Color flux tubes are a standard perspective from which to understand stopping in high-energy collisions. Mechanisms for baryon transport and polarization within a tube are considered here, both in regards to the transport of baryons from the target and projectile toward midrapidity and in regards to the correlations of baryon-antibaryon pairs created in the tube. The roles of tube merging and gluon radiation within a tube are emphasized.

The longitudinal ternary fission is studied using the generalized liquid drop model. The proximity energy and the charge and mass asymmetries are taken into account. Spherical parent and daughter nuclei are considered. The shape sequence selected to simulate the quasimolecular three-body shapes is built from different but connected elliptic half lemniscatoids. The potential barriers are much lower when the central fragment is the smallest one and particularly when it is an $\alpha$ particle. The $2\alpha$ emission can be described as a particular prolate fission with emission of two particles at the tips of the deformed nucleus. The associated potential barriers are high and thin.

Background:The accumulation of experimental data on $\mathrm{\Xi }$ hypernuclei has enabled testing the $\mathrm{\Xi }N$ interactions derived from first-principles lattice QCD simulations through many-body calculations.

Purpose:Based on the interactions derived from lattice QCD simulations, we calculate the spectrum of the ${}^{14}\mathrm{N}+{\mathrm{\Xi }}^{-}$ states in ${}_{\mathrm{\Xi }}{}^{15}\mathrm{C}$ as well as that of the ${}^{12}\mathrm{C}+{\mathrm{\Xi }}^{-}$ states in ${}_{\mathrm{\Xi }}{}^{13}\mathrm{B}$ and compare with observed data from emulsion experiments. In addition, we predict the spectrum of ${}_{\mathrm{\Xi }}{}^{12}\mathrm{Be}$ (${}^{11}\mathrm{B}+{\mathrm{\Xi }}^{-}$) using the same interaction.

Methods:Through the $G$-matrix calculations, we derive low-energy effective interactions from lattice QCD potentials, where we introduce odd-parity potentials based on the meson-exchange picture because they have not been obtained from lattice QCD simulations. Employing these interactions, we carry out molecular dynamics model calculations to obtain the spectra of ${}_{\mathrm{\Xi }}{}^{13}\mathrm{B}, {}_{\mathrm{\Xi }}{}^{15}\mathrm{C}$, and ${}_{\mathrm{\Xi }}{}^{12}\mathrm{Be}$.

Results:The $s$-wave states of ${\mathrm{\Xi }}^{-}$ in ${}_{\mathrm{\Xi }}{}^{15}\mathrm{C}$ are bound in the range of 5 to 10 MeV, while the $p$-wave states are in the range of 0 to 2 MeV. The same Hamiltonian predicts the bound $s$-wave states of ${}_{\mathrm{\Xi }}{}^{12}\mathrm{Be}$ in the range of 3 to 5 MeV. The obtained spectra show small spin-spin splitting and conversion widths.

Conclusions:The results for ${}_{\mathrm{\Xi }}{}^{13}\mathrm{B}$ and ${}_{\mathrm{\Xi }}{}^{15}\mathrm{C}$ are consistent with many of the experimental data, highlighting the capabilities of lattice QCD simulations. The binding of ${}_{\mathrm{\Xi }}{}^{12}\mathrm{Be}$ is deep enough to be observed by spectroscopy experiments. The difference between the lattice QCD and the meson-exchange models lies in the spin-spin splitting and conversion widths, underlining the importance of observations.

A new generation of phenomenological optical potentials requires robust calibration and uncertainty quantification, motivating the use of Bayesian statistical methods. These Bayesian methods usually require calculating observables for thousands or even millions of parameter sets, making fast and accurate emulators highly desirable or even essential. Emulating scattering across different energies or with interactions such as optical potentials is challenging because of the nonaffine parameter dependence, meaning the parameters do not all factorize from individual operators. Here we introduce and demonstrate the reduced-order scattering emulator (rose) framework, a reduced basis emulator that can handle nonaffine problems. rose is fully extensible and works within the publicly available band framework software suite for calibration, model mixing, and experimental design. As a demonstration problem, we use rose to calibrate a realistic nucleon-target scattering model through the calculation of elastic cross sections. This problem shows the practical value of the rose framework for Bayesian uncertainty quantification with controlled trade-offs between emulator speed and accuracy as compared to high-fidelity solvers. Planned extensions of rose are discussed.

This study focuses on estimating the level density parameters for niobium (Nb) using the unscented transform Kalman filter technique. Niobium is widely utilized in accelerator components, particularly in superconducting radiofrequency cavities. To better understand the design of accelerator components and experimental setups, accurate information on both theoretical predictions and experimental results, including the uncertainties of nuclear reactions involving niobium, is essential. In this study, we have used the unscented transform Kalman filter technique to estimate level density parameters and their correlation matrix for ${}^{93}\mathrm{Nb}(\alpha ,2n){}^{95}\mathrm{Tc}$ and ${}^{93}\mathrm{Nb}(\alpha ,n){}^{96}\mathrm{Tc}$ reactions through the talys nuclear code. We have used the measured experimental nuclear reaction cross sections from this study to estimate the level density parameters for the above nuclear reactions. A comprehensive analysis of uncertainty propagation has been also conducted, encompassing both theoretical predictions and experimentally measured nuclear reaction cross sections. We have calculated uncertainties in both the theoretical calculations using the Monte Carlo method and experimentally measured reaction cross sections through covariance analysis for these nuclear reactions. We have also calculated the correlation matrix of the experimentally measured cross sections for the ${}^{93}\mathrm{Nb}(\alpha ,n){}^{95}\mathrm{Tc}$ and ${}^{93}\mathrm{Nb}(\alpha ,n){}^{96}\mathrm{Tc}$ nuclear reactions.

We present a global nonlocal and dispersive optical model potential for neutron scattering off spherical nuclei with incident energies up to 250 MeV. This optical model is an extension of the nondispersive Perey-Buck potential. The imaginary components are chosen to be energy dependent and the dispersive constraints are taken into account. The surface imaginary part is nonlocal, whereas the volume imaginary part above 10 MeV is local, allowing one to reproduce total cross sections and scattering data for high energies. We obtain a good description of scattering observables for target nuclei ranging from $A=16$ up to 209. The inclusion of a nonlocal spin-orbit term enables a better description of the analyzing power data relative to the local dispersive model.

The invariant yield of electrons from open-heavy-flavor decays for $1<p_T<8$ GeV/$c$ at midrapidity $\left|y\right|<0.35$ in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{{}_{NN}}}$ = 200 GeV has been measured by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider. A displaced-vertex analysis with the PHENIX silicon-vertex detector enables extraction of the fraction of charm and bottom hadron decays and unfolding of the invariant yield of parent charm and bottom hadrons. The nuclear-modification factors $R_{AA}$ for electrons from charm and bottom hadron decays and heavy-flavor hadrons show both a centrality and a quark-mass dependence, indicating suppression in the quark-gluon plasma produced in these collisions that is medium sized and quark-mass dependent.

In this work, we systematically calculate the spectrum of hidden-charm pentaquark states $qqqc\overline{c}(q=u,d)$ in the chiral SU(3) quark model, which has been quite successful in reproducing consistently the energies of octet and decuplet baryon ground states, the binding energy of deuteron, and the nucleon-nucleon scattering phase shifts and mixing parameters for partial waves with total angular momentum up to $J=6$. The Hamiltonian contains the kinetic energy of the system, the confinement potential, the one-gluon-exchange (OGE) potential, and the one-boson-exchange potential stemming from the coupling of quark and chiral fields. We solve the Schrödinger equation by use of the variational method. It is found that the masses of all the experimentally observed $P_c\left(4312\right)$, $P_c\left(4380\right)$, $P_c\left(4440\right)$, and $P_c\left(4457\right)$ states are much overestimated, indicating that these states are not compact pentaquark states in the chiral SU(3) quark model. All other $qqqc\overline{c}(q=u,d)$ states are found to lie much above the corresponding baryon-meson thresholds and thus are not suggested as stable pentaquark states due to their fall-apart decays. A detailed comparison of the results with those obtained in the OGE model and the chromomagnetic interaction model is further given.

The compositeness of weakly bound states is discussed using the effective field theory from the viewpoint of the low-energy universality. We introduce a model with coupling of the single-channel scattering to the bare state, and study the compositeness of the bound state by varying the bare state energy. In contrast to the naive expectation that the near-threshold states are dominated by the molecular structure, we demonstrate that a noncomposite state can always be realized even with a small binding energy. At the same time, however, it is shown that a fine tuning is necessary to obtain the noncomposite weakly bound state. In other words, the probability of finding a model with the composite dominant state becomes larger with the decrease of the binding energy, in accordance with the low-energy universality. For the application to exotic hadrons, we then discuss the modification of the compositeness due to decay and coupled-channels effects. We quantitatively show that these contributions suppress the compositeness, because of the increase of the fraction of other components. Finally, as examples of near-threshold exotic hadrons, the structures of $T_{cc}$ and $X\left(3872\right)$ are studied by evaluating the compositeness. We find the importance of the coupled-channels and decay contributions for the structures of $T_{cc}$ and $X\left(3872\right)$, respectively.

A truncated partial-wave analysis is performed for $\eta$ photoproduction off the proton using the polarization observables ${\sigma }_0, \mathrm{\Sigma }, T, E, F$, and $G$. Through this approach, model-independent estimates of the electromagnetic multipole parameters are calculated. Based on these estimates, predictions are made for polarization observables that have not yet been measured. These predictions identify promising future measurements that could resolve the inherent mathematical ambiguities within the results. Bayesian inference is combined for the first time with truncated partial-wave analysis, analyzing different truncation orders for six energy bins near the $\eta p$-production threshold, i.e., $E_{\gamma }^{\mathrm{lab}}\in [750,1250]\mathrm{MeV}$.

Background: Within the energy density functional (EDF) approach, the use of mean-field wave functions deliberately breaking (some) symmetries of the underlying Hamiltonian is an efficient and widely utilized way to incorporate static correlations. However, the restoration of broken symmetries is eventually mandatory to recover the corresponding quantum numbers and to achieve a more precise description of nuclear properties.

Purpose: While symmetry-restored calculations are routinely performed to study ground-state properties and low-lying excitations, similar applications to the nuclear response are essentially limited to either formal studies or to schematic models. In the present paper, the effect of angular momentum restoration on the monopole and quadrupole responses of doubly open-shell nuclei is investigated.

Methods: Based on deformed Skyrme-randomphaseapproximation (RPA) calculations, the exact angular momentum projection (AMP) is implemented in the calculation of the multipole strength functions, thus defining a projection after variation (PAV-RPA) scheme. The method is employed for the first time in a realistic study to investigate the effect of AMP on the coupling of monopole and quadrupole modes in ${}^{24}\mathrm{Mg}$ resulting from its intrinsic deformation.

Results: The monopole PAV-RPA response function shows, in addition to the giant resonance peaks, a tremendous amount of strength in the low-energy part whose properties and nature are investigated and discussed. In the quadrupole channel, the AMP leads to a suppression of all the strength but the one corresponding to the isoscalar giant quadrupole resonance.

Conclusions: The nature of the anomalous low-lying monopole strength is interpreted as a contamination of the excited states via the coupling to the (noninfinitesimal) rotational motion in deformed RPA phonons. Such a spurious strength was also observed in projected generator coordinate method (PGCM) calculations based on a similar PAV approach, but was shown to disappear in its full variation after projection (VAP) counterpart. While the spurious strength could be properly subtracted in the present work, this work motivates the implementation of the full VAP-RPA in the future.

The electric dipole transition of the $3^{-}$ state at 9.64 MeV of ${}^{12}\mathrm{C}$ to the $2^{+}$ state at 4.44 MeV is speculated to play a key role in the triple-$\alpha$ reaction at high temperatures. A theoretical prediction of its transition width is a challenge to nuclear theory because it belongs to a class of isospin-forbidden transitions. We extend a microscopic $3\alpha$ cluster-model to include isospin-1 impurity components, and take into account both isovector and isoscalar electric dipole operators. Several sets of $2^{+}$ and $3^{-}$ wave functions are generated by solving a radius-constrained equation of motion with the stochastic variational method, resulting in reproducing very well the electric quadrupole and octupole transition probabilities to the ground state. The electric dipole transition width is found to be 7–31 meV, 16 meV on the average, and more than half of the width is contributed by the isospin mixing of $\alpha$ particles.

We solve the Schrödinger equation for an arbitrary one-dimensional potential energy to calculate the transmission coefficient in the fission channel of compound nucleus reactions. We incorporate the calculated transmission coefficients into the statistical Hauser-Feshbach model calculation for neutron-induced reactions on ${}^{235,238}\mathrm{U}$ and ${}^{239}\mathrm{Pu}$. The one-dimensional model reproduces the evaluated fission cross section data reasonably well considering the limited number of model parameters involved. A resonance-like structure appears in the transmission coefficient for a double-humped fission barrier shape that includes an intermediate well, which is understood to be a quantum mechanical effect in the fission channel. The calculated fission cross sections for the neutron-induced reactions on ${}^{235,238}\mathrm{U}$ and ${}^{239}\mathrm{Pu}$ all exhibit a similar structure.

Recent measurements from ALICE report that “in-jet” nucleons carry a higher probability of forming a deuteron via coalescence than the nucleons from the underlying event (UE). This study makes use of an event shape classifier to separate the “in-jet” deuterons and the deuterons in the UE produced in high multiplicity proton-proton collisions at $\sqrt{s}=13$ TeV. Event shape variables such as transverse spherocity allow the categorization of hard and soft components of an event, which can be divided into two respective classes; “jetty” and “isotropic”. The “jetty” deuterons minus the contribution of the deuterons from the “isotropic” event are taken as “in-jet” deuterons, and the coalescence mechanism is tested. The coalescence is performed with a Wigner function formalism, augmented as an afterburner to pythia8. The possible enhancement of the coalescence probability of “in-jet” deuterons is investigated by calculating the coalescence parameter ($B_2$) in different spherocity classes in high-multiplicity $pp$ collisions.

Angular distributions of charged particles relative to jet axes are studied in $\sqrt{s_{NN}}=200$ GeV Au+Au collisions as a function of the jet orientation with respect to the event plane. This differential study tests the expected path-length dependence of energy loss experienced by a hard-scattered parton as it traverses the hot and dense medium formed in heavy-ion collisions. A second-order event plane is used in the analysis as an experimental estimate of the reaction plane formed by the collision impact parameter and the beam direction. Charged-particle jets with $15<p_{\mathrm{T},\mathrm{jet}}<20$ and $20<p_{\mathrm{T},\mathrm{jet}}<40\mathrm{GeV}/c$ were reconstructed with the anti-$k_{\mathrm{T}}$ algorithm with radius parameter setting of $R=0.4$ in the 20–50% centrality bin to maximize the initial-state eccentricity of the interaction region. The reaction plane fit method is implemented to remove the flow-modulated background with better precision than prior methods. Yields and widths of jet-associated charged-hadron distributions are extracted in three angular bins between the jet axis and the event plane. The event-plane (EP) dependence is further quantified by ratios of the associated yields in different EP bins. No dependence on orientation of the jet axis with respect to the event plane is seen within the uncertainties in the kinematic regime studied. This finding is consistent with a similar experimental observation by ALICE in $\sqrt{s_{NN}}$ = 2.76 TeV Pb-Pb collision data.

A search for new neutron-rich isotopes near the $N=60$ isotones ${}^{92}\mathrm{Ge}$ and ${}^{93}\mathrm{As}$ has been performed using a 345 MeV/nucleon ${}^{238}\mathrm{U}$ beam at the RIKEN Nishina Center RI Beam Factory. Fission fragments produced were analyzed and identified in flight using the large-acceptance two-stage separator BigRIPS. We have observed a total of 15 new neutron-rich isotopes: ${}^{84}\mathrm{Cu}, {}^{86,87}\mathrm{Zn}, {}^{88,89}\mathrm{Ga}, {}^{91,92}\mathrm{Ge}, {}^{93,94,95}\mathrm{As}, {}^{96,97}\mathrm{Se}, {}^{99,100}\mathrm{Br}$, and ${}^{103}\mathrm{Kr}$.

This paper formalizes the use of integral and differential cumulants for measurements of multiparticle event-by-event transverse momentum fluctuations, rapidity fluctuations, as well as net-charge fluctuations. This enables the introduction of multiparticle balance functions, defined based on differential correlation functions (factorial cumulants), that suppress two- and three-prong resonance decays effects and enable measurements of underlying long-range correlations obeying quantum number conservation constraints. These multiparticle balance functions satisfy simple sum rules determined by quantum number conservation. It is additionally shown that these multiparticle balance functions arise as an intrinsic component of high-order net-charge cumulants. This implies that the magnitude of these cumulants, measured in a specific experimental acceptance, is strictly constrained by charge conservation and primarily determined by the rapidity and momentum width of these balance functions. The paper also presents techniques to reduce the computation time of differential correlation functions up to order $n=10$ based on the methods of moments.