As one of a series of physics cases to demonstrate the unique benefit of the new Jet Experiments in Nuclear Structure and Astrophysics (JENSA) gas-jet target for enabling next-generation transfer reaction studies, the ${}^{14}\mathrm{N}$ ($p, t$)${}^{12}\mathrm{N}$ reaction was studied for the first time, using a pure jet of nitrogen, in an attempt to resolve conflicting information on the structure of ${}^{12}\mathrm{N}$. A potentially new level at 4.561-MeV excitation energy in ${}^{12}\mathrm{N}$ was found.

The structure of $1/2^{\pm }$ states in ${}^{13}\mathrm{C}$ up to around the $3\alpha +n$ threshold ($E_x=12.3$ MeV) is investigated with a full four-body $3\alpha +n$ orthogonality condition model (OCM) calculation, where the $3\alpha$ OCM, the model space of which is the subspace of the $3\alpha +n$ model, describes well the structure of the low-lying states of ${}^{12}\mathrm{C}$, including the $2_2^{+},0_3^{+}$, and $0_4^{+}$ states, which have been recently observed above the Hoyle state ($0_2^{+}$). A full spectrum up to the $1/2_5^{-}$ ($1/2_3^{+}$) state is reproduced consistently with the lowest five $1/2^{-}$ (three $1/2^{+}$) states of experimental spectrum. It is shown that the $1/2_2^{-}$ and $1/2_3^{-}$ states are characterized by the dominant cluster configurations of ${}^9\mathrm{Be}(3/2^{-},1/2^{-})+\alpha$, while the ground state $1/2_1^{-}$ has a shell-model-like structure. The observed monopole transition strengths to the $1/2_{2,3}^{-}$ states are consistently reproduced for the first time. These results indicate that the excited $1/2^{-}$ states have cluster structures. They are compared to those by the previous work with the shell model. However, the $1/2_1^{+}$ state is found to have a loosely bound neutron structure in which the extra neutron moves around ${}^{12}\mathrm{C}\left(\text{g.s.}\right)$ core with $1S$ orbit, reflecting the fact that this state appears by $1.9$ MeV just below the ${}^{12}\mathrm{C}(\mathrm{g}.\mathrm{s}.)+n$ threshold, while the $1/2_2^{+}$ and $1/2_3^{+}$ states are characterized by ${}^9\mathrm{Be}+\alpha$ structures. We found that the $1/2_5^{+}$ state located above the $3\alpha +n$ threshold is the Hoyle analog state in ${}^{13}\mathrm{C}$, the wave function of which is described by product states of constituent clusters, ${\left(0S\right)}_{\alpha }^3{\left(S\right)}_n$, with the probability of 52%.

The parallel momentum distribution (PMD) of the residual nuclei of the ${}^{14}\mathrm{O}$($p,pn$)${}^{13}\mathrm{O}$ and ${}^{14}\mathrm{O}$($p,2p$)${}^{13}\mathrm{N}$ reactions at 100 and 200 MeV/nucleon in inverse kinematics is investigated with the framework of the distorted-wave impulse approximation. The PMD shows an asymmetric shape characterized by a steep falloff on the high momentum side and a long-ranged tail on the low momentum side. The former is found to be due to the phase volume effect reflecting the energy and momentum conservation, and the latter is to the momentum shift of the outgoing two nucleons inside an attractive potential caused by the residual nucleus. Dependence of these effects on the nucleon separation energy of the projectile and the incident energy is also discussed.

We calculate the effects of finite density and temperature of isospin asymmetric strange hadronic matter, for different strangeness fractions, on the in-medium properties of vector $\left(D^{*},D_s^{*},B^{*},B_s^{*}\right)$ and axial-vector $\left(D_1,D_{1s},B_1,B_{1s}\right)$ mesons, using the chiral hadronic SU(3) model and QCD sum rules. We focus on the evaluation of in-medium mass-shift and shift in decay constant of above vector and axial-vector mesons. In the quantum chromodynamics sum rule approach, the properties, e.g., the masses and decay constants of vector and axial-vector mesons are written in terms of quark and gluon condensates. These quark and gluon condensates are evaluated in the present work within the chiral SU(3) model, through the medium modification of scalar-isoscalar fields $\sigma$ and $\zeta$, the scalar-isovector field $\delta$, and the scalar dilaton field $\chi$, in the strange hadronic medium which includes both nucleons as well as hyperons. As we shall see in detail, the masses and decay constants of heavy vector and axial-vector mesons are affected significantly from isospin asymmetry and the strangeness fraction of the medium, and these modifications may influence the experimental observables produced in heavy-ion collision experiments. The results of present investigations of in-medium properties of vector and axial-vector mesons at finite density and temperature of strange hadronic medium may be helpful for understanding the experimental data from heavy-ion collision experiments in particular for the compressed baryonic matter (CBM) experiment of the FAIR facility at GSI, Germany.

Earlier, single-particle level densities were obtained for a large number of target nuclei from the analysis of experimental data on a $(n,p)$ reaction at 14.8 MeV neutron energy using the Kalbach model. Recently, we obtained theoretical values of excitation energy ${\varepsilon }_c$ for unbound states and Fermi energies (${\varepsilon }_f$) for bound states for these single-particle level densities for many target nuclei by using Shlomo's theory, which leads to a shell structure, when ${\varepsilon }_c$ was plotted as a function of the atomic weight $A$. This indicates support to the concept of multiple statistical direct (MSD) and multiple statistical compound preequilibrium processes that involves unbound and bound states. We have now calculated the particle-hole configurations which are dominantly involved in the reaction mechanism for creating the single-particle level densities for all target nuclei, including “spikes” and “dips” obtained in the data analysis earlier using the formulation given by Kalbach [Phys. Rev. C 23, 124 (1981)] and Shlomo [Nucl. Phys. A 539, 17 (1992)]. It seems that $h=2, p=0$ is the dominant configuration for most of the targets in the preequilibrium process, whereas spikes seem to correspond to the $h=1, p=1$ dominant configuration, corresponding to the direct reaction mechanism; and dips seem to belong to the $h=2, p=0$ configuration and $h=1, p=1$ and $h=0, p=2$ configurations somewhat equally giving compound nucleus formation due to quantum statistical fluctuations and MSD. The implication of these calculations and results is discussed.

Prompt thermal neutron-capture partial $\gamma$-ray production cross sections were measured for the first time for the ${}^{180}\mathrm{W}(n,\gamma )$ reaction using a cold guided-neutron beam at the Budapest Research Reactor. Absolute ${}^{181}\mathrm{W}\gamma$-ray cross sections were internally standardized using well-known comparator $\gamma$-ray cross sections belonging to the other tungsten isotopes present in the 11.35% enriched ${}^{180}\mathrm{W}$ sample. Transitions were assigned to levels in ${}^{181}\mathrm{W}$ based largely upon information available in the literature. The total radiative thermal neutron-capture cross section ${\sigma }_0$ was determined from the sum of direct prompt $\gamma$-ray cross sections populating the ground state and a modeled contribution accounting for ground-state feeding from the quasicontinuum. In this work, we find ${\sigma }_0=21.67\left(77\right)$ b. A new measurement of the cross section for the $5/2^{-}$ metastable isomer at 365.6 keV, ${\sigma }_{5/2^{-}}{(}^{181}{\mathrm{W}}^m,14.6\mu \mathrm{s})=19.96\left(55\right)$ b, is also determined. Additionally, primary $\gamma$ rays, observed for the first time in the ${}^{180}\mathrm{W}(n,\gamma )$ reaction, provide the most precise determination for the ${}^{181}\mathrm{W}$ neutron-separation energy, $S_n=6669.02\left(16\right)$ keV.

Recent experimental and theoretical studies suggest that the quarkonium suppression in a thermal QCD medium created in heavy ion collisions is a complex interplay of various physical processes. In this article we put together most of these processes in a unified way to calculate the charmonium survival probability (nuclear modification factor) at energies available at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) experiments. We include shadowing as the dominant cold-nuclear-matter effect. Further, gluonic dissociation and collision damping are included, which provide width to the spectral function of charmonia in a thermal medium and cause the dissociation of charmonium along with the usual color screening. We include color screening by using our recently proposed modified Chu–Matsui model. Furthermore, we incorporate the recombination of uncorrelated charm and anticharm quarks for the regeneration of charmonium over the entire temporal evolution of the QGP medium. Finally, we do a feed-down correction from the excited states to calculate the survival probability of charmonium. We find that our unified model suitably and simultaneously describes the experimental nuclear modification data of $J/\psi$ at RHIC and LHC.

We compare the statistical fluctuation properties of the baryon and meson experimental mass spectra with those obtained from theoretical models (quark models and lattice QCD). We find that for the experimental spectra the statistical properties are close to those predicted by random matrix theory for chaotic systems, while for the theoretical ones they are in general closer to those predicted for integrable systems and safely incompatible with those of chaotic systems. We stress the importance of the agreement of the fluctuation properties between experiment and theoretical models, as they determine the dynamical regime and the complexity of the real interactions. We emphasize the new statistical method we use, adapted to properly analyze the fluctuation properties for very short spectral sequences.

We study the thermal evolution of neutron stars containing deconfined quark matter in their core. Such objects are generally referred to as quark-hybrid stars. The confined hadronic matter in their core is described in the framework of nonlinear relativistic nuclear field theory. For the quark phase we use a nonlocal extension of the SU(3) Nambu–Jona-Lasinio model with vector interactions. The Gibbs condition is used to model phase equilibrium between confined hadronic matter and deconfined quark matter. Our study indicates that high-mass neutron stars may contain between 35 and 40% deconfined quark-hybrid matter in their cores. Neutron stars with canonical masses of around $1.4M_{\odot }$ would not contain deconfined quark matter. The central proton fractions of the stars are found to be high, enabling them to cool rapidly. Very good agreement with the temperature evolution established for the neutron star in Cassiopeia A (Cas A) is obtained for one of our models (based on the popular NL3 nuclear parametrization), if the protons in the core of our stellar models are strongly paired, the repulsion among the quarks is mildly repulsive, and the mass of Cas A has a canonical value of $1.4M_{\odot }$.

The deformed quasiparticle random-phase approximation with realistic nucleon-nucleon interactions is extended for the ${\beta }^{-}$ decay of odd-mass neutron-rich Kr, Sr, Zr, and Mo isotopes, from their longest-lived isotopes to the experimentally unknown nuclei. The particle-particle and particle-hole channels of residual interactions are handled in large single-particle model spaces, based on the Brückner $G$ matrix with charge-dependent Bonn nucleon-nucleon forces. Both allowed Gamow-Teller and first-forbidden transitions are considered and different treatments for odd-mass systems are emphasized. The sensitivity of the calculated results to the single-particle level scheme and the particle-particle strength is discussed. The calculated Gamow-Teller strengths are analyzed, together with the contributions from first-forbidden transitions. The calculated half-lives are found to agree well with the experimental data over the orders of magnitude from ${10}^{-2}$ to ${10}^3$ s.

We derive a coupled set of equations that describe the nonequilibrium evolution of cumulants of critical fluctuations for spacetime trajectories on the crossover side of the QCD phase diagram. In particular, novel expressions are obtained for the nonequilibrium evolution of non-Gaussian skewness and kurtosis cumulants. UBy utilizing a simple model of the spacetime evolution of a heavy-ion collision, we demonstrate that, depending on the relaxation rate of critical fluctuations, skewness and kurtosis can differ significantly in magnitude as well as in sign from equilibrium expectations. Memory effects are important and shown to persist even for trajectories that skirt the edge of the critical regime. We use phenomenologically motivated parametrizations of freeze-out curves and of the beam-energy dependence of the net baryon chemical potential to explore the implications of our model study for the critical-point search in heavy-ion collisions.

We have studied the dependence of azimuthal anisotropy $v_2$ for inclusive and identified charged hadrons in $\mathrm{Au}+\mathrm{Au}$ and $\mathrm{Cu}+\mathrm{Cu}$ collisions on collision energy, species, and centrality. The values of $v_2$ as a function of transverse momentum $p_T$ and centrality in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{{}_{\mathit{NN}}}}=200$ and 62.4 GeV are the same within uncertainties. However, in $\mathrm{Cu}+\mathrm{Cu}$ collisions we observe a decrease in $v_2$ values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both $\mathrm{Au}+\mathrm{Au}$ and $\mathrm{Cu}+\mathrm{Cu}$ collisions we find that $v_2$ depends both on eccentricity and the number of participants, $N_{\mathrm{part}}$. We observe that $v_2$ divided by eccentricity ($\varepsilon$) monotonically increases with $N_{\mathrm{part}}$ and scales as $N_{\mathrm{part}}^{1/3}$. The $\mathrm{Cu}+\mathrm{Cu}$ data at 62.4 GeV falls below the other scaled $v_2$ data. For identified hadrons, $v_2$ divided by the number of constituent quarks $n_q$ is independent of hadron species as a function of transverse kinetic energy $K{E}_T=m_T-m$ between $0.1<K{E}_T/n_q<1$ GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the $\mathrm{Cu}+\mathrm{Cu}$ data at 62.4 GeV, of $v_2/(n_q·\varepsilon ·N_{\mathrm{part}}^{1/3})$ vs $K{E}_T/n_q$ for all measured particles.

We present a systematic study of charged-pion and kaon interferometry in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{{}_{\mathit{NN}}}}=200$ GeV. The kaon mean source radii are found to be larger than pion radii in the outward and longitudinal directions for the same transverse mass; this difference increases for more central collisions. The azimuthal-angle dependence of the radii was measured with respect to the second-order event plane and similar oscillations of the source radii were found for pions and kaons. Hydrodynamic models qualitatively describe the similar oscillations of the mean source radii for pions and kaons, but they do not fully describe the transverse-mass dependence of the oscillations.

Forward calorimetry in the PHOBOS detector has been used to study charged hadron production in $d+\text{Au}, p+\text{Au}$, and $n+\text{Au}$ collisions at $\sqrt{s_{NN}}=200\mathrm{GeV}$. The forward proton calorimeter detectors are described and a procedure for determining collision centrality with these detectors is detailed. The deposition of energy by deuteron spectator nucleons in the forward calorimeters is used to identify $p+\text{Au}$ and $n+\text{Au}$ collisions in the data. A weighted combination of the yield of $p+\text{Au}$ and $n+\text{Au}$ is constructed to build a reference for $\mathrm{Au}+\mathrm{Au}$ collisions that better matches the isospin composition of the gold nucleus. The $p_{\mathrm{T}}$ and centrality dependence of the yield of this improved reference system is found to match that of $d+\text{Au}$. The shape of the charged-particle transverse momentum distribution is observed to extrapolate smoothly from $p+\overline{p}$ to central $d+\text{Au}$ as a function of the charged-particle pseudorapidity density. The asymmetry of positively and negatively charged hadron production in $p+\text{Au}$ is compared to that of $n+\text{Au}$. No significant asymmetry is observed at midrapidity. These studies augment recent results from experiments at the CERN Large Hadron Collider and BNL Relativistic Heavy Ion Collider facilities to give a more complete description of particle production in $p+A$ and $d+A$ collisions, essential for the understanding the medium produced in high-energy nucleus-nucleus collisions.

Neutron matter at densities on the order of the nuclear saturation density is believed to have neutrons paired in the ${}^{3}P_2$ channel. We study the low-lying modes of this phase and find two massless modes (angulons), resulting from the spontaneous breaking of rotational symmetry as well as three other gapped modes. We compute their masses at arbitrary temperatures.

In a single $j$-shell calculation we consider the effects of several different interactions on Gamow-Teller $B$(GT) values and magnetic moments. The interactions used are MBZE, $J=0$ pairing, $J_{\max }$ pairing, and half and half. Care is taken when there are isospin crossings and/or degeneracies.

In this theoretical study, we report an investigation on the behavior of two-neutron separation energy, a differential variation of the nucleon separation energy, the nuclear charge radii, and the single-particle energy levels along the isotopic chains of transitional nuclei. We have used the relativistic mean-field formalism with NL3 and NL3* forces for this present analysis. The study refers to the even-even nuclei such as Zr, Mo, Ru, and Pd for $N=42-86$, where a rich collective phenomena such as proton radioactivity, cluster or nucleus radioactivity, exotic shapes, island of inversion, etc. are observed. We found that there are few nonmonotonic aspects over the isotopic chain, which are correlated with the structural properties such as shell/subshell closures, the shape transition, clustering, magicity, etc. In addition to these, we have shown the internal configuration of these nuclei to get a further insight into the reason for these discrepancies.

The dependence of the evaporation residue cross section (ERCS)'s ability to produce superheavy nuclei (SHN) on the isospin of colliding nuclei is analyzed within the dinuclear system concept. ERCSs are discussed in detail and compared with existing experimental data. The fusion probabilities and surviving probabilities depend sensitively on the neutron numbers of the target and projectile nuclei. In most cases a neutron excess in the system can increase the producing cross section of a new nuclide of SHN. Some predicted ERCSs for the new isotopes of SHN were found to be as large as about 1–8 pb, which is large enough to be realized experimentally with the current existing technology. Element 120 may be produced by ${}^{50}\mathrm{Ti}+{}^{251,252}\mathrm{Cf}$, with the ERCS being about 0.03 pb, and element 119 may be produced by the reaction channel ${}^{50}\mathrm{Ti}+{}^{248,249}\mathrm{Bk}$, with the ERCS being about 0.1 pb via $3n$ and $4n$ emission channels, respectively. Radioactive projectiles are not much more favorable in comparison to stable projectiles.

Background: ${}^{45}\mathrm{Sc}$ has rarely been studied as a projectile in fusion-evaporation reactions. The synthesis of new superheavy elements with $Z>118$ will require projectiles with $Z>20$, and ${}^{45}\mathrm{Sc}$ could potentially be used for this purpose.

Purpose: Cross sections were measured for the $xn$ and $pxn$ exit channels in the reactions of ${}^{45}\mathrm{Sc}$ with lanthanide targets for comparison to previous measurements of ${}^{48}\mathrm{Ca}$ reacting with similar targets. These data provide insight on the survival of spherical, shell-stabilized nuclei against fission, and could have implications for the discovery of new superheavy elements.

Methods: Beams of ${}^{45}\mathrm{S}{\mathrm{c}}^{6+}$ were delivered from the K500 superconducting cyclotron at Texas A&M University with an energy of $\approx 5\mathrm{MeV}/\mathrm{nucleon}$. Products were purified using the Momentum Achromat Recoil Spectrometer, and excitation functions were measured for reactions of ${}^{45}\mathrm{Sc}+{}^{156-158,160}\mathrm{Gd}$, ${}^{159}\mathrm{Tb}$, and ${}^{162}\mathrm{Dy}$ at five or more energies each. Evaporation residues were identified by their characteristic $\alpha$-decay energies. Experimental data were compared to a simple theoretical model to study each step in the fusion-evaporation process.

Results: The maximum measured $4n$ cross sections for the reactions ${}^{45}\mathrm{Sc}+{}^{156-158,160}\mathrm{Gd}$, ${}^{159}\mathrm{Tb}$, and ${}^{162}\mathrm{Dy}$ are $5.8\pm 1.7$, $25\pm 5$, $39\pm 7$, $150\pm 20$, $2.4_{-1.4}^{+2.3}$, and $1.8\pm 0.6\mu \mathrm{b}$, respectively. Proton emission competes effectively with neutron emission from the excited compound nucleus in most cases. The $\alpha ,\alpha n$, and $\alpha 2n$ products were also observed in the ${}^{45}\mathrm{Sc}+{}^{162}\mathrm{Dy}$ reaction.

Conclusions: Excitation functions were reported for ${}^{45}\mathrm{Sc}$-induced reactions on lanthanide targets for the first time, and these cross sections are much smaller than for ${}^{48}\mathrm{Ca}$-induced reactions on the same targets. The relative neutron-deficiency of the compound nuclei leads to significantly increased fissility and large reductions in the survival probability. Little evidence for improved production cross sections due to shell-stabilization was observed.

A systematic study of the factorization of long-range azimuthal two-particle correlations into a product of single-particle anisotropies is presented as a function of $p_{\mathrm{T}}$ and $\eta$ of both particles and as a function of the particle multiplicity in PbPb and $p\mathrm{Pb}$ collisions. The data were taken with the CMS detector for PbPb collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}=2.76$ TeV and $p\mathrm{Pb}$ collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}=5.02$ TeV, covering a very wide range of multiplicity. Factorization is observed to be broken as a function of both particle $p_{\mathrm{T}}$ and $\eta$. When measured with particles of different $p_{\mathrm{T}}$, the magnitude of the factorization breakdown for the second Fourier harmonic reaches 20% for very central PbPb collisions but decreases rapidly as the multiplicity decreases. The data are consistent with viscous hydrodynamic predictions, which suggest that the effect of factorization breaking is mainly sensitive to the initial-state conditions rather than to the transport properties (e.g., shear viscosity) of the medium. The factorization breakdown is also computed with particles of different $\eta$. The effect is found to be weakest for mid-central PbPb events but becomes larger for more central or peripheral PbPb collisions, and also for very-high-multiplicity $p\mathrm{Pb}$ collisions. The $\eta$-dependent factorization data provide new insights to the longitudinal evolution of the medium formed in heavy ion collisions.