulated by a statistical model, GEMINI++. Results: We find that the quantal diffusion approach reproduces the measured cross sections for abundant reaction products, including both projectile-like and target-like fragments, as well as fragments of transfer-induced fission. The results underline the importance of beyond mean-field effects in describing multinucleon transfer processes. We emphasize that the quantal diffusion description does not involve any adjustable parameters, once an energy density functional is given. Possible future directions are discussed. (Shortened due to the word limit)

   ↳ nucl-thnucl-exPRC(2020)·48 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.