Prompted by recent measurements, we surveyed world data and calculated radiative and isospin-symmetry-breaking corrections for the superallowed $0^{+}\to 0^{+}$ Fermi transitions from ${}^{42}\mathrm{Ti},{}^{46}\mathrm{Cr},{}^{50}\mathrm{Fe}$, and ${}^{54}\mathrm{Ni}$. This increases the number of such transition with a complete set of calculated corrections from 20 to 23. The results are compared with their equivalents for the mirror superallowed transitions from ${}^{42}\mathrm{Sc},{}^{46}\mathrm{V},{}^{50}\mathrm{Mn}$, and ${}^{54}\mathrm{Co}$. The predicted $ft$-value asymmetries of these mirror pairs are sensitive to the correction terms and provide motivation for improving measurement precision so as to be able to test the corrections. To aid in that endeavor, we present a parametrization for calculating the $f$ values for the new transitions to $\pm 0.01\%$.

We report a measurement of the neutrino-electron elastic scattering rate of 862 keV ${}^7\mathrm{Be}$ solar neutrinos based on a 165.4 kt d exposure of KamLAND. The observed rate is $582\pm 94$(kt d)${}^{-1}$, which corresponds to an 862-keV ${}^7\mathrm{Be}$ solar neutrino flux of $(3.26\pm 0.52)\times {10}^9{\mathrm{cm}}^{-2}{\mathrm{s}}^{-1}$, assuming a pure electron-flavor flux. Comparing this flux with the standard solar model prediction and further assuming three-flavor mixing, a ${\nu }_e$ survival probability of $0.66\pm 0.15$ is determined from the KamLAND data. Utilizing a global three-flavor oscillation analysis, we obtain a total ${}^7\mathrm{Be}$ solar neutrino flux of $(5.82\pm 1.02)\times {10}^9{\mathrm{cm}}^{-2}{\mathrm{s}}^{-1}$, which is consistent with the standard solar model predictions.

A two-neutron unbound excited state of ${}^{24}\mathrm{O}$ was populated through a ($d,d^{\prime }$) reaction at 83.4 MeV/nucleon. A state at $E=715\pm 110\left(\text{stat}\right)\pm 45\left(\text{sys}\right)\mathrm{keV}$ with a width of $\mathrm{\Gamma }<2$ MeV was observed above the two-neutron separation energy placing it at $7.65\pm 0.2\mathrm{MeV}$ with respect to the ground state. Three-body correlations for the decay of ${}^{24}\mathrm{O}\to {}^{22}\mathrm{O}+2n$ show clear evidence of a sequential decay through an intermediate state in ${}^{23}\mathrm{O}$. Neither a di-neutron nor phase-space model for the three-body breakup were able to describe these correlations.

We present a comprehensive study of low-lying states in even-even Ne, Mg, Si, S, Ar isotopes with the multireference density functional theory (MR-DFT) based on a relativistic point-coupling energy density functional (EDF). Beyond mean-field (BMF) effects are taken into account by configuration mixing of both particle-number and angular-momentum projected axially deformed states with generator coordinate method. Global performance of the MR-DFT for the properties of both ground state and of the first $2^{+},4^{+}$ states is examined, in comparison with previous studies based on nonrelativistic EDFs and available data. Our results indicate that an EDF parametrized at the BMF level is demanded to achieve a quantitative description.

The neutron skin of heavy nuclei is one of the hot topics in contemporary nuclear physics. In this article, effects of differences between neutron and proton density distributions on $\alpha$ decay are investigated. $\alpha$-decay calculations are performed within the generalized density-dependent cluster model, where the $\alpha$-core potential is determined in the double-folding model using the neutron and proton density distributions of daughter nuclei. The proton and neutron density distributions, assumed to be of two-parameter Fermi form, are constrained by the experimental nuclear charge radii as well as the neutron skin thickness of heavy nuclei. The resulting distribution of daughter nuclei results in an improved $\alpha$-core potential which is important for $\alpha$-decay calculations. It is found that the neutron skin thickness plays an important role in reducing the calculated $\alpha$-decay half-lives, implying a smaller $\alpha$ preformation factor. The calculations with neutron skin thickness show good agreement with the available experimental data for even-even nuclei including the known heaviest nuclei.

An oblate rotational sequence, built on an aligned, two-quasineutron isomeric state has been established in ${}^{196}\mathrm{Pt}$. The isomer has a half-life of 7.7(7) ns and is associated with the $I^{\pi }={12}^{+},{\left(i_{13/2}\right)}^2$ neutron configuration. Excited states, with angular momentum generated primarily through successive nucleon alignments, have been populated through $1\mathit{p}$ transfer from ${}^{197}\mathrm{Au}$. The nucleus ${}^{196}\mathrm{Pt}$ is the most neutron-rich Pt isotope for which high-spin states, beyond the ${12}^{+}$ isomeric state, have been established thus far. Cranked shell model calculations have been performed to understand shape evolution with spin, and the role of nucleons occupying specific Nilsson orbitals in generating aligned angular momentum for both prolate and oblate deformations has been explored.

We estimate the range of the radiative lifetime and energy of the anomalous, low-energy $3/2^{+}(7.8\pm 0.5$ eV) state in the ${}^{229}\mathrm{Th}$ nucleus. Our phenomenological calculations are based on the available experimental data for the intensities of $M1$ and $E2$ transitions between excited levels of the ${}^{229}\mathrm{Th}$ nucleus in the $K^{\pi }\left[N{n}_Z\mathrm{\Lambda }\right]=5/2^{+}\left[633\right]$ and $3/2^{+}\left[631\right]$ rotational bands. We also discuss the influence of certain branching coefficients, which affect the currently accepted measured energy of the isomeric state. From this work, we establish a favored region, $0.66\times {10}^6{\text{s}\text{eV}}^3/{\omega }^3\le \tau \le 2.2\times {10}^6{\text{s}\text{eV}}^3/{\omega }^3$, where the transition lifetime $\tau$ as a function of transition energy $\omega$ should lie at roughly the 95% confidence level. Together with the result of Beck et al. [LLNL-PROC-415170 (2009)], we establish a favored area where transition lifetime and energy should lie at roughly the 90% confidence level. We also suggest new nuclear physics measurements, which would significantly reduce the ambiguity in the present data.

Background: Previously reported cross sections of ${}^{45}\mathrm{Sc}$-induced reactions with lanthanide targets are much smaller than ${}^{48}\mathrm{Ca}$-induced reactions on the same targets. ${}^{44}\mathrm{Ca}$ is one proton removed from ${}^{45}\mathrm{Sc}$ and could be used to produce nuclei with a relative neutron content between those produced in the ${}^{45}\mathrm{Sc}-$ and ${}^{48}\mathrm{Ca}$-induced reactions.

Purpose: As part of a systematic investigation of fusion-evaporation reactions, cross sections of ${}^{44}\mathrm{Ca}$-induced reactions on lanthanide targets were measured. These results are compared to available data for ${}^{48}\mathrm{Ca}$- and ${}^{45}\mathrm{Sc}$-induced fusion-evaporation cross sections on the same lanthanide targets. Collectively, these data provide insight into the importance of the survival against fission of excited compound nuclei produced near spherical shell closures.

Methods: A beam of ${}^{44}\mathrm{Ca}^{6+}$ at an energy of $\approx 5\mathrm{MeV}/\mathrm{u}$ was delivered by the K500 superconducting cyclotron at the Cyclotron Institute at Texas A&M University. The desired evaporation residues were selected by the Momentum Achromat Recoil Spectrometer and identified via their characteristic $\alpha$-decay energies. Excitation functions for the ${}^{44}\mathrm{Ca}+{}^{158}\mathrm{Gd},{}^{159}\mathrm{Tb}$, and ${}^{162}\mathrm{Dy}$ reactions were measured at five or more energies each. A theoretical model was employed to study the fusion-evaporation process.

Results: The ${}^{44}\mathrm{Ca}$-induced reactions have $xn$ cross sections that are two orders of magnitude larger than ${}^{45}\mathrm{Sc}$-induced reactions but two orders of magnitude smaller than ${}^{48}\mathrm{Ca}$-induced reactions on the same targets. Proton emission competes effectively with neutron emission for the ${}^{44}\mathrm{Ca}+{}^{159}\mathrm{Tb}$ and ${}^{162}\mathrm{Dy}$ reactions. The maximum $4n$ cross sections in the ${}^{44}\mathrm{Ca}+{}^{158}\mathrm{Gd},{}^{159}\mathrm{Tb}$, and ${}^{162}\mathrm{Dy}$ reactions were $2100\pm 230,230\pm 20$, and $130\pm 20\mu \mathrm{b}$, respectively. The ${}^{44}\mathrm{Ca}+{}^{158}\mathrm{Gd}$ and ${}^{159}\mathrm{Tb}$ cross sections are in good agreement with the respective cross bombardments of ${}^{48}\mathrm{Ca}+{}^{154}\mathrm{Gd}$ and ${}^{45}\mathrm{Sc}+{}^{158}\mathrm{Gd}$ once differences in capture cross sections and compound nucleus formation probabilities are corrected for.

Conclusions: Excitation functions were measured in ${}^{44}\mathrm{Ca}$-induced reactions on lanthanide targets. Evaporation residue cross sections were two orders of magnitude larger than ${}^{45}\mathrm{Sc}$-induced reactions on the same targets due to an increase in the survival probability of the compound nucleus. However, little evidence of cross-sectional enhancement due to shell stabilization of the compound nucleus was observed.

The population of the 9.50 MeV $9/2_1^{+}$ resonance in ${}^{13}\mathrm{C}$ by single-neutron transfer reactions is expected to be dominated by the two-step route through the ${}^{12}\mathrm{C}$ $2_1^{+}$ (4.44 MeV) state, with another possible contribution via the strongly excited $3_1^{-}$ (9.64 MeV) resonance in ${}^{12}\mathrm{C}$. However, we find that a good description of the angular distribution for population of this state via the ${}^{12}\mathrm{C}\left(d,p\right){}^{13}\mathrm{C}$ reaction is only possible when both direct $0_1^{+}\otimes g_{9/2}$ and two-step (via the 4.44 MeV ${}^{12}\mathrm{C}$ $2_1^{+}$ state) $2_1^{+}\otimes d_{5/2}$ paths are included in a coupled reaction channel calculation. While the calculated angular distribution is almost insensitive to the presence of the two-step path via the 9.64 MeV ${}^{12}\mathrm{C}$ $3_1^{-}$ resonance, despite a much greater contribution to the wave function from the $3_1^{-}\otimes f_{7/2}$ configuration, its inclusion is required to fit the details of the experimental angular distribution. The very large interference between the various components of the calculations, even when these are small, arises through the “kinematic” effect associated with the different transfer routes.

A system of equations for anisotropic hydrodynamics is derived that describes a mixture of anisotropic quark and gluon fluids. The consistent treatment of the zeroth, first, and second moments of the kinetic equations allows us to construct a new framework with more general forms of the anisotropic phase-space distribution functions than used before. In this way, the main deficiencies of the previous formulations of anisotropic hydrodynamics for mixtures are overcome and a good agreement with the exact kinetic-theory results is obtained.

Two-particle pseudorapidity correlations of hadrons produced in Pb+Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV at the CERN Large Hadron Collider are analyzed in the framework of a model based on viscous 3+1-dimensional hydrodynamics with the Glauber initial condition. Based on our results, we argue that the correlation from resonance decays, formed at a late stage of the evolution, produce significant effects. In particular, their contribution to the event averages of the coefficients of the expansion in the Legendre basis explain 60–70% of the experimental values. We propose an accurate way to compute these coefficients, independent of the binning in pseudorapidity, and test a double expansion of the two-particle correlation function in the azimuth and pseudorapidity, which allows us to investigate the pseudorapidity correlations between harmonics of the collective flow. In our model, these quantities are also dominated by the nonflow effects from the resonance decays. Finally, our method can be used to compute higher-order cumulants for the expansion in orthonormal polynomials [A. Bzdak and P. Bożek, arXiv:1509.02967 [hep-ph] (2015)] which offers a suitable way of eliminating the nonflow effects from the correlation analyses.

The direct photon spectra and flow ($v_2, v_3$) in heavy-ion collisions at CERN Super Proton Synchrotron, BNL Relativistic Heavy Ion Collider, and CERN Large Hadron Collider energies are investigated within a relativistic transport approach incorporating both hadronic and partonic phases, the parton-hadron-string dynamics (PHSD). In the present work, four extensions are introduced compared to our previous calculations: (i) going beyond the soft-photon approximation (SPA) in the calculation of the bremsstrahlung processes $\mathrm{meson}+\mathrm{meson}\to \mathrm{meson}+\mathrm{meson}+\gamma$, (ii) quantifying the suppression owing to the Landau-Pomeranchuk-Migdal (LPM) coherence effect, (iii) adding the additional channels $V+N\to N+\gamma$ and $\mathrm{\Delta }\to N+\gamma$, and (iv) providing PHSD calculations for $\mathrm{Pb}+\mathrm{Pb}$ collisions at $\sqrt{s_{NN}}=2.76\text{TeV}$. The first issue extends the applicability of the bremsstrahlung calculations to higher photon energies to understand the relevant sources in the region $p_T=0.5–1.5\text{GeV}$, while the LPM correction turns out to be important for $p_T<0.4\text{GeV}$ in the partonic phase. The results suggest that a large elliptic flow $v_2$ of the direct photons signals a significant contribution of photons produced in interactions of secondary mesons and baryons in the late (hadronic) stage of the heavy-ion collision. To further differentiate the origin of the direct photon azimuthal asymmetry (late hadron interactions vs electromagnetic fields in the initial stage), we provide predictions for the photon spectra, elliptic flow, and triangular flow $v_3\left(p_T\right)$ of direct photons at different centralities to be tested by the experimental measurements at the LHC energies. Additionally, we illustrate the magnitude of the photon production in the partonic and hadronic phases as functions of time and local energy density. Finally, the “cocktail” method for an estimation of the background photon elliptic flow, which is widely used in the experimental works, is supported by the calculations within the PHSD transport approach.

We analyze the constraint structure of the interaction of vector mesons with baryons using the classical Dirac constraint analysis. We show that the standard interaction in terms of two independent SU(3) structures is consistent at the classical level. We then require the self-consistency condition of the interacting system in terms of perturbative renormalizability to obtain relations for the renormalized coupling constants at the one-loop level. As a result we find a universal interaction with one coupling constant which is the same as in the massive Yang-Mills Lagrangian of the vector-meson sector.

In the EURICA campaign aimed at exploration of the ${}^{78}\mathrm{Ni}$ region, an isomeric state of ${}^{76}\mathrm{Co}$ has been observed via $\gamma$-ray spectroscopy. The nuclei were produced by in-flight fission of a ${}^{238}\mathrm{U}$ beam at the Radioactive Isotope-Beam Factory. Two coincident $\gamma$ rays of $192.02\left(30\right)$ and $446.4\left(7\right)$ keV from the decay of a $t_{1/2}=2.96{(}_{25}^{29})\mu \mathrm{s}$ isomeric state of ${}^{76}\mathrm{Co}$ have been observed. The decay of the isomer was assigned to an $E1$ transition with a reduced transition probability of $B(E1;3^{+}\to 2^{-})=1.79\left(16\right)\times {10}^{-8}$ W.u. A $\beta$-decaying state with spin-parity $1^{-}$ and a half-life of $16\left(4\right)$ ms was also observed in the data, and the known state with a half-life of $22{(}_5^7)$ ms was assigned to have a spin-parity of $8^{-}$. Furthermore, the isomer of ${}^{76}\mathrm{Ni}$ has been remeasured to $547.8\left(33\right)$ ns giving a $B(E2;8^{+}\to 6^{+})$ value of $0.786\left(5\right)$ W.u. A new excited state at $2994.6\left(5\right)$ keV, decaying via a $\gamma$ ray of 2004.5(4) keV, has also been observed. This is in agreement with either of the predicted $0_2^{+}$ or $2_2^{+}$ states. These results are discussed in terms of the shell model and the interaction of the $\nu p_{1/2}$ and $\pi f_{7/2}$ orbitals.

The existence of a secondary bow is confirmed for ${}^{13}\mathrm{C}+{}^{12}\mathrm{C}$ nuclear rainbow scattering in addition to the ${}^{16}\mathrm{O}+{}^{12}\mathrm{C}$ system. This is found by studying the experimental angular distribution of ${}^{13}\mathrm{C}+{}^{12}\mathrm{C}$ scattering at the incident ${}^{13}\mathrm{C}$ energy $E_L=250\mathrm{MeV}$ with an extended double-folding (EDF) model that describes all the diagonal and off-diagonal coupling potentials derived from the microscopic wave functions for ${}^{12}\mathrm{C}$ using a density-dependent nucleon-nucleon force. The Airy minimum at $\theta \approx {70}^{\circ }$, which is not reproduced by a conventional folding potential, is revealed to be a secondary bow generated dynamically by a coupling to the excited state $2^{+}$ (4.44 MeV) of ${}^{12}\mathrm{C}$. The essential importance of the quadruple $Y2$ term (reorientation term) of potential of the excited state $2^{+}$ of ${}^{12}\mathrm{C}$ for the emergence of a secondary bow is found. The mechanism of the secondary bow is intuitively explained by showing how the trajectories are refracted dynamically into the classically forbidden angular region beyond the rainbow angle of the primary rainbow.

Modern experiments on neutron and allowed nuclear $\beta$ decay search for new semileptonic interactions, beyond the left-handed electroweak force. We show that ongoing and planned $\beta$-decay experiments, with isotopes at rest and in flight, can be exploited as sensitive tests of Lorentz invariance. The variety of correlations that involve the nuclear spin, the direction of the emitted $\beta$ particle, and the recoil direction of the daughter nucleus allow for relatively simple experiments that give direct bounds on Lorentz violation. The pertinent observables are decay-rate asymmetries and their dependence on sidereal time. We discuss the potential of several asymmetries that together cover a large part of the parameter space for Lorentz violation in the gauge sector. High counting statistics is required.

The $\beta$-decay properties of neutron-rich ${}^{87}\mathrm{As}$ produced in the proton-induced fission of ${}^{238}\mathrm{U}$ were studied at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The low-energy excited states in $N=53 {}^{87}\mathrm{Se}$ and $N=52 {}^{86}\mathrm{Se}$ were identified through $\beta \text{−}\gamma$ and $\beta$-delayed neutron-$\gamma$ decay of ${}^{87}\mathrm{As}$, respectively. The experimental systematics of low-energy levels of $N=53$ isotones, $Z=34 {}^{87}\mathrm{Se},$ and $Z=32 {}^{85}\mathrm{Ge}$, and along with an analysis of shell-model calculations, allow us to discuss the main features of excited states expected for the next $N=53$ isotone, ${}^{83}\mathrm{Zn}$.

The cluster approach is applied to study the mechanism of termination of the negative-parity band built on the ground state of even-even nucleus. For the several even-even nuclei, the terminating spins are predicted. The method is suggested for the verification of the cluster interpretation of the band termination.