The complete set of open channels for the ${}^7\mathrm{Li}+p$ system, namely elastic scattering, inelastic scattering, breakup, the ${}^7\mathrm{Li}+p\to {}^7\mathrm{Be}+n$ charge exchange reaction, and the ${}^7\mathrm{Li}+p\to {}^4\mathrm{He}+{}^4\mathrm{He}$ reaction, was measured in the same experiment in inverse kinematics at an energy of 5.44 MeV/u. Data were also obtained for the charge exchange reaction at energies of 5.0 and 3.57 MeV/u. The elastic and inelastic scattering and breakup data were reported previously and are reviewed here and, together with the new data for the other two reactions, are discussed coherently within the same continuum-discretized coupled-channels model framework.

Neutron-rich ${}^{107}\mathrm{Mo}$ has been reinvestigated by analyzing the large statistics $\gamma -\gamma -\gamma$ and $\gamma -\gamma -\gamma -\gamma$ coincidence data from the spontaneous fission of ${}^{252}\mathrm{Cf}$ at the Gammasphere detector array. Two new bands have been identified. The potential-energy surface calculations of this nucleus have been performed. The calculations show evidence for the $5/2^{+}\left[413\right]$ configuration of the ground-state band and $7/2^{-}\left[523\right]$ configuration for the 348-keV excited band, as assigned in previous work. The two bands newly established are proposed to be one- and two-phonon $\gamma$-vibrational bands built on the $7/2^{-}\left[523\right]$ Nilsson orbital, respectively, in the current paper. Triaxial projected shell-model (TPSM) calculations have been performed to explain the level structure and are found in fair agreement with experimental data. In particular, the TPSM study confirms the $\gamma$- and $\gamma \gamma$-vibrational structure for the two observed excited band structures. Systematics of the one- and two-phonon $\gamma$-vibrational bands in the $A\sim 100$ Mo series is also discussed.

Background: A significant research effort is currently aimed at understanding the synthesis of heavy elements. For this purpose, heavy ion induced fusion reactions are used and various experimental observations have indicated the influence of shell and deformation effects in the compound nucleus (CN) formation. There is a need to understand these two effects.

Purpose: To investigate the effect of proton shell closure and deformation through the comparison of evaporation residue (ER) cross sections for the systems involving heavy compound nuclei around the $Z_{\mathrm{CN}}=82$ region.

Methods: A systematic study of ER cross-section measurements was carried out for the ${}^{48}\mathrm{Ti}+{}^{142,150}\mathrm{Nd}, {}^{144}\mathrm{Sm}$ systems in the energy range of $140–205\mathrm{MeV}$. The measurement has been performed using the gas-filled mode of the hybrid recoil mass analyzer present at the Inter University Accelerator Centre (IUAC), New Delhi. Theoretical calculations based on a statistical model were carried out incorporating an adjustable barrier scaling factor to fit the experimental ER cross section. Coupled-channel calculations were also performed using the ccfull code to obtain the spin distribution of the CN, which was used as an input in the calculations.

Results: Experimental ER cross sections for ${}^{48}\mathrm{Ti}+{}^{142,150}\mathrm{Nd}$ were found to be considerably smaller than the statistical model predictions whereas experimental and statistical model predictions for ${}^{48}\mathrm{Ti}+{}^{144}\mathrm{Sm}$ were of comparable magnitudes.

Conclusion: Though comparison of experimental ER cross sections with statistical model predictions indicate considerable non-compound-nuclear processes for ${}^{48}\mathrm{Ti}+{}^{142,150}\mathrm{Nd}$ reactions, no such evidence is found for the ${}^{48}\mathrm{Ti}+{}^{144}\mathrm{Sm}$ system. Further investigations are required to understand the difference in fusion probabilities of ${}^{48}\mathrm{Ti}+{}^{142}\mathrm{Nd}$ and ${}^{48}\mathrm{Ti}+{}^{144}\mathrm{Sm}$ systems.

The $\gamma N\to {\pi }^{0}N$ and $\gamma N\to \eta N$ reactions at photon beam energies above 4 GeV are investigated within Regge models. The models include $t$-channel exchanges of vector ($\rho$ and $\omega$) and axial-vector ($b_1$ and $h_1$) mesons. Moreover, Regge cuts of $\rho \mathbb{P},\rho f_2,\omega \mathbb{P}$, and $\omega f_2$ are investigated. A good description of differential cross sections and polarization observables at photon beam energies from 4 to 15 GeV can be achieved.

The spectroscopic electric quadrupole moment of the neutron-deficient francium isotope ${}^{203}\mathrm{Fr}$ was measured by using high-resolution collinear resonance ionization spectroscopy (CRIS) at the CERN Isotope Separation On-Line Device (ISOLDE) facility. A remeasurement of the ${}^{207}\mathrm{Fr}$ quadrupole moment was also performed, resulting in a departure from the established literature value. A sudden increase in magnitude of the ${}^{203}\mathrm{Fr}$ quadrupole moment, with respect to the general trend in the region, points to an onset of static deformation at $N=116$ in the ${}_{87}\mathrm{Fr}$ isotopic chain. Calculation of the static and total deformation parameters show that the increase in static deformation only cannot account for the observed departure of its relative charge radius from the ${}_{82}\mathrm{Pb}$ chain.

We propose a new scheme for constructing an effective-field-theory-based interaction to be used in the energy-density-functional (EDF) theory with specific assumptions for defining a power counting. This procedure is developed through the evaluation of the equation of state (EOS) of symmetric and pure neutron matter going beyond the mean-field scheme and using a functional defined up to next-to-leading order (NLO), which we call the NLO EDF. A Skyrme-like interaction is constructed based on the condition of renormalizibility and on power counting on $k_F/{\mathrm{\Lambda }}_{hi}$, where $k_F$ is the Fermi momentum and ${\mathrm{\Lambda }}_{hi}$ is the breakdown scale of our expansion. To absorb the divergences present in beyond mean-field diagrams, counter interactions are introduced for the NLO EDF and determined through renormalization conditions. In particular, three scenarios are explored and all of them lead to satisfactory results. These counter interactions contain also parameters that do not contribute to the EOS of matter and may eventually be determined through future adjustments to properties of some selected finite nuclei. Our work serves as a simple starting point for constructing a well-defined power counting within the EDF framework.

Measurements of charge distributions of fragments in the spontaneous fission of ${}^{252}\mathrm{Cf}$ have been performed using a unique detector setup consisting of a typical grid-ionization chamber coupled with a $\mathrm{\Delta }E-E$ charged particle telescope. We find that the fragment mass dependency of the kinetic-energy-averaged width of the charge distribution shows a systematically decreasing trend with obvious fluctuations. The variation of the widths of the charge distribution with kinetic energy shows a pan-like shape. This is due to the large number of neutrons emitted at the high excitation energies and cold fragmentation at the low excitation energies. Deviation of the kinetic-energy-averaged most probable charge $Z_p$ from the unchanged charge distribution (UCD), $\mathrm{\Delta }Z$, as a function of the mass number of primary fragments, $A^{*}$, changes from negative for mass asymmetric fission to positive near the symmetric fissions. Concerning the kinetic energy dependence of $Z_p$ given primary mass number $A^{*}$, obvious increasing tendencies of $Z_p$ with increasing kinetic energy are observed.

Systematics from 2001, describing prompt-fission $\gamma$-ray spectra (PFGS) characteristics as a function of mass and atomic number of the fissioning system, was revisited and parameters were revised, based on recent experimental results. Although originally expressed for spontaneous and thermal-neutron induced fission, validity for fast neutrons was assumed and applied to predict PFGS characteristics for the reaction $n+{}^{238}\mathrm{U}$ up to incident neutron energies of $E_n=20\mathrm{MeV}$. The results from this work are in good agreement with corresponding results from both model calculations and experiments.

At Institut Laue-Langevin (ILL) and Paul Scherrer Institute (PSI), we have measured the losses and depolarization probabilities of ultracold neutrons on various materials: (i) nickel-molybdenum alloys with weight percentages of 82/18, 85/15, 88/12, 91/9, and 94/6 and natural nickel Ni100, (ii) nickel-vanadium NiV93/7, (iii) copper, and (iv) deuterated polystyrene (dPS). For the different samples, storage-time constants up to $\sim 460\mathrm{s}$ were obtained at room temperature. The corresponding loss parameters for ultracold neutrons, $\eta$, varied between $1.0\times {10}^{-4}$ and $2.2\times {10}^{-4}$. All $\eta$ values are in agreement with theory except for dPS, where anomalous losses at room temperature were established with four standard deviations. The depolarization probabilities per wall collision $\beta$ measured with unprecedented sensitivity varied between $0.7\times {10}^{-6}$ and $9.0\times {10}^{-6}$. Our depolarization result for copper differs from other experiments by 4.4 and 15.8 standard deviations. The $\beta$ values of the paramagnetic NiMo alloys over molybdenum content show an increase of $\beta$ with increasing Mo content. This is in disagreement with expectations from literature. Finally, ferromagnetic behavior of NiMo alloys at room temperature was found for molybdenum contents of 6.5 at.% or less and paramagnetic behavior for more than 8.7 at.%. This may contribute to solving an ambiguity in literature.

The high-precision cross section data for the reaction $\gamma p\to K^{*+}\mathrm{\Lambda }$ reported by the CLAS Collaboration at the Thomas Jefferson National Accelerator Facility have been analyzed based on an effective Lagrangian approach in the tree-level approximation. Apart from the $t$-channel $K,\kappa ,K^{*}$ exchanges, the $s$-channel nucleon ($N$) exchange, the $u$-channel $\mathrm{\Lambda },\mathrm{\Sigma },{\mathrm{\Sigma }}^{*}\left(1385\right)$ exchanges, and the generalized contact term, the contributions from the near-threshold nucleon resonances in the $s$ channel are also taken into account in constructing the reaction amplitude. It is found that to achieve a satisfactory description of the differential cross section data, at least two nucleon resonances should be included. By including the $N\left(2060\right){5/2}^{-}$ resonance, which is responsible for the shape of the angular distribution near the $K^{*}\mathrm{\Lambda }$ threshold, and one of the $N\left(2000\right){5/2}^{+}, N\left(2040\right){3/2}^{+},N\left(2100\right){1/2}^{+},N\left(2120\right){3/2}^{-}$ and $N\left(2190\right){7/2}^{-}$ resonances, one can describe the cross section data quite well, with the fitted resonance masses and widths compatible with those advocated by the Particle Data Group. The resulted predictions of the beam, target, and recoil asymmetries are found to be quite different from various fits, indicating the necessity of the spin observable data for $\gamma p\to K^{*+}\mathrm{\Lambda }$ to further pin down the resonance contents and associated parameters in this reaction.

The emissions of $\alpha$ particles and protons are the dominant decay channels in the neutron-deficient nuclei corresponding to the $sdg$ major shell. The possibility of cluster emission is explored here. It is shown that the cluster decay mode has a small yet sizable branching ratio.

Recently, I proposed a fast computing scheme for generalized seniority on a spherical single-particle basis [J. Phys. G: Nucl. Part. Phys. 42, 115105 (2015)]. This work redesigns the scheme to make it applicable to deformed single-particle basis. The algorithm is applied to the rare-earth-metal nucleus ${}_{64}{}^{158}\mathrm{Gd}_{94}$ for intrinsic (body-fixed frame) neutron excitations under the low-momentum NN interaction $V_{\mathrm{low}\text{−}k}$. By allowing as many as four broken pairs, I compute the lowest 300 intrinsic states of several multipolarities. These states converge well to the exact ones, showing generalized seniority is very effective in truncating the deformed shell model. Under realistic interactions, the picture remains approximately valid: The ground state is a coherent pair condensate and the pairs gradually break up as excitation energy increases.

Background: The nuclear Coulomb form factor $|F_C{\left(q\right)|}^2$ is a useful tool to study nuclear structure. For spherical nuclei, $|F_C{\left(q\right)|}^2$ can be calculated by combining the spherical relativistic mean-field (RMF) model and the distorted wave Born approximation (DWBA) method.

Purpose: In a previous paper, the axially deformed RMF model + DWBA method was successfully applied to study the Coulomb form factors of deformed even-even nuclei. In this paper, we further extend this method to study the Coulomb form factors of deformed odd-$A$ nuclei.

Method: First, the charge distributions of odd-$A$ nuclei are calculated with the deformed RMF model and expanded into multipole components. Next, with the multipole moment charge distributions, the Coulomb multipoles $C0, C2$, and $C4$ are calculated. Finally, by summing over Coulomb multipoles required, the Coulomb form factors of odd-$A$ nuclei can be obtained.

Results: For deformed odd-$A$ nuclei, the theoretical Coulomb form factors calculated from the deformed RMF charge densities are in better agreement with the experimental data. For nuclei with $J\ge 1$, the diffraction minima of Coulomb form factors are much flatter, which is due to the contributions of quadrupole charge distributions.

Conclusions: Results indicate that the axially deformed RMF model can give reasonable descriptions for multipole moment charge distributions of odd-$A$ nuclei. The method in this paper can provide a useful guide for future experiments of electron scattering off exotic odd-$A$ nuclei.

An experimental scheme combining the mass resolving power of a Penning trap with contemporary decay spectroscopy has been established at GSI Darmstadt. The Universal Linear Accelerator (UNILAC) at GSI Darmstadt provided a ${}^{48}\mathrm{Ca}$ beam impinging on a thin ${}^{170}\mathrm{Er}$ target foil. Subsequent to velocity filtering of reaction products in the Separator for Heavy Ion reaction Products (SHIP), the nuclear ground state of the $5n$ evaporation channel ${}^{213}\mathrm{Ra}$ was mass-selected in SHIPTRAP, and the ${}^{213}\mathrm{Ra}$ ions were finally transferred into an array of silicon strip detectors surrounded by large composite germanium detectors. Based on comprehensive geant4 simulations and supported by theoretical calculations, the spectroscopic results call for a revision of the decay path of ${}^{213}\mathrm{Ra}$, thereby exemplifying the potential of a combination of a mass-selective Penning trap device with a dedicated nuclear decay station and contemporary geant4 simulations.

If the mass excess of neutron-deficient nuclei and their neutron-rich mirror partners are both known, it can be shown that deviations of the isobaric mass multiplet equation (IMME) in the form of a cubic term can be probed. Such a cubic term was probed by using the atomic mass of neutron-rich magnesium isotopes measured using the TITAN Penning trap and the recently measured proton-separation energies of ${}^{29}\mathrm{Cl}$ and ${}^{30}\mathrm{Ar}$. The atomic mass of ${}^{27}\mathrm{Mg}$ was found to be within $1.6\sigma$ of the value stated in the Atomic Mass Evaluation. The atomic masses of ${}^{28,29}\mathrm{Mg}$ were measured to be both within $1\sigma$, while being 7 and 33 times more precise, respectively. Using the ${}^{29}\mathrm{Mg}$ mass excess and previous measurements of ${}^{29}\mathrm{Cl}$, we uncovered a cubic coefficient of $d=28\left(7\right)\mathrm{keV}$, which is the largest known cubic coefficient of the IMME. This departure, however, could also be caused by experimental data with unknown systematic errors. Hence there is a need to confirm the mass excess of ${}^{28}\mathrm{S}$ and the one-neutron separation energy of ${}^{29}\mathrm{Cl}$, which have both come from a single measurement. Finally, our results were compared with ab initio calculations from the valence-space in-medium similarity renormalization group, resulting in a good agreement.

The synthesis of superheavy element $Z=119$ in the fusion evaporation reactions ${}^{42,44,46,48}\mathrm{Ca}+{}^{252-255}\mathrm{Es}$ and ${}^{46-50}\mathrm{Ti}+{}^{246-249}\mathrm{Bk}$ in the $3n$-, $4n$-, and $5n$-channels leading to ${}^{294-303}119$ and ${}^{292-299}119$, respectively, is evaluated. It is observed that the $3n$-channel (952.173 fb) cross section is larger for the reaction ${}^{48}\mathrm{Ca}+{}^{252}\mathrm{Es}\to {}^{300}119$; the $4n$- (155.026 fb) and $5n$- (23.11 fb) channel cross sections are larger for ${}^{48}\mathrm{Ca}+{}^{254}\mathrm{Es}\to {}^{302}119$. For the reaction ${}^{50}\mathrm{Ti}+{}^{249}\mathrm{Bk}\to {}^{299}119$, the experimental upper limit of the cross section was about 50 fb, which is very close to our calculated value (40.86 fb for the $4n$-channel). Also, the isotopic dependence of both projectile and target for the production cross section is discussed. These studies will be useful for the experimentalists to produce isotopes of element $Z=119$.

The quasifree $\gamma d\to {\pi }^{-}p\left(p\right)$ differential cross section has been measured with CLAS at photon beam energies $E_{\gamma }$ from 0.445 to 2.510 GeV (corresponding to $W$ from 1.311 to 2.366 GeV) for pion center-of-mass angles $cos{\theta }_{\pi }^{c.m.}$ from $-0.72$ to 0.92. A correction for final state interactions has been applied to these data to extract the $\gamma n\to {\pi }^{-}p$ differential cross sections. These cross sections are quoted in 8428 $(E_{\gamma },cos{\theta }_{\pi }^{c.m.})$ bins, a factor of nearly 3 increase in the world statistics for this channel in this kinematic range. These new data help to constrain coupled-channel analysis fits used to disentangle the spectrum of $N^{*}$ resonances and extract their properties. Selected photon decay amplitudes $N^{*}\to \gamma n$ at the resonance poles are determined for the first time and are reported here.

Statistical models based on different ensembles are very commonly used to describe the nuclear multifragmentation reaction in heavy ion collisions at intermediate energies. Canonical model results are more appropriate for finite nuclei calculations while those obtained from the grand canonical ones are more easily calculable. A transformation relation has been worked out for converting results of finite nuclei from grand canonical to canonical and vice versa. The formula shows that, irrespective of the particle number fluctuation in the grand canonical ensemble, exact canonical results can be recovered for observables varying linearly or quadratically with the number of particles. This result is of great significance since the baryon and charge conservation constraints can make the exact canonical calculations extremely difficult in general. This concept developed in this work can be extended in future for transformation to ensembles where analytical solutions do not exist. The applicability of certain equations (isoscaling, etc.) in the regime of finite nuclei can also be tested using this transformation relation.

Background: All elements above atomic number 113 have been synthesized using hot fusion reactions with calcium beams on statically deformed actinide target nuclei. Quasifission and fusion-fission are the two major mechanisms responsible for the very low production cross sections of superheavy elements.

Purpose: To achieve a quantitative measurement of capture and quasifission characteristics as a function of beam energy in reactions forming heavy compound systems using calcium beams as projectiles.

Methods: Fission fragment mass-angle distributions were measured for the two reactions ${}^{40}\mathrm{Ca}+{}^{186}\mathrm{W}$ and ${}^{40}\mathrm{C}+{}^{192}\mathrm{Os}$, populating ${}^{226}\mathrm{Pu}$ and ${}^{232}\mathrm{Cm}$ compound nuclei, respectively, using the Heavy Ion Accelerator Facility and CUBE spectrometer at the Australian National University. Mass ratio distributions, angular distributions, and total fission cross sections were obtained from the experimental data. Simulations to match the features of the experimental mass-angle distributions were performed using a classical phenomenological approach.

Results: Both ${}^{40}\mathrm{Ca}+{}^{186}\mathrm{W}$ and ${}^{40}\mathrm{C}+{}^{192}\mathrm{Os}$ reactions show strong mass-angle correlations at all energies measured. A maximum fusion probability of $60-70\%$ is estimated for the two reactions in the energy range of the present study. Coupled-channels calculations assuming standard Woods-Saxon potential parameters overpredict the capture cross sections. Large nuclear potential diffuseness parameters $\sim 1.5$ fm are required to fit the total capture cross sections. The presence of a weak mass-asymmetric quasifission component attributed to the higher angular momentum events can be reproduced with a shorter average sticking time but longer mass-equilibration time constant.

Conclusions: The deduced above-barrier capture cross sections suggest that the dissipative processes are already occurring outside the capture barrier. The mass-angle correlations indicate that a compact shape is not achieved for deformation aligned collisions with lower capture barriers. The average sticking time of fast quasifission events is ${10}^{-20}$ s.

The recent shell-model results of even-even chains of nuclei: ${}^{134,136,138}\mathrm{Te},{}^{136,138,140}\mathrm{Xe},{}^{138,140,142}\mathrm{Ba},{}^{140,142,144}\mathrm{Ce}$, and ${}^{142,144,146}\mathrm{Nd}$ are explored in this manuscript. The low-lying states energies, E2 and M1 transitions, are investigated using the $same$ effective interaction based on the realistic effective field theory potential N3LO. Significant quadrupole correlations appear in the $N=86$ isotonic chain, with the signature of nonaxial $\gamma \mathrm{band}$. This class of collectivity is interpreted within the SU(3) symmetries scheme and confirmed by constrained Hartree-Fock shell-model calculations.