We study the influence of the parity configuration of the parent and daughter nuclei on the $\alpha$-decay process. We consider the ground-state to ground-state favored and unfavored decays, as well as the decay modes to different excited states of the daughter nucleus. The experimental half-life and the calculated decay width based on the realistic M3Y-Paris and the Skyrme-SLy4 effective nucleon-nucleon interactions, within the Wentzel-Kramers-Brillouin approximation, are used to estimate the $\alpha$-preformation factor for each decay mode. The experimental partial half-lives and $\alpha$-decay intensities indicate a somewhat larger hindrance of the unfavored decay modes between states of different parities than that of the unfavored decays between states of different spin but with the same parity. This hindrance overcomes the enhancement from a likely increase in the $Q_{\alpha }$ value of the odd-A isotopes relative to the even-even ones, leading to an increase (decrease) in the half-life (decay intensity) of the decay modes involving a change in parity. We also find that if the states among which the unfavored decay occurs have different parities, the preformation factor of the $\alpha$ cluster inside the parent nucleus becomes less than it would be if the involved states are of the same parity.

The Coulomb effect, an essential ingredient in nuclear systems, is quantitatively investigated for certain Skyrmions with charge greater than 1. This is the first time such a calculation has been done. To do this we calculate the Coulomb energy from numerically generated multi-Skyrmions and, simultaneously, introduce an effective alpha-like particle approximation for large Skyrmions with baryon number $B$, where $B$ is a multiple of 4. The calculated Coulomb energies and the corresponding fitted curve from this approximation match well with the results from the numerical method, as well as the behavior of the Coulomb energy in the semiempirical mass formula. The Skyrme model correctly reproduces the well known results for the Coulomb energy of nuclei. This suggests that the alpha particles can be used as the fundamental degrees of freedom in the Skyrme model, like the proposals in many other models. The Coulomb effect on the binding energy of the Skyrmions increases with baryon number but has a small effect overall. However, the effect could be significantly more pronounced for loosely bound Skyrme models.

The thermal cross sections and resonance integrals of ${}^{108,110}\mathrm{Pd}$ have been deduced for radiative neutron captures leading to both the ground and metastable states of ${}^{109,111}\mathrm{Pd}$. These determinations were based on measurements of the intensity of the γ rays emitted in the decays of ${}^{109}\mathrm{Pd}^{g,m}$ and ${}^{111}\mathrm{Pd}^{g,m}$ following neutron irradiation of ${}^{108,110}\mathrm{Pd}$. To facilitate more reliable values of the cross sections, improved values for the half-lives of these decays have also been measured.

The lattice Hamiltonian method is developed for solving the Vlasov equation with nuclear mean field based on the Skyrme pseudopotential up to next-to-next-to-next-to leading order. The ground states of nuclei are obtained through varying the total energy with respect to the density distribution of nucleons. Owing to the self-consistent treatment of initial nuclear ground state and the exact energy conservation in the lattice Hamiltonian method, the present framework of solving the Vlasov equation exhibits very stable nuclear ground state evolution. As a first application of the new lattice Hamiltonian Vlasov method, we explore the isoscalar giant monopole and isovector giant dipole modes of finite nuclei. The obtained results are shown to be comparable to that from random-phase approximation and are consistent with the experimental data, indicating the capability of the present method in dealing with the long-time near-equilibrium nuclear dynamics.

We calculate the effect of intense laser fields on nuclear $\alpha$ decay processes, using realistic and quantitative nuclear potentials. We show that $\alpha$ decay rates can indeed be modified by strong laser fields to some finite extent. We also predict that $\alpha$ decays with lower decay energies are relatively easier to be modified than those with higher decay energies, due to longer tunneling paths for the laser field to act on. Furthermore, we predict that modifications to angle-resolved penetrability are easier to achieve than modifications to angle-integrated penetrability.

An analysis is made of the particle composition (hadrochemistry) of the final state in proton-proton ($p-p$), proton-lead ($p\text{-Pb}$) and lead-lead (Pb-Pb) collisions as a function of the charged particle multiplicity ($d{N}_{\mathrm{ch}}/d\eta$). The thermal model is used to determine the chemical freeze-out temperature as well as the radius and strangeness saturation factor ${\gamma }_s$. Three different ensembles are used in the analysis; namely, the grand canonical ensemble, the canonical ensemble with exact strangeness conservation, and the canonical ensemble with exact baryon number, strangeness, and electric charge conservation. It is shown that for high multiplicities (at least 20 charged hadrons in the midrapidity interval considered) the three ensembles lead to the same results.

Elliptic flow splitting $\mathrm{\Delta }{v}_2$ between $\overline{u}$ and $u$ quarks as well as between ${\pi }^{-}$ and ${\pi }^{+}$ in midcentral Au + Au collisions at $\sqrt{s_{\mathrm{NN}}}=200$ GeV is studied, based on the framework of an extended multiphase transport model with the partonic evolution described by the chiral kinetic equations of motion. Within the available statistics, the slope of $\mathrm{\Delta }{v}_2$ between $\overline{u}$ and $u$ quarks with respect to the electric charge asymmetry $A_{\mathrm{ch}}$ from the linear fit is found to be negative, due to the correlation between the velocity and the coordinate in the initial parton phase-space distribution. Simulations with the magnetic field in QGP overestimate the splitting of the spin polarization between $\mathrm{\Lambda }$ and $\overline{\mathrm{\Lambda }}$ observed experimentally, with the latter more consistent with results under the magnetic field in vacuum. Considering the uncertainties from the magnetic field, the quark-antiquark vector interaction, and the hadronization, as well as the hadronic evolution, our study shows that the experimentally observed positive slope of $\mathrm{\Delta }{v}_2$ with respect to $A_{\mathrm{ch}}$ is not likely due to the chiral magnetic wave.

We propose a new derivation of the cranking-model expression for the nuclear collective inertia tensor, introducing explicitly the slow- and fast-motion timescales together with a parameter controlling the interplay between the two modes. The new cranking formula is free from the mass tensor divergencies originating from the nucleon-level crossings in the denominators of the first-order perturbation theory expressions and allows the exploration of the unrestricted deformation space without spurious mass tensor contributions caused by those divergencies. We apply the new formalism without extra parameter adjustments to the collective vibrations in ${}^{208}\mathrm{Pb}$.

A dedicated spectroscopic study of the $\beta$ decay of ${}^{127}\mathrm{Cd}$ was conducted at the IGISOL facility at the University of Jyväskylä. Following high-resolution mass separation in a Penning trap, $\beta \text{−}\gamma \text{−}\gamma$ coincidences were used to considerably extend the decay scheme of ${}^{127}\mathrm{In}$. The $\beta$-decaying $3/2^{+}$ and $11/2^{-}$ states in ${}^{127}\mathrm{Cd}$ have been identified with the ${}^{127}\mathrm{Cd}$ ground state and the 283-keV isomer. Their respective half-lives have been measured to $0.45{(}_8^{12})\mathrm{s}$ and 0.36(4) s. The experimentally observed $\beta$ feeding to excited states of ${}^{127}\mathrm{In}$ and the decay scheme of ${}^{127}\mathrm{In}$ are discussed in conjunction with large-scale shell-model calculations.

From lattice indications we follow a Born-Oppenheimer approximation to build a quark-antiquark static potential for $J^{PC}=1^{--}$ charmonium states below their first $S$-wave meson-meson threshold. We show that a good description of the mass and decay properties of the experimentally well established $\psi \left(4260\right)$ resonance is feasible.

In the hadrocharmonium picture a $\overline{c}c$ state and a light hadron form a bound state. The effective interaction is described in terms of the chromoelectric polarizability of the $\overline{c}c$ state and energy-momentum-tensor densities of the light hadron. This picture is justified in the heavy quark limit, and may successfully account for a hidden-charm pentaquark state recently observed by the LHCb Collaboration. In this work we extend the formalism to the description of hidden-charm tetraquarks, and address the question of whether the resonant states observed by LHCb in the $J/\psi \text{−}\varphi$ spectrum can be described as hadrocharmonia. This is a nontrivial question because nothing is known about the $\varphi$ meson energy-momentum-tensor densities. With rather general assumptions about energy-momentum-tensor densities in the $\varphi$ meson we show that a $\psi \left(2S\right)\text{−}\varphi$ bound state can exist, and we obtain a characteristic relation between its mass and width. We show that the tetraquark $X\left(4274\right)$ observed by LHCb in the $J/\psi \text{−}\varphi$ spectrum is a good candidate for a hadrocharmonium. We make predictions which will allow testing this picture. Our method can be generalized to identify other potential hadrocharmonia.

Half of the elements heavier than iron are believed to be produced through the rapid neutron-capture process ($r$ process). The astrophysical environment(s) where the $r$ process occurs remains an open question, even after recent observations of neutron-star mergers and the associated kilonova. Features in the abundance pattern of $r$-process ashes may provide critical insight for distinguishing contributions from different possible sites, including neutron-star mergers and core-collapse supernovae. In particular, the largely unknown neutron-capture reaction rates on neutron-rich unstable nuclei near ${}^{132}\mathrm{Sn}$ could have a significant impact on the final $r$-process abundances. To better determine these neutron-capture rates, the $(d,p)$ reaction has been measured in inverse kinematics using radioactive ion beams of ${}^{126}\mathrm{Sn}$ and ${}^{128}\mathrm{Sn}$ and a stable beam of ${}^{124}\mathrm{Sn}$ interacting with a ${\left({\mathrm{CD}}_2\right)}_n$ target. An array of position-sensitive silicon strip detectors, including the Super Oak Ridge Rutgers University Barrel Array, was used to detect light reaction products. In addition to the present measurements, previous measurements of ${}^{130,132}\mathrm{Sn}(d,p)$ were reanalyzed using state-of-the-art reaction theory to extract a consistent set of spectroscopic factors for $(d,p)$ reactions on even tin nuclei between the heaviest stable isotope ${}^{124}\mathrm{Sn}$ and doubly magic ${}^{132}\mathrm{Sn}$. The spectroscopic information was used to calculate direct-semidirect $(n,\gamma )$ cross sections, which will serve as important input for $r$-process abundance calculations.

We compare the predictions of the superscaling approach (SuSAv2) model including two-particle two-hole meson-exchange currents with the recent JLab data for inclusive electron scattering on three different targets (C, Ar, and Ti). The agreement is very good over the full energy spectrum, with some discrepancy seen only in the deep inelastic region. The 2p2h response, peaked in the dip region between the quasielastic and $\mathrm{\Delta }$-resonance peak, is essential to reproduce the data. We also analyze the $k_F$ (Fermi momentum) dependence of the data in terms of scaling of the second kind, showing that the 2p2h response scales very differently from the quasielastic one, in full accord with what is predicted by the model. The results represent a valuable test of the applicability of the model to neutrino scattering processes on different nuclei.

Following the first experimental observation of ${}^{93m}\mathrm{Mo}$ isomer depletion via nuclear excitation by electron capture (NEEC), we consider another experimental scenario related to the ${}^{242m}\mathrm{Am}$ isomer for which the probability of the NEEC process is expected to be even higher than for the ${}^{93m}\mathrm{Mo}$ isomer. The optimum experimental conditions for the production and depletion of the ${}^{242m}\mathrm{Am}$ isomer in a beam-based scenario are discussed. The relevant beam-target reaction cross sections have been calculated striving to ensure effective production of the ${}^{242m}\mathrm{Am}$ isomer. Kinetic energies required for the NEEC process to occur have been predicted for the $n=5$, 6, and 7 subshells of ${}^{242m}\mathrm{Am}$ ions and combined with available ion charge states at subsequent stages of the ion stopping process. The NEEC resonance strengths have been estimated for the partial contributions of individual subshells to the whole NEEC process.

The $\alpha$-clustering configurations in light nuclei have attracted a great deal of attention over past years. Nuclear reactions serve as one possible way to study this topic. The aim of this paper was to discuss whether or not heavy-ion collisions at Fermi energy could be a good tool to investigate the cluster configurations in light nuclei. In particular, ${}^{16}\mathrm{O}+{}^{197}\mathrm{Au}$ collisions are simulated using a transport model to check if any observable change is sensitive to the cluster configurations. Within an extended quantum molecular dynamics model, two different $\alpha$-clustering configurations (chain and tetrahedron) of ${}^{16}\mathrm{O}$ were employed in the initialization. ${}^{16}\mathrm{O}+{}^{197}\mathrm{Au}$ collisions at a beam energy of 40 MeV/nucleon with an impact parameter of 3 fm were simulated; then the collective flow parameters ($v_1,v_2,v_3$, and $v_4$) of free protons were analyzed as a function of both the rapidity and the transverse momentum. It was found that flow parameters ($v_1,v_2,v_3$, and $v_4$) decrease with an increase of the flow order, and that the difference in the flow parameters of free protons caused by the initial $\alpha -$clustering configurations increases with transverse momentum. In the higher transverse momentum region (0.2–0.25 GeV/$c$), these flow patterns are quite sensitive to the initial $\alpha$-clustering configurations, and can be regarded as sufficiently sensitive probes that can be used to study the clustering configurations in light nuclei.

Earlier work showed how a nucleon optical model wave function could be defined as a projection of a many-nucleon scattering state within a translationally invariant second quantized many-body theory. In this paper, an optical potential operator that generates this optical model wave function is defined through a particular off-shell extension of the elastic transition operator. The theory is expressed explicitly in terms of the many-nucleon Hamiltonian in a mixed representation in which localized target nucleus states feature. No reference to a mean-field concept is involved in the definition. It is shown that the resulting optical model operator satisfies the requirements of rotational invariance and translational invariance and has standard behavior under the time-reversal transformation. The contributions to the optical potential from two different exchange mechanisms are expressed in terms of an effective Hamiltonian involving a nucleon-number-conserving one-body interaction. In the weak-binding limit, the method reduces to a version of Feshbach's projection operator formulation of the optical potential with a truncated nucleon-nucleon potential including exchange terms and recoil corrections. Definitions of the nucleon single-particle Green's function and the corresponding Dyson self-energy modified by corrections for translational invariance are presented, and different definitions of the optical potential operator are compared.

The PHENIX collaboration has measured high-$p_T$ dihadron correlations in $p+p, p+\mathrm{Al}$, and $p+\mathrm{Au}$ collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV. The correlations arise from inter- and intrajet correlations and thus have sensitivity to nonperturbative effects in both the initial and final states. The distributions of $p_{\mathrm{out}}$, the transverse-momentum component of the associated hadron perpendicular to the trigger hadron, are sensitive to initial- and final-state transverse momenta. These distributions are measured multidifferentially as a function of $x_E$, the longitudinal momentum fraction of the associated hadron with respect to the trigger hadron. The near-side $p_{\mathrm{out}}$ widths, sensitive to fragmentation transverse momentum, show no significant broadening between $p+\mathrm{Au}, p+\mathrm{Al}$, and $p+p$. The away-side nonperturbative $p_{\mathrm{out}}$ widths are found to be broadened in $p+\mathrm{Au}$ when compared to $p+p$; however, there is no significant broadening in $p+\mathrm{Al}$ compared to $p+p$ collisions. The data also suggest that the away-side $p_{\mathrm{out}}$ broadening is a function of $N_{\mathrm{coll}}$, the number of binary nucleon-nucleon collisions, in the interaction. The potential implications of these results with regard to initial- and final-state transverse-momentum broadening and energy loss of partons in a nucleus, among other nuclear effects, are discussed.

We derive a simple formula relating the cross section for light cluster production (defined via a coalescence factor) to the two-proton correlation function measured in heavy-ion collisions. The formula generalizes earlier coalescence-correlation relations found by Scheibl & Heinz and by Mrowczynski for Gaussian source models. It motivates joint experimental analyses of Hanbury-Brown–Twiss (HBT) and cluster yield measurements in existing and future data sets.

We performed an experimental search for the bound-state singlet deuteron predicted in some microscopic calculations. The predicted energy of this metastable level is in the vicinity of the deuteron disintegration threshold. This state should manifest itself in a two-photon transition following thermal neutron capture by protons. The experiment consists in the search for the second $\gamma$ ray in the cascade through a high-statistics measurement of $\gamma$-ray spectra after cold neutron capture by hydrogen nuclei. The upper limit $2\mu \mathrm{b}(2\sigma$ level) is obtained for the cross section of the singlet deuteron production with the binding energy in the range 10–125 keV.

Structure of weakly bound/unbound light nuclei is often related to the low-energy decay channels involving composite particles like deuteron or $\alpha$ particle. These channels are essential to understand the appearance of light nuclei in the Big Bang nucleosynthesis or the helium fusion. We generalize the Gamow shell model (GSM) in coupled-channel (GSM-CC) representation to include reaction channels with the composite particles. In the core + valence particle formulation, this unified microscopic approach for structure and reactions involving weakly bound/unbound nuclei can be also applied to study low-energy properties of heavy nuclei. As the first application of this generalized GSM-CC approach, we describe the structure of ${}^6\mathrm{Li}$ and deuteron-$\alpha$-particle elastic scattering using the same effective Furutani-Horiuchi-Tamagaki (FHT)-type nucleon-nucleon interaction. Asymptotically, the deuteron structure including its continuum is described using the ${\mathrm{N}}^3\mathrm{LO}$ chiral force. The bulk of the data, including low-energy spectrum of ${}^6\mathrm{Li}$, asymptotic normalization coefficients, and angular differential cross sections are satisfactorily described.