In the light of the recent Large Hadron Collider data on proton-proton and lead-lead collisions, we examine the question of the multiplicity scaling of Hanbury-Brown–Twiss (HBT) radii in relativistic nuclei and particle interactions. Within the Ultrarelativistic Quantum Molecular Dynamics transport approach we study a large variety of system sizes at different beam energies and extract the HBT radii. In the calculation, we find a good scaling of the radii as a function of charged particle multiplicity, if the change in the multiplicity is caused by a change of centrality at the same energy. However, the scaling is only approximate when the energy, $\sqrt{s}$, is changed and breaks down when comparing proton-proton to nucleus-nucleus reactions.

The final analysis of the experiment determining both components of the transverse polarization of electrons (${\sigma }_{T_1}$, ${\sigma }_{T_2}$) emitted in the $\beta$ decay of polarized, free neutrons is presented. The $T$-odd, $P$-odd correlation coefficient quantifying ${\sigma }_{T_2}$, perpendicular to the neutron polarization and electron momentum, was found to be $R=$ 0.004 $\pm$ 0.012 $\pm$ 0.005. This value is consistent with time-reversal invariance and significantly improves both the earlier result and limits the relative strength of the imaginary scalar couplings in the weak interaction. The value obtained for the correlation coefficient associated with ${\sigma }_{T_1}$, $N=$ 0.067 $\pm$ 0.011 $\pm$ 0.004, agrees with the standard model expectation, providing an important sensitivity test of the experimental setup. The present result sets constraints on the imaginary part of scalar and tensor couplings in weak interactions. Implications for parameters of the leptoquark exchange model and the minimal supersymmetric model with $R$-parity violation are discussed.

We study the formation and final structure of the rare-earth peak ($A\sim 160$) of the $r$-process nucleosynthesis. Under high-entropy conditions ($S>100k_B$), the rare-earth peak forms at late times in the $r$-process after neutron exhaustion (neutron-to-seed ratio $R=1$) as matter decays back to stability. Since rare-earth peak formation does not occur during $(n,\gamma )\rightleftarrows (\gamma ,n)$ equilibrium it is sensitive to the strong interplay between late-time thermodynamic evolution and nuclear physics input. Depending on the conditions, the peak forms either because of the pattern of the neutron capture rates or because of the pattern of the separation energies. We analyze three nuclear data sets under different thermodynamic conditions. We find that the subtleties of each nuclear data set, including separation energies and neutron capture rates, influence not only the final shape of the peak but also when it forms. We identify the range of nuclei which are influential in rare-earth peak formation.

The annihilation reaction $e^{+}+e^{-}\to \overline{\rho }+\rho$ is considered. The constraint on time-like $\rho$-meson form factors from the measurement done by the BaBar Collaboration at $\sqrt{s}=10.58$ GeV is analyzed.

Excited states in ${}^{67}$Ni were populated in deep-inelastic reactions of a ${}^{64}$Ni beam at 430 MeV on a thick ${}^{238}$U target. A level scheme built on the previously known 13-$\mu$s isomer has been delineated up to an excitation energy of 5.3 MeV and a tentative spin and parity of (21/2${}^{-}$). Shell model calculations have been carried out using two effective interactions in the $f_{5/2}p{g}_{9/2}$ model space with a ${}^{56}$Ni core. Satisfactory agreement between experiment and theory is achieved for the measured transition energies and branching ratios. The calculations indicate that the yrast states are associated with rather complex configurations, herewith demonstrating the relative weakness of the $N=40$ subshell gap and the importance of multi-particle-hole excitations involving the $g_{9/2}$ neutron orbital.

The triple shape coexistence specific for the 0${}^{+}$ states and the evolution of the shape coexistence and mixing in the neutron-rich $N=58$ Sr and Zr isotopes are studied within the complex excited VAMPIR approach using a realistic effective interaction based on the Bonn A potential in a large model space. The influence of the shape mixing on the structure and dynamics of the positive-parity states up to spin 20${}^{+}$ in ${}^{96}$Sr and ${}^{98}$Zr is discussed and comparison to the available data is presented.

We study the resonance spectroscopy of the proton-rich nucleus ${}^8$C in the $\alpha$+$p$+$p$+$p$+$p$ cluster model. Many-body resonances are treated on the correct boundary condition as the Gamow states using the complex scaling method. We obtain the ground state of ${}^8$C as a five-body resonance for the first time, which has dominantly the subclosed ${\left(p_{3/2}\right)}^4$ configuration and agrees with the recent experiment for energy and decay width. We predict the second $0^{+}$ state with the excitation energy of 5.6 MeV, which corresponds to the 2p2h state from the ground state. We evaluate the occupation numbers of four valence-protons in the ${}^8$C states and also the $J^{\pi }$ distribution of proton-pair numbers of the two $0^{+}$ states of ${}^8$C. The ground state involves a large amount of the $2^{+}$ proton-pair fraction, while the excited $0_2^{+}$ state almost consists of two of the $0^{+}$ proton pairs, which can be understood from the ${\left(p_{3/2}\right)}^2{\left(p_{1/2}\right)}^2$ configuration. We also discuss the mirror symmetry between ${}^8$C and ${}^8$He with an $\alpha$+four nucleon picture. It is found that the $0^{+}$ states retain the mirror symmetry well for the configuration properties of two nuclei.

Methods of extraction of the symmetry energy (or enthalpy) coefficient to temperature ratio from isobaric and isotopic yields of fragments produced in Fermi-energy heavy-ion collisions are discussed. We show that the methods are consistent when the hot fragmenting source is well characterized and its excitation energy and isotopic composition are properly taken into account. The results are independent of the mass number of the detected fragments, which suggests that their fate is decided very early in the reaction.

Differential and total cross sections for the $pp\to pp{K}^{+}{K}^{-}$ reaction have been measured at a proton beam energy of 2.83 GeV using the COSY-ANKE magnetic spectrometer. Detailed model descriptions fitted to a variety of one-dimensional distributions permit the separation of the $pp\to pp\phi$ cross section from that of non-$\phi$ production. The differential spectra show that higher partial waves represent the majority of the $pp\to pp\phi$ total cross section at an excess energy of 76 MeV, whose energy dependence would then seem to require some $s$-wave $\phi p$ enhancement near threshold. The non-$\phi$ data can be described in terms of the combined effects of two-body final state interactions using the same effective scattering parameters determined from lower energy data.

The high-velocity transient-field (HVTF) technique was used to measure the $g$ factor of the 2${}^{+}$ state of ${}^{72}$Zn produced as a radioactive beam. The transient-field strength was probed at high velocity in ferromagnetic iron and gadolinium hosts using ${}^{76}$Ge beams. The potential of the HVTF method is demonstrated and the difficulties that need to be overcome for a reliable use of the TF technique with high-$Z$, high-velocity radioactive beams are revealed. The polarization of $K$-shell vacancies at high velocity, which shows more than an order of magnitude difference between $Z=20$ and $Z=30$ is discussed. The $g$-factor measurement hints at the theoretically predicted transition in the structure of the Zn isotopes near $N=40$.

We perform shell-model calculations for nuclei below ${}^{100}$Sn, focusing attention on the two $N=Z$ nuclei, ${}^{96}$Cd and ${}^{92}$Pd, the latter having recently been the subject of great experimental and theoretical interest. We consider nuclei for which the $0g_{9/2}$ orbit plays a dominant role and employ a realistic low-momentum two-body effective interaction derived from the CD-Bonn nucleon-nucleon potential. This implies that no phenomenological input enters our effective Hamiltonian. The calculated results for ${}^{92}$Pd are in very good agreement with the available experimental data, which gives us confidence in our predictions for ${}^{96}$Cd. An analysis of the wave functions of both ${}^{96}$Cd and ${}^{92}$Pd is performed to investigate the role of the isoscalar spin-aligned coupling.

Calculations of half-lives of superheavy (SH) nuclei show an unexpected result: for some of them cluster radioactivity (CR) dominates over $\alpha$ decay. We changed the concept of CR to allow emitted particles with $Z_e>28$ from parents with $Z>110$ (daughter around ${}^{208}$Pb). We find a trend toward shorter half-lives and larger branching ratios relative to $\alpha$ decay for heavier SHs. A table of measured masses along with theoretical tables are used to determine Q values.

The neutron-induced fission cross section of ${}^{245}$Cm was measured at n_TOF in a wide energy range and with high resolution. The energy dependence, measured in a single measurement from 30 meV to 1 MeV neutron energy, has been determined with 5$\%$ accuracy relative to the ${}^{235}$U(n,f) cross section. In order to reduce the uncertainty on the absolute value, the data have been normalized at thermal energy to recent measurements performed at ILL and BR1. In the energy range of overlap, the results are in fair agreement with some previous measurements and confirm, on average, the evaluated cross section in the ENDF/B-VII.0 database, although sizable differences are observed for some important resonances below 20 eV. A similar behavior is observed relative to JENDL/AC-2008, a reactor-oriented database for actinides. The new results contribute to the overall improvement of the databases needed for the design of advanced reactor systems and may lead to refinements of fission models for the actinides.

In terms of the hadron-string-dynamics (HSD) approach, we investigate the correlation function in the azimuthal angle $\psi$ of charged hadrons that is expected to be sensitive to a signal of local strong parity violation. Our analysis of $\text{Au}+\text{Au}$ collisions is based on the recent STAR data within the RHIC beam-energy-scan (BES) program. The HSD model reasonably reproduces STAR data for $\sqrt{s_{NN}}=$7.7 GeV, while there are some deviations from the experiment at the collision energy of 11.5 GeV and an increase of deviations between theory and experiment at $\sqrt{s_{NN}}=39$ GeV. For reference, the results for $\sqrt{s_{NN}}=200$ GeV are given as well. The role of the retarded electromagnetic field is discussed and a compensation effect for the action of its electric and magnetic components is pointed out. We conclude that the recent RHIC BES data at $\sqrt{s_{NN}}=7.7$ and 11.5 GeV can be understood on the hadronic level without involving the idea of a strong parity violation; however, the HSD model fails to reproduce data for $\sqrt{s_{NN}}\sim 40$ GeV and above which suggests that at these energies one has to take into account explicit partonic (quark-qluon) degrees of freedom for a proper treatment of the dynamics as well as a coupling of the partons to fluctuating color fields.

Production of proton-rich nuclei beyond iron in stars proceeds via the $p$ process, i.e., a sequence of photodisintegration reactions, ($\gamma$,$n$), ($\gamma$,$p$), and ($\gamma$,$\alpha$) on heavy nuclei at temperatures of $2–3\times {10}^9$ K. The involved reaction rates are typically calculated with the statistical Hauser-Feshbach (HF) model. However, the HF model performs poorly in calculating the critical ($\gamma$,$\alpha$) rates due to the uncertainty of the alpha optical potentials applied. To test the reliability of the HF calculations and provide a systematic understanding of the $\alpha$ optical potential at energies of astrophysical interest, a series of precision $\alpha$ scattering measurements were carried out at the Notre Dame FN Tandem Accelerator. Specifically, ${}^{106}$Cd, ${}^{118}$Sn, and ${}^{120,124,126,128,130}$Te were studied at energies both below and above the Coulomb barrier. A new parametrization of the $\alpha$ optical potential was derived of the elastic scattering cross section data. The derived potential was applied for calculating the $\alpha$-induced reaction cross sections on these nuclei using the HF approach. The results were compared to the corresponding experimental values obtained from previous activation measurements on Cd, Sn, and Te isotopes.

The interaction cross sections of ${}^{22,23}$O nuclei at 900 MeV/nucleon have been measured recently by Kanungo et al. [Phys. Rev. C 84, 061304(R) (2011)]. We show that the odd-even staggering parameter of interaction cross sections deduced from these new data agrees well with the theoretical systematics expected for the neutron separation energy of $S_n=2.74\pm 0.120$ MeV for ${}^{23}$O. We also discuss briefly the energy dependence of the staggering parameter.

A systematic study of energy spectra throughout the rare-earth region (even-even nuclei from ${}_{58}$Ce to ${}_{74}$W) is carried out in the framework of the interacting boson model (IBM), leading to an accurate description of the spherical-to-deformed shape transition in the different isotopic chains. The resulting IBM Hamiltonians are then used for the calculation of nuclear charge radii (including isotope and isomer shifts) and electric monopole transitions with consistent operators for the two observables. The main conclusion of this study is that an IBM description of charge radii and electric monopole transitions is possible for most of the nuclei considered but that it breaks down in the tungsten isotopes. It is suggested that this failure is related to hexadecapole deformation.

An iterative matrix diagonalization algorithm endowed with an importance sampling, recently reformulated and tested through large-scale shell model calculations on some heavy Xe isotopes, is here applied to $N=80$ isotones. For these nuclei, the iterative sampling procedure is shown to converge more rapidly than in the case of Xe isotopes. The improved convergence rate enables us to produce accurate eigenvalues and eigenfunctions even in spaces of dimensions $N\sim {10}^9$. It is therefore possible to offer an exhaustive description of low-energy spectroscopic properties for all $N=80$ isotones from ${}^{132}$Te up to ${}^{140}$Nd through the calculation of spectra and transition strengths. The results are fairly consistent with the available experimental data and with other shell model calculations based on the Lanczos algorithm.

The heavy-ion radiative capture reaction ${}^{12}$C(${}^{16}$O,$\gamma$)${}^{28}$Si has been studied at three energies $E_{\mathrm{c}.\mathrm{m}.}=8.5$, 8.8, and 9 MeV which are close to the Coulomb barrier. The weak radiative capture process has been identified by measuring the ${}^{28}$Si recoils in the highly selective 0${}^{\circ }$ spectrometer DRAGON at TRIUMF (Vancouver). The coincident $\gamma$ rays have been recorded in the associated BGO array. This has allowed a complete measurement of the $\gamma$ spectrum and the relative strength of all decay pathways. An important part of the decay through quasibound states close to the particle threshold and the feeding of bound states with particular deformation have been identified for the first time. Comparisons with Monte Carlo simulations allowed the extraction of the full experimental radiative capture cross section. Our results suggest an important contribution of spins $J^{\pi }=5^{-}$ and 6${}^{+}$ in the entrance channel. The surprisingly large cross sections from 12 $\mu$b at $E_{\mathrm{c}.\mathrm{m}.}=8.5$ MeV to 25 $\mu$b at $E_{\mathrm{c}.\mathrm{m}.}=9.0$ MeV for the heavy-ion radiative capture process are discussed in terms of the interplay between statistical and structural aspects of the process.

Glasma produced in high-energy heavy-ion collisions is made up of longitudinal classical color electric and magnetic fields. The color electric field has been shown to produce quark and antiquark pairs and to oscillate with time in nonexpanding glasma, that is, plasma oscillation. However, we show that the field decreases with the plasma oscillation in the expanding glasma. We can explicitly obtain the solutions representing such temporal behaviors in $\tau$ and $\eta$ coordinates. We show the results in massless QED as a simplified model of QCD.