Radioactive isotopes produced through cosmic muon spallation are a background for rare-event detection in $\nu$ detectors, double-$\beta$-decay experiments, and dark-matter searches. Understanding the nature of cosmogenic backgrounds is particularly important for future experiments aiming to determine the $\mathit{pep}$ and CNO solar neutrino fluxes, for which the background is dominated by the spallation production of ${}^{11}\mathrm{C}$. Data from the Kamioka liquid-scintillator antineutrino detector (KamLAND) provides valuable information for better understanding these backgrounds, especially in liquid scintillators, and for checking estimates from current simulations based upon MUSIC, FLUKA, and GEANT4. Using the time correlation between detected muons and neutron captures, the neutron production yield in the KamLAND liquid scintillator is measured to be $Y_n=(2.8\pm 0.3)\times {10}^{-4}\hspace{0.5em}{\mu }^{-1}\hspace{0.5em}{\mathrm{g}}^{-1}\hspace{0.5em}{\mathrm{cm}}^2$. For other isotopes, the production yield is determined from the observed time correlation related to known isotope lifetimes. We find some yields are inconsistent with extrapolations based on an accelerator muon beam experiment.

The thermal neutron capture cross sections of the ${}^{74}\mathrm{Ge}$($n,\gamma$)${}^{75}\mathrm{Ge}$ and the ${}^{74}\mathrm{Ge}$($n,\gamma$)${}^{75m}\mathrm{Ge}$ reactions have been measured by the activation method. Cold neutrons were used to activate ${\mathrm{GeO}}_2$ targets depleted in ${}^{76}\mathrm{Ge}$. From the decay spectra of ${}^{75}\mathrm{Ge}$ measured with high-purity germanium detectors, the cross sections relative to ${}^{197}\mathrm{Au}$ were derived. For the ${}^{74}\mathrm{Ge}$($n,\gamma$)${}^{75m}\mathrm{Ge}$ reaction, a value of ($130.5\pm 5.6$) mb was found and the ground state was populated with a cross section of ($497\pm 52$) mb.

The Germanium Detector Array (GERDA) collaboration will be searching for neutrinoless double $\beta$ decay of ${}^{76}\mathrm{Ge}$. As a result it will measure the half-life $T_{1/2}$ of this rare process; or at least a new value for the lower limit for $T_{1/2}$ will be derived. The sensitivity of the GERDA experiment on the effective electron neutrino mass $\langle m_{\beta \beta }\rangle$ depends on the theoretical value for the nuclear matrix element $\mathcal{M}$ and the kinematical phase space factor $G$.

In this Brief Report we focus on existing difficulties in applying the dimensionless values of $\mathcal{M}$ calculated by various theoretical groups, which use different methods and parametrizations. The implicit radius dependencies in $\mathcal{M}$ and $G$ are discussed. Resulting values of the neutrino mass are tabulated for various representative half-lives $T_{1/2}$ representing the sensitivity of the various phases of the GERDA experiment.

It is shown that a disagreement regarding predictions of pion polarizabilities remains between the dispersion sum rule and the chiral perturbatin theory.

We show that the alleged discrepancies between chiral perturbation theory (ChPT) and dispersion theory, reported for the polarizability of the pion by Fil’kov and Kashevarov [Phys. Rev. C 72, 035211 (2005)], result from applying dispersion theory to nonanalytic functions.

We show that the $E1$ and $E2\hspace{0.5em}S$ factors recommended by Katsuma [Phys. Rev. C 78, 034606 (2008)] do not include well-known constraints and that the model is inappropriate for the ${}^{12}\mathrm{C}$($\alpha ,\gamma$)${}^{16}\mathrm{O}$ reaction.

Complete fusion cross sections for ${}^9\mathrm{Be}$ incident on ${}^{208}\mathrm{Pb}$ and ${}^{209}\mathrm{Bi}$ have been measured at energies greater than the fusion barrier to investigate the large differences in their reported complete fusion cross sections. Relative $\mathit{xn}$ and fission cross sections are in good agreement. Thus, it is concluded that the differences arise from errors in absolute normalization in the previous measurements. The present measurements show that the above-barrier complete fusion cross sections for the reactions of ${}^9\mathrm{Be}$ with ${}^{209}\mathrm{Bi}$ and ${}^{208}\mathrm{Pb}$ are very similar, which resolves the previously observed anomaly. Complete fusion for the reaction of ${}^9\mathrm{Be}$ with ${}^{209}\mathrm{Bi}$ is found to be suppressed by $~32\%$ compared to the expectations of a single-barrier penetration model, which is in close agreement with the value previously determined for the reaction with ${}^{208}\mathrm{Pb}$.

Excited states of ${}_{17}^{38}\mathrm{Cl}{}_{21}$ were populated in binary grazing reactions during the interaction of a beam of ${}_{16}^{36}\mathrm{S}$${}_{20}$ ions of energy 215 MeV with a ${}_{82}^{208}\mathrm{Pb}$${}_{126}$ target. The combination of the PRISMA magnetic spectrometer and the CLARA $\gamma$-ray detector array was used to identify the reaction fragments and to detect their decay via $\gamma$-ray emission. A level scheme for ${}^{38}\mathrm{Cl}$ is presented and discussed within the context of the systematics of neighboring nuclei and is compared with the results of state-of-the-art shell-model calculations.

The two-step cascade method previously used in neutron-capture experiments is now applied to a proton-capture reaction. The spectrum of two-step cascades populating the first $2^{+}$ level of ${}^{60}\mathrm{Ni}$ has been measured with the ${}^{59}\mathrm{Co}$($p,2\gamma$)${}^{60}\mathrm{Ni}$ reaction. The simulation technique used for the spectrum analysis allows one to reveal the range of possible shapes of both $E1$ and $M1$ $\gamma$-strength functions. The low-energy enhancement previously observed in ${}^3\mathrm{He}$-induced reactions is seen to appear in $M1$ strength functions of ${}^{60}\mathrm{Ni}$.

The isotopic dependence of two-quasiparticle isomeric states in Fm and No is treated for future experiments. The population of the isomeric states in evaporation residues is considered. In several even isotopes of Rf, Sg, Hs, and Ds, the $K$ isomers and their decay modes are predicted. An $\alpha$-decay chain through the isomeric states of superheavy nuclei is demonstrated for the first time and proposed for the experimental verification.

Spin distributions for various evaporation residues populated via complete and incomplete fusion of ${}^{16}\mathrm{O}$ with ${}^{124}\mathrm{Sn}$ at $6.3$  MeV/nucleon have been measured, using charged particles ($Z=1,2$)-$\gamma$ coincidence technique. Experimentally measured spin distributions of the residues produced as incomplete fusion products associated with “fast” $\alpha$- and $2\alpha$-emission channels observed in the “forward cone” are found to be distinctly different from those of the residues produced as complete fusion products. Moreover, “fast” $\alpha$-particles that arise from larger angular momentum in the entrance channel are populated at relatively higher driving input angular momentum than those produced through complete fusion. The incomplete fusion residues are populated in a limited, higher-angular-momentum range, in contrast to the complete fusion products, which are populated over a broad spin range.

We applied the quasiparticle random-phase approximation to neutrino reactions on ${}^{12}\mathrm{C}$ target. The quasiparticle random-phase approximation (QRPA) has been found to successfully explain the nuclear $\beta$ and $\beta \beta$ decays. To describe neutrino-nucleus reactions, various multipole transitions by weak interactions with finite momentum transfers are added to the Gamow Teller transition in the $\beta$ decays. Our results are shown to well reproduce most of experimental data for neutrino reactions on ${}^{12}\mathrm{C}$ target. In particular, energy dependence of cross sections for the exclusive reaction, ${}^{12}\mathrm{C}$$({\nu }_e,e^{-})$${}^{12}\mathrm{N}$${}_{\mathrm{g}.\mathrm{s}.(1^{+})}$, is discussed in detail by comparing the QRPA calculations to related experimental data.

We study the properties of hot neutrino-trapped $\beta$-stable stellar matter using an equation of state of nuclear matter within the Brueckner-Hartree-Fock approach including three-body forces, combined with a standard chiral model for kaon condensation at finite temperature. The properties of (proto)neutron stars are then investigated within this framework.

We report the mass measurement of the short-lived ${}^{12}\mathrm{Be}$ nuclide ($T_{1/2}=21.5$ ms) performed using the Penning trap mass spectrometer TITAN at TRIUMF. Our mass excess value of $25\hspace{0.5em}078.0(2.1)$ keV is in agreement with previous measurements, but is a factor of 7 more precise than the Atomic Mass Evaluation of 2003. To address an unresolved discussion on the spin assignment of isospin $T=2$ states in ${}^{12}\mathrm{C}$ and ${}^{12}\mathrm{O}$, we reevaluate the isobaric mass multiplet equation for the lowest lying $T=2$ multiplet in the $A=12$ system and use the extracted parameters to extrapolate from the known excited $2^{+}$ and $0^{+}$ states in ${}^{12}\mathrm{Be}$. Though this analysis favors the second known $T=2$ state in ${}^{12}\mathrm{C}$ to be $2^{+}$, $0^{+}$ cannot be excluded.

We perform an extensive investigation on $\alpha$ decays in both even-$A$ and odd-$A$ nuclei within the new version of the generalized density-dependent cluster model. The microscopic deformed potential is numerically constructed in the double-folding model by the multipole expansion method. The coupled-channel effect resulting from nuclear deformation is included by using the coupled-channel Schrödinger equation with outgoing wave boundary conditions. The fine structure observed in $\alpha$ decay is well described by taking into account the angular momentum of the emitted $\alpha$ particle and the Boltzmann distribution of excitation spectrum in daughter nuclei. A good agreement between experiment and theory is achieved, and the results of our calculations are discussed in detail, together with the sensitivity of the calculated half-lives and branching ratios to some physical quantities used in the calculations.

We study one-quasiproton excitations in the rare-earth region in the framework of the nuclear density functional theory in the Skyrme-Hartree-Fock-Bogoliubov variant. The blocking prescription is implemented exactly, with the time-odd mean field fully taken into account. The equal filling approximation is compared with the exact blocking procedure. We show that both procedures are strictly equivalent when the time-odd channel is neglected and discuss how nuclear alignment properties affect the time-odd fields. The impact of time-odd fields on calculated one-quasiproton band-head energies is found to be rather small, of the order of $100–200$ keV; hence, the equal filling approximation is sufficiently precise for most practical applications. The triaxial polarization of the core induced by the odd particle is studied. We also briefly discuss the occurrence of finite-size spin instabilities that are present in calculations for odd-mass nuclei when certain Skyrme functionals are employed.

Second RPA (SRPA) calculations of nuclear response are performed and analyzed. Unlike in most other SRPA applications, the ground state, approximated by the Hartree-Fock (HF) ground state, and the residual couplings are described by the same Hamiltonian and no arbitrary truncations are imposed on the model space. Finite-range interactions are used and thus divergence problems are not present. We employ a realistic interaction, derived from the Argonne V18 potential using the unitary correlation operator method (UCOM), as well as the simple Brink-Boeker interaction. Representative results are discussed, mainly on giant resonances and low-lying collective states. The focus of the present work is not on the comparison with data, but rather on technical and physical aspects of the method. We present how the large-scale eigenvalue problem that SRPA entails can be treated, and demonstrate how the method operates in producing self-energy corrections and fragmentation. The so-called diagonal approximation is conditionally validated. Stability problems are traced back to missing ground-state correlations.

The hyperdeformed nuclei treated as dinuclear or quasimolecular configurations are suggested to be directly produced in heavy-ion reactions at bombarding energies near the Coulomb barrier. The excited dinuclear system formed in the entrance channel of the heavy-ion collision can be cooled down by neutron emission to be transformed into the hyperdeformed nuclear system. This transition from the excited dinuclear system to a hyperdeformed configuration is described within the statistical approach. The reactions ${}^{48}\mathrm{Ca}+{}^{124,128,130,132,134}\mathrm{Sn}$, ${}^{48}\mathrm{Ca}+{}^{136,138}\mathrm{Xe}$, ${}^{48}\mathrm{Ca}+{}^{137,138,140}\mathrm{Ba}$, ${}^{40}\mathrm{Ca}+{}^{83,84}\mathrm{Kr}$, ${}^{48}\mathrm{Ca}+{}^{83,84,86}\mathrm{Kr}$, ${}^{40,48}\mathrm{Ca}+{}^{40,48}\mathrm{Ca}$, ${}^{58,60}\mathrm{Ni}+{}^{58,60}\mathrm{Ni}$, and ${}^{40}\mathrm{Ca}+{}^{58}\mathrm{Ni}$ are suggested for the population of hyperdeformed states. The production cross sections, quadrupole moments, and moments of inertia of hyperdeformed states formed in these reactions are calculated, and the optimal conditions for the experimental identification of such states are proposed.

For heavy-ion collisions at the BNL Relativistic Heavy Ion Collider (RHIC) a scaling behavior is found in the dependencies on azimuthal angle $\varphi$ and impact parameter $b$ for pion production at high $p_T$ essentially independent of the hadronization process. The scaling variable is in terms of a dynamical path length $\xi$ that takes into account detailed properties of geometry, medium density, and probability of hard scattering. It is shown in the recombination model how the nuclear modification factor depends on the average $\mathrm{\xi ̄}(\varphi ,b)$. The data for ${\pi }^0$ production at $p_T=4–5$ and $7–8$ GeV/$c$ at RHIC are shown to exhibit the same scaling behavior as found in the model calculation. Extension to back-to-back dijet production has been carried out, showing the existence of $\mathrm{\xi ̄}$ scaling also in the away-side yield per trigger. At the CERN Large Hadron Collider the hard-parton density can be high enough to realize the likelihood of recombination of shower partons arising from neighboring jets. It is shown that such two-jet recombination can cause strong violation of $\mathrm{\xi ̄}$ scaling. Furthermore, the large value of $R_{\mathrm{AA}}$ that exceeds 1 can become a striking signature of such a hadronization process at high energy.