Tue·Jul 21, 2020Tuesday·July 21, 2020

1. 01*

   Comment on "Erratum: Negative-parity high-spin states and a possible magnetic rotation band in ${}_{59}^{135}$Pr${}_{76}$ [Phys. Rev. C 92, 054325 (2015)]"

   S. Guo🇨🇳 · C. M. Petrache🇫🇷

   In [Ritika Garg et al., Phys. Rev. C 100, 069901(E) (2019)] the experimental results on the polarization asysmetry were revised due to a claimed change of the geometry asymmetry. However, the revised results can not be reproduced as claimed in the erratum by simply changing the geometry asymmetry in extracting the polarization asymmetry, without re-extracting the polarization asymmetry from the original experimental data. It is possible that the quoted errors were significantly underestimated.

   nucl-ex2 citations
2. 02*

   Prompt-delayed $\gamma$-ray spectroscopy of neutron-rich ${}^{119,121}$In isotopes

   S. Biswas🇫🇷 · A. Lemasson🇫🇷 · M. Rejmund🇫🇷 · A. Navin🇫🇷 · Y.H. Kim🇫🇷 · C. Michelagnoli🇫🇷 · I. Stefan🇫🇷 · R. Banik🇮🇳 · P. Bednarczyk🇵🇱 · Soumik Bhattacharya🇮🇳 · S. Bhattacharyya🇮🇳 · E. Clément🇫🇷 and 14 other authors

   The fusion and transfer induced fission reaction ${}^9$Be(${}^{238}$U,~f) with 6.2 MeV/u beam energy, using a unique setup consisting of AGATA, VAMOS++ and EXOGAM detectors, was used to populate through the fission process and study the neutron-rich ${}^{119,121}$In isotopes. This setup enabled the prompt-delayed $\gamma$-ray spectroscopy of isotopes in the time range of $100\mathrm{ns}-200\mu \mathrm{s}$. In the odd-$A$ ${}^{119,121}$In isotopes, indications of a short half-life $19/2^{-}$ isomeric state, in addition to the previously known $25/2^{+}$ isomeric state, were observed from the present data. Further, new prompt transitions above the $25/2^{+}$ isomer in ${}^{121}$In were identified along with reevaluation of its half-life. The experimental data were compared with the theoretical results obtained in the framework of large-scale shell-model calculations in a restricted model space. The $⟨\pi g_{9/2}\nu h_{11/2};I\text{arrowvert}\hat{\mathcal{H}}\text{arrowvert}\pi g_{9/2}\nu h_{11/2};I⟩$ two-body matrix elements of residual interaction were modified to explain the excitation energies and the $B(E2)$ transition probabilities in the neutron-rich In isotopes. The (i) decreasing trend of $E(29/2^{+})-E(25/2^{+})$ in odd-In (with dominant configuration $\pi g_{9/2}^{-1}\nu h_{11/2}^{-2}$ and maximum aligned spin of $29/2^{+}$) and (ii) increasing trend of $E(27/2^{+})-E(23/2^{+})$ in odd-Sb (with dominant configuration $\pi g_{7/2}^{+1}\nu h_{11/2}^{-2}$ and maximum aligned spin of $27/2^{+}$) with increasing neutron number could be understood as a consequence of hole-hole and particle-hole interactions, respectively.

   nucl-exnucl-thPRC(2020)·4 citations
3. 03*

   Probing in-medium nucleon-nucleon inelastic scattering cross section by using energetic n/p ratio

   Zong-Zhen Zhang🇨🇳 · Ya-Fei Guo🇨🇳 · Gao-Chan Yong🇨🇳

   Based on the Isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) transport model, the in-medium nucleon-nucleon inelastic scattering ( which is dominated by pion production at low and intermediate energies) is explored. It is found that the in-medium modification of nucleon-nucleon inelastic scatterings appears to reduce the neutron to proton ratio n/p at higher kinetic energies. Although the in-medium modification of nucleon-nucleon inelastic scatterings, as expected, affects the value of ${\pi }^{-}/{\pi }^{+}$ ratio, considering a series of undetermined properties of delta resonance and $\pi$ in medium, the energetic neutron to proton ratio n/p is more suitable to be used to probe the in-medium correction of nucleon-nucleon inelastic scatterings.

   ↳ nucl-thnucl-exPRC(2021)·4 citations
4. 04*

   An efficient solution for Dirac equation in 3D lattice space with the conjugate gradient method

   B. Li🇺🇸 · Z. X. Ren🇨🇳 · P. W. Zhao🇨🇳

   An efficient method, preconditioned conjugate gradient method with a filtering function (PCG-F), is proposed for solving iteratively the Dirac equation in 3D lattice space for nuclear systems. The filtering function is adopted to avoid the variational collapsed problem and a momentum-dependent preconditioner is introduced to promote the efficiency of the iteration. The PCG-F method is demonstrated in solving the Dirac equation with given spherical and deformed Woods-Saxon potentials. The solutions given by the inverse Hamiltonian method in 3D lattice space and the shooting method in radial coordinate space are reproduced with a high accuracy. In comparison with the existing inverse Hamiltonian method, the present PCG-F method is much faster in the convergence of the iteration, in particular for deformed potentials. It may also provide a promising way to solve the relativistic Hartree-Bogoliubov equation iteratively in the future.

   ↳ nucl-thnucl-exPRC(2020)·23 citations
5. 05*

   Thermal photons as a sensitive probe of $\alpha$-cluster in C+Au collisions at the BNL Relativistic Heavy Ion Collider

   Pingal Dasgupta🇨🇳 · Guo-Liang Ma🇨🇳 · Rupa Chatterjee🇮🇳 · Li Yan🇨🇳 · Song Zhang🇨🇳 · Yu-Gang Ma🇨🇳

   Different orientations of $\alpha$-clustered carbon nuclei colliding with heavy ions can result in a large variation in the value of anisotropic flow. Thus, photon flow observables from clustered ${}^{12}\mathrm{C}$ and ${}^{197}\mathrm{Au}$ collisions could be a potential probe to study the `direct photon puzzle'. We calculate the transverse momentum spectra and anisotropic flow coefficients ($v_n$) of thermal photons from collisions of triangular $\alpha$-clustered carbon and gold at $\sqrt{s_{\mathrm{NN}}}=200$ GeV at RHIC using a hydrodynamic model framework and compare the results with those obtained from unclustered carbon and gold collisions. The slope of the thermal photon spectra is found to vary moderately for different orientations of collisions. However, we find that the elliptic ($v_2$) and triangular flow ($v_3$) coefficients of direct photons for specific configurations are significantly larger and predominantly formed by the QGP radiation. A strong anti-correlation between initial spatial ellipticity and triangularity is observed in an event-by-event framework of $\alpha$-clustered $\mathrm{C}+\mathrm{Au}$ collisions. These special features provide us an opportunity to detect the exotic nature of cluster structure inside carbon nucleus using the photon probe in the future experiments.

   ↳ nucl-thhep-phnucl-exEPJA(2021)·20 citations
6. 06*

   Probing high-density symmetry energy using heavy-ion collisions at intermediate energies

   Gao-Chan Yong🇨🇳 · Ya-Fei Guo🇨🇳

   The nuclear symmetry energy, which describes the energy difference of per proton and neutron in nuclear matter, has been extensively studied within the last two decades. Around saturation density, both the value and the slope of the nuclear symmetry energy have been roughly constrained, its high-density behavior is now still in argument. Probing high-density symmetry energy at terrestrial laboratories is being carried out at facilities that offer radioactive beams worldwide. While relevant experiments are being conducted, we theoretically developed more advanced isospin-dependent transport model including new physics such as nucleon-nucleon short-range correlations and in-medium isospin-dependence of baryon-baryon scattering cross section. New sensitive probes of high-density symmetry energy are provided, such as squeezed-out neutron to proton ratio, photon and light cluster as well as the production of mesons with strangeness or hidden strangeness. The blind spots of probing the high-density symmetry energy by sensitive observable are demonstrated. Model dependence of frequently used sensitive probes of the symmetry energy has been studied thoroughly based on different transport models. A qualitative observable of neutron to proton ratio at high emitting energy is proposed to probe the high-density symmetry energy qualitatively. The probed density regions of the symmetry energy are carefully studied. Effects of nucleon-nucleon short-range correlations on the some sensitive observables of the symmetry energy in heavy-ion collisions are explored carefully. Probing the curvature of the symmetry energy by involving the slope information of the symmetry energy at saturation point in the transport model is proposed.

   ↳ nucl-thnucl-exNucl.Phys.Rev.(2020)·11 citations
7. 07*

   Anisotropy fluctuation and correlation in central $\alpha$-clustered ${}^{12}$C+${}^{197}$Au collisions

   L. Ma. Y. G. Ma · S. Zhang

   In the framework of a multi-phase transport model, fluctuation and correlation of the azimuthal anisotropies in ${}^{12}$C+${}^{197}$Au collisions at $\sqrt{S_{NN}}$ = 200 GeV are explored. Properties of the initial eccentricity and final harmonic flow fluctuation resulted from ${}^{12}$C+${}^{197}$Au collisions with Woods-Saxon configuration and triangular $\alpha$-clustering configurations of ${}^{12}$C are investigated via scaled variance, skewness and kurtosis. Comparisons are made between results from $\alpha$-clustered configurations and Woods-Saxon configuration. The triangular flow fluctuation is found to have particular sensitivity in distinguishing triangular $\alpha$-clustering structure of ${}^{12}$C. Furthermore, correlations between initial eccentricities and final flow harmonics are studied with strong multiplicity dependence observed for the correlation functions.

   ↳ hep-phnucl-exnucl-thPRC(2020)·22 citations
8. 08*

   Nature of the $\Lambda nn$ $(J^{\pi }=1/2^{+},I=1)$ and ${}_{\mathrm{\Lambda }}^3{\mathrm{H}}^{\ast }(J^{\pi }=3/2^{+},I=0)$ states

   M. Schäfer🇨🇿 · B. Bazak🇮🇱 · N. Barnea🇮🇱 · J. Mareš🇨🇿

   The nature of the $\Lambda nn$ and ${}_{\mathrm{\Lambda }}^3{\mathrm{H}}^{\ast }(J^{\pi }=3/2^{+},I=0)$ states is investigated within a pionless effective field theory at leading order, constrained by the low energy $\Lambda N$ scattering data and hypernuclear 3- and 4-body data. Bound state solutions are obtained using the stochastic variational method, the continuum region is studied by employing two independent methods - the inverse analytic continuation in the coupling constant method and the complex scaling method. Our calculations yield both the $\Lambda nn$ and ${}_{\mathrm{\Lambda }}^3{\mathrm{H}}^{\ast }$ states unbound. We conclude that the excited state ${}_{\mathrm{\Lambda }}^3{\mathrm{H}}^{\ast }$ is a virtual state and the $\Lambda nn$ pole located close to the three-body threshold in a complex energy plane could convert to a true resonance with Re$(E)>0$ for some considered $\Lambda N$ interactions. Finally, the stability of resonance solutions is discussed and limits of the accuracy of performed calculations are assessed.

   ↳ nucl-thnucl-exPRC(2021)·18 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.