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Starting from a |ϕ|4 field theory with universal pn interacting angular and distance coordinates (θ,r) to depict nuclear long-range correlations, we have derived a cubic Schrödinger equation for NpNn pn interacting virtual bosons, which are believed to dominate the generic evolution of nuclear structure from spherical multi-nucleon shell-model states to deformed collective rotational states. It is shown that two-soliton solution in θ space manifests two opposite pn-type Ising-like chains existing in ground states and their gradual alignment responsible for nuclear rotational excitations. Of particular prominence is two-soliton solution with respect to r: the mutual relative motion of valence protons and neutrons around valence-nucleon mass centers considered as the dynamic equilibrium positions of a non-linear Schrödinger breather. And the resulting non-vanishing root mean square 〈r2〉 divides half the valence nucleons belonging to a chain into four local mass centers and proposes two chain-corresponding molecule-like tetrads outside inert cores pairwise hidden in ground states. Such solitons turn out to be an analogue of opposite axion fluids around a local mass center in the galactic dark-matter halo outside the soliton core (Garnier et al. (2021) [67]) and the present study facilitates making the latter more clear. The generalized molecule-like structure arouses a requisite to the addition of cluster-interior and cluster-to-core electric dipole moments in particular to pear-shaped nuclei, whose variants Schiff moments play an important role in measuring diamagnetic atomic electric dipole moments and therefore understanding CP-violating new physics beyond the standard model. We put additional parts in evidence by befitting the NpNn scheme verified already by electric quadrupole moments in same nuclei.

A new isotope 203Ac was produced in the reaction 40Ca + 169Tm at beam energy of 226 MeV. One correlated α-decay chain was attributed to 203Ac. The α-particle energy and half-life were determined to be 8217(16) keV and 56−26+269 μs, respectively. The reduced α-decay width (δ2) of 203Ac was deduced to be 1096−906+921 keV, which indicates a favored α decay. The systematics of δ2 and single-particle energy levels indicate that the new state probably arises from the intruder s1/2 configuration, which shows an onset of deformation in Ac isotopes. The proton separation energy Sp of 203Ac was extracted as −1214(22) keV and the systematics of Sp for odd-A isotopes beyond proton drip line were discussed.

This study analyzes the evolution of single-proton states within the odd-A isotopes of 117−133Sb. We identified the monopole force interaction between the πg7/2 and νh11/2 orbitals as the key driver of the ground-state inversion observed in 121Sb. Moreover, we provide an additional asset for this monopole force by investigating the negative-parity states in 132Sb and demonstrating its manifestation through a comparative assessment of πg-νh multiplets. Our results provide conclusive evidence, for the first time, explaining the ground-state inversion in 121Sb through observations in 132Sb. The increasing occupation and configurations of the orbit πd5/2 revealed that the single-proton property of state 5/2+ remained robust even in the neutron mid-shell region.

A new proton-unbound isotope 204Ac was produced in the fusion-evaporation reaction Tm(40169Ca,5n)204Ac and identified via the recoil-α correlation at the gas-filled recoiled separators SHANS2 and SHANS. The excitation function for producing 204Ac was measured and the optimal beam energy was evaluated to be 212 MeV. Nineteen ER - α1 - α2 - α3 decay chains were observed for this isotope. Based on these chains, the α-particle energy and half-life of 204Ac were determined to be 7948(15) keV and 7.4−1.4+2.2 ms, respectively. Both are consistent with the theoretical prediction. The reduced α-decay width was deduced to be 49−15+10 keV, which indicates a favored α decay for 204Ac. In addition, more precise decay properties of Eα = 7883(15) keV and T1/2 = 7.7−1.6+2.7 ms were obtained for 205Ac.

The precession of an atomic nucleus can be approximately described as wobbling motion, arising from the coupling of a rotation and a harmonic vibration. Recently, a number of wobbling bands were reported at low spin, which violate the wobbling approximation that can be valid only at high spin. In the present work, we explore the nature of the reported low-spin wobbling bands. Via a new experiment including both angular correlation and linear polarization measurements, we demonstrate that one such band in 187Au is generated by dominant single-particle excitation rather than by the excitation of a wobbling phonon. Assessing the experimental proofs and discussions to assign the reported low-spin wobbling bands, we further point out that the imperfect research paradigm used previously would lead to unreliable identification of low-spin wobbling bands.

Prolate-oblate shape coexistence close to the ground state in the strongly-deformed proton-rich A≈120 nuclei is reported for the first time. One of the four reported bands in 119Cs, built on a 11/2− state at 670 keV, consists of nearly degenerate signature partners, and has properties which unequivocally indicate the strongly-coupled πh11/2[505]11/2− configuration associated with oblate shape. Together with the decoupled πh11/2[541]3/2− band built on the 11/2− prolate state at 110 keV, for which a half-life of T1/2=55(5)μs has been measured, the new bands bring evidence of shape coexistence at low spin in the proton-rich strongly deformed A≈120 nuclei, a phenomenon predicted since long time, but not yet observed. Calculations using the particle-number conserving cranked shell model and two dimensional tilted axis cranking covariant density functional theory support and well reproduce the observed oblate and prolate coexisting low-energy states in 119Cs.

Several new bands have been identified in 130Ba, among which there is one with band-head spin 8+. Its properties are in agreement with the Fermi-aligned νh11/22, 7/2−[523]⊗9/2−[514] Nilsson configuration. This is the first observation of a two-quasiparticle t-band in the A=130 mass region. The t-band is fed by a dipole band involving two additional h11/2 protons. The odd-spin partners of the proton and neutron S-bands and the ground-state band at high spins are also newly identified. The observed bands are discussed using several theoretical models, total Routhians surfaces (TRS), tilted axis cranking (TAC), particle rotor model (PRM) and projected shell model (PSM), which strongly suggest the coexistence of prolate and oblate shapes polarized by rotation aligned two-proton and two-neutron configurations, as well as prolate collective rotations around axes with different orientations. With the new results, 130Ba presents one of the best and most complete sets of collective excitations that a γ-soft nucleus can manifest at medium and high spins, revealing a diversity of shapes and rotations for the nuclei in the A=130 mass region. Keywords: Nuclear structure, Collective rotations, Shape coexistence, Particle rotor model, Projected shell model, Tiltid axis cranking

Three nearly degenerate pairs of doublet bands are identified in 131Ba. Two of them, with positive-parity, are interpreted as pseudospin-chiral quartet bands. This is the first time that a complete set of chiral doublet bands built on the pseudospin partners π(d5/2,g7/2) is observed. The chiral bands with opposite parity built on 3-quasiparticle configurations are directly connected by many E1 transitions, without involving an intermediary non-chiral configuration. The observed band structures in 131Ba have been investigated by using the reflection-asymmetric particle rotor model. The energies and the electromagnetic transition ratios of the three pairs of doublet bands observed in 131Ba are reproduced and they are interpreted as chiral doublet bands with three-quasiparticle configurations. It is the first time that multiple chiral bands are observed in the presence of enhanced octupole correlations and pseudospin symmetry.

The mass of 27P is expected to impact the X-ray burst (XRB) model predictions of burst light curves and the composition of the burst ashes, but large uncertainties and inconsistencies still exist in the reported 27P masses. We have used the β-decay spectroscopy of 27S to determine the most precise mass excess of 27P to date to be −659(9) keV, which is 63 keV (2.3σ) higher and a factor of 3 more precise than the value recommended in the 2016 Atomic Mass Evaluation. Based on the new 27P mass, the Si26(p,γ)27P reaction rate and its uncertainty were recalculated using Monte Carlo techniques. We also estimated the previously unknown mass excess of 27S to be 17678(77) keV, based on the measured β-delayed two-proton energy and the Coulomb displacement energy relations. The impact of these well-constrained masses and reaction rates on the modeling of the explosive astrophysical scenarios has been investigated by post-processing XRB and hydrodynamic nova models. Compared to the model calculations based on the masses and rates from databases, the abundance of A=26 in the burst ashes is increased by a factor of 2.4, while no substantial change was found in the XRB energy generation rate or the light curve. Our calculation also suggests that 27S is not a significant waiting point in the rapid proton capture process, and the change of the Si26(p,γ)27P reaction rate is not sufficiently large to affect the conclusion previously drawn on the nova contribution to the synthesis of galactic 26Al. Keywords: Masses of 27P and 27S, Si26(p,γ)27P reaction, X-ray bursts, Nova outbursts

Fine structure in the α decay of 223U was observed in the fusion-evaporation reaction 187Re(40Ar, p3n) by using fast digital pulse processing technique. Two α-decay branches of 223U feeding the ground state and 244 keV excited state of 219Th were identified by establishing the decay chain 223U →α1 219Th →α2 215Ra →α3 211Rn. The α-particle energy for the ground-state to ground-state transition of 223U was determined to be 8993(17) keV, 213 keV higher than the previous value, the half-life was updated to be 62−10+14 μs. Evolution of nuclear structure for N = 131 even-Z isotones from Po to U was discussed in the frameworks of nuclear mass and reduced α-decay width, a weakening octupole deformation in the ground state of 223U relative to its lighter isotones 219Ra and 221Th was suggested. Keywords: Fine structure, α decay, Spin and parity, Reduced α-decay width, Quadrupole-octupole deformation

The semi-magic nucleus 219Np was produced in the fusion reaction 187Re(36Ar, 4n)219Np at the gas-filled recoil separator SHANS (Spectrometer for Heavy Atoms and Nuclear Structure). A fast electronics system based on waveform digitizers was used in the data acquisition and the sampled pulses were processed by digital algorithms. The reaction products were identified using spatial and time correlations between the implants and subsequent α decays. According to the observed α-decay chain, an energy of Eα=9039(40) keV and a half-life of T1/2=0.15−0.07+0.72 ms were determined for 219Np. The deduced proton binding energy of 219Np fits well into the systematics, which gives another evidence of that there is no sub-shell closure at Z=92. The influence of the N=126 shell closure on the stability of Np isotopes is discussed within the framework of α-decay reduced widths. Keywords: N=126 shell closure, Digital algorithm, α-particle energy, Half-life, Proton drip-line

The N=130 short-lived isotope 223Np was produced as evaporation residue (ER) in the fusion reaction 40Ar + 187Re at the gas-filled recoil separator Spectrometer for Heavy Atom and Nuclear Structure (SHANS). It was identified through temporal and spatial correlations with α decays of 215Ac and/or 211Fr, the third and fourth members of the α-decay chain starting from 223Np. The pileup signals of ER(223Np)–α(223Np)–α(219Pa) were resolved by using the digital pulse processing technique. An α decay with half-life of T1/2=2.15(52100) μs and energy of Eα=9477(44)keV was attributed to 223Np. Spin and parity of 9/2− were tentatively proposed for the ground state of 223Np by combining the reduced α-decay width and large-scale shell-model calculations. This assignment together with the proton separation energy disprove the existence of a Z=92 subshell closure. Keywords: New isotope, Short-lived α radioactivity, Proton separation energy, Subshell closure

The decay of the lightest nucleus with Tz=−3, 22Si, was studied by a silicon array. A charged-particle group at 5600 (70) keV in the decay-energy spectrum was identified experimentally as β-delayed two-proton emission from the isobaric analog state (IAS) of 22Al. Experimental results of the IAS fed by a superallowed Fermi transition were compared with our large-scale shell-model calculations. The ground-state mass of 22Si was obtained indirectly in the experiment for the first time. Two-proton separation energy for 22Si is deduced to be −108 (125) keV, which indicates that it is a very marginal candidate for two-proton ground-state emission.

Excited states in neutron-rich nuclei located south-east of 132Sn are investigated by shell-model calculations. A new shell-model Hamiltonian is constructed for the present study. The proton–proton and neutron–neutron interactions of the Hamiltonian are obtained through the existing CD-Bonn G matrix results, while the proton–neutron interaction across two major shells is derived from the monopole based universal interaction plus the M3Y spin–orbit force. The present Hamiltonian can reproduce well the experimental data available in this region, including one-neutron separation energies, level energies and the experimental B(E2) values of isomers in 134,136,138Sn, 130Cd, and 128Pd. New isomers are predicted in this region, e.g. in 135Sn, 131Cd, 129Pd, 132,134In and 130Ag, in which almost no excited states are known experimentally yet. In the odd–odd 132,134In and 130Ag, the predicted very long E2 life-times of the low-lying 5− states are discussed, demanding more information on the related proton–neutron interaction. The low-lying states of 132In are discussed in connection with the recently observed γ rays. The predicted 19/2− isomer in 129Pd could decay by both electromagnetic transitions and neutron emission with comparable partial life-times, making it a good candidate for neutron radioactivity, a decay mode which is yet to be discovered.

BACKGROUND Defective sperm–zona pellucida (ZP) binding (DSZPB) is a common cause of failure of fertilization in vitro. This study was to determine if DSZPB is caused by defective pathways upstream of protein kinase A (PKA) and C (PKC), or reduced protein tyrosine phosphorylation (TP). METHODS Infertile men with DSZPB and either normal sperm morphology (NSM) ≥ 14% (n = 15) or ≤5% (n = 15) were studied. Sperm–ZP binding test was performed by incubation of motile sperm with oocytes for 2 h with or without dibutyryl cyclic AMP (dbcAMP, PKA activator) or phorbol myristate acetate (PMA, PKC activator). TP of capacitated sperm in medium was assessed by immunofluorescence with an anti-phosphotyrosine monoclonal antibody. RESULTS For normal sperm with normal sperm–ZP binding, both PMA and dbcAMP significantly enhanced sperm–ZP binding in a dose–response manner. Only dbcAMP, but not PMA, significantly increased TP of capacitated sperm. In DSZPB men with severe teratozoospermia (NSM ≤ 5%), neither PMA nor dbcAMP enhanced sperm–ZP binding, despite dbcAMP significantly increasing the TP of capacitated sperm for all samples. In contrast, for DSZPB with NSM ≥ 14%, PMA caused significantly increased sperm binding up to normal levels (≥40 sperm bound/ZP) in five men, and dbcAMP had a similar result in two men. Again TP was significantly enhanced only by dbcAMP, but not by PMA. CONCLUSIONS There is defective signalling in pathways upstream of PKC and PKA in some men with DSZPB and normal semen analysis. Stimulation of TP by dbcAMP does not enhance sperm–ZP binding capacity in DSZPB men with low TP, regardless of sperm morphology. [ABSTRACT FROM AUTHOR]

BACKGROUND The aim of this study was to determine the relationship between human sperm hyperactivation (HA), sperm–zona pellucida (ZP) binding and the ZP-induced acrosome reaction (AR) of ZP-bound sperm in vitro. METHODS Sperm samples from 129 infertile men were studied. Motile sperm (2 × 106) selected by Pure sperm were incubated with four oocytes in 1 ml human tubal fluid supplemented with 10% human serum. After 2-h incubation, the number of sperm bound to the ZP and the AR of ZP-bound sperm were examined. Velocities and HA of sperm in insemination medium were assessed by Hamilton-Thorn Sperm Analyzer. RESULTS The HA was highly correlated with the ZP-induced AR in all the subjects (rho = 0.626, P P CONCLUSIONS The correlation of HA with the ZP-induced AR of ZP-bound sperm suggests a mechanistic link between HA and the physiological AR in humans. Assessment of HA of capacitated sperm in vitro may be a useful clinical test for male infertility associated with defective ZP-induced AR that does not require the use of human oocytes. [ABSTRACT FROM AUTHOR]