The spin structure of parity violating and time reversal invariance violating effects in neutron scattering is discussed. The explicit relations between these effects are presented in terms of functions nuclear spins and neutron partial widths of $p$-wave resonances.

The masses of the exotic isotopes ${}^{210-214}\mathrm{Ac}$ and ${}^{210-214}\mathrm{Ra}$ have been measured with a multireflection time-of-flight mass spectrograph. These isotopes were obtained in flight as fusion-evaporation products behind the gas-filled recoil ion separator GARIS-II at RIKEN. The new direct mass measurements serve as an independent and direct benchmark for existing $\alpha \text{−}\gamma$ spectroscopy data in this mass region. Further, new mass anchor points are set for U and Np nuclei close to the $N=126$ shell closure for a future benchmark of the $Z=92$ subshell for neutron-deficient heavy isotopes. Our mass results are in general in good agreement with the previously indirectly determined mass values. Together with the measurement data, reasons for possible mass ambiguities from decay-data links between ground states are discussed.

In the present work we propose a new way of constructing the initial state for further hydrodynamic simulation of relativistic heavy ion collisions based on Bjorken-like solution applied streak by streak in the transverse plane. Previous fluid dynamical calculations in Cartesian coordinates with an initial state based on a streak by streak Yang-Mills field led for peripheral higher energy collisions to large angular momentum, initial shear flow and significant local vorticity. Recent experiments verified the existence of this vorticity via the resulting polarization of emitted $\mathrm{\Lambda }$ and $\overline{\mathrm{\Lambda }}$ particles. At the same time parton cascade models indicated the existence of more compact initial state configurations, which we are going to simulate in our approach. The proposed model satisfies all the conservation laws, including conservation of a strong initial angular momentum, which is present in noncentral collisions. As a consequence of this large initial angular momentum we observe the rotation of the whole system as well as the fluid shear in the initial state, which leads to large flow vorticity. Another advantage of the proposed model is that the initial state can be given in both [t,x,y,z] and $[\tau ,x,y,\eta ]$ coordinates and thus can be tested by all 3+1D hydrodynamical codes which exist in the field.

Products resulting from 3.02 MeV deuterons incident on a natural boron target have been investigated by way of $\gamma$-ray spectroscopy and activation analysis. This study uses observed $\gamma$ rays and cascades to deduce the populated states from the reaction products. Die-away measurements are included to investigate the built-up activation from the target and compared with tabulated half-lives to further understand the plethora of reactions taking place. Many of the observed $\gamma$ rays, such as 15.1 MeV, result from the formation of excited states of ${}^{12}\mathrm{C}$, while others are secondary and tertiary processes from $\alpha$ breakup resulting in ${}^8\mathrm{Be}$.

Spin distributions of nine evaporation residues ${}^{164}\mathrm{Yb}\left(xn\right)$, ${}^{163}\mathrm{Tm}\left(pxn\right)$, ${}^{168,167}\mathrm{Er}\left(2pxn\right)$, ${}^{163-161}\mathrm{Ho}\left(\alpha pxn\right)$, ${}^{164}\mathrm{Dy}\left(\alpha 2pxn\right)$, and ${}^{160}\mathrm{Dy}\left(2\alpha xn\right)$ produced through complete- and incomplete-fusion reactions have been measured in the system ${}^{16}\mathrm{O}+{}^{154}\mathrm{Sm}$ at projectile energy $=6.1\mathrm{MeV}/\mathrm{nucleon}$ using the in-beam charged-particle ($Z=1,2$)–γ-ray coincidence technique. The results indicate the occurrence of incomplete fusion involving the breakup of ${}^{16}\mathrm{O}$ into ${}^4\mathrm{He}+{}^{12}\mathrm{C}$ and/or ${}^8\mathrm{Be}+{}^8\mathrm{Be}$ followed by fusion of one of the fragments with target nucleus ${}^{154}\mathrm{Sm}$. The pattern of measured spin distributions of the evaporation residues produced through complete and incomplete fusion are found to be entirely different from each other. It has been observed from these present results that the mean input angular momentum for the evaporation residues produced through complete fusion is relatively lower than that of evaporation residues produced through incomplete-fusion reactions. The pattern of feeding intensity of evaporation residues populated through complete- and incomplete-fusion reactions has also been studied. The evaporation residues populated through complete-fusion channels are strongly fed over a broad spin range and widely populated, while evaporation residues populated through incomplete-fusion reactions are found to have narrow range feeding only for high spin states. Comparison of present results with earlier data suggests that the value of mean input angular momentum is relatively higher for a deformed target and more mass asymmetric system than that of a spherical target and less mass asymmetric system by using the same projectile and the same energy. Thus, present results indicate that the incomplete-fusion reactions not only depend on the mass asymmetry of the system, but also depend on the deformation of the target.

We consider a set of three-cluster systems (${}^4\mathrm{He}, {}^7\mathrm{Li}, {}^7\mathrm{Be}, {}^8\mathrm{Be}, {}^{10}\mathrm{Be}$) within a microscopic model which involves hyperspherical harmonics to represent intercluster motion. We selected three-cluster systems which have at least one binary channel. Our aim is to study whether hyperspherical harmonics are able, and under what conditions, to describe two-body channel(s) (nondemocratic motion) or if they are suitable for describing the three-cluster continuum only (democratic motion). It is demonstrated that a rather restricted number of hyperspherical harmonics allows us to describe bound states and scattering states in the two-body continuum for a three-cluster system.

We study the formation of fluid vorticity and the hyperon polarization in heavy-ion collisions at energies available at the JINR Nuclotron-based Ion Collider fAcility in the framework of the parton-hadron-string dynamic model, taking into account both hadronic and quark-gluonic (partonic) degrees of freedom. The vorticity properties in peripheral Au+Au collisions at $\sqrt{s_{NN}}=7.7$ GeV are demonstrated and confronted with other models. The obtained result for the $\mathrm{\Lambda }$ polarization is in agreement with the experimental data by the STAR Collaboration, whereas the model is not able to explain the observed high values of the antihyperon $\overline{\mathrm{\Lambda }}$ polarization.

We study the phase structure of dense hadronic matter including $\mathrm{\Delta }\left(1232\right)$ as well as $N\left(939\right)$ based on the parity partner structure, where the baryons have their chiral partners with a certain amount of chiral invariant masses. We show that, in symmetric matter, $\mathrm{\Delta }$ enters into matter in the density region of about one to four times normal nuclear matter density, ${\rho }_B\sim 1-4{\rho }_0$. The onset density of $\mathrm{\Delta }$ matter depends on the chiral invariant mass of $\mathrm{\Delta },m_{\mathrm{\Delta }0}$: As $m_{\mathrm{\Delta }0}$ increases, the onset density becomes bigger. The stable $\mathrm{\Delta }$-nucleon matter is realized for ${\rho }_B\gtrsim 1.5{\rho }_0$, i.e., the phase transition from nuclear matter to $\mathrm{\Delta }$-nucleon matter is of first order for small $m_{\mathrm{\Delta }0}$, and it is of second order for large $m_{\mathrm{\Delta }0}$. We find that, associated with the phase transition, the chiral condensate changes very rapidly; i.e., the chiral symmetry restoration is accelerated by $\mathrm{\Delta }$ matter. As a result of the accelerations, there appear $N^{*}\left(1535\right)$ and $\mathrm{\Delta }\left(1700\right)$, which are the chiral partners to $N\left(939\right)$ and $\mathrm{\Delta }\left(1232\right)$, in high-density matter, signaling the partial chiral symmetry restoration. Furthermore, we find that complete chiral symmetry restoration itself is delayed by $\mathrm{\Delta }$ matter. We also calculate the effective masses, pressure, and symmetry energy to study how the transition to $\mathrm{\Delta }$ matter affects such physical quantities. We observe that the physical quantities change drastically at the transition density.

The largest, at the moment, statistics of $7\times {10}^6\eta \to 3{\pi }^0$ decays, based on $6.2\times {10}^7\eta$ mesons produced in the $\gamma p\to \eta p$ reaction, has been accumulated by the A2 Collaboration at the Mainz Microtron, MAMI. It allowed a detailed study of the $\eta \to 3{\pi }^0$ dynamics beyond its conventional parametrization with just the quadratic slope parameter $\alpha$ and enabled, for the first time, a measurement of the second-order term and a better understanding of the cusp structure in the neutral decay. The present data are also compared to recent theoretical calculations that predict a nonlinear dependence along the quadratic distance from the Dalitz-plot center.

Quasimolecular $\alpha$-like ground rotational bands were evidenced a long time ago in light nuclei, but they cannot be detected in heavy nuclei due to large Coulomb barriers. In order to search for rotational bands built on excited states in these nuclei, we investigate the shape of an $\alpha$-nucleus quasimolecular potential matched to a realistic external $\alpha$-daughter interaction by using as input data $\alpha$-decay widths. It turns out that its Gaussian length parameter lies in a narrow interval, $b_0\in [0.6,0.8]$ fm, and the equilibrium radius is slightly larger than the predicted Mott transition point from nucleonic to the $\alpha$-cluster phase in finite nuclei, confirming that $\alpha$ clusters are born on the nuclear surface at low densities. We point out that the $\alpha$ emitters above magic nuclei have the largest spectroscopic factors $S_{\alpha }\sim 10\%$. In addition, we predict that for nuclei with $b_0>0.75$ fm, the first excited vibrational resonant state in the quasimolecular potential is close to the Coulomb barrier and therefore the rotational band built on it can be evidenced by the structure of the $\alpha$-scattering cross section versus energy. Moreover, its detection by a highly sensitive $\gamma$-ray beam produced by laser facilities would provide an additional proof for the existence of $\alpha$ molecules in heavy nuclei.

We calculate the single-particle spectrum of the double magic nucleus ${\displaystyle {}^{78}\mathrm{Ni}}$ in a Hartree-Fock approach using the Skyrme density-dependent effective interaction containing central, spin-orbit, and tensor parts. We show that the tensor part has an important effect on the spin-orbit splitting of the proton ${\displaystyle 1f}$ orbit that may explain the survival of magicity so far from the stability valley. We confirm the inversion of the ${\displaystyle 1f5/2}$ and ${\displaystyle 2p3/2}$ levels at the neutron number 48 in the Ni isotopic chain expected from previous Monte Carlo shell-model calculations and supported by experimental observation.

Background: The reaction ${}^{20}\mathrm{Ne}(p,\gamma ){}^{21}\mathrm{Na}$ influences the nucleosynthesis of Ne, Na, and Mg isotopes while contributing to hydrogen burning in several stellar sites, such as red giants, asymptotic giant branch (AGB) stars, massive stars, and oxygen-neon (ONe) novae. In the relevant temperature range for these environments ($T$ = 0.05–0.5 GK), the main contributions to this reaction rate are from the direct capture process as well as the high-energy tail of a subthreshold resonance in the ground-state transition at $E_x$ = 2425 keV in the ${}^{21}\mathrm{Na}$ compound nucleus.

Purpose: The previous measurement of this reaction reports cross sections with large uncertainties for the ground-state transition. At higher energies, where the subthreshold resonance makes a smaller contribution to the total cross section, only upper limits are provided. This work aims to reduce the uncertainty in the cross section where direct capture dominates, as well as provide cross-section data in previously unmeasured regions.

Method: The ${}^{20}\mathrm{Ne}(p,\gamma ){}^{21}\mathrm{Na}$ reaction was measured over a wide proton energy range ($E_p$ = 0.5–2.0 MeV) at ${\theta }_{\text{lab}}$ = ${90}^{\circ }$. Transitions to the ground state and to the 332 and 2425 keV excited states were observed. The primary transitions to these three bound states were utilized in an $R$-matrix analysis to determine the contributions of the direct capture and the subthreshold resonance to the total cross section.

Results: The cross sections of the present measurements have been found to be in good agreement with the previous data at low energy. Significantly improved cross-section measurements have been obtained over the $E_p$ = 1300–1900 keV region. The narrow resonance at $E_{\text{c.m.}}$ = 1113 $\mathrm{keV}(E_x$ = 3544.3 keV) has also been remeasured and its strength has been found to be in good agreement with previous measurements.

Conclusions: An extrapolation of the $S$ factor of ${}^{20}\mathrm{Ne}(p,\gamma ){}^{21}\mathrm{Na}$ has been made to low energies using the $R$-matrix fit. The reaction rate from the subthreshold resonance was found to be the main contributor to the reaction rate at temperatures below about 0.1 GK. The present rate is lower in the temperature range of interest than those presented in current reaction rate libraries by up to 20%.

We have combined the complex momentum representation method with the Green's function method in the relativistic mean-field framework to establish the RMF-CMR-GF approach. This new approach is applied to study the halo structure of ${}^{74}\mathrm{Ca}$. All the continuum level density of concerned resonant states are calculated accurately without introducing any unphysical parameters, and they are independent of the choice of integral contour. The important single-particle wave functions and densities for the halo phenomenon in ${}^{74}\mathrm{Ca}$ are discussed in detail.

A self-consistent mean-field approach within the extended Thomas-Fermi approximation with Skyrme forces is applied to the calculations of the statistical level density in spherical nuclei. Landau's concept of quasiparticles with the nucleon effective mass and the correct description of the continuum states for the finite-depth potentials are taken into consideration. The $A$ dependence and the temperature dependence of the statistical inverse level-density parameter $K$ is obtained in a good agreement with experimental data.

The production of $\alpha$-particle decaying heavy nuclei in reactions of 7.5–6.1 MeV/nucleon ${}^{238}\mathrm{U}$ +${}^{232}\mathrm{Th}$ was explored using an in-beam detection array composed of YAP scintillators and gas ionization chamber-Si telescopes. Comparisons of $\alpha$ energies and half-lives for the observed products with those of the previously known isotopes and with theoretically predicted values indicate the observation of a number of previously unreported $\alpha$ emitters. $\alpha$-particle decay energies reaching as high as 12 MeV are observed. Many of these are expected to be from decay of previously unseen relatively neutron rich products. While the contributions of isomeric states require further exploration and specific isotope identifications need to be made, the production of heavy isotopes with quite high atomic numbers is suggested by the data.

The ${}^{33}\mathrm{S}(n,\alpha ){}^{30}\mathrm{Si}$ cross section has been measured at the neutron time-of-flight ($\mathrm{n}\_\mathrm{TOF}$) facility at CERN in the neutron energy range from 10 to 300 keV relative to the ${}^{10}\mathrm{B}(n,\alpha ){}^7\mathrm{Li}$ cross-section standard. Both reactions were measured simultaneously with a set of micromegas detectors. The flight path of 185 m has allowed us to obtain the cross section with high-energy resolution. An accurate description of the resonances has been performed by means of the multilevel multichannel $R$-matrix code sammy. The results show a significantly higher area of the biggest resonance (13.45 keV) than the unique high-resolution ($n,\alpha$) measurement. The new parametrization of the 13.45-keV resonance is similar to that of the unique transmission measurement. This resonance is a matter of research in neutron-capture therapy. The ${}^{33}\mathrm{S}(n,\alpha ){}^{30}\mathrm{Si}$ cross section has been studied in previous works because of its role in the production of ${}^{36}\mathrm{S}$ in stars, which is currently overproduced in stellar models compared to observations.

The particle yields and particle number ratios in Pb+Pb collisions at the CERN Large Hadron Collider (LHC) energy $\sqrt{s_{NN}}=2.76$ TeV are described within the integrated hydrokinetic model (iHKM) at two different equations of state (EoS) for quark-gluon matter and the two corresponding hadronization temperatures $T=165$ MeV and $T=156$ MeV. The role of particle interactions at the final afterburner stage of the collision in the particle production is investigated by means of comparison of the results of full iHKM simulations with those where the annihilation and other inelastic processes (except for resonance decays) are switched off after hadronization/particlization, similarly as in the thermal models. An analysis supports the picture of continuous chemical freeze-out in the sense that the corrections to the sudden chemical freeze-out results, which arise because of the inelastic reactions at the subsequent evolution times, are noticeable and improve the description of particle number ratios. An important observation is that, although the particle number ratios with switched-off inelastic reactions are quite different at different particlization temperatures which are adopted for different equations of state to reproduce experimental data, the complete iHKM calculations bring very close results in both cases.

Hyperon-nucleon interactions serve as basic inputs to studies of hypernuclear physics and dense (neutron) stars. Unfortunately, a precise understanding of these important quantities has lagged far behind that of the nucleon-nucleon interaction due to lack of high-precision experimental data. Historically, hyperon-nucleon interactions are either formulated in quark models or meson exchange models. In recent years, lattice QCD simulations and chiral effective field theory approaches start to offer new insights from first principles. In the present work, we contrast the state-of-the-art lattice QCD simulations with the latest chiral hyperon-nucleon forces and show that the leading order relativistic chiral results can already describe the lattice QCD data reasonably well. Given the fact that the lattice QCD simulations are performed with pion masses ranging from the (almost) physical point to 700 MeV, such studies provide a useful check on both the chiral effective field theory approaches as well as lattice QCD simulations. Nevertheless more precise lattice QCD simulations are eagerly needed to refine our understanding of hyperon-nucleon interactions.

The $(n,\gamma f)$ process is reviewed in light of modern nuclear reaction calculations in both slow and fast neutron-induced fission reactions on ${}^{235}\mathrm{U}$ and ${}^{239}\mathrm{Pu}$. Observed fluctuations of the average prompt fission neutron multiplicity and average total $\gamma$-ray energy below 100-eV incident neutron energy are interpreted in this framework. The surprisingly large contribution of the $M1$ transitions to the prefission $\gamma$-ray spectrum of ${}^{239}\mathrm{Pu}$ is explained by the dominant fission probabilities of $0^{+}$ and $2^{+}$ transition states, which can only be accessed from compound nucleus states formed by the interaction of $s$-wave neutrons with the target nucleus in its ground state, and decaying through $M1$ transitions. The impact of an additional low-lying $M1$ scissors mode in the photon strength function is analyzed. We review experimental evidence for fission fragment mass and kinetic-energy fluctuations in the resonance region and their importance in the interpretation of experimental data on prompt neutron data in this region. Finally, calculations are extended to the fast energy range where $(n,\gamma f)$ corrections can account for up to 3% of the total fission cross section and about 20% of the capture cross section.

The ${}^{10}\mathrm{B}(p,{\alpha }_0){}^7\mathrm{Be}$ excitation function has been studied in a wide energy range, from 2.2 MeV down to astrophysical energies, reproducing the cross section above and below the Coulomb barrier in a single experiment. An optimized experimental setup ensured good energy resolution and for the first time a clear separation of ${\alpha }_0$ and ${\alpha }_1$ channels of the ${}^{10}\mathrm{B}+{}^2\mathrm{H}$ interaction has been achieved by applying the Trojan Horse method. An improved normalization of the Trojan Horse bare-nucleus astrophysical $S$($E$)-factor to direct data was performed and a value of $U_e=391\pm 74\mathrm{eV}$ was obtained for the electron screening potential.