We have investigated the axial charges of the ground octet baryons within the extended chiral constituent quark model, where all the possible compact five-quark Fock components $qqq\left(q\overline{q}\right)(q=u,d,s)$ in the baryons are considered. The transition couplings between the three- and five-quark components in the baryons are assumed to be via the ${}^3{P}_0$ mechanism, which could reproduce the sea asymmetry in proton very well. The numerical results for the flavor-dependent axial charges of the octet baryons are comparable to those predicted by other theoretical approaches. It is shown that the singlet axial charges of the octet baryons, which should indicate total baryons spin arising from the spin of the quarks, fall in the range $0.45–0.75$ in present model. This is in consistent with the predictions by lattice QCD and chiral perturbation theory. It is also very interesting that the light quarks spin $\mathrm{\Delta }u$ and $\mathrm{\Delta }d$ in the $\mathrm{\Lambda }$ baryon are of small but negative values, which exactly vanish in the traditional three-quark model.

We report on a detailed study of longitudinal strength in the nucleon resonance region, presenting new results from inclusive electron-proton cross sections measured at Jefferson Lab Hall C in the four-momentum transfer range $0.2<Q^2<5.5{\mathrm{GeV}}^2$. The data have been used to accurately perform 167 Rosenbluth-type longitudinal/transverse separations. The precision $R={\sigma }_L/{\sigma }_T$ data are presented here, along with the first separate values of the inelastic structure functions $F_1$ and $F_L$ in this regime. The resonance longitudinal component is found to be significant, both in magnitude and in the existence of defined mass peaks. Additionally, quark-hadron duality is here observed above $Q^2=1{\mathrm{GeV}}^2$ in the separated structure functions independently.

The Cryogenic Underground Observatory for Rare Events (CUORE) is a large-scale cryogenic experiment searching for neutrinoless double-beta decay ($0\nu \beta \beta$) in ${}^{130}\mathrm{Te}$. The CUORE detector is made of natural tellurium, providing the possibility of rare event searches on isotopes other than ${}^{130}\mathrm{Te}$. In this work we describe a search for neutrinoless positron-emitting electron capture (${\beta }^{+}\mathrm{EC}$) decay in ${}^{120}\mathrm{Te}$ with a total ${\mathrm{TeO}}_2$ exposure of 355.7 kg yr, corresponding to 0.2405 kg yr of ${}^{120}\mathrm{Te}$. Albeit $0\nu \beta \beta$ with two final-state electrons represents the most promising channel, the emission of a positron and two 511-keV $\gamma$'s make $0\nu {\beta }^{+}\mathrm{EC}$ decay signature extremely clear. To fully exploit the potential offered by the detector modularity we include events with different topology and perform a simultaneous fit of five selected signal signatures. Using blinded data we extract a median exclusion sensitivity of $3.4\times {10}^{22}$ yr at 90% credibility interval (C.I.). After unblinding we find no evidence of $0\nu {\beta }^{+}\mathrm{EC}$ signal and set a 90% C.I. Bayesian lower limit of $2.9\times {10}^{22}$ yr on ${}^{120}\mathrm{Te}$ half-life. This result improves by an order of magnitude the existing limit from the combined analysis of CUORE-0 and Cuoricino.

In this paper we study atomic masses of the major shells to the northwest of the ${}^{208}\mathrm{Pb}$ nucleus, namely, those with neutron numbers $N<126$ and proton numbers $Z>82$, in terms of neutron-proton interactions. With statistical corrections, we are able to construct mass formulas for nuclei in this region with root-mean-squared deviation close to 30 keV, which is more accurate than all previous efforts. Predicted results of some unaccessible masses are tabulated in the Supplemental Material of this article.

We propose to extend the optimal Fermi averaging procedure theoretically in order to calculate an in-medium $K^{-}n\to {\pi }^{-}\mathrm{\Lambda }$ amplitude for the exothermic ($K^{-},{\pi }^{-}$) reaction on nuclei in the framework of a distorted-wave impulse approximation, taking into account the local momentum transfer generated by semiclassical distorted waves for $K^{-}$ and ${\pi }^{-}$ mesons. Angular distributions for the ${}^{12}\mathrm{C}(K^{-},{\pi }^{-}){}_{\mathrm{\Lambda }}{}^{12}\mathrm{C}$ reaction in which a momentum transfer is $q\lesssim 80$ MeV/$c$ at $p_K=800$ MeV/$c$ in the ${\pi }^{-}$ forward direction are estimated by applying the extended procedure. The result shows that the calculated angular distributions are in good agreement with those of the data, and this extension is a successful prescription making it possible to describe the reaction cross sections in near-recoilless reactions such as ($K^{-},{\pi }^{-}$) in our framework.

While ample evidence for the so-called empirical parabolic law of the equation of state (EOS) of isospin asymmetric nuclear matter (ANM) has been obtained in many studies within both nonrelativistic and relativistic nuclear many-body theories using various interactions, it has been unclear if there is any fundamental physics reason for the small quartic symmetry energy compared to the quadratic one even as the ANM approaches pure neutron matter. Within both relativistic and nonrelativistic free Fermi gas (FFG) models in coordinate spaces of arbitrary dimension $d$ with and without considering short-range correlations (SRCs) as well as nonlinear relativistic mean field models, we study effects of relativistic kinematics, dimensionality, interactions, and SRC on the ratio $\mathrm{\Psi }\left(\rho \right)$ of quartic over quadratic symmetry energies in ANM EOSs. We found that the ratio $\mathrm{\Psi }\left(\rho \right)$ in the FFG model depends strongly on the dimension $d$. While it is very small already in the normal three-dimensional space, it could be even smaller in spaces with reduced dimensions for subsystems of particles in heavy-ion reactions and/or whole neutron stars due to constraints, collectivities, and/or symmetries. We also found that the ratio $\mathrm{\Psi }\left(\rho \right)$ could theoretically become very large only at the ultrarelativistic limit far above the density reachable in neutron stars. However, nuclear interaction directly and/or indirectly through SRC-induced high-momentum nucleons affects significantly the density dependence of $\mathrm{\Psi }\left(\rho \right)$ compared to the relativistic FFG model prediction. The SRCs affect significantly not only the kinetic energy of symmetric nuclear matter but also the ratio $\mathrm{\Psi }\left(\rho \right)$ while the relativistic corrections are found negligible. Although we found no fundamental physics reason for the $\mathrm{\Psi }\left(\rho \right)$ to be very small especially at high densities, the results may help better understand the EOS of dense neutron-rich matter.

Nuclei with an octupole deformation have a nonzero electric octupole moment, electric dipole moment (EDM), Schiff moment, and magnetic quadrupole moment (MQM) in the intrinsic frame, which rotates with the nucleus. In a state with definite angular momentum in the laboratory frame, these moments are forbidden by parity ($P$) and time-reversal ($T$) invariance conservation, meaning their expectation values vanish due to nuclear rotation. However, nuclei with an octupole deformation have doublets of close opposite parity rotational states with the same spin, which are mixed by $T$-, $P$-odd nuclear forces. This mixing produces the orientation of the nuclear axis along nuclear spin and all moments existing in the intrinsic frame appear in the laboratory frame (provided the nuclear spin $I$ is sufficiently large to allow such moment). Such a mechanism produces enhanced $T$-. $P$-violating nuclear moments. This enhancement also takes place in nuclei with a soft octupole vibration mode. Schiff moments in such nuclei have been calculated in previous works. In the present paper we consider the magnetic quadrupole moment, which appears in isotopes with nuclear spin $I\ge 1$. Magnetic interaction between the nuclear MQM and electrons produces an atomic EDM and $T$-, $P$-violating nuclear spin-molecular axis interaction constants for molecules in electronic states with nonzero electron angular momentum. Measurements of these constants may be used to test $CP$-violation theories and search for axion dark matter in atomic, molecular, and solid state experiments. Potential candidate nuclei include ${}^{153}\mathrm{Eu}, {}^{161}\mathrm{Dy}, {}^{221}\mathrm{Fr}, {}^{223}\mathrm{Fr}, {}^{223}\mathrm{Ra}, {}^{223}\mathrm{Rn}, {}^{225}\mathrm{Ac}, {}^{227}\mathrm{Ac}, {}^{229}\mathrm{Th}, {}^{229}\mathrm{Pa}, {}^{233}\mathrm{U}$, and ${}^{235}\mathrm{U}$. We subsequently consider molecules containing these nuclei (EuO, ${\mathrm{EuN}}^{+}$, RaF, AcO, ${\mathrm{AcN}}^{+}, {\mathrm{AcF}}^{+}$, ThO, and ${\mathrm{ThF}}^{+}$).

About 100 isotopes with $(N-Z)$ from 1–9 produced by 300 MeV/nucleon ${}^{78}\mathrm{Kr}$ projectiles impinging on an ${\mathrm{Al}}_2{\mathrm{O}}_3$ target have been separated and identified at the RIBLL2 separator of HIRFL, where their production yields have been measured. The odd-even staggering (OES) in these experimental yields is quantitatively studied by employing a third-order difference formula. Measured data are used to validate the universality of this OES by comparing with other experimental data produced by fragmentation of different krypton projectiles on various targets as well as the OES evaluated from thousands of accurate cross sections measured in many different reactions. These comparisons between experimental data from a large variety of fragmentation reactions provide strong evidence that the OES magnitude almost does not depend on the projectile-target combinations and thus the OES is universal for different reaction systems. The OES magnitudes in these experimental data are also applied to examine the OES predicted by the abrasion-ablation model. There are large discrepancies between the OES magnitudes in predicted and measured cross sections.

The extremely neutron-rich system ${}^6\mathrm{H}$ was studied in the direct ${}^2\mathrm{H}({}^8\mathrm{He},{}^4\mathrm{He}){}^6\mathrm{H}$ transfer reaction with a $26A$ MeV secondary ${}^8\mathrm{He}$ beam. The measured missing mass spectrum shows a broad bump at $\approx 4–8$ MeV above the ${}^3\mathrm{H}+3n$ decay threshold. This bump can be interpreted as a broad resonant state in ${}^6\mathrm{H}$ at 6.8(5) MeV. The population cross section of such a presumably $p$-wave state (or it may be few overlapping states) in the energy range from 4 to 8 MeV is $d\sigma /d{\mathrm{\Omega }}_{\text{c.m.}}\simeq {190}_{-80}^{+40}\mu \mathrm{b}/\mathrm{sr}$ in the angular range $5^{\circ }<{\theta }_{\text{c.m.}}<{16}^{\circ }$. The obtained missing mass spectrum is practically free of ${}^6\mathrm{H}$ events below 3.5 MeV ($d\sigma /d{\mathrm{\Omega }}_{\text{c.m.}}\lesssim 5\mu \mathrm{b}/\mathrm{sr}$ in the same angular range). The steep rise of the ${}^6\mathrm{H}$ missing mass spectrum at $\approx 3$ MeV allows us to derive the lower limit for the possible resonant-state energy in ${}^6\mathrm{H}$ to be 4.5(3) MeV. According to the paring energy estimates, such a 4.5(3) MeV resonance is a realistic candidate for the ${}^6\mathrm{H}$ ground state (g.s.). The obtained results confirm that the decay mechanism of the ${}^7\mathrm{H}$ g.s. (located at 2.2 MeV above the ${}^3\mathrm{H}+4n$ threshold) is the “true” (or simultaneous) $4n$ emission. The resonance energy profiles and the momentum distributions of fragments of the sequential ${}^6\mathrm{H}\to {}^5\mathrm{H}$(g.s.)$+n\to {}^3\mathrm{H}+3n$ decay were analyzed by the theoretically updated direct four-body-decay and sequential-emission mechanisms. The measured momentum distributions of the ${}^3\mathrm{H}$ fragments in the ${}^6\mathrm{H}$ rest frame indicate very strong “dineutron-type” correlations in the ${}^5\mathrm{H}$ ground state decay.

The equation of state (EOS) of spin-polarized nuclear matter (NM) is studied within the Hartree-Fock (HF) formalism using the realistic density-dependent nucleon-nucleon interaction. With a nonzero fraction $\mathrm{\Delta }$ of spin-polarized baryons in NM, the spin- and spin-isospin dependent parts of the HF energy density give rise to the spin symmetry energy that behaves in about the same manner as the isospin symmetry energy, widely discussed in the literature as the nuclear symmetry energy. The present HF study shows a strong correlation between the spin symmetry energy and nuclear symmetry energy over the whole range of baryon densities. The important contribution of the spin symmetry energy to the EOS of the spin-polarized NM is found to be comparable with that of the nuclear symmetry energy to the EOS of the isospin-polarized or asymmetric (neutron-rich) NM. Based on the HF energy density, the EOS of the spin-polarized ($\beta$-stable) $npe\mu$ matter is obtained for the determination of the macroscopic properties of neutron stars (NS). A realistic density dependence of the spin-polarized fraction $\mathrm{\Delta }$ has been suggested to explore the impact of the spin symmetry energy on the gravitational mass $M$ and radius $R$, as well as the tidal deformability of NS. Based on the empirical constrains inferred from a coherent Bayesian analysis of gravitational wave signals of the NS merger GW170817 and the observed masses of the heaviest pulsars, the present study shows the strong impact of the spin symmetry energy $W$, nuclear symmetry energy $S$, and nuclear incompressibility $K$ on the EOS of nucleonic matter in magnetar.

The production of light nuclei and hypernuclei together with heavy baryons, both hyperons and $\mathrm{\Delta }$ baryons, in low-density matter as found in stellar environments such as supernova or binary mergers is studied within relativistic mean-field models. Five light nuclei were considered together with three light hypernuclei. The presence of both hyperons and $\mathrm{\Delta }$ baryons shift the dissolution of clusters to larger densities and increase the abundance of clusters. This effect is larger the smaller the charge fraction and the higher the temperature. The couplings of the $\mathrm{\Delta }$ baryons were chosen imposing that the nucleon effective mass remains finite inside neutron stars.

We investigate the appearance of resonances in three-body systems using pionless effective field theory at leading order with two complementary methods. The Faddeev equation is analytically continued to the unphysical sheet adjacent to the positive real energy axis using a contour rotation. We consider both the three-boson system and the three-neutron system. For the former, we calculate the trajectory of Borromean three-body Efimov states turning into resonances as they cross the three-body threshold. For the latter, we find no sign of three-body resonances or virtual states at leading order. This result is validated by exploring the level structure of three-body states in a finite volume approach.

This paper presents an analysis of neutron skins based on fully microscopic equations of state, including chiral two- and three-nucleon forces consistently at next-to-next-to-next-to-leading order (${\mathrm{N}}^3\mathrm{LO}$). Other theoretical predictions and recent constraints are also addressed, such as those from the PREX II experiment and the latest parity-violating electron scattering measurement of the ${}^{27}\mathrm{Al}$ neutron skin.

The elastic $\alpha \text{−}{}^{12}\mathrm{C}$ scattering for $l=2$ at low energies is studied in an effective Lagrangian approach. I explicitly include two resonant $2_2^{+}$ and $2_3^{+}$ states of ${}^{16}\mathrm{O}$ in the scattering amplitudes and construct an $S$ matrix assuming that three amplitudes, nonresonant part of the amplitude which has the subthreshold $2_1^{+}$ state of ${}^{16}\mathrm{O}$ and those of the two resonant states, are represented by the summation of corresponding parts of the phase shift. Then, I fit the parameters in the $S$ matrix to the phase shift data by imposing three conditions at the very low energies where the phase shift data are not available. By using the fitted parameters, the asymptotic normalization coefficients (ANC) of the $2_1^{+}$ state of ${}^{16}\mathrm{O}$ are calculated, and I find that the previously reported small and large values of the ANC can be reproduced depending on the imposed conditions. While large error bars for the large ANC values which are reported from the $\alpha$ transfer reactions are also obtained.

Transverse momentum integrated and differential $J/\psi R_{AA}$ are systematically studied in Au-Au collisions at energies selected for the beam energy scan at the BNL Relativistic Heavy Ion Collider using a transport approach, including cold and hot nuclear effects respectively in the initial conditions and the collision terms. With decreasing energy, while the temperature, lifetime, and size of the quark-gluon plasma (QGP) fireball decrease, the nuclear absorption of the initially produced charmonia is more and more strong, and the nuclear shadowing effect on charmonium regeneration goes to antishadowing first and then to shadowing again. As a competition between the cold and hot nuclear effects, the QGP phase is still important for charmonium production at $\sqrt{s_{NN}}=200$, 62.4, 54,4 and 39 GeV but becomes negligible at $\sqrt{s_{NN}}=14.5$ GeV.

We perform the ab initio no-core shell model (NCSM) calculation to investigate the bound state problem of the three-body $\mathrm{\Lambda }nn$ system in chiral next-to-next-to-leading-order $NN$ and chiral leading-order $YN$ interactions. The calculations show that no $\mathrm{\Lambda }nn$ bound state exists, but predict a low-lying $\mathrm{\Lambda }nn$ resonant state near the threshold with an energy of $E_r=0.124$ MeV and a width of about $\mathrm{\Gamma }=1.161$ MeV. In searching for $\mathrm{\Lambda }nn$ resonances, we extend the NCSM calculation to the continuum state by employing the $J$-matrix formalism in the scattering theory with the hyperspherical oscillator basis.

We investigate the long-standing question of the effect of proton-antiproton annihilation on the (anti-)proton yield, while respecting detailed balance for the five-body back-reaction for the first time in a full microscopic description of the late stages of heavy-ion collisions. This is achieved by employing a stochastic collision criterion in a hadronic transport approach (SMASH), which is used to account for the regeneration of (anti-)protons via $5\pi \to \mathrm{p}\overline{\mathrm{p}}$. We investigate $\mathrm{Au}+\mathrm{Au}$ and $\mathrm{Pb}+\mathrm{Pb}$ collisions from $\sqrt{s_{NN}}=17.3\mathrm{GeV}-5.02$ TeV in a viscous hybrid approach. Our results show that back-reactions happen for a fraction of 15%–20% of all annihilations, independent of the beam energy or centrality of the system. The inclusion of the back-reaction results in the regeneration of half of the (anti-)proton yield lost to annihilations at midrapidity. We also find that, concerning the multiplicities, treating the back-reaction as a chain of two-body reactions is equivalent to a single 5-to-2 reaction.

Excited state contamination remains one of the most challenging sources of systematic uncertainty to control in lattice QCD calculations of nucleon matrix elements and form factors: early time separations are contaminated by excited states and late times suffer from an exponentially bad signal-to-noise problem. High-statistics calculations at large time separations $\gtrsim 1$ fm are commonly used to combat these issues. In this work, focusing on $g_A$, we explore the alternative strategy of utilizing a large number of relatively low-statistics calculations at short to medium time separations (0.2–1 fm), combined with a multistate analysis. On an ensemble with a pion mass of approximately 310 MeV and a lattice spacing of approximately 0.09 fm, we find this provides a more robust and economical method of quantifying and controlling the excited state systematic uncertainty. A quantitative separation of various types of excited states enables the identification of the transition matrix elements as the dominant contamination. The excited state contamination of the Feynman-Hellmann correlation function is found to reduce to the 1% level at approximately 1 fm while, for the more standard three-point functions, this does not occur until after 2 fm. Critical to our findings is the use of a global minimization, rather than fixing the spectrum from the two-point functions and using them as input to the three-point analysis. We find that the ground state parameters determined in such a global analysis are stable against variations in the excited state model, the number of excited states, and the truncation of early-time or late-time numerical data.

In order to estimate qualitatively the influence of nonequilibrium evolution in relativistic heavy ion collisions, we use the three-dimensional Ising model with Metropolis algorithm to study the evolution from nonequilibrium to equilibrium on the phase boundary. The evolution of order parameter approaches its equilibrium value exponentially, the same as that given by the Langevin equation. The average relaxation time is defined which is demonstrated to well represent the relaxation time in dynamical equations. It is shown that the average relaxation time at critical temperature diverges as the $z\mathrm{th}$ power of system size. The third and the fourth cumulants of order parameter during the nonequilibrium evolution could be either positive or negative, depending on the observation time, consistent with dynamical models at $T>T_{\mathrm{c}}$. It is found that the nonequilibrium evolution at $T>T_{\mathrm{c}}$ lasts very shortly, and the influence is weaker than that at $T<T_{\mathrm{c}}$. Those qualitative features are instructive to determine experimentally the critical point and the phase boundary of quantum chromodynamics.