The role of the breakup process and one-neutron stripping on the near barrier fusion are investigated for the weakly bound projectile ${}^9\mathrm{Be}$ on ${}^{28}\mathrm{Si}$, ${}^{89}\mathrm{Y}$, ${}^{124}\mathrm{Sn}$, ${}^{144}\mathrm{Sm}$, and ${}^{208}\mathrm{Pb}$ targets. Continuum-discretized coupled channels (CDCC) calculations for the breakup with a ${}^8\mathrm{Be}+n$ model of the ${}^9\mathrm{Be}$ nucleus and coupled-reactions channel (CRC) calculations for the one-neutron stripping to several single-particle states in the target are performed for these systems. A good description of the experimental fusion cross sections above the Coulomb barrier is obtained from the CDCC-CRC calculations for all the systems. The calculated incomplete fusion probabilities for different target systems are found to be consistent with the systematic behavior of the complete fusion suppression factors as a function of target atomic mass, obtained from the experimental data.

The invariant mass spectrum and the elliptic flow of lepton pairs produced in relativistic heavy-ion collisions at RHIC are studied with viscous hydrodynamics. The effects of viscous corrections on dilepton observables are explored. The lepton pairs originating from charm quarks evolving in the viscous background are seen to be a good probe of quark energy loss and gain, as quantified by the dilepton spectrum and by the dilepton elliptic flow.

Elastic scattering of photons from ${}^{12}\mathrm{C}$ has been investigated using quasimonoenergetic tagged photons with energies in the range 65–115 MeV at laboratory angles of 60${}^{\circ }$, 120${}^{\circ }$, and 150${}^{\circ }$ at the Tagged-Photon Facility at the MAX IV Laboratory in Lund, Sweden. A phenomenological model was employed to provide an estimate of the sensitivity of the ${}^{12}\mathrm{C}$($\gamma ,\gamma$)${}^{12}\mathrm{C}$ cross section to the bound-nucleon polarizabilities.

Background: The $B\left(E2\right)$ transition strength to the $2_2{}^{+}$ state in ${}^{94}$Zr was initially reported to be larger by a factor of 1.63 than the one to the $2_1{}^{+}$ state from lifetime measurements with the Doppler-shift attenuation method using the $(n,n^{\prime }\gamma )$ reaction [Elhami et al., Phys. Rev. C 75, 011301(R) (2007)]. This surprising behavior was recently revised in a new measurement by the same group using the same experimental technique leading to a ratio below unity as expected in vibrational nuclei.

Purpose: The goal is an independent determination of the ratio of $B\left(E2\right)$ strengths for the transitions to the $2_{1,2}{}^{+}$ states of ${}^{94}$Zr with inelastic electron scattering.

Method: The relative population of the $2_{1,2}{}^{+}$ states in the ($e,e^{\prime }$) reaction was measured at the S-DALINAC in a momentum transfer range $q=0.17$–0.51 fm${}^{-1}$ and analyzed in plane-wave Born approximation with the method described by Scheikh Obeid et al. [Phys. Rev. C 87, 014337 (2013)].

Results: The extracted $B\left(E2\right)$ strength ratio of $0.789\left(43\right)$ between the excitation of the $2_1{}^{+}$ and $2_2{}^{+}$ states of ${}^{94}$Zr is consistent with but more precise than the latest $(n,n^{\prime }\gamma$) experiment. Using the $B\left(E2\right)$ transition strength to the first excited state from the literature a value of 3.9(9) Weisskopf units is deduced for the $B(E2;2_2{}^{+}\to 0_1{}^{+}$) transition.

Conclusions: The electron scattering result independently confirms the latest interpretation of the different $(n,n^{\prime }\gamma$) results for the transition to the $2_2{}^{+}$ state in ${}^{94}$Zr.

The evaporation residue (ER) cross sections for producing superheavy nuclei with charge number 118 in some ${}^{48}$Ca-induced reactions are studied theoretically with the dinuclear system model with dynamical potential energy surface (DNS-DyPES model) for the experiment, which is aimed to produce the isotopes of element $Z=118$. The experiment is under way at the Flerov Laboratory of the Joint Institute for Nuclear Research in Dubna, Russia. The calculated ER cross sections for ${}^{48}$Ca + ${}^{249}$Cf are found to be in good agreement with the experimental results. The excitation functions for ${}^{48}$Ca + ${}^{250,251,252}$Cf are calculated and predicted, and the dependence of the residue cross sections for producing ${}^{293,294,295,296,297}$118 on the bombarding energies is also calculated for an isotopic composition of the Cf target. The possibilities for producing element 118 with other projectile-target combinations such as ${}^{50}$Ti + ${}^{248}$Cm and ${}^{54}$Cr + ${}^{244}$Pu at different mass asymmetries of entrance channels are also investigated.

We show that there exist two types of universal phenomena for three-boson systems with isospin degrees of freedom. In the isospin symmetric limit, there is only one universal three-boson bound state with the total isospin one, whose binding energy is proportional to that of the two-boson bound state. With large isospin symmetry breaking, the standard Efimov states of three identical bosons appear at low energies. Both phenomena can be realized by three pions with the pion mass appropriately tuned in lattice QCD simulations, or by spin-one bosons in cold atom experiments. Implication to the in-medium softening of multi-pion states is also discussed.

The rapidity dependence of the initial energy density in heavy-ion collisions is calculated from a three-dimensional McLerran-Venugopalan model introduced by Lam and Mahlon. This model is infrared safe since global color neutrality is enforced. In this framework, the nuclei have nonzero thickness in the longitudinal direction. This leads to Bjorken-$x$-dependent unintegrated gluon distribution functions, which in turn result in a rapidity-dependent initial energy density after the collision. These unintegrated distribution functions are substituted in the initial energy density expression, which has been derived for the boost-invariant case. We argue that using three-dimensional ($x$-dependent) unintegrated distribution functions together with the boost-invariant energy formula is consistent given that the overlap of the two nuclei lasts less than the natural time scale for the evolution of the fields ($1/Q_s$) after the collision. The initial energy density and its rapidity dependence are important initial conditions for the quark gluon plasma and its hydrodynamic evolution.

Strongly intensive measures $\Delta [P_T,N]$ and $\Sigma [P_T,N]$ are used to study the event-by-event fluctuations of the transverse momentum $P_T$ and particle multiplicity $N$ in nucleus-nucleus collisions. A special normalization for these fluctuation measures ensures that they are dimensionless and yields a common scale required for a quantitative comparison of fluctuations. In this paper basic properties of the $\Delta [P_T,N]$ and $\Sigma [P_T,N]$ measures are tested within different phenomenological models using the Monte Carlo simulations (the so-called fast generators) and analytical solutions. The obtained results are helpful to elucidate the properties of the $\Delta [P_T,N]$ and $\Sigma [P_T,N]$ measures.

Background: Knowing the energy dependence of the $(\gamma ,n)$ cross section is mandatory to predict the abundances of heavy elements using astrophysical models. The data can be applied directly or used to constrain the cross section of the inverse ($n$,$\gamma$) reaction.

Purpose: The measurement of the reaction ${}^{142}\mathrm{Ce}$${(\gamma ,n)}^{141}$Ce just above the reaction threshold amends the existing experimental database in that mass region for $p$-process nucleosynthesis and helps to understand the $s$-process branching at the isotope ${}^{141}\mathrm{Ce}$.

Method: The quasi-monoenergetic photon beam of the High Intensity $\gamma$-ray Source (HI$\gamma$S), TUNL, USA, is used to irradiate naturally composed Ce targets. The reaction yield is determined afterwards with high-resolution $\gamma$-ray spectroscopy.

Results: The experimental data are in agreement with previous measurements at higher energies. Since the cross-section prediction of the ${}^{142}\mathrm{Ce}$$(\gamma ,n)$ reaction is exclusively sensitive to the $\gamma$-ray strength function, the resulting cross-section values were compared to Hauser-Feshbach calculations using different $\gamma$-ray strength functions. A microscopic description within the framework of the Hartree-Fock-BCS model describes the experimental values well within the measured energy range.

Conclusions: The measured data show that the predicted $(\gamma ,n)$ reaction rate is correct within a factor of 2 even though the closed neutron shell $N=82$ is approached. This agreement allows us to constrain the ($n$,$\gamma$) cross section and to improve the understanding of the $s$-process branching at ${}^{141}\mathrm{Ce}$.

Excited states in the transitional doubly odd ${}^{98}\mathrm{Rh}$ nucleus were populated in the ${}^{75}\mathrm{As}$(${}^{28}\mathrm{Si}$,2$p$3$n$) fusion-evaporation reaction using the 120-MeV incident ${}^{28}\mathrm{Si}$ beam. The subsequent de-excitations were investigated through in-beam $\gamma$-ray spectroscopic techniques using an early implementation phase of the Indian National Gamma Array (INGA) spectrometer equipped with 18 clover Ge detectors. The level structures in ${}^{98}\mathrm{Rh}$ have been established up to excitation energy $\approx$10 MeV and angular momentum $\sim$23$\hslash$. The previously reported level schemes are considerably modified and extended substantially. Significant expansion of the level scheme at low excitation energies stipulates that the previously reported 842-726-994-980-265 keV $\gamma$-transition cascade in ${}^{98}\mathrm{Rh}$ is not directly based on the ground state (T${}_{1/2}$ = 8.7 min). Tilted-axis cranking (TAC) shell-model calculations have been used to put the present level scheme of ${}^{98}\mathrm{Rh}$ in perspective. Level structures have been interpreted in terms of the rotational bands based on the $\pi p_{1/2}\otimes \nu h_{11/2}$ [triaxiality parameter ($\gamma$) = 25${}^{\circ }$], and $\pi f_{5/2}\otimes \nu h_{11/2}$ proton-neutron configurations having moderate quadrupole deformation (${\epsilon }_2$ $\approx$ 0.13) and the admixtures. Excited band structures are based on the $\pi p_{1/2}/f_{5/2}\otimes \pi$($g_{9/2}$)${}^2\otimes \nu h_{11/2}$ configuration and the fully stretched [$\pi p_{1/2}\otimes \nu$($h_{11/2}$)${}^2\otimes \nu d_{5/2}$]${}_{{13}^{-}}$ configuration.

The dynamical cluster-decay model (DCM), an extended version of the preformed cluster model (PCM) for ground-state ($T=0$) decays, is applied to study the decay of the proton-rich compound nucleus ${}^{124}\mathrm{Ce}$${}^{*}$ formed in the ${}^{32}\mathrm{S}$ + ${}^{92}\mathrm{Mo}$ reaction at an above-barrier beam energy of 150 MeV. Application of the statistical code pace4 to experimental data shows large deviations in all cases of proton clusters' (2$p$, 3$p$, and 4$p$) evaporation residue (ER) and the non-$\alpha$ nucleus ${}^6\mathrm{Be}$ intermediate mass fragment (IMF). Furthermore, the $\alpha$-nucleus ${}^8\mathrm{Be}$ decay is not observed in this experiment (not even the upper limit is given). Using the DCM, with effects of deformations up to hexadecapole and “compact” orientations included, for the best-fitted cross sections of 2$p$ and 3$p$ ERs and of ${}^5\mathrm{Li}$ and ${}^6\mathrm{Be}$ IMFs, the relative cross section of ${}^8\mathrm{Be}$ is found to be more than that of ${}^6\mathrm{Be}$, possibly due to the $\alpha$-nucleus structure of ${}^8\mathrm{Be}$. The same is shown to be true for ${}^{12}\mathrm{C}$ versus ${}^{10}\mathrm{C}$, i.e., $\alpha$-nuclei clusters are populated strongly relative to non-$\alpha$ clusters, similar to what was predicted by one of us (R.K.G.) et al. [S. Kumar, D. Bir, and R. K. Gupta, Phys. Rev. C 51, 1762 (1995)] for ground-state decays of such nuclei and the decay of ${}^{116}\mathrm{Ba}$${}^{*}$ formed in the ${}^{58}\mathrm{Ni}$ + ${}^{58}\mathrm{Ni}$ reaction at various compound nucleus excitation energies [R. K. Gupta et al., J. Phys. G: Nucl. Part. Phys. 32, 345 (2006)]. The only parameter of the DCM is the neck-length $\Delta R$, related to the “barrier-lowering” parameter. The compound nucleus formation probability and “barrier-lowering/-modification” effects are analyzed, and the role of varying the deformations of ${}^6\mathrm{Be}$ and/or ${}^8\mathrm{Be}$ nuclei on relative cross sections is studied, since the measured deformations are not available. The ones used here are from relativistic mean-field calculations [${\beta }_2{(}^6\mathrm{Be})=-0.087$ and ${\beta }_2{(}^8\mathrm{Be})=-0.094$]. Calculations are also presented for a beam energy of 140 MeV, supporting the above result.

Within the context of relativistic nuclear collisions aimed at exploring hot and baryon-dense matter, we investigate how the general features of the expansion dynamics, as well as a number of specific observables, depend on the equation of state used in dynamical simulations of the non-equilibrium confinement phase transition.

A model with nucleons in a charge-independent potential well interacting by an isovector pairing force is considered. For a 24-dimensional valence space, the Hartree-Bogolyubov (HB) plus random phase approximation (RPA) to the lowest eigenvalue of the Hamiltonian is shown to be accurate except near values of the pairing-force coupling constant $G$ where the HB solution shifts from a zero to a nonzero pair gap. In the limit $G\to \infty$ the HB + RPA is asymptotically exact. The inaccuracy of the HB + RPA in the critical regions of $G$ can be remedied by interpolation. The resulting algorithm is used to calculate pairing corrections in the framework of a Nilsson-Strutinsky calculation of nuclear masses near $N=Z$ for $A=$ 24–100, where $N$ and $Z$ are the numbers of neutrons and protons and $A=N+Z$. The dimension of the valence space is 2$A$ in these calculations. Adjusting five liquid drop parameters and a power law expression for the constant $G$ as a function of $A$ allows us to reproduce the measured binding energies of 112 doubly even nuclei in this range with a root mean square deviation of 0.95 MeV. Several combinations of the masses for different $N$, $Z$, and isospin $T$ are considered and the calculations found to be in good agreement with the data. It is demonstrated by examples how fluctuations as a function of $A$ of the constant $X$ in an expansion of the symmetry energy of the form $T(T+X)/2\theta$ can be understood from the shell structure.

Possible $H$-like dibaryon states ${\Lambda }_c{\Lambda }_c$ and ${\Lambda }_b{\Lambda }_b$ are investigated within the framework of the quark delocalization color screening model. The results show that the interaction between two ${\Lambda }_c$'s is repulsive, so it cannot be a bound state by itself. However, the strong attraction in ${\Sigma }_c{\Sigma }_c$ and ${\Sigma }_c^{*}{\Sigma }_c^{*}$ channels and the strong channel coupling, due to the central interaction of one-gluon exchange and one-pion exchange, among ${\Lambda }_c{\Lambda }_c$, ${\Sigma }_c{\Sigma }_c$ and ${\Sigma }_c^{*}{\Sigma }_c^{*}$ push the energy of system below the threshold of ${\Lambda }_c{\Lambda }_c$ by 3-20 MeV. The ${\Lambda }_b{\Lambda }_b$ system has properties similar to those of the ${\Lambda }_c{\Lambda }_c$ system, and a bound state is also possible in the ${\Lambda }_b{\Lambda }_b$ system.

The thermonuclear rate of the ${}^{42}\mathrm{Ti}$(${p,\gamma )}^{43}$V reaction has been reevaluated based on a recent precise proton separation energy measurement of $S_p{(}^{43}\mathrm{V})=83\pm 43$ keV. The astrophysical impact of our new rates has been investigated through one-zone postprocessing type-I x-ray burst calculations. It shows that the new experimental value of $S_p$ significantly affects the yields of species for $A\approx 40$–45. As well, the precision of the recent experimental $S_p$ value constrains these yields to better than a factor of 3.

It is shown that a simple BCS model with a quadrupole-quadrupole interaction provides a consistent description of the measured quadrupole moments of a sequence of odd-mass Sn and Cd isotopes and allows the extraction of the neutron single-particle occupation probabilities.

We perform a dynamical calculation of the $\Delta \Delta$ dibaryon candidates with $I{J}^P={03}^{+}$ and $I{J}^P={30}^{+}$ in the framework of two constituent quark models: the quark delocalization color screening model and the chiral quark model. Our results show that the dibaryon resonances with $I{J}^P={03}^{+}$ and $I{J}^P={30}^{+}$ can be formed in both models. The mass and width of $I{J}^P={03}^{+}$ state are smaller than that of $I{J}^P={30}^{+}$ state due to the one-gluon-exchange interaction between quarks. The resonance mass and decay width of $I{J}^P={03}^{+}$ state in both models agree with that of the recently observed resonance in the reaction $pn\to d{\pi }^0{\pi }^0$. The $I{J}^P={30}^{+}$ $\Delta \Delta$ is another dibaryon candidate with smaller binding energy and larger width. The hidden-color channel coupling is added to the chiral quark model, and we find it can lower the mass of the dibaryons by 10$-$20 MeV.

We calculate the capture (fusion) cross sections for nine reactions involving spherical nuclei: ${}^{16}\mathrm{O}$ + ${}^{16}\mathrm{O}$, ${}^{28}\mathrm{Si}$, ${}^{92}\mathrm{Zr}$, ${}^{144}\mathrm{Sm}$, ${}^{208}\mathrm{Pb}$; ${}^{28}\mathrm{Si}$ + ${}^{28}\mathrm{Si}$, ${}^{92}\mathrm{Zr}$, ${}^{208}\mathrm{Pb}$; ${}^{32}\mathrm{S}$ + ${}^{208}\mathrm{Pb}$. For six of them precision data are available in the literature. Analysis of these precision data within the framework of the single-barrier penetration model based on the Woods-Saxon profile for the strong nucleus-nucleus interaction potential (SnnP) gave rise to the problem of the apparently large diffuseness of the SnnP [Newton et al., Phys. Rev. C 70, 024605 (2004)]. Our fluctuation-dissipation trajectory model is based on the double-folding approach with the density-dependent M3Y NN forces including the finite-range exchange part. For the nuclear matter density the Skyrme-Hartree-Fock approach including the tensor interaction is applied. The resulting nucleus-nucleus potential possesses rather small (normal) diffuseness. The strength of the radial friction $K_R$ is used as the free parameter of the model. It turns out that for four of the five reactions induced by ${}^{16}\mathrm{O}$ (except ${}^{16}\mathrm{O}$ + ${}^{208}\mathrm{Pb}$) the calculated cross sections cannot be brought into agreement with the data within the experimental errors. This suggests that the calculated nuclear density is incorrect for ${}^{16}\mathrm{O}$. For the reactions not involving ${}^{16}\mathrm{O}$ and, surprisingly, for the ${}^{16}\mathrm{O}$ + ${}^{208}\mathrm{Pb}$ reaction the agreement with the data within 2-5% is achieved at $K_R=1.2\times {10}^{-2}$ to $3.0\times {10}^{-2}{\mathrm{MeV}}^{-1}\mathrm{zs}$ which is in accord with the previous works.

We estimate the maximum possible contribution to the early spin deceleration of protoneutron stars because of asymmetric neutrino absorption. We calculate the neutrino scattering in the context of a fully relativistic mean field theory and estimate for the first time the spin deceleration of neutron stars because of asymmetric neutrino absorption in a toroidal magnetic field configuration. We find that the deceleration can be much larger for asymmetric neutrino absorption in a toroidal magnetic field than the braking due to magnetic dipole radiation. Nevertheless, the effect is estimated to be less than the angular momentum loss due to the transport of magnetically locked material in the neutrino energized wind.

In the doubly magic nucleus ${}^{208}\mathrm{Pb}$, many states contain fractions of particle-hole configurations whose strength can be determined from experiment. However, some configurations are not excited in a directly detectable way. Their strengths can be determined by observing an ensemble of states which consists entirely of an equivalent set of configurations with a given spin and parity among which only one or two configurations are not detected. Examples for spins $2^{-}$–$5^{-}$ are evaluated. Excitation energies of states in ${}^{208}\mathrm{Pb}$ are determined with a precision down to 100 eV by experiments on the ${}^{208}\mathrm{Pb}$$\left(p,p^{\prime }\right)$ and ${}^{207}\mathrm{Pb}$$\left(d,p\right)$ reactions with the Q3D magnetic spectrograph (Maier-Leibnitz-Laboratorium, Garching, Germany). Six doublets with distances between the states of less than 2 keV are resolved. 72 negative parity states below $E_x=6.1$ MeV are identified. They correspond to 70 states predicted by the schematic shell model without residual interaction below $E_x=6361$ keV. The $1^{-}$ and $3^{-}$ yrast states appear in addition. Six new spins are assigned to negative parity states, three new spins to positive parity states, and two spins suggested by the Nuclear Data Sheets are verified. The state at $E_x=4953$ keV is identified as the 3${}^{+}$ member of the configuration $g_{9/2}$$i_{13/2}$. Among about hundred states, the configuration mixing for unnatural parity is shown to be less than for natural parity.