The Airy structure in ${}^{16}\mathrm{O}+{}^{14}\mathrm{C}$ rainbow scattering is studied with an extended double-folding (EDF) model that describes all the diagonal and off-diagonal coupling potentials derived from the microscopic realistic wave functions for ${}^{16}\mathrm{O}$ by using a density-dependent nucleon-nucleon force. The experimental angular distributions at $E_L=132$, 281, and 382.2 MeV are well reproduced by the calculations. By studying the energy evolution of the Airy structure, the Airy minimum around $\theta ={76}^{\circ }$ in the angular distribution at $E_L=132$ MeV is assigned as the second-order Airy minimum $A2$ in contrast to the recent literature which assigns it as the third order $A3$. The Airy minima in the ${90}^{\circ }$ excitation function is investigated in comparison with well-known ${}^{16}\mathrm{O}+{}^{16}\mathrm{O}$ and ${}^{12}\mathrm{C}+{}^{12}\mathrm{C}$ systems. Evolution of the Airy structure into the molecular resonances with the ${}^{16}\mathrm{O}+{}^{14}\mathrm{C}$ cluster structure in the low-energy region around $E_{\mathrm{c}.\mathrm{m}.}=30$ MeV is discussed. It is predicted theoretically for the first time for a non-$4N{}^{16}\mathrm{O}+{}^{14}\mathrm{C}$ system that Airy elephants in the ${90}^{\circ }$ excitation function are present.

Background: Resonances with pronounced single-particle characteristics are crucial for quantitative descriptions of exotic nuclei near and beyond the drip lines, and often impact halo formation and nucleon decay processes. Since the majority of nuclei are deformed, the interplay between deformation and orbital structure near threshold can lead to improved descriptions of exotic nuclei.

Purpose: Develop a method to study single-particle resonant orbital structure in the Dirac equation with a quadrupole-deformed Woods-Saxon potential. Determine the structure evolution of bound and resonant levels with deformation in this scheme, and examine the impact on halo formation in loosely bound systems, with a focus on the recent halo candidate nucleus ${}^{37}\mathrm{Mg}$.

Method: Analytical continuation of the coupling constant (ACCC) method is developed on the basis of the Dirac equation with a deformed Woods-Saxon potential. The scalar and vector terms in the deformed potential are determined by the energies of the valence neutron and nearby orbitals, which are extracted from a self-consistent relativistic Hartree-Bogoliubov (RHB) calculation with the PC-PK1 density functional.

Results: We compare the energies and widths of resonant orbitals in the recent halo nucleus candidate ${}^{37}\mathrm{Mg}$ using the ACCC method based on the Dirac coupled-channel equations with those determined from the scattering phase shift (SPS) method. It is found that the results from the two methods agree well for narrow resonances, whereas the SPS method fails for broad resonances. Nilsson levels for bound and resonant orbitals from the ACCC method are calculated over a wide range of deformations and show some decisive hints of halo formation in ${}^{37}\mathrm{Mg}$.

Conclusions: In our ACCC model for deformed potentials in the coupled-channel Dirac equations, the crossing of the configuration $1/2\left[321\right]$ and $5/2\left[312\right]$ orbitals at a deformation of approximately 0.5 enhances the probability to occupy the $1/2\left[321\right]$ orbital coming from $2p_{3/2}$ thereby explaining the recent observation of a $\mathit{p}$-wave one-neutron halo configuration in ${}^{37}\mathrm{Mg}$. The resonant $1/2\left[301\right]$ configuration plays a crucial role in halo formation in the magnesium isotopes beyond $A=40$ for a wide range of deformations larger than 0.2.

Background: At energies near the Coulomb barrier, capture reactions in heavy-ion collisions result either in fusion or in quasifission. The former produces a compound nucleus in statistical equilibrium, while the second leads to a reseparation of the fragments after partial mass equilibration without formation of a compound nucleus. Extracting the compound nucleus formation probability is crucial to predict superheavy-element formation cross sections. It requires a good knowledge of the fragment angular distribution which itself depends on quantities such as moments of inertia and excitation energies which have so far been somewhat arbitrary for the quasifission contribution.

Purpose: Our main goal is to utilize the time-dependent Hartee-Fock (TDHF) approach to extract ingredients of the formula used in the analysis of experimental angular distributions. These include the moment-of-inertia and temperature.

Methods: We investigate the evolution of the nuclear density in TDHF calculations leading to quasifission. We study the dependence of the relevant quantities on various initial conditions of the reaction process.

Results: The evolution of the moment of inertia is clearly nontrivial and depends strongly on the characteristics of the collision. The temperature rises quickly when the kinetic energy is transformed into internal excitation. Then, it rises slowly during mass transfer.

Conclusions: Fully microscopic theories are useful to predict the complex evolution of quantities required in macroscopic models of quasifission.

Background: Langevin equations have been suggested as a key approach to the dynamical analysis of energy dissipation in excited nuclei, formed during heavy-ion fusion-fission reactions. Recently, a few researchers theoretically reported investigations of fission for light nuclei in a low excitation energy using the Langevin approach, without considering the contribution of pre- and post-scission particles and $\gamma$-ray emission.

Purpose: We study the dynamical evolution of mass distribution of fission fragments, and neutron and $\gamma$-ray multiplicity for ${}^{236}\mathrm{U}$ as compound nuclei that are constructed after fusion of a neutron and ${}^{235}\mathrm{U}$.

Method: Energy dissipation of the compound nucleus through fission is calculated using the Langevin dynamical approach combined with a Monte Carlo method. Also the shape of the fissioning nucleus is restricted to “funny hills” parametrization.

Results: Fission fragment mass distribution, neutron and $\gamma$-ray multiplicity, and the average kinetic energy of emitted neutrons and $\gamma$ rays at a low excitation energy are calculated using a dynamical model, based on the four-dimensional Langevin equations.

Conclusions: The theoretical results show reasonable agreement with experimental data and the proposed dynamical model can well explain the energy dissipation in low energy induced fission.

The dynamics of compound nuclei formed in the reactions using loosely bound projectiles are analyzed within the framework of the dynamical cluster-decay model (DCM) of Gupta and Collaborators. We have considered the reactions with neutron-rich and neutron-deficient projectiles, respectively, as ${}^7\mathrm{Li}$, ${}^9\mathrm{Be}$, and ${}^7\mathrm{Be}$, on various targets at three different $E_{\mathrm{lab}}$ energies, forming compound nuclei in the mass region $\mathrm{A}\sim 30–200.$ For these reactions, the contributions of light-particle (LP, $A\le 4$) cross sections ${\sigma }_{\mathrm{LP}}$, energetically favored intermediate-mass-fragment (IMF, $5\le A_2\le 20$) cross sections ${\sigma }_{\mathrm{IMF}}$, as well as the fusion-fission ff cross sections ${\sigma }_{\mathrm{ff}}$ constitute the ${\sigma }_{\mathrm{fus}}\left(={\sigma }_{\mathrm{LP}}+{\sigma }_{\mathrm{IMF}}+{\sigma }_{\mathrm{ff}}\right)$, i.e., the contributions of the emitted LPs, IMFs, and ff fragments are added for all the angular momenta up to the ${\ell }_{\max }$ value for the respective reactions. Interestingly, we find that the empirically fitted neck-length parameter $\mathrm{\Delta }{R}^{\mathrm{emp}}$, the only parameter of the DCM, is uniquely fixed to address ${\sigma }_{\mathrm{fus}}$ for all the reactions having the same loosely bound projectile at a chosen incident laboratory energy. It may be noted that, in DCM, the dynamical collective mass motion of preformed LPs, IMFs, and ff fragments or clusters, through the modified interaction potential barrier, are treated on parallel footing. The modification of the barrier is due to nonzero $\mathrm{\Delta }{R}^{\mathrm{emp}}$, and the values of corresponding modified interaction-barrier heights $\mathrm{\Delta }{V}_B^{\mathrm{emp}}$ for such reactions are almost of the same order, specifically at the respective ${\ell }_{\max }$ value.

High momentum hadron suppression is considered to be an excellent probe of jet-medium interactions in QCD matter created in ultrarelativistic heavy ion collisions. We previously showed that our dynamical energy loss formalism can accurately explain suppression measurements at 200 GeV Au + Au collisions at the Relativistic Heavy Ion Collider (RHIC) and 2.76 TeV Pb + Pb collisions at the CERN Large Hadron Collider (LHC). With the upcoming LHC measurements at notably higher collision energies, there is a question of what differences, with respect to the current (2.76 TeV) measurements, can be expected. In this paper we concentrate on heavy flavor suppression at the upcoming 5.1 TeV Pb + Pb collisions energy at the LHC. Naively, one would expect a notably $\left(\sim 30\%\right)$ larger suppression at 5.1 TeV collision energy, due to estimated (significant) energy loss increase when transitioning from 2.76 to 5.1 TeV. Surprisingly, more detailed calculations predict nearly the same suppression results at these two energies. We show that this unexpected result is due to an interplay of the following two effects, which essentially cancel each other: (i) flattening of the initial charm and bottom momentum distributions with increasing collision energies, and (ii) significantly slower than naively expected increase in the energy loss. Therefore, the obtained theoretical predictions, which suggest nearly the same heavy flavor suppression at 2.76 and 5.1 TeV, provide a clear (qualitative and quantitative) test of our energy loss formalism.

The nucleon's peripheral transverse charge and magnetization densities are computed in chiral effective field theory. The densities are represented in first-quantized form, as overlap integrals of chiral light-front wave functions describing the transition of the nucleon to soft pion-nucleon intermediate states. The orbital motion of the pion causes a large left-right asymmetry in a transversely polarized nucleon. The effect attests to the relativistic nature of chiral dynamics [pion momenta $k=O\left(M_{\pi }\right)$] and could be observed in form factor measurements at low momentum transfer.

I have used a simple potential model to calculate single-particle widths in ${}^{27}\mathrm{P}$. Assuming mirror symmetry, I have combined them with the spectroscopic factor from the reaction ${}^{26}\mathrm{Mg}(d,p)$ to compute proton widths for the $3/2^{+}$ first-excited state. I present results for the resonance strength parameter $\omega \gamma$ and for the $(p,\gamma )$ reaction rate for two values of the $\gamma$ width and two values of the resonance energy.

Fusion of very neutron rich nuclei may be important to determine the composition and heating of the crust of accreting neutron stars. We present an exploratory study of the effect of the neutron-gas environment on the structure of nuclei and the consequences for pycnonuclear fusion cross sections in the neutron drip region. We studied the formation and properties of oxygen and calcium isotopes embedded in varying neutron-gas densities. We observe that the formed isotope is the drip-line nucleus for the given effective interaction. Increasing the neutron-gas density leads to the swelling of the nuclear density. We have used these densities to study the effect of this swelling on the fusion cross sections using the São Paulo potential. At high neutron-gas densities the cross section is substantially increased but at lower densities the modification is minimal.

An exploratory experiment performed at REX-ISOLDE to investigate cluster-transfer reactions with radioactive beams in inverse kinematics is presented. The aim of the experiment was to test the potential of cluster-transfer reactions at the Coulomb barrier as a mechanism to explore the structure of exotic neutron-rich nuclei. The reactions ${}^7\mathrm{Li}({}^{98}\mathrm{Rb},\alpha \mathrm{xn})$ and ${}^7\mathrm{Li}({}^{98}\mathrm{Rb},\mathrm{t}\mathrm{xn})$ were studied through particle-$\gamma$ coincidence measurements, and the results are presented in terms of the observed excitation energies and spins. Moreover, the reaction mechanism is qualitatively discussed as a transfer of a clusterlike particle within a distorted-wave Born approximation framework. The results indicate that cluster-transfer reactions can be described well as a direct process and that they can be an efficient method to investigate the structure of neutron-rich nuclei at medium-high excitation energies and spins.

High-spin states in ${}^{49}\mathrm{V}$ have been studied through the ${}^{28}\mathrm{Si}$(${}^{28}\mathrm{Si},\alpha 3\mathrm{p}$) reaction using the EUROBALL $\gamma$-ray detector array. The ${}^{49}\mathrm{V}$ level scheme has been extended up to 13.1 MeV including 21 new states. Both negative and positive parity states have been interpreted in the framework of the shell model. The $27/2^{-}$ and the 31/$2{}^{+}$ band-termination states have been observed in agreement with theoretical predictions.

Background: Multinucleon transfer reactions (MNT) are a competitive tool to populate exotic neutron-rich nuclei in a wide region of nuclei, where other production methods have severe limitations or cannot be used at all.

Purpose: Experimental information on the yields of MNT reactions in comparison with theoretical calculations are necessary to make predictions for the production of neutron-rich heavy nuclei. It is crucial to determine the fraction of MNT reaction products which are surviving neutron emission or fission at the high excitation energy after the nucleon exchange.

Method: Multinucleon transfer reactions in ${}^{136}\text{Xe}+{}^{238}\text{U}$ have been measured in a high-resolution $\gamma$-ray/particle coincidence experiment. The large solid-angle magnetic spectrometer PRISMA coupled to the high-resolution Advanced Gamma Tracking Array (AGATA) has been employed. Beamlike reaction products after multinucleon transfer in the Xe region were identified and selected with the PRISMA spectrometer. Coincident particles were tagged by multichannel plate detectors placed at the grazing angle of the targetlike recoils inside the scattering chamber.

Results: Mass yields have been extracted and compared with calculations based on the grazing model for MNT reactions. Kinematic coincidences between the binary reaction products, i.e., beamlike and targetlike nuclei, were exploited to obtain population yields for nuclei in the actinide region and compared to x-ray yields measured by AGATA.

Conclusions: No sizable yield of actinide nuclei beyond $Z=93$ is found to perform nuclear structure investigations. In-beam $\gamma$-ray spectroscopy is feasible for few-neutron transfer channels in U and the $-2\mathrm{p}$ channel populating Th isotopes.

Flux-averaged cross sections for cosmogenic-neutron activation of natural tellurium were measured using a neutron beam containing neutrons of kinetic energies up to $\sim 800$ MeV and having an energy spectrum similar to that of cosmic-ray neutrons at sea level. Analysis of the radioisotopes produced reveals that ${}^{110\mathrm{m}}\mathrm{Ag}$ will be a dominant contributor to the cosmogenic-activation background in experiments searching for neutrinoless double-$\beta$ decay of ${}^{130}\mathrm{Te}$, such as the Cryogenic Underground Observatory for Rare Events (CUORE) and the Sudbury Neutrino Observatory Plus $\left(\mathrm{SNO}+\right)$. An estimate of the cosmogenic-activation background in the CUORE experiment has been obtained using the results of this measurement and cross-section measurements of proton activation of tellurium. Additionally, the measured cross sections in this work are also compared with results from semiempirical cross-section calculations.

It is argued that there exist natural shell-model spaces optimally adapted to the operation of two variants of Elliott's SU3 symmetry that provide accurate predictions of quadrupole moments of deformed states. A self-consistent Nilsson-like calculation describes the competition between the realistic quadrupole force and the central field, indicating a remarkable stability of the quadrupole moments—which remain close to their quasi- and pseudo-SU3 values—as the single-particle splittings increase. A detailed study of the $N=Z$ even nuclei from ${}^{56}\mathrm{Ni}$ to ${}^{96}\mathrm{Cd}$ reveals that the region of prolate deformation is bounded by a pair of transitional nuclei ${}^{72}\mathrm{Kr}$ and ${}^{84}\mathrm{Mo}$ in which prolate ground-state bands are predicted to dominate, though coexisting with oblate ones.

The electromagnetic features of the $11/2^{-}$ isomers in the ${}^{111-127}\mathrm{Cd}$ isotopes are reproduced by numerically optimized shell-model wave functions. A sudden phase change of the wave functions at $N=70$ is identified and further confirmed by the evolution of $B(E2$, $7/2_1^{-}\to 11/2_1^{-})$ values. This phase change gives rise to different linear relations for the $Q$ and $\mu$ values with $N<70$ and $N>70$, as needed to reproduce the experimental data. The particle-hole transformation properties for $h_{11/2}$ neutrons in a well-isolated subshell involving degenerate $s_{1/2}$, $d_{3/2}$, $d_{5/2}$, and $h_{11/2}$ orbits is suggested as a possible explanation for this phase change.

Near shell closures, the presence of unexpected states at low energies provides a critical test of our understanding of the atomic nucleus. New measurements for the $N=42$ isotones ${}_{27}{}^{69}\mathrm{Co}$ and ${}_{29}{}^{71}\mathrm{Cu}$, along with recent data and calculations in the Ni isotopes, establish a full set of complementary, deformed, intruder states astride the closed-shell ${}_{28}\mathrm{Ni}$ isotopes. Nuclei with a one-proton hole or one-proton particle adjacent to $Z=28$ were populated in $\beta$-decay experiments and in multinucleon transfer reactions. A $\beta$-decaying isomer, with a 750(250)-ms half-life, has been identified in ${}_{27}{}^{69}\mathrm{Co}_{42}$. It likely has low spin and accompanies the previously established $7/2^{-}$ state. Complementary data for the levels of isotonic ${}_{29}{}^{71}\mathrm{Cu}_{42}$ support the presence of a deformed, $\mathrm{\Delta }J=1$ band built on the proton intruder $7/2^{-}$ level at 981 keV. These data, together with recent studies of lower-mass Co and Cu isotopes and extensive work near ${}^{68}\mathrm{Ni}$, support the view that intruder states based on particle-hole excitations accompany all closed proton shells with $Z\ge 28$.

We investigate the effects of chiral three-nucleon force (3NF) on proton scattering at 65 MeV and ${}^4\mathrm{He}$ scattering at 72 MeV/nucleon from heavier targets, using the standard microscopic framework composed of the Brueckner-Hartree-Fock (BHF) method and the $g$-matrix folding model. For nuclear matter, the $g$ matrix is evaluated from chiral two-nucleon force (2NF) of ${\mathrm{N}}^3\mathrm{LO}$ and chiral 3NF of NNLO by using the BHF method. Because the $g$ matrix thus obtained is numerical and nonlocal, an optimum local form is determined from the on-shell and near-on-shell components of $g$ matrix that are important for elastic scattering. For elastic scattering, the optical potentials are calculated by folding the local chiral $g$ matrix with projectile and target densities. This microscopic framework reproduces the experimental data without introducing any adjustable parameter. Chiral-3NF effects are small for proton scattering, but sizable for ${}^4\mathrm{He}$ scattering at middle angles where the data are available. Chiral 3NF, mainly in the $2\pi$-exchange diagram, makes the folding potential less attractive and more absorptive for all the scattering.

We extract the freezeout hypersurface in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2760$ GeV at the CERN Large Hadron Collider by analyzing the data on transverse momentum spectra within a unified model for chemical and kinetic freezeout. The study is done within two schemes of freezeout: single freezeout, where all the hadrons freeze out together, versus double-freezeout, where those hadrons with nonzero strangeness content have different freezeout parameters compared to the nonstrange ones. We demonstrate that the data are better described within the latter scenario. We obtain a strange freezeout hypersurface which is smaller in volume and hotter compared to the nonstrange freezeout hypersurface for all centralities, with a reduction in ${\chi }^2/N_{\mathrm{df}}$ around $40\%$. We observe from the extracted parameters that the ratio of the transverse size to the freezeout proper time is invariant under expansion from the strange to the nonstrange freezeout surfaces across all centralities. Moreover, except for the most peripheral bins, the ratio of the nonstrange-to-strange freezeout proper times is close to 1.3.