We report the first observation of the $2^{+}$ isomer in ${}^{52}\mathrm{Co}$, produced in the $\beta$ decay of the $0^{+}$, ${}^{52}\mathrm{Ni}$ ground state. We have observed three $\gamma$ rays at 849, 1910, and 5185 keV characterizing the $\beta$ de-excitation of the isomer. We have measured a half-life of 102(6) ms for the isomeric state. The Fermi and Gamow-Teller transition strengths for the $\beta$ decay of ${}^{52m}\mathrm{Co}$ to ${}^{52}\mathrm{Fe}$ have been determined. We also add new information on the $\beta$ decay of the $6^{+}$, ${}^{52}\mathrm{Co}$ ground state, for which we have measured a half-life of 112(3) ms.

Lifetime of the $3/2^{-}$ first excited state in ${}^{37}\mathrm{S}$ populated by the ${\beta }^{-}$ decay of ${}^{37}\mathrm{P}$ has been measured using $\beta -\gamma$ delayed coincidence technique. The $B(E2;7/2^{-}\to 3/2^{-})$ value in ${}^{37}\mathrm{S}$ deduced from the lifetime comes close to the $B(E2;0^{+}\to 2_1^{+})$ value in weakly deformed ${}^{38}\mathrm{S}$ but deviates significantly from that in spherical ${}^{36}\mathrm{S}$. This manifests that ${}^{37}\mathrm{S}$ is a weakly deformed rather than spherical nucleus.

We perform a feasibility study for the search of proton decay from Pm, the last element without an isotope found, that decays by proton emission in the region of charges between 50 and 83. The behaviors of the half-lives for decay from the ground and possible isomeric states of ${}^{125}\mathrm{Pm}$ are discussed as a function of deformation, spin of the decaying state, and energy of the emitted proton, indicating the most probable regions of energy where proton radioactivity might be detected. We find that within our predictions, proton decay from ${}^{125}\mathrm{Pm}$ could be measurable.

We report measurements of target- and double-spin asymmetries for the exclusive channel $\vec{e}\vec{p}\to e{\pi }^{+}\left(n\right)$ in the nucleon resonance region at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). These asymmetries were extracted from data obtained using a longitudinally polarized ${\mathrm{NH}}_3$ target and a longitudinally polarized electron beam with energies 1.1, 1.3, 2.0, 2.3, and 3.0 GeV. The new results are consistent with previous CLAS publications but are extended to a low $Q^2$ range from 0.0065 to $0.35{(\mathrm{GeV}/c)}^2$. The $Q^2$ access was made possible by a custom-built Cherenkov detector that allowed the detection of electrons for scattering angles as low as $6^{\circ }$. These results are compared with the unitary isobar models JANR and MAID, the partial-wave analysis prediction from SAID, and the dynamic model DMT. In many kinematic regions our results, in particular results on the target asymmetry, help to constrain the polarization-dependent components of these models.

The present work starts by providing a clear identification of correlations between critical parameters ($T_c$, $P_c$, ${\rho }_c$) and bulk quantities at zero temperature of relativistic mean-field models (RMF) presenting third- and fourth-order self-interactions in the scalar field $\sigma$. Motivated by the nonrelativistic version of this RMF model, we show that the effective nucleon mass ($M^{*}$) and the incompressibility ($K_o$), at the saturation density, are correlated with $T_c$, $P_c$, and ${\rho }_c$, as well as the binding energy and the saturation density itself. We verify the agreement of results with previous theoretical ones regarding different hadronic models. Concerning recent experimental data of the symmetric nuclear matter critical parameters, our study allows a prediction of $T_c$, $P_c$, and ${\rho }_c$ compatible with such values, by combining them, through the correlations found, with previous constraints related to $M^{*}$ and $K_o$. An improved RMF parametrization, which better agrees with experimental values for $T_c$, is also indicated.

Background: We study heavy-ion reactions from barrier up to Fermi energy. The data were acquired with the INDRA detector at the GANIL (Caen, France) facility.

Purpose: We aim to determine the reaction and fusion cross sections for the reactions induced by ${}^{129}\mathrm{Xe}$ projectiles on ${}^{\mathrm{nat}}\mathrm{Sn}$ targets for incident energies ranging from $8A$ to $35A$ MeV. In particular, the evaluation of the fusion and incomplete fusion cross sections is the main purpose, altogether with the comparison with the systematics of Eudes et al. [Europhys. Lett. 104, 22001 (2013)].

Method: The reaction cross sections are evaluated at each beam energy with data acquired thanks to the INDRA $4\pi$ array. The events are sorted with the help of the observable $E_{\text{iso,max}}$. We focus therefore our study on a selected sample of events, in such a way that the fusion and incomplete fusion cross sections can be estimated.

Results: We present the excitation function of reaction and fusion cross sections for the heavy and nearly symmetric system ${}^{129}\mathrm{Xe}+{}^{\mathrm{nat}}\mathrm{Sn}$ from $8A$ to $35A$ MeV. For the fusion excitation function the comparison with the systematics of Eudes et al. seems to be in a fair agreement starting from the beam energy $20A$ MeV. For the lower beam energies ($8A$ and $12A$ MeV) discrepancies are observed.

Conclusions: The evaluated fusionlike cross sections show a good agrement with a recent systematics for beam energies greater than $20A$ MeV. For low beam energies the cross-sectional values are lower than the expected ones. A probable reason for these low values is in the fusion hindrance at energies above or close to the barrier.

A study of fusion-barrier distributions through an analysis of their moments is presented. The moments can be obtained from least-squares fits of the energy-weighted fusion cross sections without the need of calculating second derivatives. The zeroth and first moments determine the fusion radius $R$ and the Coulomb barrier $V_C$. These two quantities are the same as the parameters $R$ and $V_C$ that are used in the well-known expression, $E\sigma =\pi R^2(E-V_C)$, for the fusion cross section at high energies. The second and third moments, $M_2$ and $M_3$, determine the width and skewness of the barrier distribution, respectively. From these global parameters new correlations for the study of heavy-ion-induced fusion reactions can be obtained. Systems exhibiting a large coupling to transfer reactions show a small fusion radius as well as a large second moment. A negative third moment is correlated with a prolate deformation of the target nucleus.

We study the rotational collective motion of the quark-gluon plasma in relativistic heavy-ion collisions using the widely adopted a multiphase transport (AMPT) model. The global angular momentum, the average vorticity carried by the quark-gluon plasma, and the locally defined vorticity fields are computed for $\mathrm{Au}+\mathrm{Au}$ collisions, with detailed information of their time evolution, spatial distribution, as well as the dependence on beam energy and collision centrality.

We present predictions of the binding energy per nucleon and the neutron skin thickness in highly neutron-rich isotopes of oxygen, magnesium, and aluminum. The calculations are carried out at and below the neutron drip line as predicted by our model. The nuclear properties are obtained via an energy functional whose input is the equation of state of isospin-asymmetric infinite matter. The latter is based on a microscopic derivation of the energy per particle in neutron matter applying chiral few-nucleon forces together with a phenomenological model for the equation of state of symmetric nuclear matter. We highlight the impact of the neutron matter equation of state at different orders of chiral effective field theory on neutron skins and the binding energy per particle and quantify the uncertainty carried by our predictions.

Even tin isotopes of mass number $A=108–124$ are calculated with realistic interactions in the generalized-seniority approximation of the nuclear shell model. For each nucleus, we compute the lowest 10 000 states (5000 of each parity) up to around 8 MeV in excitation energy, by allowing as many as four broken pairs. The lowest 50 eigen energies of each parity are compared with the exact results of the large-scale shell-model calculation. The wave functions of the midshell nuclei show a clear pattern of the stepwise breakup of condensed coherent pairs with increasing excitation energy. We also compute in the canonical ensemble the thermal properties—level density, entropy, and specific heat—in relation to the thermal pairing phase transition.

We have examined within a fully self-consistent theoretical framework the energy difference between the anti-analog giant dipole resonance (AGDR) and the isobaric analog state (IAS), $E_{\mathrm{AGDR}}-E_{\mathrm{IAS}}$, as an indicator of the neutron skin and of the density behavior of the symmetry energy. We have improved two specific points in our HF+RPA calculations: (1) the exchange term of the two-body Coulomb interaction is treated exactly without Slater approximation; and (2) the two-parameters spin-orbit interaction is treated in a consistent way within the energy density functional theory. The estimated values for the neutron skin in ${}^{208}\mathrm{Pb}$ and the slope parameter of symmetry energy are compared with previous analysis available in the literature.

The structure of even-even neutron-rich Ru, Mo, Zr, and Sr nuclei in the $A\approx 100$ mass region is studied within the interacting boson model (IBM) with microscopic input from the self-consistent mean-field approximation based on the Gogny-D1M energy density functional. The deformation-energy surface in the quadrupole deformation space $(\beta ,\gamma )$, computed within the constrained Hartree–Fock–Bogoliubov framework, is mapped onto the expectation value of the appropriately chosen IBM Hamiltonian with configuration mixing in the boson condensate state. The mapped IBM Hamiltonian is used to study the spectroscopic properties of ${}^{98–114}\mathrm{Ru}, {}^{96–112}\mathrm{Mo}, {}^{94–110}\mathrm{Zr}$, and ${}^{92–108}\mathrm{Sr}$. Several cases of $\gamma$-soft behavior are predicted in Ru and Mo nuclei while a pronounced coexistence between strongly prolate and weakly oblate deformed shapes is found for Zr and Sr nuclei. The method describes well the evolution of experimental yrast and nonyrast states as well as selected $B\left(E2\right)$ transition probabilities.

Background: In ($n,n^{\prime }$) reactions on stable Ir and Au isotopes in the mass $A=190$ region, the experimentally established feeding of the isomers relative to the feeding of the corresponding ground states increases with increasing neutron energy, up to the neutron energy where the ($n,2n$) reaction channel opens up, and then decreases.

Purpose: In order to check for similar behavior in the mass $A=100$ region, the feeding of isomers and ground states in fast-neutron-induced reactions on stable isotopes in this mass region was studied. This is of especial interest for Rh which can be used as a radiochemical detector.

Methods: Excited states were studied using the ($n,n^{\prime }\gamma$), ($n,2n\gamma$), and ($n,3n\gamma )$ reactions on ${}^{103}\mathrm{Rh}$ and ${}^{109}\mathrm{Ag}$. A germanium detector array for $\gamma$-ray detection and the broad-spectrum pulsed neutron source of the Los Alamos Neutron Science Center's Weapons Neutron Research facility were used for the measurement. The energy of the incident neutrons was determined using the time-of-flight technique.

Results: Absolute partial $\gamma$-ray cross sections were measured for 57 transitions feeding isomers and ground states in ${}^{101,102,103}\mathrm{Rh}$ and ${}^{107,108,109}\mathrm{Ag}$. The feeding of the isomers was found to be very similar in the corresponding reaction channels and it is compared to the feeding determined for the ground states.

Conclusions: The opening of reaction channels at higher neutron energies removes angular momentum from the residual nucleus and reduces the population of the higher-spin isomers relative to the feeding of the lower-spin ground states. Similar behavior was observed in the mass $A=190$ region in the feeding of higher-spin isomers, but the reverse behavior was observed in ${}^{176}\mathrm{Lu}$ with a lower-spin isomer and a higher-spin ground state.

Abstract. A stochastic approach based on four-dimensional Langevin equations was applied to calculate the anisotropy of fission fragment angular distributions, average prescission neutron multiplicity, and the fission probability in a wide range of fissile parameters for the compound nuclei ${}^{197}\mathrm{Tl},{}^{225}\mathrm{Pa},{}^{248}\mathrm{Cf}$, and ${}^{264}\mathrm{Rf}$ produced in fusion reactions. Three collective shape coordinates plus the projection of total spin of the compound nucleus to the symmetry axis $K$ were considered in the four-dimensional dynamical model. In the dynamical calculations, nuclear dissipation was generated through the chaos-weighted wall and window friction formula. Furthermore, in the dynamical calculations the dissipation coefficient of $K,{\gamma }_k$ was considered as a free parameter, and its magnitude inferred by fitting measured data on the anisotropy of fission fragment angular distributions for the compound nuclei ${}^{197}\mathrm{Tl},{}^{225}\mathrm{Pa},{}^{248}\mathrm{Cf}$, and ${}^{264}\mathrm{Rf}$. Comparison of the calculated results for the anisotropy of fission fragment angular distributions with the experimental data showed that the results of the calculations are in good agreement with the experimental data by using values of the dissipation coefficient of $K$ equal to (0.185–0.205), (0.175–0.192), (0.077–0.090), and (0.075–0.085) ${\left(\mathrm{MeV}\mathrm{zs}\right)}^{-1/2}$ for the compound nuclei ${}^{197}\mathrm{Tl},{}^{225}\mathrm{Pa},{}^{248}\mathrm{Cf}$, and ${}^{264}\mathrm{Rf}$, respectively. It was also shown that the influence of the dissipation coefficient of $K$ on the results of the calculations of the prescission neutron multiplicity and fission probability is small.

We here show that at lower momentum (i.e., $p_{\perp }\sim 10\mathrm{GeV}$) single particle suppression for different types of probes exhibit a clear mass hierarchy, which is a direct consequence of the differences in the energy loss, rather than the differences in the initial distributions. On the other hand, we predict that the mass hierarchy is not expected at high momentum (i.e., $p_{\perp }\sim 100\mathrm{GeV}$); i.e., while we surprisingly predict that suppression for charged hadrons will be somewhat smaller than the suppression for heavy mesons, we find that this difference will be a consequence of fragmentation functions, not the finite mass effects. That is, apart from the fragmentation functions, the probes of different masses exhibit nearly the same suppression in the high momentum region. We also argue that the same insensitivity on the probe types also appears for jets. In particular, the experimental data in the momentum regions where they exist for both types of probes, show similar suppressions of charged hadrons and inclusive jet data. Interestingly, we also find that our state-of-the-art suppression predictions for high momentum single particles are also in agreement with the jet suppression data, where the reasons behind this agreement yet remain to be understood. Finally, the available jet data also show (though with large error bars) an overlap between b jets (heavy) and inclusive jets (light) probes. Consequently, our results suggest that single particles in the momentum region below 50 GeV present an excellent tool for mass tomography, while high momentum single particles and (possibly) jets are somewhat insensitive to the details of the interaction with quark-gluon plasma.

We report calculations regarding recent measurements of near-side jetlike yields obtained from the angular correlations with pions and protons as trigger particles and unindentified charged hadrons as associated at intermediate transverse momentum ($p_T$). Events generated from the string melting version of a multiphase transport model (AMPT) and HIJING are analyzed to calculate the near-side jetlike yields associated with pion and proton triggers in $p$-Pb collisions at 5.02 TeV. Multiplicity dependence of the near-side jetlike yield is studied by subtracting the so-called long-range correlations. In $A-A$ collisions, at intermediate $p_T$, jetlike yield associated with baryon trigger shows a gradual suppression from peripheral to central events following an initial rise. This suppression was interpreted as a combined effect of parton energy loss due to jet-quenching and particle production via quark recombination generating anomalous baryon to meson enhancement at intermediate $p_T$. Similar enhancement was also observed in small collision systems like $p$-Pb at CERN Large Hadron Collider (LHC) energy. In absence of any significant jet-medium interplay in small systems, trigger species dependence of the associated jetlike yield may be attributed dominantly to the dynamics of quark coalescence and/or radial flow. The multiplicity evolution of the trigger species dependence of jetlike yields, obtained from AMPT, found to be completely different from the same when extracted from a hydrodynamical model, EPOS. With the data available at LHC, these results may be tested to achieve further insight on the underlying dynamics in small collision systems, and the mechanism of hadronization at intermediate $p_T$ as well.

Background: Complete fusion of two nuclei leading to formation of a heavy compound nucleus (CN) is known to be hindered by various fission-like processes, in which the composite system reseparates after capture of the target and the projectile inside the potential barrier. As a consequence of these non-CN fission (NCNF) processes, fusion probability $\left(P_{\mathrm{CN}}\right)$ starts deviating from unity. Despite substantial progress in understanding, the onset and the experimental signatures of NCNF and the degree of its influence on fusion have not yet been unambiguously identified.

Purpose: This work aims to investigate the presence of NCNF, if any, in pre-actinide nuclei by systematic study of fission angular anisotropies and fission cross sections $\left({\sigma }_{\mathrm{fis}}\right)$ in a number of nuclear reactions carried out at and above the Coulomb barrier $\left(V_{\mathrm{B}}\right)$.

Method: Fission fragment angular distributions were measured for six ${}^{28}\mathrm{Si}\text{-induced}$ reactions involving isotopically enriched targets of ${}^{169}\mathrm{Tm},{}^{176}\mathrm{Yb},{}^{175}\mathrm{Lu},{}^{180}\mathrm{Hf},{}^{181}\mathrm{Ta}$, and ${}^{182}\mathrm{W}$ leading to probable formation of CN in the pre-actinide region, at a laboratory energy $\left(E_{\mathrm{lab}}\right)$ range of 129–146 MeV. Measurements were performed with large angular coverage $({\theta }_{\mathrm{lab}}={41}^{\circ }$–${170}^{\circ })$ in which fission fragments (FFs) were detected by nine hybrid telescope $\left(E\text{−}\mathrm{\Delta }E\right)$ detectors. Extracted fission angular anisotropies and ${\sigma }_{\mathrm{fis}}$ were compared with statistical model (SM) predictions.

Results: Barring two reactions involving targets with large non-zero ground state spin $\left(\mathcal{J}\right)$, viz., ${}^{175}\mathrm{Lu}\left({\frac{7}{2}}^{+}\right)$ and ${}^{181}\mathrm{Ta}\left({\frac{7}{2}}^{+}\right)$, experimental fission angular anisotropies were found to be higher in comparison with predictions of the statistical saddle point model (SSPM), at $E_{\mathrm{c}.\mathrm{m}.}$ near $V_{\mathrm{B}}$. Comparison of present results with those from neighboring systems revealed that experimental anisotropies increasingly deviated from SSPM predictions as one moved from pre-actinide to actinide nuclei. For reactions involving targets with large nonzero $\mathcal{J}$, this deviation was subdued. Comparison between measured ${\sigma }_{\mathrm{fis}}$ and predictions of SM indicated the presence of NCNF in at least four systems, when shell effects, both in the level density and the fission barrier, were included in the calculation.

Conclusions: Systematic SM analysis of measured fission angular anisotropies and ${\sigma }_{\mathrm{fis}}$ confirmed the onset of NCNF in pre-actinide nuclei. Discrepancies between results about the degree of its influence on complete fusion, as deduced from various experimental probes, remain challenges to be solved. Complete measurement of all signatures of NCNF for many systems and preferably a dynamical description of the collisions between projectile and target nuclei are warranted for a deeper understanding.

Production of $d,t$, and ${}^3\mathrm{He}$ nuclei in central $\mathrm{Pb}+\mathrm{Pb}$ interactions was studied at five collision energies ($\sqrt{s_{NN}}=6.3$, 7.6, 8.8, 12.3, and 17.3 GeV) with the NA49 detector at the CERN Super Proton Synchrotron. Transverse momentum spectra, rapidity distributions, and particle ratios were measured. Yields are compared to predictions of statistical models. Phase-space distributions of light nuclei are discussed and compared to those of protons in the context of a coalescence approach. The coalescence parameters $B_2$ and $B_3$, as well as coalescence radii for $d$ and ${}^3\mathrm{He}$ were determined as a function of transverse mass at all energies.

We extend the impact-parameter-dependent Glasma model to three dimensions using explicit small-$x$ evolution of the two incoming nuclear gluon distributions. We compute rapidity distributions of produced gluons and the early-time energy momentum tensor as a function of space-time rapidity and transverse coordinates. We study rapidity correlations and fluctuations of the initial geometry and multiplicity distributions and make comparisons to existing models for the three-dimensional initial state.