The cross section of the exclusive $\eta$ electroproduction reaction $ep\to e^{\prime }{p}^{\prime }\eta$ was measured at Jefferson Laboratory with a 5.75 GeV electron beam and the CLAS detector. Differential cross sections $d^4\sigma /dtd{Q}^{2}d{x}_{B}d{\varphi }_{\eta }$ and structure functions ${\sigma }_U={\sigma }_T+\epsilon {\sigma }_L,{\sigma }_{TT}$, and ${\sigma }_{LT}$, as functions of $t$, were obtained over a wide range of $Q^2$ and $x_B$. The $\eta$ structure functions are compared with those previously measured for ${\pi }^0$ at the same kinematics. At low $t$, both ${\pi }^0$ and $\eta$ are described reasonably well by generalized parton distributions (GPDs) in which chiral-odd transversity GPDs are dominant. The ${\pi }^0$ and $\eta$ data, when taken together, can facilitate the flavor decomposition of the transversity GPDs.

We calculate the low-lying spectrum of the ${}^{16}\mathrm{O}$ nucleus using an $\alpha$-cluster model which includes the important tetrahedral and square configurations. Our approach is motivated by the dynamics of $\alpha$-particle scattering in the Skyrme model. We are able to replicate the large energy splitting that is observed between states of identical spin but opposite parities. We also provide a novel interpretation of the first excited state of ${}^{16}\mathrm{O}$ and make predictions for the energies of $6^{-}$ states that have yet to be observed experimentally.

A quantal and a semiclassical analysis of two-nucleon transfer intensities is done within the framework of the interacting boson model. The expected features of these quantities for the quantum phase transition (QPT) between spherical, U(5), and axially deformed, SU(3), shapes are discussed. Experimental data for ($p,t$) and $(t,p$) transfer reactions clearly show the occurrence of QPTs in Gd, Sm, and Nd.

The ${}^{13}\mathrm{C}({}^{18}\mathrm{O},{}^{16}\mathrm{O}){}^{15}\mathrm{C}$ reaction is studied at 84 MeV incident energy. Excitation energy spectra and absolute cross-section angular distributions for the strongest transitions are measured with good energy and angular resolutions. Strong selectivity for two-neutron configurations in the states of the residual nucleus is found. The measured cross-section angular distributions are analyzed by exact finite-range coupled reaction channel calculations. The two-particle wave functions are extracted using the extreme cluster and the independent coordinate scheme with shell-model derived coupling strengths. A new approach also is introduced, the microscopic cluster, in which the spectroscopic amplitudes in the center-of-mass reference frame are derived from shell-model calculations using the Moshinsky transformation brackets. This new model is able to describe well the experimental cross section and to highlight cluster configurations in the involved wave functions.

The PHENIX Collaboration has measured the ratio of the yields of $\psi \left(2S\right)$ to $\psi \left(1S\right)$ mesons produced in $p+p$, $p+\mathrm{Al}$, $p+\mathrm{Au}$, and ${}^3\mathrm{He}+\mathrm{Au}$ collisions at $\sqrt{s_{{}_{\mathit{NN}}}}=200$ GeV over the forward and backward rapidity intervals $1.2<\left|y\right|<2.2$. We find that the ratio in $p+p$ collisions is consistent with measurements at other collision energies. In collisions with nuclei, we find that in the forward ($p$-going or ${}^3\mathrm{He}$-going) direction, the relative yield of $\psi \left(2S\right)$ mesons to $\psi \left(1S\right)$ mesons is consistent with the value measured in $p+p$ collisions. However, in the backward (nucleus-going) direction, the $\psi \left(2S\right)$ meson is preferentially suppressed by a factor of $\sim 2$. This suppression is attributed in some models to the breakup of the weakly bound $\psi \left(2S\right)$ meson through final-state interactions with comoving particles, which have a higher density in the nucleus-going direction. These breakup effects may compete with color screening in a deconfined quark-gluon plasma to produce sequential suppression of excited quarkonia states.

Measurement of four-particle symmetric cumulants has been considered to be a good tool to study the correlations between amplitudes of different orders of anisotropic flow harmonics in heavy-ion collisions. These new observables have not yet been measured at the Relativistic Heavy Ion Collider. Using a multiphase transport (AMPT) model, a set of predictions for the centrality dependence of the normalized four-particle symmetric cumulants in Au+Au collisions at $\sqrt{s_{NN}}=200\mathrm{GeV}$ is given. In addition, the effects of shear viscosity and hadronic rescattering on the magnitude of symmetric cumulants are discussed using the AMPT model at $\sqrt{s_{NN}}=200\mathrm{GeV}$. It is shown that $\text{sc}(2,3)$ is found to be more sensitive to hadronic rescattering, whereas $\text{sc}(2,4)$ is more sensitive to the shear viscosity. Rapidity dependence of symmetric cumulants is also shown. A relation between symmetric cumulant and event-plane correlation is investigated using the AMPT model.

The ${}^{58}\mathrm{Ni}(n,\gamma ){}^{59}\mathrm{Ni}$ cross section was measured with a combination of the activation technique and accelerator mass spectrometry (AMS). The neutron activations were performed at the Karlsruhe 3.7 MV Van de Graaff accelerator using the quasistellar neutron spectrum at $kT=25$ keV produced by the ${}^7\mathrm{Li}(p,n){}^7\mathrm{Be}$ reaction. The subsequent AMS measurements were carried out at the 14 MV tandem accelerator of the Maier-Leibnitz Laboratory in Garching using the gas-filled analyzing magnet system (GAMS). Three individual samples were measured, yielding a Maxwellian-averaged cross section at $kT=30$ keV of ${\langle \sigma \rangle }_{30\text{keV}}$ = 30.4 (23)${}^{\mathrm{syst}}$(9)${}^{\mathrm{stat}}$ mbarn. This value is slightly lower than two recently published measurements using the time-of-flight (TOF) method, but agrees within the uncertainties. Our new results also resolve the large discrepancy between older TOF measurements and our previous value.

The ${}^2\mathrm{H}(d,p){}^3\mathrm{H}$ bare nucleus astrophysical $S\left(E\right)$ factor has been measured indirectly at energies from about 500 keV down to several keV by means of the Trojan-horse method applied to the ${}^2\mathrm{H}({}^6\mathrm{Li},pt){}^4\mathrm{He}$ quasifree reaction induced at 11 MeV. The obtained results are compared with direct data as well as with previous indirect investigation of the same binary reactions. It shows that the precision of $S\left(E\right)$ data in the low-energy range extracted via the same Trojan-horse nucleus [${}^6\mathrm{Li}=(d\oplus \alpha )$] increases while the incident energy of the virtual binary process approaches the zero-quasi-free-energy point. The very good agreement between data extracted from different Trojan-horse nuclei $[{}^6\mathrm{Li}=(d\oplus \alpha )$ vs ${}^3\mathrm{He}=(d\oplus p)]$ gives a strong updated test for the independence of the binary indirect cross section on the chosen Trojan-horse nucleus at low energies.

Theoretical predictions need quantified uncertainties for a meaningful comparison to experimental results. This is an idea which presently permeates the field of theoretical nuclear physics. In light of the recent progress in estimating theoretical uncertainties in ab initio nuclear physics, I here present and compare methods for evaluating the statistical part of the uncertainties. A special focus is put on the (for the field) novel method of Lagrange multipliers (LM). Uncertainties from the fit of the nuclear interaction to experimental data are propagated to a few observables in light-mass nuclei to highlight any differences between the presented methods. The main conclusion is that the LM method is more robust, while covariance-based methods are less demanding in their evaluation.

We investigate the mass fractions and in-medium properties of heavy nuclei in stellar matter at characteristic densities and temperatures for supernova (SN) explosions. The individual nuclei are described within the compressible liquid-drop model taking into account modifications of bulk, surface, and Coulomb energies. The equilibrium properties of nuclei and the full ensemble of heavy nuclei are calculated self-consistently. It is found that heavy nuclei in the ensemble are either compressed or decompressed depending on the isospin asymmetry of the system. The compression or decompression has a little influence on the binding energies, total mass fractions, and average mass numbers of heavy nuclei, although the equilibrium densities of individual nuclei themselves are changed appreciably above one-hundredth of normal nuclear density. We find that nuclear structure in the single-nucleus approximation deviates from the actual one obtained in the multinucleus description, since the density of free nucleons is different between these two descriptions. This study indicates that a multinucleus description is required to realistically account for in-medium effects on the nuclear structure in supernova matter.

The $\vec{p}p\to p{K}^{+}\mathrm{\Lambda }$ reaction has been measured with the COSY-TOF detector at a beam momentum of $2.7\mathrm{GeV}/c$. The polarized proton beam enables the measurement of the beam analyzing power by the asymmetry of the produced kaon $\left(A_N^K\right)$. This observable allows the $p\mathrm{\Lambda }$ spin triplet scattering length to be extracted for the first time model independently from the final state interaction in the reaction. The obtained value is $a_t=(-2.{55}_{-1.39}^{+0.72}{}_{\mathrm{stat}.}\pm 0.6_{\mathrm{syst}.}\pm 0.3_{\mathrm{theo}.})\mathrm{fm}$. This value is compatible with theoretical predictions and results from model-dependent analyses.

We employ a collective vibration coupled-channel model to describe the nucleon-${}^{16}\mathrm{O}$ cluster systems, obtaining low-excitation spectra for ${}^{17}\mathrm{O}$ and ${}^{17}\mathrm{F}$. Bound and resonance states of the compound systems have been deduced, showing good agreement with experimental spectra. Low-energy scattering cross sections of neutrons and protons from ${}^{16}\mathrm{O}$ also have been calculated and the results compare well with available experimental data.

The excitation functions for the production of ${}^{262}\mathrm{Rf}$, ${}^{261}\mathrm{Rf}$, and ${}^{260}\mathrm{Rf}$ isotopes via $4n$-, $5n$-, and $6n$-decay channels from the ${}^{266}\mathrm{Rf}^{*}$ compound nucleus are studied within the dynamical cluster-decay model (DCM), including deformations ${\beta }_{2i}$ and so-called hot-optimum orientations ${\theta }_i$ which support symmetric fission, in agreement with experiments. The data are available for ${}^{18}\mathrm{O}+{}^{248}\mathrm{Cm}$ and ${}^{22}\mathrm{Ne}+{}^{244}\mathrm{Pu}$ reactions, respectively, at the energy ranges of $E_{\mathrm{lab}}=88.2$ to 101.3 and 109.0 to 124.8 MeV. For the nuclear interaction potentials, we use the Skyrme energy density functional (SEDF) based on semiclassical extended Thomas Fermi (ETF) approach, which means an extension of the earlier study of excitation functions of ${}^{266}\mathrm{Rf}^{*}$ formed in ${}^{18}\mathrm{O}+{}^{248}\mathrm{Cm}$ reaction, based on the DCM using the pocket formula for nuclear proximity potential, showing interaction dependence. The Skyrme forces used here are the old SIII and SIV and new GSkI and KDE0(v1) given for both normal and isospin-rich nuclei, with densities added in frozen density approximation. Interestingly, the DCM gives an excellent fit to the measured data on fusion evaporation residue (ER) for both the incoming channels (${}^{18}\mathrm{O}+{}^{248}\mathrm{Cm}$ and ${}^{22}\mathrm{Ne}+{}^{244}\mathrm{Pu}$) at the energy range $E_{\mathrm{lab}}=88.2$ to 124.8 MeV, independent of the entrance channel and Skyrme force used. The possible fusion-fission (ff) and quasifission (qf) mass regions of fragments on DCM are also predicted. The DCM with Skyrme forces is further used to look for all the possible target-projectile (t-p) combinations forming the cold compound nucleus (CN) ${}^{266}\mathrm{Rf}^{*}$ at the CN excitation energy of $E_{\mathrm{lab}}$ for hot compact configurations. The fusion evaporation residue cross sections, for the proposed new reactions in synthesizing the CN ${}^{266}\mathrm{Rf}^{*}$, are also estimated for the future experiments, and role of mass asymmetry of nuclei is indicated.

We study the formation of domain structures due to spontaneous breakdown of center symmetry at high temperatures in quenched QCD. We develop a phenomenological model for the explicit propagation of the Polyakov loop as the relevant order parameter of the deconfinement phase transition. The surface tension in the equation of motion is fit in comparison with lattice QCD data. Results give insight into the dynamical formation of center domains as well as the formation of energy bands along domain walls and let us estimate the required time to form such structures above the critical temperature.

An analytical solution based on the Laplace transformation technique for the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equations is presented at next-to-leading order accuracy in perturbative QCD. This technique is also applied to extract the analytical solution for the proton structure function, $F_2^p(x,Q^2)$, in the Laplace $s$ space. We present the results for the separate parton distributions of all parton species, including valence quark densities, the antiquark and strange sea parton distribution functions (PDFs), and the gluon distribution. We successfully compare the obtained parton distribution functions and the proton structure function with the results from GJR08 [Gluck, Jimenez-Delgado, and Reya, Eur. Phys. J. C 53, 355 (2008)] and KKT12 [Khanpour, Khorramian, and Tehrani, J. Phys. G 40, 045002 (2013)] parametrization models as well as the $x$-space results using QCDnum code. Our calculations show a very good agreement with the available theoretical models as well as the deep inelastic scattering (DIS) experimental data throughout the small and large values of $x$. The use of our analytical solution to extract the parton densities and the proton structure function is discussed in detail to justify the analysis method, considering the accuracy and speed of calculations. Overall, the accuracy we obtain from the analytical solution using the inverse Laplace transform technique is found to be better than 1 part in ${10}^4$ to ${10}^5$. We also present a detailed QCD analysis of nonsinglet structure functions using all available DIS data to perform global QCD fits. In this regard we employ the Jacobi polynomial approach to convert the results from Laplace $s$ space to Bjorken $x$ space. The extracted valence quark densities are also presented and compared to the JR14, MMHT14, NNPDF, and CJ15 PDFs sets. We evaluate the numerical effects of target mass corrections (TMCs) and higher twist (HT) terms on various structure functions, and compare fits to data with and without these corrections.

In this work, we introduce a new approach which is meant to be a first step towards complete self-consistent low-lying spectroscopy of odd nuclei. So far, we essentially limit ourselves to the description of a double-magic core plus an extra nucleon. The model does not contain any free adjustable parameter and is instead based on a Hartree-Fock (HF) description of the particle states in the core, together with self-consistent random-phase approximation (RPA) calculations for the core excitations. We include both collective and noncollective excitations, with proper care of the corrections due to the overlap between them (i.e., due to the nonorthonormality of the basis). As a consequence, with respect to traditional particle-vibration coupling calculations in which one can only address single-nucleon states and particle-vibration multiplets, we can also describe states of shell-model types like 2 particle–1 hole. We will report results for ${}^{49}\mathrm{Ca}$ and ${}^{133}\mathrm{Sb}$ and discuss future perspectives.