Large-amplitude collective dynamics of shape phase transition in the low-lying states of ${}^{30-36}$Mg is investigated by solving the five-dimensional (5D) quadrupole collective Schrödinger equation. The collective masses and potentials of the 5D collective Hamiltonian are microscopically derived with use of the constrained Hartree-Fock-Bogoliubov plus local quasiparticle random phase approximation method. Good agreement with the recent experimental data is obtained for the excited $0^{+}$ states as well as the ground bands. For ${}^{30}$Mg, the shape coexistence picture that the deformed excited $0^{+}$ state coexists with the spherical ground state approximately holds. On the other hand, large-amplitude quadrupole-shaped fluctuations dominate in both the ground and the excited $0^{+}$ states in ${}^{32}$Mg, providing a picture that is different from the interpretation of the “coexisting spherical excited $0^{+}$ state” based on the naive inversion picture of the spherical and deformed configurations.

We calculate the maximum mass of neutron stars for three different equations of state (EOSs) based on generalized Skyrme functionals that are simultaneously fitted to essentially all the 2003 nuclear mass data (the rms deviation is 0.58 MeV in all three cases) and to one or other of three different equations of state of pure neutron matter, each determined by a different many-body calculation using realistic two- and three-body interactions but leading to significantly different degrees of stiffness at the high densities prevailing in neutron-star interiors. The observation of a neutron star with mass 1.97 $\pm$ 0.04 ${\mathcal{M}}_{\odot }$ eliminates the softest of our models (BSk19), but does not discriminate between BSk20 and BSk21. However, nuclear-mass measurements that have been made since our models were constructed strongly favor BSk21, our stiffest functional.

One- and two-neutron removal reactions from ${}^{19}$C and ${}^{20}$C have been studied using a liquid-hydrogen target at 40$A$ MeV. A small cross section has been observed in the one-neutron removal reaction from ${}^{20}$C. The observed inclusive removal cross sections are compared with theoretical removal cross sections calculated by using shell model spectroscopic factors and Glauber-model single-particle cross sections. The observed momentum distributions are also compared with those calculated by using continuum-discretized coupled-channel methods. Good consistency between theory and experiment is shown in the one-neutron removal reaction from ${}^{19}$C. However, our theoretical calculation fails to reproduce the neutron removal reactions from ${}^{20}$C, which suggests that further improvements of the theoretical descriptions are necessary.

The meaning of the fact that the angular momenta of protons and neutrons are oriented in opposite directions, shown by Otsuka [Phys. Rev. Lett. 71, 1804 (1993)] for the angular-momentum-projected Nilsson wave functions, is reexamined using a two-rotor model. It is shown that this fact does not necessarily mean an unphysical situation that proton and neutron ellipsoids are rotating freely in opposite directions. On the contrary, it originates in a close binding of the two ellipsoids, which is accompanied by a large spreading of the relative angular momentum due to the uncertainty principle. It is also demonstrated that the elimination of the spurious center-of-mass motion does not substantially change the situation.

The production cross sections of projectilelike fragments from the interaction of 15 MeV/nucleon ${}^{86}$Kr with ${}^{64}$Ni and ${}^{58}$Ni and with ${}^{124}$Sn and ${}^{112}$Sn were measured using a magnetic separator with emphasis on the neutron-rich isotopes. Neutron pickup isotopes (with up to six neutrons picked up from the target) were observed with large cross sections. Calculations involving the the deep-inelastic transfer model as well as the microscopic constrained molecular dynamics model (CoMD) for the primary interaction stage coupled to the statistical deexcitation code gemini were used to describe the gross properties of the product distributions. The present results were also compared with our previous data of the same reactions at 25 MeV/nucleon. The data at 15 MeV/nucleon show enhanced production of neutron-rich isotopes very close to the projectile, relative to the corresponding data at 25 MeV/nucleon. This enhancement in the cross sections is possibly associated with very peripheral collisions and longer interaction times of the neutron-rich ${}^{86}$Kr projectile with the neutron-rich targets. The large cross sections of such reactions well above the Coulomb barrier, but below the Fermi energy, involving peripheral nucleon exchange, suggest that both the $N\text{/}Z$ of the projectile and the $N\text{/}Z$ of the target may properly be exploited in the production of neutron-rich rare isotopes. These reactions offer a novel and attractive route to access extremely neutron-rich rare isotopes toward the the astrophysical $r$-process path and, possibly, the neutron drip-line.

Both the valence nucleons (holes) and the isospin asymmetry dependencies of the preformation probability of an α-cluster inside parents radioactive nuclei are investigated. The calculations are employed in the framework of the density-dependent cluster model of an α-decay process for the even-even spherical parents nuclei with protons number around the closed shell $Z_0$ $=$ 82 and neutrons number around the closed shells $Z_0$ $=$ 82 and $Z_0$ $=$ 126. The microscopic α-daughter nuclear interaction potential is calculated in the framework of the Hamiltonian energy density approach based on the SLy4 Skyrme-like effective interaction. Also, the calculations based on the realistic effective M3Y-Paris nucleon-nucleon force have been used to confirm the results. The calculations then proceed to find the assault frequency and the α penetration probability within the WKB approximation. The half-lives of the different mentioned α decays are then determined and have been used in turn to find the α spectroscopic factor. We found that the spectroscopic factor increases with increasing the isospin asymmetry of the parent nuclei if they have valence protons and neutrons. When the parent nuclei have neutron or proton holes in addition to the valence protons or neutrons, then the spectroscopic factor is found to decrease with increasing isospin asymmetry. The obtained results show also that the deduced spectroscopic factors follow individual linear behaviors as a function of the multiplication of the valence proton ($N_p$) and neutron ($N_n$) numbers. These linear dependencies are correlated with the closed shells core $(Z_0,N_0)$. The same individual linear behaviors are obtained as a function of the multiplication of $N_p{N}_n$ and the isospin asymmetry parameter, $N_p{N}_{n}I$. Moreover, the whole deduced spectroscopic factors are found to exhibit a nearly general linear trend with the function $N_p{N}_n/(Z_0+N_0)$.

We compute net-proton probability distributions in heavy ion collisions within the hadron resonance gas model. The model results are compared with data taken by the STAR Collaboration in Au-Au collisions at $\sqrt{s_{NN}}=200$ GeV for different centralities and for the central energy bin at $\sqrt{s_{NN}}=39$ GeV. We show that, in central Au-Au collisions at $\sqrt{s_{NN}}=39$ GeV, the measured distribution is consistent with the hadron resonance gas model but differs from the predictions of the model at $\sqrt{s_{NN}}=200$ GeV. At the highest energy, deviations from model results are smaller for peripheral collisions. We argue that such properties of probability distributions are expected if the freeze-out conditions probed by fluctuations are located close to the QCD crossover transition.

We present a phenomenological theory of nuclei that incorporates clustering at the nuclear surface in a general form. The theory explains the recently extracted large symmetry energy by Natowitz et al., at low densities of nuclear matter and is fully consistent with the static properties of nuclei. In a phenomenological way, clusters of all sizes and shapes along with medium modifications are included. Symmetric nuclear matter properties are discussed in detail. Arguments are given that lead to an equation of state of nuclear matter consistent with clustering in the low-density region. We also discuss properties of asymmetric nuclear matter. Because of clustering, an interesting interpretation of the equation of state of asymmetric nuclear matter emerges. As a framework, an extended version of Thomas-Fermi theory is adopted for nuclei which also contain phenomenological pairing and Wigner contributions. This theory connects the nuclear matter equation of state, which incorporates clustering at low densities, with clustering in nuclei at the nuclear surface. Calculations are performed for various equations of state of nuclear matter. We consider measured binding energies of 2149 nuclei for $N$, $Z$ ⩾ 8. The importance of the quartic term in symmetry energy is demonstrated at and below the saturation density of nuclear matter. It is shown that it is largely related to the use of, ab initio, a realistic equation of state of neutron matter, particularly the contribution arising from the three neutron interactions and somewhat to clustering. Reasons for these are discussed. Because of clustering the neutron skin thickness in nuclei is found to reduce significantly. The developed theory predicts situations and regimes to be explored both theoretically and experimentally.

We calculate the energy-level displacement of the excited $np$ state of kaonic deuterium in terms of the $p$-wave scattering length of $K^{-}d$ scattering. We solve the Faddeev equations for the amplitude of $K^{-}d$ scattering in the fixed-center approximation and derive the complex $p$-wave scattering length of $K^{-}d$ scattering in terms of the $s$-wave and $p$-wave scattering lengths of $\overline{K}N$ scattering. The estimated uncertainty of the complex $p$-wave scattering length is of about $15\%$. For the calculated width ${\Gamma }_{2p}=10.203$ meV of the excited $2p$ state of kaonic deuterium we evaluate the yield $Y_{K^{-}d}=0.27\%$ of x rays for the $K_{\alpha }$ emission line of kaonic deuterium. Using the complex $s$-wave and $p$-wave scattering lengths of $\overline{K}N$ scattering, calculated in B. Borasoy, R. Nißler, and W. Weise [Eur. Phys. J. A 25, 79 (2005)] and W. Weise and R. Härtle [Nucl. Phys. A 804, 173 (2008)], we get the width ${\Gamma }_{2p}=2.675$ meV of the excited $2p$ state and the yield $Y_{K^{-}d}=1.90\%$ of x rays for the $K_{\alpha }$ emission line of kaonic deuterium. The results obtained in this paper can be used for planning experiments on the measurements of the energy-level displacement of the ground state of kaonic deuterium, caused by strong low-energy interactions.

The time evolution and space distribution of internal electromagnetic fields in heavy-ion reactions at beam energies between 200 and 2000 MeV/nucleon are studied within an isospin-dependent Boltzmann-Uhling-Uhlenbeck transport model (ibuu11). While the magnetic field can reach about $7\times {10}^{16}$ G, which is significantly higher than the estimated surface magnetic field ($\sim$$1\times {10}^{15}$ G) of magnetars, it has almost no effect on nucleon observables because the Lorentz force is normally much weaker than the nuclear force. Very interestingly, however, the magnetic field generated by the projectilelike (targetlike) spectator has a strong focusing and defocusing effect on positive and negative pions at forward (backward) rapidities. Consequently, the differential ${\pi }^{-}/{\pi }^{+}$ ratio as a function of rapidity is significantly altered by the magnetic field, whereas the total multiplicities of both positive and negative pions remain about the same. At beam energies above about 1 GeV/nucleon, while the integrated ratio of total ${\pi }^{-}$ to ${\pi }^{+}$ multiplicities is not, the differential ${\pi }^{-}/{\pi }^{+}$ ratio is sensitive to the density dependence of nuclear symmetry energy $E_{\mathrm{sym}}\left(\rho \right)$. Our findings suggest that magnetic effects should be carefully considered in future studies of using the differential ${\pi }^{-}/{\pi }^{+}$ ratio as a probe of the $E_{\mathrm{sym}}\left(\rho \right)$ at suprasaturation densities.

Evaporation residue cross sections for the reaction ${}^{16}\text{O}+{}^{194}\text{Pt}$ were measured at beam energies in the range 75.4–103.1 MeV using the gas-filled separator Hybrid Recoil Mass Analyzer at the Inter University Accelerator Centre, New Delhi. The transmission efficiency of the separator was obtained using the calibration system ${}^{16}\text{O}+{}^{184}\text{W}$ and a Monte Carlo simulation code. Measured evaporation residue cross sections were fitted with statistical model calculations using Kramers' formula. The present measurement provides further evidence for the onset of dissipative forces in fission in the mass $\sim$200 region.

We investigate the possibilities of using measurements in present and future experiments on heavy ion collisions to answer some longstanding problems in hadronic physics, namely, identifying hadronic molecular states and exotic hadrons with multiquark components. The yields of a selected set of exotic hadron candidates in relativistic heavy ion collisions are discussed in the coalescence model in comparison with the statistical model. We find that the yield of a hadron is typically an order of magnitude smaller when it is a compact multiquark state, compared to that of an excited hadronic state with normal quark numbers. We also find that some loosely bound hadronic molecules are formed more abundantly than the statistical model prediction by a factor of two or more. Moreover, owing to the significant numbers of charm and bottom quarks produced at RHIC and even larger numbers expected at LHC, some of the proposed heavy exotic hadrons could be produced with sufficient abundance for detection, making it possible to study these new exotic hadrons in heavy ion collisions.

Excited states in the odd-odd neutron deficient nucleus ${}^{162}\mathrm{Ta}$ ($Z=73$, $N=89$) have been studied for the first time. The gamma spectroscopy analysis using $\gamma -\gamma -\gamma$ coincidences revealed a strongly coupled rotational structure that was established up to large angular momentum states. The rotational band was assigned to the configuration $\pi h_{11/2}\left[514\right]9/2\otimes \nu i_{13/2}\left[660\right]1/2$ based on its rotational and electromagnetic properties. The data are interpreted within the framework of total Routhian surface calculations, which suggests an axially symmetric shape with a $\gamma$-soft minimum at ${\beta }_2\approx 0.16$ and $\gamma \approx 6^{\circ }$. The crossing of the signature partners observed in heavier ($N⩾91$) odd-odd nuclides in this mass region is found to be absent at $N=89$. This might be correlated with a change in $S$-band structure above the paired band crossing at these neutron numbers.

Fusion and transfer $+$ breakup channels have been studied in the collision induced by the two-neutron-halo ${}^6$He on a ${}^{64}$Zn target at energies from below to above the Coulomb barrier. For comparison, the reaction induced by the stable isotope ${}^4$He on the same target has been studied. The fusion cross section has been measured by using an activation technique, detecting off-line the delayed x-ray activity following the electron capture decay of the evaporation residues. New measurements of the ${}^4$He $+$ ${}^{64}$Zn fusion cross section at sub-barrier energies have been performed in order to cover the same energy range of the ${}^6$He $+$ ${}^{64}$Zn fusion cross section and to compare the excitation functions for the two systems down to the lowest energy data point measured for ${}^6$He. From the new comparison a sub-barrier fusion enhancement has been observed in the ${}^6$He case with respect to the ${}^4$He one whereas no effect on the ${}^6$He fusion cross section has been seen at energies above the barrier. It has been concluded that such enhancement seems to be due to the diffuse halo structure properties of the ${}^6$He nucleus. Moreover, the reactions induced by ${}^6$He have shown a strong yield of $\alpha$ particles coming from direct processes.

Production of the $K^{*}{\left(892\right)}^0$ and ${\overline{K}}^{*}{\left(892\right)}^0$ resonances was studied via their $K^{+}{\pi }^{-}$ and $K^{-}{\pi }^{+}$ decay modes in central $\mathrm{Pb}+\mathrm{Pb}$, $\mathrm{Si}+\mathrm{Si}$, $\mathrm{C}+\mathrm{C}$, and inelastic $p+p$ collisions at 158$A$ GeV($\sqrt{s_{NN}}=17.3$ GeV) with the NA49 detector at the CERN SPS. Transverse momentum and rapidity distributions were measured and total yields were estimated. The yield of $K^{*}$ exceeds that of ${\overline{K}}^{*}$ by about a factor of two in nucleus-nucleus reactions. The total yield ratios $\langle K^{*}\rangle$$/\langle K^{+}\rangle$ and $\langle {\overline{K}}^{*}\rangle$$/\langle K^{-}\rangle$ are strongly suppressed in central $\mathrm{Pb}+\mathrm{Pb}$ compared to $p+p$, $\mathrm{C}+\mathrm{C}$, and $\mathrm{Si}+\mathrm{Si}$ collisions, in agreement with the expected attenuation of these short-lived resonance states in the hadronic phase of the expanding fireball. The UrQMD model, although incorporating such a scenario, does not provide a quantitative description of the experimental results. The statistical hadron gas model assuming the same freeze-out parameters for stable hadrons and resonances overestimates the $\langle K^{*}\rangle$$/\langle K\rangle$ ratios in central $\mathrm{Pb}+\mathrm{Pb}$ collisions by about a factor of 2.5.

The dynamics of the movement of gas is discussed for two-chambered polarized ${}^3$He target cells of the sort that have been used successfully for many electron-scattering experiments. A detailed analysis is presented showing that diffusion is a limiting factor in target performance, particularly as these targets are run at increasingly high luminosities. Measurements are presented on a new prototype polarized ${}^3$He target cell in which the movement of gas is due largely to convection instead of diffusion. Nuclear magnetic resonance tagging techniques have been used to visualize the gas flow, showing velocities along a cylindrically shaped target of between 5 and 80 cm/min. The new target design addresses one of the principle obstacles to running polarized ${}^3$He targets at substantially higher luminosities while simultaneously providing new flexibility in target geometry.

Starting from the calculation of the neutrino distribution function, as a function of the active-sterile neutrino mixing parameters, we calculate primordial abundances of light nuclei (D, ${}^4$He, and ${}^7$Li) using a modified version of Kawano’s code. The active-sterile neutrino mixing parameters and the baryon-to-photon ratio $\left({\eta }_B\right)$ enter the calculation as free parameters. By using the observational data of D, ${}^4$He, and ${}^7$Li, we set constraints on ${\eta }_B$ and on the active-sterile neutrino mixing parameters. It is found that the value for the baryon-to-photon ratio depends strongly on the inclusion of ${}^7$Li data in the sample, while the value for the mixing angles remain small.

We study the perturbative renormalizability of chiral two-pion exchange in nucleon-nucleon scattering for $p$ and $d$ waves within the effective field theory approach. The one-pion exchange potential is fully iterated at the leading order in the expansion, a choice generating a consistent and well-defined power counting that we explore in detail. The results show that perturbative chiral two-pion exchange reproduces the data up to a center-of-mass momentum of $k_{\mathrm{cm}}\sim 300\mathrm{MeV}$ at next-to-next-to-leading order and that the effective field theory expansion converges up to $k_{\mathrm{cm}}\sim 350\mathrm{MeV}$.

The nuclear electron capture (EC) process in lithium-like ions is studied. We find that the daughter helium-like ions are created mostly in the $2{}^1{S}_0$ and $2{}^3{S}_1$ excited states with probabilities denoted as $P_0$ and $P_1$, respectively. The ratio of probabilities depends on spin $I$ of a mother nucleus and the type of the EC transition. For allowed EC transitions $I\to I\pm 1$ the ratio has a simple form $\frac{P_0}{P_1}=\frac{2I+1}{2(I\pm 1)+1}$. Additionally, we found the simple relation between probabilities of EC decay for lithium- and hydrogen-like ions $P_{Li}=P_H(\frac{2(I\pm 1/2)+1}{(2I+1)}+\frac{{\rho }^{2s}\left(Z\right)}{2{\rho }^{1s}\left(Z\right)}){(1-\frac{q}{Z})}^3$, where $q=0.464$. We also discuss applications of excited states formed in helium-like ions, especially the parity nonconservation effect.

The experiments that provide information about the level structure of the “island of inversion” isotopes ${}^{31}$Mg and ${}^{33}$Mg are reviewed. Since the model-independent measurement of their ground-state spins was done, much experimental data can be reinterpreted, and spins and parities can be assigned to their excited states. Both experimental level schemes are found in very good agreement with calculations based on antisymmetrized molecular dynamics combined with the generator coordinate method. These calculations predict that both ground states are dominated by $2\hslash \omega$ neutron excitations (more than 85$\%$ of the wave function). In the case of ${}^{33}$Mg, the energy of the $1\hslash \omega$ and $3\hslash \omega$ levels are calculated about 400 keV too high with respect to the ground state, while in ${}^{31}$Mg the $1\hslash \omega$ levels are calculated only 200 keV too high. New key experiments are suggested.