Using a novel concept for efficient laser spectroscopy, we investigated the hyperfine splittings of three different atomic transitions in the long-lived isotopes ${}^{97-99}\mathrm{Tc}$. Despite the refractory character of the element technetium, sample sizes as low as ${10}^{11}$ atoms were sufficient to achieve excellent signal-to-noise ratios at a spectroscopic linewidth of less than 100 MHz. The obtained spectra were analyzed in detail, which results in a very good consistency for the extracted hyperfine parameters from the different transitions. The presented measurements provide the first hyperfine structure data for the isotopes ${}^{97,98}\mathrm{Tc}$ from which, in combination with the known nuclear moments of ${}^{99}\mathrm{Tc}$, their nuclear magnetic dipole and electric quadrupole moments were extracted. In addition, the experimental data confirm the predicted nuclear spin of ${}^{98}\mathrm{Tc}$ to $I=6$. In combination with atomic Multiconfiguration Dirac-Hartree-Fock calculations, the observed isotope shifts were investigated and the changes in mean-square charge radii were determined.

A recent experimental campaign was completed at the LOHENGRIN spectrometer. It was dedicated to the determination of the local odd-even effect as a function of the fission product kinetic energy for a given mass. We discuss here the mass $A=139$ produced from the thermal neutron induced fission of ${}^{241}\mathrm{Pu}$. A comparison with the Monte Carlo code fifrelin allows one to interpret these data in regards to the neutron emission process. The long term goal is to test and validate the phenomenological temperature ratio law used in fifrelin to split the total excitation energy between both fission fragments.

Background: In heavy-ion-induced fusion reactions, cross sections in the sub-barrier region are enhanced compared to predictions of the one-dimensional barrier penetration model. This enhancement is often understood by invoking deformation and coupling of the relative motion with low-lying inelastic states of the reaction partners. However, effects of nucleon transfer on fusion below the barrier, especially for the systems having positive $Q$ value neutron transfer (PQNT) channels, are yet to be disentangled completely.

Purpose: We intend to study the role of the PQNT effect on the sub-barrier fusion of the ${}^{18}\mathrm{O} + {}^{116}\mathrm{Sn}$ system having positive $Q$ value for the two-neutron stripping channel. Also we reflect on the interplay of couplings involved in the system around the Coulomb barrier.

Method: The fusion excitation function was measured at energies from $11\%$ below to $46\%$ above the Coulomb barrier for ${}^{18}\mathrm{O} + {}^{116}\mathrm{Sn}$ using a recoil mass spectrometer, viz., the Heavy-Ion Reaction Analyser (HIRA). Fusion barrier distributions were extracted from the data. Results from the experiment were analyzed within the framework of the coupled-channels model.

Results: Fusion cross sections at energies below the Coulomb barrier showed strong enhancement compared to predictions of the one-dimensional barrier penetration model. The fusion process is influenced by couplings to the collective excitations with coupling to single- and two-phonon vibrational states of the target and the projectile respectively. Inclusion of the two-neutron transfer channel in the calculation along with these couplings could reproduce the data satisfactorily.

Conclusions: The significant role of PQNT in enhancing the sub-barrier fusion cross section for the chosen system is not observed. It simply reduced the sub-barrier fusion cross section. Therefore, a consistent link between PQNT and sub-barrier fusion enhancement could not be established vividly while comparing the fusion excitation function from this work with the same from other ${}^{16,18}\mathrm{O}$-induced reactions. This clearly points to the need for more experimental as well as theoretical investigation in this field.

Nonequilibrium dynamics for relativistic fluid or quark gluon plasma (QGP) have already been calculated earlier up to third order using both kinetic and thermodynamic approaches. Calculations presented in this article are based on thermodynamics principles. The expressions for third order dissipative fluxes have been derived from equation for entropy four-current developed earlier by Muronga. The relaxation equations in the present work have been developed in a simple Bjorken ($1+1$) dimensional scenario and Eckart frame. The relaxation equations are found to have slightly different values for the coupling coefficients as compared to calculations from earlier models. The solutions to the differential equations have been found to be sensitive to values of these coefficients. The shear relaxation equations derived in third order theory are discussed term by term. Effects of third order theory on shear relaxation time have been discussed. Thermodynamic quantities related to hot and dense matter have been calculated as functions of proper time. Moreover, various initial conditions for the relaxation equations have been assumed to study their effects on above mentioned observables. A CERN Large Hadron Collider QGP formation time of ${\tau }_0=0.4\mathrm{fm}/c$ and temperature of $T_0=500\mathrm{MeV}$ have been assumed.

The quasiparticle random phase approximation is used in evaluation of the total muon capture rates for final nuclei participating in double-$\beta$ decay. Several variants of the method are used, depending on the size of the single-particle model space used, or treatment of the initial bound muon wave function. The resulting capture rates are all reasonably close to each other. In particular, the variant that appears to be most realistic results in rates that are in good agreement with the experimental values. There is no necessity for an empirical quenching of the axial current coupling constant $g_A$. Its standard value $g_A=1.27$ seems to be adequate.

Based on the realistic nuclear force of the high-precision CD-Bonn potential, we have performed comprehensive calculations for neutron-rich calcium isotopes using the Gamow shell model (GSM) which includes resonance and continuum. The realistic GSM calculations produce well binding energies, one- and two-neutron separation energies, predicting that ${}^{57}\mathrm{Ca}$ is the heaviest bound odd isotope and ${}^{70}\mathrm{Ca}$ is the dripline nucleus. Resonant states are predicted, which provides useful information for future experiments on particle emissions in neutron-rich calcium isotopes. Shell evolutions in the calcium chain around neutron numbers $N=32$, 34, and 40 are understood by calculating effective single-particle energies, the excitation energies of the first $2^{+}$ states and two-neutron separation energies. The calculations support shell closures at ${}^{52}\mathrm{Ca}$ ($N=32$) and ${}^{54}\mathrm{Ca}$ ($N=34$) but show a weakening of shell closure at ${}^{60}\mathrm{Ca}$ ($N=40$). The possible shell closure at ${}^{70}\mathrm{Ca}$ ($N=50$) is predicted.

The neutron total cross sections ${\sigma }_{\mathrm{tot}}$ of ${}^{16,18}\mathrm{O},{}^{58,64}\mathrm{Ni}$, ${}^{103}\mathrm{Rh}$, and ${}^{112,124}\mathrm{Sn}$ have been measured at the Los Alamos Neutron Science Center from low to intermediate energies $(3\le E_{\mathrm{lab}}\le 450 \mathrm{MeV})$ by leveraging wave-form-digitizer technology. The ${\sigma }_{\mathrm{tot}}$ relative differences between isotopes are presented, revealing additional information about the isovector components needed for an accurate optical-model description away from stability. Digitizer-enabled ${\sigma }_{\mathrm{tot}}$-measurement techniques are discussed and a series of uncertainty-quantified dispersive optical model (DOM) analyses using these new data is presented, validating the use of the DOM for modeling light systems $\left({}^{16,18}\mathrm{O}\right)$ and systems with open neutron shells $({}^{58,64}\mathrm{Ni} \mathrm{and} {}^{112,124}\mathrm{Sn})$. The valence-nucleon spectroscopic factors extracted for each isotope reaffirm the usefulness of high-energy proton reaction cross sections for characterizing depletion from the mean-field expectation.

To describe dynamics of bulk and fluctuations near the QCD critical point we develop general relativistic fluctuation formalism for a fluid carrying baryon charge. Feedback of fluctuations modifies hydrodynamic coefficients including bulk viscosity and conductivity and introduces nonlocal and noninstantaneous terms in constitutive equations. We perform necessary ultraviolet (short-distance) renormalization to obtain cutoff-independent deterministic equations suitable for numerical implementation. We use the equations to calculate the universal nonanalytic small-frequency dependence of transport coefficients due to fluctuations (long-time tails). Focusing on the critical mode we show how this general formalism matches existing $\text{Hydro+}$ description of fluctuations near the QCD critical point and nontrivially extends it inside and outside of the critical region.

Background: Neutron-rich nuclei around neutron number $N=60$ show a dramatic shape transition from spherical ground states to prolate deformation in ${}^{98}\mathrm{Sr}$ and heavier nuclei.

Purpose: The purpose of this study is to investigate the single-particle structure approaching the shape transitional region.

Method: The level structures of neutron-rich ${}^{93,94,95}\mathrm{Sr}$ were studied via the ${}^2\mathrm{H}({}^{94,95,96}\mathrm{Sr},t)$ one-neutron stripping reactions at TRIUMF using a beam energy of 5.5 $A\mathrm{MeV}$. $\gamma$-rays emitted from excited states and recoiling charged particles were detected by using the TIGRESS and SHARC arrays, respectively. States were identified by gating on the excitation energy and, if possible, the coincident $\gamma$ radiation.

Results: Triton angular distributions for the reactions populating states in ejectile nuclei ${}^{93,94,95}\mathrm{Sr}$ were compared with distorted wave Born approximation calculations to assign and revise spin and parity quantum numbers and extract spectroscopic factors. The results were compared with shell-model calculations and the reverse $(d,p)$ reactions and good agreement was obtained.

Conclusions: The results for the ${}^2\mathrm{H}({}^{94}\mathrm{Sr},t){}^{93}\mathrm{Sr}$ and ${}^2\mathrm{H}({}^{95}\mathrm{Sr},t){}^{94}\mathrm{Sr}$ reactions are in good agreement with shell-model calculations. A two-level mixing analysis for the $0^{+}$ states in ${}^{94}\mathrm{Sr}$ suggest strong mixing of two shapes. For the ${}^2\mathrm{H}({}^{96}\mathrm{Sr},t){}^{95}\mathrm{Sr}$ reaction the agreement with the shell-model is less good. The configuration of the ground state of ${}^{96}\mathrm{Sr}$ is already more complex than predicted, and therefore indications for the shape transition can already be observed before $N=60$.

The ${}^{86}\mathrm{Zr}$ nucleus, which has a low-lying level scheme characteristic of a transitional nucleus, presents, according to the existing electromagnetic transition data, a subunitary ${\mathrm{B}}_{4/2}=B(E2,4_1^{+}\to 2_1^{+})/B(E2,2_1^{+}\to 0_1^{+})$ ratio, which is anomalously low for a nonmagic nucleus, as it is outside the range of the traditional collective models values. In order to check this anomaly, we performed new measurements of the lifetimes of its low-lying states, with the $\gamma$-ray coincident recoil distance Doppler shift method, using the ROSPHERE detector array. New lifetimes were determined for the positive-parity yrast states up to the ${10}^{+}$ one, and for the $8_2^{+},5_1^{-}$, and $7_1^{-}$ states. The newly determined values of the $B\left(E2\right)$ values for the $2_1^{+}$ and $4_1^{+}$ states characterize a nucleus with a moderate quadrupole deformation and are well described by the interacting boson model. The ratio $B_{4/2}=1.38\left(22\right)$ is no longer anomalous. The low $B\left(E2\right)$ value of the $6_1^{+}$ state indicates a noncollective structure.

Excited states of ${}^{129}\mathrm{In}$ populated following the $\beta$ decay of ${}^{129}\mathrm{Cd}$ were experimentally studied with the GRIFFIN spectrometer at the ISAC facility of TRIUMF, Canada. A 480-MeV proton beam was impinged on a uranium carbide target and ${}^{129}\mathrm{Cd}$ was extracted using the Ion Guide Laser Ion Source (IG-LIS). $\beta$ and $\gamma$ rays following the decay of ${}^{129}\mathrm{Cd}$ were detected with the GRIFFIN spectrometer comprising the plastic scintillator SCEPTAR and 16 high-purity germanium (HPGe) clover-type detectors. From the $\beta \text{−}\gamma \text{−}\gamma$ coincidence analysis, 32 new transitions and seven new excited states were established, expanding the previously known level scheme of ${}^{129}\mathrm{In}$. The $logft$ values deduced from the $\beta$-feeding intensities suggest that some of the high-lying states were populated by the $\nu 0g_{7/2}\to \pi 0g_{9/2}$ allowed Gamow-Teller (GT) transition, which indicates that the allowed GT transition is more dominant in the ${}^{129}\mathrm{Cd}$ decay than previously reported. Observation of fragmented Gamow-Teller strengths is consistent with theoretical calculations.

Barrier distributions derived from fusion and back-angle quasielastic scattering excitation functions are important tools in understanding the reaction mechanisms in nucleus-nucleus collision at near-barrier energies. The excitation functions for the quasielastic scattering of ${}^7\mathrm{Li}$ from the medium-mass target ${}^{64}\mathrm{Ni}$ are measured at the angles ${150}^{\circ }$ and ${170}^{\circ }$ for the energy range of 12 to 24 MeV. The corresponding quasielastic barrier distribution function for this system is derived. The extracted barrier distribution is then compared with the previously measured fusion barrier distribution for the same system to look for any shift in the peak location to below-barrier energy as observed for the ${}^6\mathrm{Li}+{}^{64}\mathrm{Ni}$ system. Further, the barrier distributions of the system ${}^7\mathrm{Li}+{}^{64}\mathrm{Ni}$ from complementary measurements of the fusion and back-angle excitation functions are compared with the barrier distribution functions of ${}^6\mathrm{Li}+{}^{64}\mathrm{Ni}$. While ${}^6\mathrm{Li}$ behaves like a weakly bound projectile, another stable isotope of Li, ${}^7\mathrm{Li}$, behaves more like a strongly bound projectile in collision with the same medium-mass target ${}^{64}\mathrm{Ni}$.

The secondary $\gamma$ rays emitted following a nuclear reaction are often relatively straightforward to detect experimentally. Despite the large volume of such data, a practical formalism for describing these $\gamma$ rays in terms of partial-wave $T$-matrix elements has never been given. The partial-wave formalism is applicable when $R$-matrix methods are used to describe the reaction in question. This paper supplies the needed framework, and it is demonstrated by the application to the ${}^{15}\mathrm{N}(p,{\alpha }_1\gamma ){}^{12}\mathrm{C}$ reaction.

For states of ${}^{19}\mathrm{F}$ from $E_x=8.1$ to 10.9 MeV, I have examined the proton spectroscopic factors from the reaction ${}^{18}\mathrm{O}(d,n)$ and compared them with spectroscopic factors computed from the proton widths. Even though the widths cover a range greater than a factor ${10}^5$, the two sets of spectroscopic factors agree to within about a factor of 2.

I have applied a simple two-state mixing model to $E2$ strengths among low-lying states in ${}^{72}\mathrm{Kr}$. Solutions are found with basis states in ${}^{72}\mathrm{Kr}$ similar to those in ${}^{74}\mathrm{Kr}$. As expected, the amount of the more collective basis state in the yrast states increases with $J$ for $J=0$, 2, and 4.

We carry out simulations using a multiphase transport (AMPT) model to describe the response relation between $v_2$ and ${\varepsilon }_2$ in Pb-Pb and $p$-Pb collisions at $\sqrt{s_{NN}}=5.02\mathrm{TeV}$, respectively. To simulate such relation, two methods have been introduced in the calculation: One is the directed response (DR) method, which correlates the outgoing particles with the initial anisotropy directly, and the other one is the cumulant response (CR) method, which is constructed from a cumulant correlation between outgoing particles. Based on calculations of the DR and CR methods, the response relations as a function of the transverse momentum are both shown in Pb-Pb and $p$-Pb collisions. By comparing the DR and CR methods, we found that the linear response relations are almost identical in all the present collisions. Similar results of $\text{linear}+\text{cubic}$ response relations are also shown in the higher multiplicity systems, and it has become a significant difference in the lower multiplicity systems, i.e., the peripheral Pb-Pb collisions and $p$-Pb collisions. Throughout the whole $p_T$-dependent simulations, the ${\kappa }_2$ in the linear response and in the $\text{linear}+\text{cubic}$ response are almost identical, except for in the lower multiplicity systems by the DR method. If one implements a pseudorapidity gap by the CR calculation, the $p_T$-dependent and $\eta$-independent response relations are similarly shown in peripheral Pb-Pb systems and $p$-Pb systems, which may imply that a collective response exists in the most central $p$-Pb collisions. These collective behaviors are dominantly produced on the stage of the medium expansions.

We investigate the contribution of the $2_2^{+}$ resonance in ${}^6\mathrm{He}$ to observables via analysis of the ${}^6\mathrm{He}(p, p\prime )$ reaction by using the continuum-discretized coupled channels method combined with the complex-scaling method. In this Rapid Communication, we obtain the $2_2^{+}$ state with the resonant energy 2.25 MeV and the decay width 3.75 MeV and analyze contributions of resonances and nonresonant continuum states to the cross section separately. It is found that the $2_2^{+}$ state plays an important role in the energy spectrum. Furthermore, contributions of nonresonant continuum states are also important to clarify the properties of the $2_2^{+}$ state.

The possibility of the ${}^8\mathrm{He}$ and ${}^9\mathrm{Li}$ clusters in atomic nuclei is discussed. Until now most of the clusters in the conventional models have been limited to the closures of the three-dimensional harmonic oscillators, such as ${}^4\mathrm{He}$, ${}^{16}\mathrm{O}$, and ${}^{40}\mathrm{Ca}$. In the neutron-rich nuclei, however, the neutron-to-proton ratio ($N/Z$) is not unity, and it is worthwhile to think about more neutron-rich objects with $N>Z$ as the building blocks of cluster structures. Here the nuclei with the neutron number six, which is the subclosure of the $p_{3/2}$ subshell of the $jj$-coupling shell model, are assumed to be clusters, and thus we study the ${}^8\mathrm{He}$ and ${}^9\mathrm{Li}$ cluster structures in ${}^{16}\mathrm{Be}$ (${}^8\mathrm{He}+{}^8\mathrm{He}$), ${}^{17}\mathrm{B}$ (${}^8\mathrm{He}+{}^9\mathrm{Li}$), ${}^{18}\mathrm{C}$ (${}^9\mathrm{Li}+{}^9\mathrm{Li}$), and ${}^{24}\mathrm{C}$ (${}^8\mathrm{He}+{}^8\mathrm{He}+{}^8\mathrm{He}$). Recent progress of the antisymmetrized quasi-cluster model (AQCM) enables us to utilize $jj$-coupling shell-model wave functions as the clusters rather easily. It is shown that the ${}^8\mathrm{He}+{}^9\mathrm{Li}$ and ${}^9\mathrm{Li}+{}^9\mathrm{Li}$ cluster configurations cover the lowest shell-model states of ${}^{17}\mathrm{B}$ and ${}^{18}\mathrm{C}$, respectively. To predict cluster states with large relative distances, we increase the expectation value of the principal quantum numbers by adding the nodes to the lowest states under the condition that the total angular momentum is unchanged (equal to $J^{\pi }=0^{+}$). As a result, developed cluster states are obtained around the corresponding threshold energies. The rotational band structure of ${}^{24}\mathrm{C}$, which reflects the symmetry of equilateral triangular configuration ($D_{3h}$ symmetry) of three ${}^8\mathrm{He}$ clusters, also appears around the threshold energy. We suggest a novel mechanism whereby the spin-orbit interaction induces the clustering, which is distinctive of neutron-rich nuclei.

The nuclide ${}^{266}\mathrm{Bh}$ was produced in the ${}^{248}\mathrm{Cm}({}^{23}\mathrm{Na},5n){}^{266}\mathrm{Bh}$ reaction at beam energies of 125.9, 130.6, and 135.3 MeV. Decay properties of ${}^{266}\mathrm{Bh}$ were investigated with a rotating wheel apparatus for $\alpha$ and spontaneous fission (SF) spectrometry under low background conditions attained by a gas-jet transport system coupled to the RIKEN gas-filled recoil ion separator. Based on genetically correlated $\alpha \text{−}\alpha$ and $\alpha$-SF decay chains, a total of 23 chains were assigned to ${}^{266}\mathrm{Bh}$ and its daughter nuclide ${}^{262}\mathrm{Db}$ and granddaughter ${}^{258}\mathrm{Lr}$. The half-life of ${}^{266}\mathrm{Bh}$ was measured to be $T_{1/\phantom{12}2}=10.0_{-1.7}^{+2.6}\mathrm{s}$ which is an order of magnitude longer than the literature data. The $\alpha$-particle energies of ${}^{266}\mathrm{Bh}$ disperse widely in the range of $E_{\alpha }=8.62–9.40\mathrm{MeV}$. The maximum production cross section for the ${}^{248}\mathrm{Cm}({}^{23}\mathrm{Na},5n){}^{266}\mathrm{Bh}$ reaction was determined to be $\sigma =57\pm 14$ pb at 130.6 MeV, whereas the upper limit for the ${}^{248}\mathrm{Cm}$(${}^{23}\mathrm{Na},4n$)${}^{267}\mathrm{Bh}$ reaction was $\sigma \le 14$ pb at 121.2 MeV. These cross sections are discussed by comparing with the literature data as well as the theoretical calculations.

Possible correlations of the global polarization of $\mathrm{\Lambda }$ hyperons with angular momentum and transverse flow in the central region of colliding nuclei are studied based on a refined estimate of the global polarization. Simulations of $\mathrm{Au}+\mathrm{Au}$ collisions at collision energies $\sqrt{s_{NN}}=6–40\mathrm{GeV}$ are performed within the model of the three-fluid dynamics. Within the crossover and first-order-phase-transition scenarios this refined estimate quite satisfactorily reproduces the experimental STAR data. Hadronic scenario fails at high collision energies, $\sqrt{s_{NN}}>10$ GeV, and even predicts the opposite sign of the global polarization. It is found that the global polarization correlates with neither the angular momentum accumulated in the central region nor with directed and elliptic flow. At the same time we observed correlation between the angular momentum and directed flow in both their time and collision-energy dependence. These results suggest that, although initially the angular momentum is the driving force for the vortex generation, later the angular momentum and vortex motion become decorrelated in the midrapidity region. Then the midrapidity angular momentum is determined by the pattern of the directed flow and even becomes negative when the antiflow occurs. At the freeze-out stage, the dominant part of the participant angular momentum is accumulated in the fragmentation regions.