In this paper, we address the problem of the post-prior equivalence in the calculation of inclusive breakup and transfer cross sections. For that, we employ the model proposed by Ichimura et al. [Phys. Rev. C 32, 431 (1985)], conveniently generalized to include the part of the cross section corresponding the transfer to bound states. We pay particular attention to the case in which the unobserved particle is left in a bound state of the residual nucleus, in which case the theory prescribes the use of a complex potential, responsible for the spreading width of the populated single-particle states. We see that the introduction of this complex potential gives rise to an additional term in the prior cross-section formula, not present in the usual case of real binding potentials. The equivalence is numerically tested for the ${}^{58}\mathrm{Ni}\left(d,pX\right)$ reaction.

The ultracold neutron (UCN) source at Los Alamos National Laboratory (LANL), which uses solid deuterium as the UCN converter and is driven by accelerator spallation neutrons, has been successfully operated for over 10 years, providing UCN to various experiments, as the first production UCN source based on the superthermal process. It has recently undergone a major upgrade. This paper describes the design and performance of the upgraded LANL UCN source. Measurements of the cold neutron spectrum and UCN density are presented and compared to Monte Carlo predictions. The source is shown to perform as modeled. The UCN density measured at the exit of the biological shield was $184\left(32\right) \mathrm{UCN}/{\mathrm{cm}}^3$, a fourfold increase from the highest previously reported. The polarized UCN density stored in an external chamber was measured to be $39\left(7\right) \mathrm{UCN}/{\mathrm{cm}}^3$, which is sufficient to perform an experiment to search for the nonzero neutron electric dipole moment with a one-standard-deviation sensitivity of $\sigma \left(d_n\right)=3\times {10}^{-27}e\mathrm{cm}$.

Excited states of the ${}^{64}\mathrm{Cu}(Z=29,N=35)$ nucleus have been probed using heavy-ion-induced fusion evaporation reaction and an array of Compton-suppressed Clovers as detection system for the emitted $\gamma$ rays. More than 50 new transitions have been identified and the level scheme of the nucleus has been established up to an excitation energy $E_x\sim 6$ MeV and spin $\sim 10\hslash$. The experimental results have been compared with those from large-basis shell-model calculations that facilitated an understanding of the single-particle configurations underlying the level structure of the nucleus.

The properties of neutron stars with the strangeness degree of freedom are studied in the relativistic mean-field (RMF) model via including a logarithmic interaction as a function of the scalar meson field. This interaction, named the $\sigma$-cut potential, can largely reduce the attractive contributions of the scalar meson field at high density without any influence on the properties of nuclear structure around the normal saturation density. In this work, the TM1 parameter set is chosen as the RMF interaction, while the strengths of $\sigma$-cut potential are constrained by the properties of finite nuclei so that we can obtain a reasonable effective nucleon-nucleon interaction. The hyperons $\mathrm{\Lambda },\mathrm{\Sigma }$, and $\mathrm{\Xi }$ are considered in neutron stars within this framework, whose coupling constants with mesons are determined by the latest hyperon-nucleon and $\mathrm{\Lambda }-\mathrm{\Lambda }$ potentials extracted from the available experimental data of hypernuclei. The maximum mass of neutron star can be larger than $2M_{\odot }$ with these hyperons in the present framework. Furthermore, the nucleon mass at high density will be saturated due to this additional $\sigma$-cut potential, which is consistent with the conclusions obtained by other calculations such as Brueckner-Hartree-Fock theory and quark mean-field model.

Proofs are given of exact analytical solutions for general principal value integrations of the dispersion relations of $pp$ and $p\overline{p}$ scattering amplitudes. The proofs are based on recent developments in the study of properties of the Lerch's transcendent of the mathematical literature. Dispersion relations for the slopes of the amplitudes are mathematically defined and also solved exactly. The results are explicitly expanded, providing an important basis for improvement in the phenomenology of the hadronic interactions.

The probable cluster radioactivity (CR) of ${}^{294}118$, ${}^{296}120$, and ${}^{298}122$ is studied by using the unified description (UD) formula, universal (UNIV) curve, Horoi formula, and universal decay law (UDL). The predictions by the former three models suggest that the probable emitted clusters are lighter nuclei, and the calculations within the UDL formula give a different prediction: that both the lighter clusters and heavier ones can be emitted from the parent nuclei. A further study on the competition between $\alpha$ decay and CR of $Z=104–124$ isotopes is performed. The former three models predict that $\alpha$ decay is the dominant decay mode, but the UDL formula suggests that CR dominates over $\alpha$ decay for $Z\ge 118$ nuclei and the isotopes of ${}^{292\text{–}296,308\text{–}318}118$, ${}^{284\text{–}304,308\text{–}324}120,$ and ${}^{316\text{–}322}122$ are the most likely candidates as the cluster emitters. Because the former three formulas are just preformation models, the lighter cluster emissions can be described. However, the UDL formula can predict the lighter and heavier CR owing to the inclusion of the preformation and fissionlike mechanisms. Finally, it is found that the shortest CR half-lives are always obtained when the daughter nuclei are around the double magic ${}^{208}\mathrm{Pb}$ within the UDL formula, which indicates that shell effect has an important influence on CR.

The cumulative yields of various fission products within the 77–153 mass regions in the 2.5-GeV bremsstrahlung-induced fission of ${}^{232}\mathrm{Th}$ have been determined by using the recoil catcher and an off-line γ-ray spectrometric technique at the Pohang Accelerator Laboratory, Korea. The mass-yield distributions were obtained from the cumulative yields after charge-distribution corrections. The peak-to-valley ($\mathrm{P}/\mathrm{V}$) ratio, the average value of light mass ($\langle A_L\rangle$) and heavy mass ($\langle A_H\rangle$), and the average postfission number of neutrons (${\langle v\rangle }_{\mathrm{expt}}$) were obtained from the mass yield of the ${}^{232}\mathrm{Th}(\gamma ,f)$ reaction. The present and literature data in the ${}^{232}\mathrm{Th}(\gamma ,f)$ reaction were compared with the similar data in the ${}^{238}\mathrm{U}(\gamma ,f)$ reaction at various excitation energies to examine the role of potential energy surface and the effect of standard I and standard II asymmetric modes of fission. It was found that (i) even at the bremsstrahlung end-point energy of 2.5 GeV, the mass-yield distribution in the ${}^{232}\mathrm{Th}(\gamma ,f)$ reaction is triple humped, unlike ${}^{238}\mathrm{U}(\gamma ,f)$ reaction, where it is double humped. (ii) The peak-to-valley ($\mathrm{P}/\mathrm{V}$) ratio decreases with the increase of excitation energies. However, the $\mathrm{P}/\mathrm{V}$ ratio of the ${}^{232}\mathrm{Th}(\gamma ,f)$ reaction is always lower than that of the ${}^{238}\mathrm{U}(\gamma ,f)$ reaction due to the presence of a third peak in the former. (iii) In both the ${}^{232}\mathrm{Th}(\gamma ,f)$ and ${}^{238}\mathrm{U}(\gamma ,f)$ reactions, the nuclear structure effect almost vanishes at the bremsstrahlung end-point energies of 2.5–3.5 GeV.

A new global phenomenological optical model potential for the ${}^7\mathrm{Li}$ projectile is derived from the available experimental data of elastic-scattering angular distributions and reaction cross sections from ${}^{27}\mathrm{Al}$ to ${}^{208}\mathrm{Pb}$ with incident energies below 200 MeV. It is based on a smooth, unique functional form for the energy dependence of the potential depths, and physically constrained geometry parameters. The elastic-scattering angular distributions and reaction cross sections for other targets are also predicted by the obtained ${}^7\mathrm{Li}$ global phenomenological optical model potential at different incident energies. These results are further compared with the corresponding experimental data. The performance shows that the ${}^7\mathrm{Li}$ global phenomenological optical model potential can give a satisfactory description for ${}^7\mathrm{Li}$ elastic scattering.

In this article, a mistake in the formulation of the modified Fisher model (MFM) derived in the pioneering works of the Purdue group is addressed and corrected by reversing the sign of the mixing entropy term in the original formulation. The errors in the results of the previous MFM-related studies, such as isotopic yield distribution, isobaric yield ratios, isoscaling, $m$ scaling, self-consistent determination of density, symmetry energy, and temperature, and density and temperature determination related to the intermediate mass fragment (IMF) freezeout, are quantitatively analyzed. It is found that the errors originating from the mistake in sign of the mixing entropy term are generally small and even have no effect in some cases.

We calculate the dissociation and recombination rates of $\mathrm{{\rm Y}}\left(1S\right)$ in quark-gluon plasma by using potential nonrelativistic QCD. We then study the dynamical in-medium evolution of the $b\overline{b}-\mathrm{{\rm Y}}$ system in a periodic box via the Boltzmann equation and explore how the system reaches equilibrium. We find that interactions between the free heavy quarks and the medium are necessary for the system to reach equilibrium. We find that the angular distribution of $\mathrm{{\rm Y}}\left(1S\right)$ probes the stages at which recombination occurs. Finally, we study the system under a longitudinal expansion and show that different initial conditions evolve to distinct final ratios of hidden and open $b$ flavors. We argue that experimental measurements of the ratio could address open questions in the quarkonium production in heavy ion collisions.

We present a quantitative analysis of superfluidity and superconductivity in dense matter from observations of isolated neutron stars in the context of the minimal cooling model. Our new approach produces the best fit neutron triplet superfluid critical temperature, the best fit proton singlet superconducting critical temperature, and their associated statistical uncertainties. We find that the neutron triplet critical temperature is likely $2.{09}_{-1.41}^{+4.37}\times {10}^8$ K and that the proton singlet critical temperature is $7.{59}_{-5.81}^{+2.48}\times {10}^9$ K. However, we also show that this result only holds if the Vela neutron star is not included in the data set. If Vela is included, the gaps increase significantly to attempt to reproduce Vela's lower temperature given its young age. Further including neutron stars believed to have carbon atmospheres increases the neutron critical temperature and decreases the proton critical temperature. Our method demonstrates that continued observations of isolated neutron stars can quantitatively constrain the nature of superfluidity in dense matter.

This paper reports the first observation of the Jacobi shape transition in ${}^{31}\mathrm{P}$ using high energy $\gamma$ rays from the decay of giant dipole resonance (GDR) as a probe. The measured GDR spectrum in the decay of ${}^{31}\mathrm{P}$ shows a distinct low energy component around 10 MeV, which is a clear signature of Coriolis splitting in a highly deformed rotating nucleus. Interestingly, a self-conjugate $\alpha$-cluster nucleus ${}^{28}\mathrm{Si}$, populated at similar initial excitation energy and angular momentum, exhibits a vastly different GDR lineshape. Even though the angular momentum of the compound nucleus ${}^{28}\mathrm{Si}$ is higher than the critical angular momentum required for the Jacobi shape transition, the GDR lineshape is akin to a prolate deformed nucleus. Considering the present results for ${}^{28}\mathrm{Si}$ and similar observation recently reported in ${}^{32}\mathrm{S}$, it is proposed that the nuclear orbiting phenomenon exhibited by $\alpha$-cluster nuclei hinders the Jacobi shape transition. The present experimental results suggest a possibility to investigate the nuclear orbiting phenomenon using high energy $\gamma$ rays as a probe.

We use microscopic ${}^9\mathrm{Be}$ wave functions defined in a $\alpha +\alpha +n$ multicluster model to compute ${}^9\mathrm{Be}$+target scattering cross sections. The parameter sets describing ${}^9\mathrm{Be}$ are generated in the spirit of the stochastic variational method, and the optimal solution is obtained by superposing Slater determinants and by diagonalizing the Hamiltonian. The ${}^9\mathrm{Be}$ three-body continuum is approximated by square-integral wave functions. The ${}^9\mathrm{Be}$ microscopic wave functions are then used in a continuum-discretized coupled-channel (CDCC) calculation of ${}^9\mathrm{Be}+{}^{208}\mathrm{Pb}$ and of ${}^9\mathrm{Be}+{}^{27}\mathrm{Al}$ elastic scattering. Without any parameter fitting, we obtain a fair agreement with experiment. For a heavy target, the influence of ${}^9\mathrm{Be}$ breakup is important, while it is weaker for light targets. This result confirms previous nonmicroscopic CDCC calculations. One of the main advantages of the microscopic CDCC is that it is based on nucleon-target interactions only; there is no adjustable parameter. The present work represents a first step towards more ambitious calculations involving heavier Be isotopes.

By applying a Bayesian model-to-data analysis, we estimate the temperature and momentum dependence of the heavy quark diffusion coefficient in an improved Langevin framework. The posterior range of the diffusion coefficient is obtained by performing a Markov chain Monte Carlo random walk and calibrating on the experimental data of $D$-meson $R_{\mathrm{AA}}$ and $v_2$ in three different collision systems at the Relativistic Heavy-Ion Collidaer (RHIC) and the Large Hadron Collider (LHC): Au-Au collisions at 200 GeV and Pb-Pb collisions at 2.76 and 5.02 TeV. The spatial diffusion coefficient is found to be consistent with lattice QCD calculations and comparable with other models' estimation. We demonstrate the capability of our improved Langevin model to simultaneously describe the $R_{\mathrm{AA}}$ and $v_2$ at both RHIC and the LHC energies, as well as the higher order flow coefficient such as $D$ meson $v_3$. We show that by applying a Bayesian analysis, we are able to quantitatively and systematically study the heavy flavor dynamics in heavy-ion collisions.

We develop a formalism for calculating the distribution of the axial quadrupole operator in the laboratory frame within the rotationally invariant framework of the configuration-interaction shell model. The calculation is carried out using a finite-temperature auxiliary-field quantum Monte Carlo method. We apply this formalism to isotope chains of even-mass samarium and neodymium nuclei and show that the quadrupole distribution provides a model-independent signature of nuclear deformation. Two technical advances are described that greatly facilitate the calculations. The first is to exploit the rotational invariance of the underlying Hamiltonian to reduce the statistical fluctuations in the Monte Carlo calculations. The second is to determine quadruple invariants from the distribution of the axial quadrupole operator in the laboratory frame. This allows us to extract effective values of the intrinsic quadrupole shape parameters without invoking an intrinsic frame or a mean-field approximation.

The $\alpha$-decay half-lives of superheavy nuclei (SHN) with $Z\ge 104$ are investigated by employing the effective liquid drop model (ELDM). By comparison between the calculated half-lives and the experimental ones, it is shown that the ELDM is a successful model to reproduce the experimental half-lives of SHN. Within the ELDM the $\alpha$-decay half-lives of $Z=118\text{–}120$ isotopes are predicted by inputting the $\alpha$-decay energy ($Q_{\alpha }$) values extracted from the newest Weizsäcker-Skyrme-4 (WS4) model, the finite-range droplet model (FRDM), the Kourra-Tachibaba-Uno-Yamada (KTUY) formula, and the Hartree-Fock-Bogoliubov mean field with the D1S Gogny force (GHFB). It is found that the shell effects at $N=178$ and 184 are evident by analyzing the $Q_{\alpha }$ values and half-lives versus the neutron number $N$. Because the WS4 $Q_{\alpha }$ values have the smallest rms deviation, the predicted $\alpha$-decay half-lives could be more accurate than the ones of other models, which will be helpful for future experiments.

The measurement of one-neutron stripping cross sections for the ${}^{89}\mathrm{Y}\left({}^6\mathrm{Li},{}^5\mathrm{Li}\right){}^{90}\mathrm{Y}^{*}$ reaction at 22 MeV and 34 MeV is reported, using both in-beam and off-beam $\gamma$-ray spectroscopy methods. Characteristic $\gamma$ lines of ${}^{90}\mathrm{Y}$ are clearly identified by both the $\gamma \text{−}\gamma$ and proton-$\gamma$ coincidence methods. The obtained cross section of one-neutron stripping at 34 MeV is found to be much smaller than that at 22 MeV. The one-neutron stripping cross sections measured for this system have the same order of magnitude as the one measured for the same reaction for the ${}^6\mathrm{Li}+{}^{96}\mathrm{Zr}$ system at energies around the Coulomb barrier. Parameter-free coupled reaction channel calculations agree quite well with the experimental data. Theoretical study of the effect of the one-neutron transfer on the elastic total fusion cross section is performed.

The nucleon-nucleon $J$-matrix inverse scattering potential JISP16 is applied to elastic nucleon-deuteron scattering and the deuteron breakup process at the laboratory nucleon energies up to 135 MeV. The formalism of the Faddeev equations is used to obtain three-nucleon scattering states. We compare predictions based on the JISP16 force with data and with results based on various two-body interactions, including the CD Bonn, the Argonne AV18, the chiral force with the semilocal regularization at the fifth order of the chiral expansion and with low-momentum interactions obtained from the CD Bonn force as well as with the predictions from the combination of the AV18 $\mathit{NN}$ interaction and the Urbana IX $3N$ force. JISP16 provides a satisfactory description of some observables at low energies but strong deviations from data as well as from standard and chiral potential predictions with increasing energy. However, there are also polarization observables at low energies for which the JISP16 predictions differ from those based on the other forces by a factor of two. The reason for such a behavior can be traced back to the $P$-wave components of the JISP16 force. At higher energies the deviations can be enhanced by an interference with higher partial waves and by the properties of the JISP16 deuteron wave function. In addition, we compare the energy and angular dependence of predictions based on the JISP16 force with the results of the low-momentum interactions obtained with different values of the momentum cutoff parameter. We found that such low-momentum forces can be employed to interpret the nucleon-deuteron elastic scattering data only below some specific energy which depends on the cutoff parameter. Since JISP16 is defined in a finite oscillator basis, it has properties similar to low momentum interactions and its application to the description of nucleon-deuteron scattering data is limited to a low momentum transfer region.