Nuclear Theory·nucl-th
9 papers—5 primary·4 cross-listed
This paper presents an analysis of neutron skins based on fully microscopic equations of state, including chiral two- and three-nucleon forces consistently at N3LO. Other theoretical predictions and recent constraints are also addressed, such as those from the PREX II experiment and the latest parity-violating electron scattering measurement of the 27Al neutron skin.
In non-central high energy heavy ion collisions, the colliding system possesses a huge orbital angular momentum along the normal direction of the reaction plane. Due to the spin orbit interaction in the system, such a huge orbital angular momentum leads to the spin polarization of quarks and anti-quarks in the quark matter system produced in the collision. Such an effect, known as the global polarization effect, was predicted many years ago and has been confirmed by the STAR collaboration at RHIC. The discovery of the global polarization effect opens a new avenue in heavy ion physics in general and in studying the properties of quark-gluon plasma in particular. This talk will briefly review the original ideas and calculations that lead to the prediction and summarize progresses and problems in related aspects.
A simultaneous calculation for the shape evolution and the related spectroscopic properties of the low-lying states, and the -decay properties in the even- and odd-mass Ge and As nuclei in the mass region, within the framework of the nuclear density functional theory and the particle-core coupling scheme, is presented. The constrained self-consistent mean-field calculations using a universal energy density functional (EDF) and a pairing interaction determines the interacting-boson Hamiltonian for the even-even core nuclei, and the essential ingredients of the particle-boson interactions for the odd-nucleon systems, and of the Gamow-Teller and Fermi transition operators. A rapid structural evolution from -soft oblate to prolate shapes, as well as the spherical-oblate shape coexistence around the neutron sub-shell closure , is suggested to occur in the even-even Ge nuclei. The predicted low-energy spectra, electromagnetic transition rates, and -decay values are in a reasonable agreement with experiment. The predicted values reflect the structures of the wave functions for the initial and final nuclei of decay, which are, to a large extent, determined by the microscopic input provided by the underlying EDF calculation.
Lu-Meng Liu🇨🇳 · Chun-Jian Zhang🇺🇸 · Jia Zhou🇨🇳 · Jun Xu🇨🇳 · Jiangyong Jia🇺🇸 · Guang-Xiong Peng🇨🇳
We show that the yield ratio of free spectator neutrons produced in high-energy Zr+Zr to Ru+Ru collisions is a clean probe of the neutron-skin thickness of colliding nuclei and the slope parameter of the symmetry energy. The idea is demonstrated based on the proton and neutron density distributions via a state-of-the-art Skyrme-Hartree-Fock-Bogolyubov calculation. Among spectator nucleons given by the Glauber model, free spectator neutrons include those from direct production that survive from clusterization as well as those from deexcitation of heavy clusters described by the popular GEMINI model. More free neutrons are produced in collisions of Zr nucleus due to its larger neutron skin, compared to those produced in collisions of Ru nucleus with a smaller neutron skin. The difference of the free spectator neutron yield is further increased with the increasing difference of the neutron-skin thickness between Zr and Ru with a larger value, and the increase in ultracentral collisions is particularly insensitive to model details and experimental uncertainties. Since the production of free spectator neutrons is not affected by the complicated dynamics in the mid-rapidity region, the ratio of their multiplicities in ultracentral isobaric collisions is a robust observable for constraining the neutron skin and value.
T. Franco-Munoz · R. González-Jiménez · J.M. Udías
Longitudinal () and transverse () responses from inclusive electron scattering from carbon 12 and calcium 40 nuclei are computed within a fully relativistic and unfactorized model for the initial and final states, and one- and two-body current operators leading to the one-particle one-hole responses. We find that the two-body contributions have no effect on but they increase by up to 30%, depending on the energy and momentum transfer. Inclusive cross sections have also been computed. In this case, the increase of due to two-body currents will translate into an increase in the cross-sections depending on the degree of transversity of each kinematic. The comparison with carbon data is good for the responses and the cross sections. In the case of calcium, while the model compares well with the cross section data, the agreement with the responses is generally poor. However, the inconsistencies between different data sets for the separate responses in this nucleus points to uncertainties underlying the procedure to extract the responses that are not considered (or largely underestimated) in the experimental error bars. Our calculation is fully relativistic and considers within the full quantum mechanical description both the initial and final nucleon states involved in the process. We also show that it is essential to go beyond the plane-wave approach, since incorporating the distortion of the nucleons while making the initial and final states orthogonal, allows to reproduce both the shape and magnitude of the cross section data and carbon responses. The good agreement with the electron scattering experimental data supports the use of this approach to describe the analogous neutrino-induced scattering reaction.
Vincenzo Cirigliano🇺🇸 · Kaori Fuyuto🇺🇸 · Michael J. Ramsey-Musolf🇨🇳 · Evan Rule🇺🇸
Within a class of models in which lepton flavor violation is induced dominantly by scalar particle exchanges, we estimate the conversion rate in several nuclei. We include next-to-leading order (NLO) terms in the one- and two-nucleon interactions in chiral effective theory, rectifying some incorrect results in the previous literature. We provide an uncertainty budget for the conversion rates and we find that NLO contributions affect the amplitudes at the level of , which could be larger than the uncertainty on the leading order couplings, dominated by the strange and non-strange nucleon sigma terms. We study the implications of our results for testing Higgs-mediated CLFV in the future by combining results from various experimental searches, such as conversion in multiple target nuclei and .
Chao-Wei Shen🇩🇪 · Ulf-G. Meißner🇩🇪
We analyze the possibility of the existence of a fully exotic pentaquark state , which is made from the five different flavors participarting in the strong interactions. We investigate the coupled channel effects of the system through -channel vector meson exchange to search for such states. A and a bound state are found to have binding energies of about ~MeV with and being the possible decay channels. Similarly, a bound state is formed in the and channels, respectively. These states could be searched for through the or processes by the LHCb collaboration.
Iskander Mukatayev🇫🇷 · Benoît Sklénard🇫🇷 · Valerio Olevano🇫🇷 · Jing Li🇫🇷
X-ray photoelectron spectroscopy (XPS) measures electron removal energies, providing direct access to core and valence electron binding energies, hence probing the electronic structure. In this work, we benchmark for the first time the ab initio many-body GW approximation on the complete electron binding energies of noble gas atoms (He-Rn), which spans 100~keV. Our results demonstrate that GW achieves an accuracy within 1.2% in XPS binding energies, by systematically restoring the underestimation from density-functional theory (DFT, error of 14%) or the overestimation from Hartree-Fock (HF, error of 4.7%). Such results also imply the correlations of electrons are very well described by GW.
Roy A. Lacey (1) · Niseem Magdy (2) · Petr Parfenov (3) · Arkadiy Taranenko (3) ((1) Depts. of Chemistry and Physics, Stony Brook University, Stony Brook, New York, USA (2) Department of Physics, University of Illinois at Chicago, Chicago, Illinois, USA (3) National Research Nuclear University MEPhI, Moscow, Russia)
The Anomalous Viscous Fluid Dynamics model, AVFD, is used in concert with the charge-sensitive correlator to investigate the scaling properties of background- and chiral-magnetically-driven (CME) charge separation (), characterized by the inverse variance of the distributions obtained in collisions at GeV. The values for the background are observed to be event-shape-independent. However, they scale with the reciprocal charged-particle multiplicity , indicating an essential constraint for discerning background from the signal and a robust estimate of the difference between the backgrounds in Ru+Ru and Zr+Zr collisions. By contrast, the values for signal + background show characteristic scaling violations that characterize the CME-driven contributions. Corrections to recent measurements \cite{STAR:2021mii} that account for the background difference in Ru+Ru and Zr+Zr collisions indicate a charge separation difference compatible with the CME. The results further suggest that measurements for peripheral and central collisions in concert with scaling, provides a robust constraint to quantify the background and aid characterization of the CME.
first authorsco-authorsvia INSPIRE