Within the density-dependent cluster model (DDCM), the decay half-lives of 22 cluster emitters are calculated by using experimental decay energies. Based on our previous study on cluster radioactivity [Phys. Rev. C 90, 064310 (2014)], not only the quadratic symmetry energy $E_2\left({\rho }_0\right)$ and its slope $L_2\left({\rho }_0\right)$ but also the quartic symmetry energy $E_4\left({\rho }_0\right)$ and its slope $L_4\left({\rho }_0\right)$ at the saturation density ${\rho }_0$ are constrained by considering the neutron skin thicknesses in the daughter nuclei. With the extracted values of $E_2\left({\rho }_0\right)$ and $L_2\left({\rho }_0\right)$, the exponent $\gamma$ of the quadratic density-dependent symmetry energy $E_2\left(\rho \right)=E_2\left({\rho }_0\right){(\rho /{\rho }_0)}^{\gamma }$ is estimated. Moreover, the symmetry energy coefficient of nuclei $a_{\mathrm{sym}}\left(A\right)$ and the ratio $\kappa$ of the surface symmetry coefficient to the volume symmetry coefficient are extracted as well.

We report $B(E2;0_1^{+}\to 2_n^{+})$ strengths for the neutron-rich ${}^{88,90}\mathrm{Kr}$ and ${}^{86}\mathrm{Se}$ isotopes from intermediate-energy Coulomb excitation. The electric quadrupole transition strengths to the first $2^{+}$ states complete, with considerably improved uncertainties, the evolution of quadrupole collectivity in the Kr and Se isotopes approaching $N=60$, for which ${}^{90}\mathrm{Kr}$ and ${}^{86}\mathrm{Se}$ had previously been the most uncertain. We also report significant excitation strength to several higher-lying $2^{+}$ states in the krypton isotopes. This fragmentation of $B\left(E2\right)$ strength in ${}^{88,90}\mathrm{Kr}$ confirms shell-model calculations in the $\pi \left(fpg\right)\text{−}\nu \left(sdgh\right)$ shell with an only minimally tuned shell-model setup that is based on a nucleon-nucleon interaction derived from effective field theory and effective charges adjusted to ${}^{86}\mathrm{Kr}$.

Background: The ${}^{17}\mathrm{F}(p,\gamma ){}^{18}\mathrm{Ne}$ reaction is part of the astrophysical “hot CNO” cycles that are important in astrophysical environments like novas. Its thermal reaction rate is low owing to the relatively high energy of the resonances and therefore is dominated by direct, nonresonant capture in stellar environments at temperatures below 0.4 GK.

Purpose: An experimental method is established to extract the proton strength to bound and unbound states in experiments with radioactive ion beams and to determine the parameters of direct and resonant capture in the ${}^{17}\mathrm{F}(p,\gamma ){}^{18}\mathrm{Ne}$ reaction.

Method: The ${}^{17}\mathrm{F}(d,n){}^{18}\mathrm{Ne}$ reaction is measured in inverse kinematics using a beam of the short-lived isotope ${}^{17}\mathrm{F}$ and a compact setup of neutron, proton, $\gamma$-ray, and heavy-ion detectors called resoneut.

Results: The spectroscopic factors for the lowest $l=0$ proton resonances at ${\mathrm{E}}_{\mathrm{c}.\mathrm{m}.}=0.60$ and 1.17 MeV are determined, yielding results consistent within $1.4\sigma$ of previous proton elastic-scattering measurements. The asymptotic normalization coefficients of the bound $2_1^{+}$ and $2_2^{+}$ states in ${}^{18}\mathrm{Ne}$ are determined and the resulting direct-capture reaction rates are extracted.

Conclusions: The direct-capture component of the ${}^{17}\mathrm{F}(p,\gamma ){}^{18}\mathrm{Ne}$ reaction is determined for the first time from experimental data on ${}^{18}\mathrm{Ne}$.

We develop a reaction model for $\eta$ photoproduction off the deuteron ($\gamma d\to \eta pn$) and study the reaction at a special kinematics, where the photon beam energy is $\sim 0.94$ GeV and the scattered proton is detected at $\sim 0^{\circ }$, for the purpose of determining the $\eta$-nucleon scattering length ($a_{\eta N}$) and effective range ($r_{\eta N}$). In this kinematics, the $\eta$-nucleon elastic rescattering is significantly enhanced while other background mechanisms are suppressed. We show that a ratio $R$, the $\gamma d\to \eta pn$ cross section divided by the $\gamma p\to \eta p$ cross section convoluted with the proton momentum distribution in the deuteron, has a very good resolving power of $a_{\eta N}$ and $r_{\eta N}$. We conclude that the $R$ data with 5% error, binned in 1 MeV width of the $\eta$-neutron invariant mass, can determine $\mathrm{Re}\left[a_{\eta N}\right]$ ($\mathrm{Re}\left[r_{\eta N}\right]$) at the precision of $\sim \pm 0.1$ fm ($\sim \pm 0.5$ fm), significantly narrowing down the previously estimated ranges of the parameters. To arrive at the conclusion, it is essential to use the $\gamma d\to \eta pn$ reaction model equipped with elementary amplitudes that are well constrained by $\pi N$ and $\gamma N$ reaction data through a sophisticated coupled-channel analysis. This result strongly motivates the Research Center for Electron Photon Science (ELPH) at Tohoku University to measure $R$.

Sensitivity of two-proton emitting decay to nuclear pairing correlation is discussed within a time-dependent three-body model. We focus on the ${}^6\mathrm{Be}$ nucleus assuming $\alpha +p+p$ configuration, and its decay process is described as a time evolution of the three-body resonance state. For a proton-proton subsystem, a schematic density-dependent contact (SDDC) pairing model is employed. From the time-dependent calculation, we observed the exponential decay rule of a two-proton emission. It is shown that the density dependence does not play a major role in determining the decay width, which can be controlled only by the asymptotic strength of the pairing interaction. This asymptotic pairing sensitivity can be understood in terms of the dynamics of the wave function driven by the three-body Hamiltonian, by monitoring the time-dependent density distribution. With this simple SDDC pairing model, there remains an impossible trinity problem: it cannot simultaneously reproduce the empirical $Q$ value, decay width, and the nucleon-nucleon scattering length. This problem suggests that a further sophistication of the theoretical pairing model is necessary, utilizing the two-proton radioactivity data as the reference quantities.

${}^{111}\mathrm{Ag}$ and ${}^{113}\mathrm{Ag}$ were produced in induced fission reaction, where yrast and near-yrast states were populated. To interpret the new data the Interacting Boson-Fermion Model was used. A good agreement with the experimental data is achieved, suggesting that the two Ag nuclei have a well-developed collectivity, superimposed on $\pi g_{9/2}^{-3}$ excitations previously observed throughout the entire isotopic chain.

The GRIFFIN spectrometer at TRIUMF-ISAC has been used to study excited states and transitions in ${}^{50}\mathrm{Sc}$ following the $\beta$ decay of ${}^{50}\mathrm{Ca}$. Branching ratios were determined from the measured $\gamma$-ray intensities, and angular correlations of $\gamma$ rays have been used to firmly assign the spins of excited states. The presence of an isomeric state that decays by an $M3$ transition with a $B\left(M3\right)$ strength of 13.6(7) W.u. has been confirmed. We compare the first ab initio calculations of $B(M3$) strengths in light- and medium-mass nuclei from the valence-space in-medium similarity renormalization group approach, using consistently derived effective Hamiltonians and effective $M3$ operator. The experimental data are well reproduced for isoscalar $M3$ transitions when using bare $g$ factors, but the strength of isovector $M3$ transitions are found to be underestimated by an order of magnitude.

We present the development of the extended Skyrme N2LO pseudopotential in the case of spherical even-even nuclei calculations. The energy density functional is first presented. Then we derive the mean-field equations and discuss the numerical method used to solve the resulting fourth-order differential equation together with the behavior of the solutions at the origin. Finally, a fitting procedure for such an N2LO interaction is discussed and we provide a first parametrization. Typical ground-state observables are calculated and compared against experimental data.

The investigation of the characteristics of low-energy heavy ion reactions covering both fusion and quasifission is carried out within the dinuclear system (DNS) concept, which is developed to include the deformation variables of fragments in addition to the mass numbers of the fragments, so that the energy dissipation, nucleon exchange, and deformation evolutions of the colliding nuclei as well as their correlations are treated simultaneously, and the potential energy surface of the system is thus reaction-time dependent. The direct consequence of introducing the deformation of fragments as dynamical variables is that one must treat the orientation between the two deformed nuclei. This is solved by introducing a barrier function. It is found that the model can reproduce data about the mass, as well as the total kinetic energy and its dispersion, of the reaction products very well, revealing that the DNS model has a reasonable theoretical foundation and thus can reliably describe the reaction mechanism.

The cross section for the ${}^{238}\mathrm{U}(n,2n){}^{237}\mathrm{U}$ reaction has been measured in the incident neutron energy range from 6.5 to 14.8 MeV in small energy steps using an activation technique. Monoenergetic neutron beams were produced via the ${}^2\mathrm{H}(d,n){}^3\mathrm{He}$ and ${}^3\mathrm{H}(d,n){}^4\mathrm{He}$ reactions. ${}^{238}\mathrm{U}$ targets were activated along with Au and Al monitor foils to determine the incident neutron flux. The activity of the reaction products was measured in TUNL's low-background counting facility using high-resolution $\gamma$-ray spectroscopy. The results are compared with previous measurements and latest data evaluations. Statistical-model calculations, based on the Hauser-Feshbach formalism, have been carried out using the ${\mathrm{CoH}}_3$ code and are compared with the experimental results. The present self-consistent and high-quality data are important for stockpile stewardship and nuclear forensic purposes as well as for the design and operation of fast reactors.

I present a discussion of the models of nuclear effects used to describe the inclusive electron-nucleus scattering in the quasielastic (QE) peak region, aiming to compare them and to draw conclusions about their reliability when applied in neutrino-nucleus interactions. A basic motivation is to reduce the systematic errors in the neutrino oscillation experiments. I concentrate on the neutrino energy profile of the T2K experiment, which provides me with a region of the greatest importance in terms of the highest contribution to the charge-current quasielastic (CCQE) cross section. Only electron-nucleus data that overlap with this region is chosen. In order to clarify the analysis, I split the data sets into three groups and draw conclusions separately from each one of them. Six models are selected for this comparison: Benhar's spectral function with and without the final-state interactions (Benhar's SF + FSI); the Valencia spectral function (Valencia SF), for higher energy transfers only with the hole spectral function; the Giessen Boltzmann-Uehling-Uhlenbeck (GiBUU) model; and the local and global Fermi gas models. The latter two are included as a benchmark to quantify the roles of various nuclear effects. All six models are often used in neutrino scattering studies. A short theoretical description of each model is given. Although in the selected data sets the QE mechanism dominates, I also discuss the possible impact of the 2p2h and the $\mathrm{\Delta }$ contributions.

Contact formalism, a useful tool for analyzing short-range correlations, is generalized here for systems with coupled channels, such as in nuclear physics. The relevant asymptotic form is presented and contact matrices are defined. Generally, for the case of two coupled channels, two two-body functions are included in the asymptotic form, resulting a $2\times 2$ contact matrix. Nevertheless, it is shown that if the coupling terms of the potential are very weak or very strong, only a single two-body function is needed, resulting in a single contact. This universal result is directly relevant to nuclear systems, and provides a theoretical explanation for the fact that proton-neutron short-range correlations can be described using the single bound-state deuteron wave function. It is achieved by applying an appropriate boundary condition on the two-body functions. This boundary condition can be interpreted as a mean-field potential imposed on the correlated pair due to the residual system.

Background: Elastic scattering is probably the main event in the interactions of nucleons with nuclei. Even if this process has been extensively studied in the past years, a consistent description, i.e., starting from microscopic two- and many-body forces connected by the same symmetries and principles, is still under development.

Purpose: In a previous paper [M. Vorabbi, P. Finelli, and C. Giusti, Phys. Rev. C 93, 034619 (2016)] we derived a theoretical optical potential from $NN$ chiral potentials at fourth order (${\mathrm{N}}^3\mathrm{LO}$). In the present work we use $NN$ chiral potentials at fifth order (${\mathrm{N}}^4\mathrm{LO}$), with the purpose to check the convergence and to assess the theoretical errors associated with the truncation of the chiral expansion in the construction of an optical potential.

Methods: Within the same framework and with the same approximations as the previous paper [M. Vorabbi, P. Finelli, and C. Giusti, Phys. Rev. C 93, 034619 (2016)], the optical potential is derived as the first-order term within the spectator expansion of the nonrelativistic multiple scattering theory and adopting the impulse approximation and the optimum factorization approximation.

Results: The $pp$ and $np$ Wolfenstein amplitudes and the cross section, analyzing power, and spin rotation of elastic proton scattering from ${}^{16}\mathrm{O}$, ${}^{12}\mathrm{C}$, and ${}^{40}\mathrm{Ca}$ nuclei are presented at an incident proton energy of 200 MeV. The results obtained with different versions of chiral potentials at ${\mathrm{N}}^4\mathrm{LO}$ are compared.

Conclusions: Our results indicate that convergence has been reached at ${\mathrm{N}}^4\mathrm{LO}$. The agreement with the experimental data is comparable with the agreement obtained in the previous paper [M. Vorabbi, P. Finelli, and C. Giusti, Phys. Rev. C 93, 034619 (2016)]. We confirm that building an optical potential within chiral perturbation theory is a promising approach for describing elastic proton-nucleus scattering.

The ${}^{98}\mathrm{Ru}$ structure has been investigated in the framework of the IBA-2 model, extending previous works to exploit the whole set of new spectroscopic data. The occurrence of states of mixed symmetry character in the proton and neutron degrees of freedom is of prominent importance in enlightening the structure of this nucleus, which displays features close to those of the $U_{\pi ,\nu }$(5) limit of the model.

We study the initial three-dimensional spatial configuration of the quark-gluon plasma (QGP) produced in relativistic heavy-ion collisions using centrality and pseudorapidity-dependent measurements of the medium's charged particle density and two-particle correlations. A cumulant-generating function is first used to parametrize the rapidity dependence of local entropy deposition and extend arbitrary boost-invariant initial conditions to nonzero beam rapidities. The model is then compared to $p+\text{Pb}$ and Pb + Pb charged-particle pseudorapidity densities and two-particle pseudorapidity correlations and systematically optimized using Bayesian parameter estimation to extract high-probability initial condition parameters. The optimized initial conditions are then compared to a number of experimental observables including the pseudorapidity-dependent anisotropic flows, event-plane decorrelations, and flow correlations. We find that the form of the initial local longitudinal entropy profile is well constrained by these experimental measurements.

We calculate the total cross sections and probabilities of electromagnetic productions of electron, muon, and tauon pairs simultaneously. At the CERN Large Hadron Collider (LHC), the available electromagnetic energy is sufficient to produce all kinds of leptons coherently. The masses of muons and tauons are large, so their Compton wavelengths are small enough to interact with the colliding nuclei. Therefore, the realistic nuclear form factors are included in the calculations of electromagnetic pair productions. The cross section calculations show that, at LHC energies, the probabilities of simultaneous productions of all kinds of leptons are increased significantly compared to energies available at the BNL Relativistic Heavy Ion Collider (RHIC) . Experimentally, observing this simultaneous production can give us important information about strong QED.

Using a multiphase transport (AMPT) model, we study the dependence on the specific shear viscosity of the transverse momentum spectra, Hanbury Brown–Twiss parameters, and elliptic flow with a temperature-independent shear viscous approach. The shear viscosity strengthens the transverse pressure gradients, raises the transverse momentum spectra, and gives smaller values of $R_{\mathrm{o}}$, $R_{\mathrm{l}}$, and $R_{\mathrm{o}}/R_{\mathrm{s}}$, but increases value of $R_{\mathrm{s}}$. The transverse momentum dependence of $v_2$ is suppressed with increasing $\eta /s$ and can hold at finite $\eta /s$ within a partonic cascade approach in the AMPT model.

Coherent superposition of nuclear states in tripod systems using three x-ray laser pulses is investigated theoretically. The laser pulses transfer the population from one ground state to an arbitrary superposition of other ground states using coincident pulses and stimulated Raman adiabatic passage techniques. The short wavelengths needed in the frame of the nuclei are achieved by envisaging an accelerated nucleus interacting with three x-ray laser pulses. This study exploits the Morris-shore transformation to reduce the tripod system into a coupled three-state $\mathrm{\Lambda }$-like system and a noncoupled state. We calculated the required laser intensities which satisfy the conditions of coincident pulses and adiabatic passage techniques. Considering the spontaneous emission from excited state $|4\rangle$ and unstable ground states $\left(|2\rangle ,|3\rangle \right)$ to other states, we have used a master equation for numerical study, and the final fidelity of desired states with respect to the tolerance of laser intensities is studied numerically.

Cross sections of the ${}^{10}\mathrm{B}(n,t2\alpha )$ three-body reaction were measured at $E_n=4.0,4.5$, and 5.0 MeV using a twin gridded ionization chamber and a thin-film ${}^{10}\mathrm{B}$ sample. The present paper is the first part of the work. The experimental spectrum of the ${}^{10}\mathrm{B}(n,t2\alpha )$ reaction measured by the gridded ionization chamber (GIC) was predicted. The ${}^{10}\mathrm{B}(n,t2\alpha )$ reaction can proceed in three ways, which are referred to as ${}^7\mathrm{L}{\mathrm{i}}^{**},{}^8\mathrm{Be}$, and breakup channels. The energies and directional angles of the three particles in the final states for the ${}^7\mathrm{L}{\mathrm{i}}^{**},{}^8\mathrm{Be}$, and breakup channels were calculated, respectively. Based on these results, the one-dimensional and two-dimensional spectra were calculated through integration. Three kinds of interference reactions were taken into account, which were the ${}^{10}\mathrm{B}{(n,\alpha )}^7\mathrm{Li}$ reaction, the $\text{H}(n,n)\text{p}$ reaction, and the $(n$,α) reactions from the working gas of the GIC. Two effects were considered in the prediction of the experimental spectrum, which were the energy loss of the products in the sample and the wall effect of the sample position well. The predicted spectra play an important role in the guidance of the implementation of the experiment and the processing of the experimental data.