We predict a new three-body hadronic molecule composed of antikaon $\overline{K}$, anticharm meson $\overline{D}$, and nucleon $N$ with spin-parity $J^P=1/2^{+}$ and isospin $I=1/2$. This state behaves like an explicit pentaquark state because its minimal quark configuration is $uuds\overline{c}$ or $udds\overline{c}$. Owing to the attraction between every pair of two hadrons, in particular the $\overline{K}\overline{D}$ attraction which dynamically generates $D_{s0}{\left(2317\right)}^{-}$ and $\overline{K}N$ attraction which dynamically generates $\mathrm{\Lambda }\left(1405\right)$, the $\overline{K}\overline{D}N$ system is bound, and the real (imaginary) part of its eigenenergy is calculated as $3253\text{MeV}$ (minus a few MeV) in a nonrelativistic three-body potential model. We discuss properties of this $\overline{K}\overline{D}N$ quasibound state which emerge uniquely in three-body dynamics.

Background: The understanding and description of forbidden decays provides interesting challenges for nuclear theory. These calculations could help to test underlying nuclear models and interpret experimental data.

Purpose: Compare a direct measurement of the ${}^{138}\mathrm{La}\beta$-decay $Q$ value with the $\beta$-decay spectrum end-point energy measured by Quarati et al. using ${\mathrm{LaBr}}_3$ detectors [Appl. Radiat. Isot. 108, 30 (2016)]. Use new precise measurements of the ${}^{138}\mathrm{La}\beta$-decay and electron capture (EC) $Q$ values to improve theoretical calculations of the $\beta$-decay spectrum and EC probabilities.

Method: High-precision Penning trap mass spectrometry was used to measure cyclotron frequency ratios of ${}^{138}\mathrm{La}$, ${}^{138}\mathrm{Ce}$, and ${}^{138}\mathrm{Ba}$ ions from which $\beta$-decay and EC $Q$ values for ${}^{138}\mathrm{La}$ were obtained.

Results: The ${}^{138}\mathrm{La}\beta$-decay and EC $Q$ values were measured to be $Q_{\beta }=1052.42\left(41\right)$ keV and $Q_{\mathrm{EC}}=1748.41\left(34\right)$ keV, improving the precision compared to the values obtained in the most recent atomic mass evaluation [Wang et al., Chin. Phys. C 41, 030003 (2017)] by an order of magnitude. These results are used for improved calculations of the ${}^{138}\mathrm{La}\beta$-decay shape factor and EC probabilities. New determinations for the ${}^{138}\mathrm{Ce}$ 2EC $Q$ value and the atomic masses of ${}^{138}\mathrm{La}$, ${}^{138}\mathrm{Ce}$, and ${}^{138}\mathrm{Ba}$ are also reported.

Conclusion: The ${}^{138}\mathrm{La}\beta$-decay $Q$ value measured by Quarati et al. is in excellent agreement with our new result, which is an order of magnitude more precise. Uncertainties in the shape factor calculations for ${}^{138}\mathrm{La}\beta$ decay using our new $Q$ value are reduced by an order of magnitude. Uncertainties in the EC probability ratios are also reduced and show improved agreement with experimental data.

The nuclear scattering at energies well above the Coulomb barrier allows for a fairly sensitive examination of the parameters of the optical potential when the relevant couplings are included into the calculations. In this work we present experimental angular distribution data for the elastic and inelastic scatterings of ${}^{16}\mathrm{O}$ impinging on ${}^{27}\mathrm{Al}$ and ${}^{28}\mathrm{Si}$ target nuclei at $E_{\mathrm{lab}}=240\mathrm{MeV}$. The experimental data were measured at $7^{°}<{\theta }_{\text{c.m.}}<{16}^{°}$ with good angular resolution. Experimental data are compared with coupled channel calculations with the inclusion of couplings to excited states in the target and projectile. We show that the shape of angular distributions are sensitive to the mass diffuseness parameter and the best agreement is achieved for $a=0.62\mathrm{fm}$.

Background: Measurements of two-particle azimuthal angle correlations are a useful tool to study the distribution of jet energy loss; however, they are complicated because of the significant anisotropic flow background.

Purpose: We devise a data-driven method for subtracting anisotropic flow background in jet-like correlation analysis.

Method: We first require a large recoil momentum $\left(P_x\right)$ within a given pseudorapidity $\left(\eta \right)$ range from a high-transverse momentum particle to enhance in-acceptance population of away-side jet-like correlations. Then we take the difference of two-particle correlations in the close region and far region with respect to the $\eta$ region of $P_x$ to subtract the anisotropic flow background.

Results: We use a toy model which contains only anisotropic flow and pythia8 which has jets, to demonstrate the validity of our data-driven method.

Conclusions: The results indicate that the data-driven method can subtract anisotropic flow effectively.

Particle oscillations in absorbing matter are considered. The approach based on the optical potential is shown to be inapplicable in the strong absorption region. Models with Hermitian Hamiltonian are analyzed. They give an increase of the process width in comparison with the model based on the optical potential.

The spin and parity of the 3.004-MeV level in ${}^{27}\mathrm{Al}$ have been determined by measuring the angular correlation function of radiation emitted from levels populated by resonant absorption of polarized photons. The nuclear resonance fluorescence experiments were carried out at the High Intensity $\gamma$-ray Source ($\mathrm{HI}\gamma \mathrm{S}$) facility at Duke University using quasimonoenergetic linearly polarized photon beams. The spin and parity of levels in ${}^{27}\mathrm{Al}$ were deduced from a comparison of the measured angular distribution ratios and azimuthal intensity asymmetries with theoretical predictions. The observed resonance properties were compared with shell model calculations using the universal $sd$ interaction. Monte Carlo shell model calculations were also performed to investigate the low-energy structure of ${}^{27}\mathrm{Al}$.

Background: The phenomenological optical model has been extensively used to study the nucleon-nucleus scattering process. However, its use in describing the observables for nucleon scattering off light $1p$-shell nuclei has been somewhat limited and less successful. This is a result of their diffuse edges and deformations that complicate fitting the experimental data. Therefore, global optical models usually exclude light nuclei and only consider intermediate and heavy nuclei with mass number $A\ge 24$.

Purpose: We test the effectiveness of a semimicroscopic optical model with channel coupling in describing observables for neutron scattering off nuclei covering a wide mass range from ${}^{12}\mathrm{C}$ to ${}^{208}\mathrm{Pb}$ corresponding to neutron incident energies in the range $E=10–30\mathrm{MeV}$.

Method: The real central part of the optical model is constructed by single folding the density-independent M3Y-Paris bare nucleon-nucleon interaction over the density of the target nucleus. The rest of the potential terms are of Woods-Saxon form or its derivative. The potential parameters are determined by fitting the elastic and inelastic angular distributions in addition to polarization data for neutron scattering from ${}^{12}\mathrm{C}, {}^{16}\mathrm{O}, {}^{54}\mathrm{Fe}, {}^{58}\mathrm{Ni}, {}^{120}\mathrm{Sn}$, and ${}^{208}\mathrm{Pb}$. In doing so the ground state is coupled to few, low-lying rotational and vibrational excitation channels.

Results: Despite considering a wide mass range of nuclei, the model resulted in good descriptions for the elastic data and, at least, the overall features of the inelastic angular distributions and polarization data are reproduced. Our potential depths are expressed as linear functions of energy while, for each target nucleus, the geometric parameters are fixed. This is unlike purely phenomenological optical models which, in many cases, resulted in best-fit parameters that show unclear energy-dependence trends. In addition, the total cross sections predicted using our parameters are in good overall agreement with experiment.

Conclusions: The semimicroscopic model based on the M3Y-Paris bare $NN$ interaction succeeded in, at least, reproducing the overall features of the inelastic experimental data. However, the predicted elastic angular distributions are in good agreement with experiment and progressively improved with increasing mass number of the target. Furthermore, the weak energy dependence, introduced into the M3Y-Paris interaction via the knock-on exchange term, led to improving our data fits. Finally, other density-dependent bare $NN$ interactions resulted in potential parameters that showed less systematic behaviors with energy.

We calculate the gravitational form factors of the pion, $\sigma$ meson, and $\rho$ meson in the Nambu–Jona-Lasinio model of quantum chromodynamics. The canonical energy-momentum tensor (EMT) is used in their derivation, allowing the possibility of an antisymmetric contribution when the hadron has intrinsic spin. We show that the asymmetric graviton vertex arising from the canonical EMT satisfies a simpler Ward-Takahashi identity (WTI) than the symmetric graviton vertex of the Belinfante EMT. The necessity of fully dressing the graviton vertex through the relevant Bethe-Salpeter equation is demonstrated for observing both the WTI and a low-energy pion theorem. Lastly, we calculate static moments of the meson EMT decompositions, obtaining predictions for the meson mass radii. We find light cone mass radii of 0.27 fm for the pion, 0.32 fm for the $\sigma$, and 0.32 fm for the $\rho$. For the pion and $\rho$, these are smaller than the light cone charge radii, respectively 0.51 fm and 0.45 fm, while we have a $\sigma$ charge radius of zero. Our light cone pion mass radius agrees with a phenomenological extraction from KEKB data.

In this study, we derive the magnetized Taub adiabat (TA) equation from the hydrodynamic conservation conditions. For the conversion of one phase to other the combustion adiabat (CA) equation is the same as the TA equation, only the equation of state (EoS) of the upstream phase is different from that of the EoS of the downstream phase. We employ the magnetized CA equations to study the evolution of a magnetized neutron star to a magnetized quark star. The pressure of the burnt quark matter has a maximum, which indicates a bound on the maximum mass of the quark star. The central density of the neutron star and the angle between the rotation axis and the magnetic axis (defined as the tilt angle) are seen to be significant in determining the magnetic field, and the tilt of the quark star. The magnetic field and the tilt of the quark star can have important observational significance and can help in understanding the physics at high density and strong magnetic field.

In order to study the nucleon-nucleon pairing effects in clustering nuclei, we formulate a superposed Tohsaki-Horiuchi-Schuck-Röpke (THSR) wave function, which includes both molecular-orbit and pairing configurations explicitly. With this new wave function, we investigate the anomalous deuteronlike $pn$-pairing effect in ${}^{10}\mathrm{B}$ with $T=0$ and $S=1$ (isoscalar) by comparing with isovector $NN$ pairs $\left(T=1,S=0\right)$ in ${}^{10}\mathrm{Be}$ and ${}^{10}\mathrm{C}$. Energies are calculated for the ground states of ${}^{10}\mathrm{Be},{}^{10}\mathrm{B}$ and ${}^{10}\mathrm{C}$ nuclei, and the $1_1^{+}0$ excited state of ${}^{10}\mathrm{B}$. These energies are essentially improved comparing with studies using a previous version of THSR wave function. Furthermore, overlaps between the total wave function and the pairing component indicate that the $NN$ pairing effect is more visible in ${}^{10}\mathrm{B}$ than in ${}^{10}\mathrm{Be}$ and ${}^{10}\mathrm{C}$. By analyzing the energies and the overlaps between wave function components, we observe two different mechanisms enhancing the formation of deuteronlike pairs in ${}^{10}\mathrm{B}$. We also discuss the pairing effect by showing average distances between components in each nucleus and density distributions of valence nucleons.

Cold gas experiments can be tuned to achieve strongly-interacting regimes such as that of low-density neutron matter found in neutron-stars' crusts. We report $T=0$ diffusion Monte Carlo results (i) for the ground state of both spin-1/2 fermions with short-range interactions and low-density neutron matter in a cylindrical container, and (ii) properties of these systems with a vortex line excitation. We calculate the equation of state for cold atoms and low-density neutron matter in the bulk systems, and we contrast it to our results in the cylindrical container. We compute the vortex line excitation energy for different interaction strengths, and we find agreement between cold gases and neutron matter for very low densities. We also calculate density profiles, which allow us to determine the density depletion at the vortex core, which depends strongly on the short-ranged interaction in cold atomic gases, but it is of $\approx 25\%$ for neutron matter in the density regimes studied in this work. Our results can be used to constrain neutron matter properties by using measurements from cold Fermi gases experiments.

We present a study of the skewness of nuclear matter, which is proportional to the third derivative of the energy per nucleon with respect to the baryon density at the saturation point, in the framework of the Landau-Migdal theory. We derive an exact relation between the skewness, the nucleon effective mass, and two-particle and three-particle interaction parameters. We also present qualitative estimates, which indicate that three-particle correlations play an important role for the skewness.

The masses of ${}^{34}\mathrm{Si}$, ${}^{33,34}\mathrm{Mg}$, and ${}^{34}\mathrm{Al}$ have been measured with the ISOLTRAP Penning-trap spectrometer at ISOLDE/CERN. The results are in agreement with previous mass measurements and uncertainties have been decreased. The mass of ${}^{34}\mathrm{Al}$ was determined in two configurations, one following direct production by the ISOLDE facility, favoring the $4^{-}$ state, expected to be the ground state, second by in-trap decay of ${}^{34}\mathrm{Mg}$, followed by recoil-ion trapping, favoring the production of the isomeric $1^{+}$ state. A position-sensitive detector was used to clean the ToF-ICR resonance. In addition, the mass of the refractory doubly magic ${}^{34}\mathrm{Si}$ nucleus was directly measured, using the in-trap decay of ${}^{34}\mathrm{Mg}$, following two sequential recoil-ion captures. The approach, challenges and conclusions are discussed.

The new nuclides ${}^{165}\mathrm{Pt}$ and ${}^{170}\mathrm{Hg}$ were produced in the reactions ${}^{92}\mathrm{Mo}({}^{78}\mathrm{Kr},5n)$ and ${}^{96}\mathrm{Ru}({}^{78}\mathrm{Kr},4n)$ at bombarding energies of 418 MeV and 390 MeV, respectively. For ${}^{170}\mathrm{Hg}$ an $\alpha$-particle energy of $E_{\alpha }=7590\left(30\right)\mathrm{keV}$ and half-life of $t_{1/2}=0.{08}_{-0.04}^{+0.40}\mathrm{ms}$ were deduced, while for ${}^{165}\mathrm{Pt}$ the corresponding values were 7272(14) keV and $0.{26}_{-0.09}^{+0.26}\mathrm{ms}$. Comparison of the reduced $\alpha$-decay widths with systematics indicates that both $\alpha$ decays are unhindered. Although combining the measured $\alpha$-decay $Q$ values with extrapolated masses suggests that both new nuclides are unbound to two-proton emission by more than 1 MeV, their $\alpha$-decay half-lives are too short for this decay mode to compete. Improved data were also obtained for ${}^{166,167}\mathrm{Pt}$, produced via the ${}^{96}\mathrm{Ru}({}^{78}\mathrm{Kr},\alpha 4n)$ and ${}^{96}\mathrm{Ru}({}^{78}\mathrm{Kr},\alpha 3n)$ reactions at bombarding energies of 390 MeV and 418 MeV.

We formulate microscopic optical potentials for nucleon-nucleus scattering from chiral two- and three-nucleon forces. The real and imaginary central terms of the optical potentials are obtained from the nucleon self-energy in infinite nuclear matter at a given density and isospin asymmetry, calculated self-consistently to second order in many-body perturbation theory. The real spin-orbit term is extracted from the same chiral potential using an improved density matrix expansion. The density-dependent optical potential is then folded with the nuclear density distributions of ${}^{40,42,44,48}\mathrm{Ca}$ from which we study proton-nucleus elastic scattering and total reaction cross sections using the reaction code talys. We compare the results of the microscopic calculations to those of phenomenological models and experimental data up to projectile energies of $E=180$ MeV. While overall satisfactory agreement with the available experimental data is obtained, we find that the elastic scattering and total reaction cross sections can be significantly improved with a weaker imaginary optical potential, particularly for larger projectile energies.

Background: A diversity of fragmentation modes has been observed in several types of nuclear reactions, which may correspond to different breakup mechanisms.

Purpose: The present work is an attempt to compare the mechanisms of the fragment emission in central heavy-ion collision near the Fermi energy, projectile fragmentation, and proton-induced spallation.

Method: The collisions until the prefragments with excitation energy less than 2 MeV/nucleon are studied using the isospin-dependent quantum molecular dynamics (IQMD) model, while the evaporations of light particles from the prefragments are described by the statistical code gemini. In the IQMD model, the binary nucleon-nucleon collisions with the Pauli blocking are applied to treat some features of fermionic motion phenomenologically. However, the binary collisions are scarce in the region where the relative momenta between the nucleons are small. Thus, the method of the phase space density constraint (PSDC) are applied in the IQMD model in order to treat phenomenologically the features of fermionic motion.

Results: The calculations of various observables are compared to the available data. The comparison not only shows the similar regularities of the calculations to the data, but also emphasizes the role of the PSDC method. The dynamical $E-\rho$ trajectories show that the compression-expansion phase in the central HIC near the Fermi energy results in the spinodal decomposition. While in the projectile fragmentation and proton-induced spallation, the projectiles are heated without compression and then cool down with slight expansion. However, driven by the dynamical fluctuations, the spinodal instability is possible for a part of the events. The perhaps most important result of this study is the significant role of the fermionic feature in the mechanisms of the fragment emission.

Conclusions: The $\mathrm{IQMD}+\mathrm{GEMINI}$ framework provides a uniform description of breakup mechanisms in central collision, projectile fragmentation, and proton-induced spallation.

The quark matter created in relativistic nuclear collisions is interpreted as a nearly perfect fluid. The recent efforts to explore its finite-density properties in the beam energy scan programs motivate one to revisit the issue of the local rest frame fixing in off-equilibrium hydrodynamics. I first investigate full second-order relativistic hydrodynamics in the Landau and the Eckart frames. Then numerical hydrodynamic simulations are performed to elucidate the effect of frame choice on flow observables in relativistic nuclear collisions. The results indicate that the flow can differ in the Landau and the Eckart frames but charged particle and net baryon rapidity distributions are mostly frame independent when off-equilibrium kinetic freeze-out is considered.

We report the first measurements of a complete second-order cumulant matrix of net-charge, net-proton, and net-kaon multiplicity distributions for the first phase of the beam energy scan program at the Relativistic Heavy Ion Collider. This includes the centrality and, for the first time, the pseudorapidity window dependence of both diagonal and off-diagonal cumulants in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}$= 7.7–200 GeV. Within the available acceptance of $\left|\eta \right|<0.5$, the cumulants grow linearly with the pseudorapidity window. Relative to the corresponding measurements in peripheral collisions, the ratio of off-diagonal over diagonal cumulants in central collisions indicates an excess correlation between net-charge and net-kaon, as well as between net-charge and net-proton. The strength of such excess correlation increases with the collision energy. The correlation between net-proton and net-kaon multiplicity distributions is observed to be negative at $\sqrt{s_{NN}}$= 200 GeV and change to positive at the lowest collision energy. Model calculations based on nonthermal (UrQMD) and thermal (HRG) production of hadrons cannot explain the data. These measurements will help map the quantum chromodynamics phase diagram, constrain hadron resonance gas model calculations and provide new insights on the energy dependence of baryon-strangeness correlations.

In the $\mathrm{UCN}\tau$ experiment, ultracold neutrons (UCN) are confined by magnetic fields and the Earth's gravitational field. Field-trapping mitigates the problem of UCN loss on material surfaces, which caused the largest correction in prior neutron experiments using material bottles. However, the neutron dynamics in field traps differ qualitatively from those in material bottles. In the latter case, neutrons bounce off material surfaces with significant diffusivity and the population quickly reaches a static spatial distribution with a density gradient induced by the gravitational potential. In contrast, the field-confined UCN—whose dynamics can be described by Hamiltonian mechanics—do not exhibit the stochastic behaviors typical of an ideal gas model as observed in material bottles. In this report, we will describe our efforts to simulate UCN trapping in the $\mathrm{UCN}\tau$ magnetogravitational trap. We compare the simulation output to the experimental results to determine the parameters of the neutron detector and the input neutron distribution. The tuned model is then used to understand the phase-space evolution of neutrons observed in the $\mathrm{UCN}\tau$ experiment. We will discuss the implications of chaotic dynamics on controlling the systematic effects, such as spectral cleaning and microphonic heating, for a successful UCN lifetime experiment to reach a 0.01% level of precision.