Tue·Mar 26, 2019Tuesday·March 26, 2019

1. 01*

   Triple {\alpha} Resonances in the Decay of Hot Nuclear Systems *

   S. Zhang

   The Efimov (Thomas) trimers in excited 12 C nuclei, for which no observation exists yet, are discussed by means of analyzing the experimental data of 70(64) Zn( 64 Ni) + 70(64) Zn( 64 Ni) reactions at beam energy of E/A=35MeV/nucleon. In heavy ion collisions, the {\alpha}s interact with each other and can form complex systems such as 8 Be and 12 C. For the 3{\alpha} systems, multi resonance processes give rise to excited levels of 12 C. The interaction between any two of the 3{\alpha} particles provides events with one, two or three 8 Be. Their interfering levels are clearly seen in the minimum relative energy distributions. Events of three couple {\alpha} relative energies consistent with the ground state of 8 Be are observed with the decrease of the instrumental error at the reconstructed 7.458 MeV excitation energy of 12C, which was suggested as the Efimov (Thomas) state.

   nucl-exCPC(2019)·8 citations
2. 02*

   The $\Delta I$=2 bands in ${}^{109}$In: possible antimagnetic rotation

   Meng Wang🇨🇳 · Wu-ji Sun🇨🇳 · Bao-hua Sun🇨🇳 · Jian Li🇨🇳 · Li-hua Zhu🇨🇳 · Yun Zheng🇨🇳 · Gao-long Zhang · Liu-chun He🇨🇳 · Wei-wei Qu · Feng Wang🇺🇸 · Tao-feng Wang🇯🇵 · Chang Xiong🇨🇳 and 9 other authors

   The high-spin structure of ${}^{109}$In was investigated with the ${}^{100}$Mo(${}^{14}$N, 5$n$)${}^{109}$In fusion-evaporation reaction at CIAE, Beijing. Eleven new $\gamma$-rays of ${}^{109}$In were identified, by which the bandheads of the $\Delta I$=2 rotational bands were confirmed. The configurations were assigned with the help of the systematic discussion. Furthermore, the rotational bands are compared with the tilted-axis cranking calculations based on a relativistic mean-field approach. The rotational bands involving the $1p1h$ excitation to the $\pi$$d_{5/2}$ and $\pi$$g_{7/2}$ orbitals are suggested as candidates for antimagnetic rotation based on the theoretical results.

   nucl-exEPJA(2020)·8 citations
3. 03*

   Characterization of ${}^{233}$U alpha recoil sources for ${}^{229(m)}$Th beam production

   I. Pohjalainen🇫🇮 · I.D. Moore🇫🇮 · T. Sajavaara

   Radioactive ${}^{233}$U alpha recoil sources are being considered for the production of a thorium ion source to study the low-energy isomer in ${}^{229}$Th with high-resolution collinear laser spectroscopy at the IGISOL facility of the University of Jyväskylä. In this work two different ${}^{233}$U sources have been characterized via alpha and gamma spectroscopy of the decay radiation obtained directly from the sources and from alpha-recoils embedded in implantation foils. These measurements revealed rather low ${}^{229}$Th recoil efficiencies of only a few percent. Although the low efficiency of one of the two sources can be attributed to its inherent thickness, the low recoil efficiency of the second, thinner source, was unexpected. Rutherford backscattering spectrometry (RBS) was performed to investigate the elemental composition as a function of depth revealing a contamination layer on top of the thin source. The combination of spectroscopic methods proves to be a useful approach in the assessment of alpha recoil source performance in general.

   nucl-exphysics.ins-detNucl.Instrum.Meth.B(2020)·2 citations
4. 04*

   Principal Component Analysis of collective flow in Relativistic Heavy-Ion Collisions

   Ziming Liu🇨🇳 · Wenbin Zhao🇨🇳 · Huichao Song (Peking U.)🇨🇳

   In this paper, we implement Principal Component Analysis (PCA) to study the single particle distributions generated from thousands of {\tt VISH2+1} hydrodynamic simulations with an aim to explore if a machine could directly discover flow from the huge amount of data without explicit instructions from human-beings. We found that the obtained PCA eigenvectors are similar to but not identical with the traditional Fourier bases. Correspondingly, the PCA defined flow harmonics $v_n^{\prime }$ are also similar to the traditional $v_n$ for $n=2$ and 3, but largely deviated from the Fourier ones for $n\ge 4$. A further study on the symmetric cumulants and the Pearson coefficients indicates that mode-coupling effects are reduced for these flow harmonics defined by PCA.

   ↳ nucl-thcond-mat.dis-nnhep-phnucl-exEPJC(2019)·36 citations
5. 05*

   Nucleosynthesis in heavy-ion collisions at the LHC via the Saha equation

   Volodymyr Vovchenko🇩🇪 · Kai Gallmeister🇩🇪 · Jürgen Schaffner-Bielich🇩🇪 · Carsten Greiner🇩🇪

   The production of light (anti-)(hyper-)nuclei in heavy-ion collisions at the LHC is considered in the framework of the Saha equation, making use of the analogy between the evolution of the early universe after the Big Bang and that of "Little Bangs" created in the lab. Assuming that disintegration and regeneration reactions involving light nuclei proceed in relative chemical equilibrium after the chemical freeze-out of hadrons, their abundances are determined through the famous cosmological Saha equation of primordial nucleosynthesis and show no exponential dependence on the temperature typical for the thermal model. A quantitative analysis, performed using the hadron resonance gas model in partial chemical equilibrium, shows agreement with experimental data of the ALICE collaboration on d, ${}^3$He, ${}_{\Lambda }^3$H, and ${}^4$He yields for a very broad range of temperatures at $T\lesssim 155$ MeV. The presented picture is supported by the observed suppression of resonance yields in central Pb-Pb collisions at the LHC.

   ↳ hep-phnucl-exnucl-thPLB(2020)·50 citations
6. 06*

   On resonance contribution to balance functions

   Igor Altsybeev🇷🇺

   It is known that resonance decays influence the shape of the charge-balance functions measured in hadronic collisions. That is reflected in their rapidity and azimuthal widths and the integral, and therefore has consequences for different model interpretations. In this paper, we show that the contribution from neutral resonance decays can be removed from the balance function in an analytical way, and test the performance of the removal procedure with PYTHIA events. Prospects for applications of the procedure to real data analysis of balance functions are also discussed.

   ↳ nucl-thnucl-exActa Phys.Polon.B(2019)·3 citations
7. 07*

   Relativistic self-energy decomposition of nuclear symmetry energy and equation of state of neutron matter within QCD sum rules

   Bao-Jun Cai🇨🇳 · Lie-Wen Chen🇨🇳

   Abstract (abridged edition): Properties of the relativistic nucleon self-energy decomposition of the symmetry energy as well as the equation of state (EOS) of pure neutron matter (PNM) are explored systematically within the QCD sum rules (QCDSR). Our results in the present work have demonstrated that the QCDSR approach can be used to explore the properties of asymmetric nuclear matter (ANM) in a quantitative manner, at least in lower density region. The QCDSR approach establishes a bridge connecting the EOS of ANM and the non-perturbative QCD vacuum, and thus provides a useful way to understand the properties of dense nucleonic matter from non-perturbative QCD vacuum. These studies are helpful to investigate the QCD origins about the uncertainties of nucleonic matter properties, e.g., the uncertainties of the symmetry energy. On the other hand, the exact knowledge on the EOS of ANM extracted from experiments, observations and model-independent calculations is also very useful for understanding the quark/gluon condensates in nuclear medium, which can provide important information on the chiral symmetry restoration phase transition in nuclear matter as well as the in-medium effects of hadron properties.

   ↳ nucl-thhep-phnucl-exPRC(2019)·12 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.