The reduced transition probabilities $B(E2;0_{\mathrm{g}.\mathrm{s}.}^{+}\to 2_1^{+})$ of the ${}^{46}\mathrm{Ar}$ and ${}^{44}\mathrm{Ca}$ nuclei were studied using the Coulomb excitation technique at intermediate energy at the LISE/GANIL facility. The in-flight $\gamma$ rays, emitted after the Coulomb excitation of their first $2^{+}$ states, were detected in an array of $64{\mathrm{BaF}}_2$ crystals. The present $\text{B}\left(\mathrm{E}2\uparrow \right)$ value for ${}^{44}\mathrm{Ca}$, 475(36) ${\mathrm{e}}^2{\mathrm{fm}}^4$, agrees well with the value of 495(35) ${\mathrm{e}}^2{\mathrm{fm}}^4$ obtained by averaging results of previous experiments. Consistent $B(E2;0_{\mathrm{g}.\mathrm{s}.}^{+}\to 2_1^{+})$ values of 225(29) ${\mathrm{e}}^2{\mathrm{fm}}^4$ and 234(19) ${\mathrm{e}}^2{\mathrm{fm}}^4$ have been obtained for ${}^{46}\mathrm{Ar}$ from an absolute and a relative measurement, normalized to the ${}^{44}\mathrm{Ca}$ value. Both results agree with the ones obtained with the same experimental technique at the NSCL facility but are a factor of 2 smaller than the shell model predictions. The drop in $B(E2;0_{\mathrm{g}.\mathrm{s}.}^{+}\to 2_1^{+})$ in the Ar chain at $N=28$, confirmed in this experiment, shows that ${}^{46}\mathrm{Ar}$ is sensitive to the $N=28$ shell closure.

In order to find a way to produce superheavy nuclei (SHN), which appear in the gap between the SHN synthesized by cold fusion and those by hot fusion, or those so far not yet been produced in the laboratory, we tried to make use of a set of projectile isotopic chains, to use a radioactive beam projectile, and to test symmetric fusion reactions for gaining more neutrons to synthesize neutron-richer SHN based on the dinuclear system (DNS) model via cold fusion reactions. It is found that the nuclei ${}^{265}\mathrm{Mt},{}^{268,272}\mathrm{Ds},{}^{273}\mathrm{Rg}$, and ${}^{274,275,276}\mathrm{Cn}$ may be produced with the detectable evaporation residual cross sections. The intensities of radioactive beams are significantly less than those of the stable beams, therefore using a stable beam is predicted to be the most favorable method for producing SHN. From the symmetric reaction system ${}^{136}\mathrm{Xe}+{}^{136}\mathrm{Xe}$, no fusion event was found.

Background: The stable isotopes of Li, ${}^6\text{Li}$ and ${}^7\text{Li}$, have two-body cluster structures of $\alpha +d$ and $\alpha +t$ with $\alpha$-separation energies or breakup thresholds at 1.47 and 2.47 MeV, respectively. The weak binding of these projectiles introduces several new reaction channels not usually observed in the case of strongly bound projectiles. The impact of these breakup or breakup-like reaction channels on fusion, the dominant reaction process at near-barrier energies, with different target masses is of current interest.

Purpose: Our purpose is to explore the fusion, at above and below the Coulmb barrier, of ${}^7\text{Li}$ with ${}^{64}\text{Ni}$ target in order to understand the effect of breakup or breakup-like processes with medium-mass target in comparison with ${}^6\text{Li}$, which has a lower breakup threshold.

Measurement: The total fusion (TF) excitation of the weakly bound projectile ${}^7\text{Li}$ with the medium-mass target ${}^{64}\text{Ni}$ has been measured at the near-barrier energies (0.8 to $2 V_B$). The measurement was performed using the online characteristic $\gamma$-ray detection method. The complete fusion (CF) excitation function for the system was obtained using the $xn$-evaporation channels with the help of statistical model predictions.

Results: At the above barrier energies CF cross sections exhibit an average suppression of about 6.5% compared to the one-dimensional barrier penetration model (1DBPM) predictions, while the model describes the measured TF cross section well. But below the barrier, both TF and CF show enhancements compared to 1DBPM predictions. Unlike ${}^6\text{Li}$, enhancement of CF for ${}^7\text{Li}$ could not be explained by inelastic coupling alone.

Conclusion: Whereas the ${\sigma }_{\mathrm{TF}}$ cross sections are almost the same for both the systems in the above barrier region, the suppression of ${\sigma }_{\mathrm{CF}}$ at above the barrier is less for the ${}^7\text{Li}+{}^{64}\text{Ni}$ system than for the ${}^6\text{Li}+{}^{64}\text{Ni}$ system. Also direct cluster transfer has been identified as the probable source for producing large enhancement in TF cross sections.

We calculate total and differential cross sections for $J/\psi$ photoproduction in ultrarelativistic lead-lead collisions at the LHC energy $\sqrt{s_{NN}}=2.76$ TeV. In the present approach we use a simple model based on vector dominance picture and multiple scattering of the hadronic $\left(c\overline{c}\right)$ state in a cold nucleus as an example. In our analysis we use both the classical mechanics and quantum (Glauber) formulas for calculating ${\sigma }_{\mathrm{tot},J/\psi Pb}$ which is a building block of our model. We compare our UPC results with ALICE and CMS data. For semicentral collisions $\left(b<R_A+R_B\right)$ a modification of the photon flux seems necessary. We discuss differences motivated by physics approximations. We try to estimate the cross sections for different centrality bins and for $J/\psi$ mesons emitted in forward rapidity range $\left(2.5<y<4\right)$ corresponding to recent ALICE experimental results. Reasonable results are obtained and open questions are discussed.

Hydrodynamic calculations of ultrarelativistic heavy-ion collisions are performed using the iebe-vishnu 2+1-dimensional code with fluctuating initial conditions and three different parametrizations of the lattice QCD equations of state: continuum extrapolations for stout and HISQ/tree actions, as well as the s95p-v1 parametrization based upon calculations using the p4 action. All parametrizations are matched to a hadron resonance gas equation of state at $T=155$ MeV, at which point the calculations are continued using the urqmd hadronic cascade. Simulations of $\sqrt{s_{NN}}=200$ GeV Au+Au collisions in three centrality classes are used to quantify anisotropic flow developed in the hydrodynamic phase of the collision as well as particle spectra and pion Hanbury-Brown-Twiss (HBT) radii after hadronic rescattering, which are compared with experimental data. Experimental observables for the stout and HISQ/tree equations of state are observed to differ by less than a few percent for all observables, while the s95p-v1 equation of state generates spectra and flow coefficients which differ by $\sim 10–20\%$. Calculations in which the HISQ/tree equation of state is sampled from the published error distribution are also observed to differ by less than a few percent.

The quark susceptibility ${\chi }_q$ at zero and finite quark chemical potential provides a critical benchmark to determine the quark-gluon-plasma (QGP) degrees of freedom in relation to the results from lattice QCD (lQCD) in addition to the equation of state and transport coefficients. Here we extend the familiar dynamical quasiparticle model (DQPM) to partonic propagators that explicitly depend on the three-momentum with respect to the partonic medium at rest in order to match perturbative QCD (pQCD) at high momenta. Within the extended dynamical quasiparticle model (${\mathrm{DQPM}}^{*}$) we reproduce simultaneously the lQCD results for the quark number density and susceptibility and the QGP pressure at zero and finite (but small) chemical potential ${\mu }_q$. The shear viscosity $\eta$ and the electric conductivity ${\sigma }_e$ from the extended quasiparticle model (${\mathrm{DQPM}}^{*}$) also turn out to be in close agreement with lattice results for ${\mu }_q=0$. The ${\mathrm{DQPM}}^{*}$, furthermore, allows one to evaluate the momentum $p$, temperature $T$, and chemical potential ${\mu }_q$ dependencies of the partonic degrees of freedom also for larger ${\mu }_q$, which are mandatory for transport studies of heavy-ion collisions in the regime $5<\sqrt{s_{NN}}<10$ GeV.

Di-hadron correlationsand jet-hadron correlations are frequently used to study interactions of the quark gluon plasma with the hard partons that form jets. The existing background subtraction methods for these studies depend on several assumptions and independent measurements of the Fourier coefficients of the combinatorial background. In this paper, we present a method for determining the background using a fit to the reaction plane dependence of the background-dominated region of the near side to extract the background. We also fit the of the background-dominated region of the near side without the reaction plane dependence. To test the accuracy of these methods, a simple model is used to simulate di-hadron and jet-hadron correlations with a combinatorial background similar to that observed in the data. The true signal is compared to the extracted signal. The results are compared to results from two variants of the zero-yield-at-minimum (ZYAM) method. We test these methods for midperipheral and central collisions and for di-hadron and jet-hadron correlations. These methods are more precise than the ZYAM method with fewer assumptions about the shape and level of the combinatorial background, even in central collisions where the experimental resolution on the measurement of the reaction plane dependence is poor. These methods will allow more accurate studies of modifications of the away-side jet and will be particularly useful for studies of jet-hadron correlations, where the combinatorial background is poorly constrained from previous studies.

We describe in detail the methods used to obtain the lower bound on the lifetime of neutrinoless double-beta ($0\nu \beta \beta$) decay in ${}^{130}\mathrm{Te}$ and the associated limit on the effective Majorana mass of the neutrino using the CUORE-0 detector. CUORE-0 is a bolometric detector array located at the Laboratori Nazionali del Gran Sasso that was designed to validate the background reduction techniques developed for CUORE, a next-generation experiment scheduled to come online in 2016. CUORE-0 is also a competitive $0\nu \beta \beta$ decay search in its own right and functions as a platform to further develop the analysis tools and procedures to be used in CUORE. These include data collection, event selection and processing, as well as an evaluation of signal efficiency. In particular, we describe the amplitude evaluation, thermal gain stabilization, energy calibration methods, and the analysis event selection used to create our final $0\nu \beta \beta$ search spectrum. We define our high level analysis procedures, with emphasis on the new insights gained and challenges encountered. We outline in detail our fitting methods near the hypothesized $0\nu \beta \beta$ decay peak and catalog the main sources of systematic uncertainty. Finally, we derive the $0\nu \beta \beta$ decay half-life limits previously reported for CUORE-0, $T_{1/2}^{0\nu }>2.7\times {10}^{24}\mathrm{yr}$, and in combination with the Cuoricino limit, $T_{1/2}^{0\nu }>4.0\times {10}^{24}\mathrm{yr}$.

The mass of ${}^{31}\mathrm{Cl}$ has been measured with the JYFLTRAP double-Penning-trap mass spectrometer at the Ion Guide Isotope Separator On-Line (IGISOL) facility. The determined mass-excess value, $-7034.7\left(34\right)$ keV, is 15 times more precise than in the Atomic Mass Evaluation 2012. The quadratic form of the isobaric multiplet mass equation for the $T=3/2$ quartet at $A=31$ fails $\left({\chi }_n^2=11.6\right)$ and a nonzero cubic term, $d=-3.5\left(11\right)$ keV, is obtained when the new mass value is adopted. ${}^{31}\mathrm{Cl}$ has been found to be less proton-bound, with a proton separation energy of $S_p=264.6\left(34\right)$ keV. Energies for the excited states in ${}^{31}\mathrm{Cl}$ and the photodisintegration rate on ${}^{31}\mathrm{Cl}$ have been determined with significantly improved precision by using the new $S_p$ value. The improved photodisintegration rate helps to constrain astrophysical conditions where ${}^{30}\mathrm{S}$ can act as a waiting point in the rapid proton capture process in type-I x-ray bursts.

Decays of neutron-rich nuclei ${}^{82,83}\mathrm{Zn}$ and ${}^{82,83}\mathrm{Ga}$ produced in proton-induced fission of ${}^{238}\mathrm{U}$ were studied at the Holifield Radioactive Ion Beam Facility using on-line mass separation and $\beta \text{−}\gamma$ spectroscopy techniques. New $\gamma$-ray transitions were identified and level schemes, which include states at high excitation energies in the range between 3–7 MeV were constructed. These high-energy levels were identified to be populated through allowed Gamow-Teller $\beta$ transitions, and their structure was interpreted with new shell-model calculations. A $\beta$-delayed neutron branching ratio of $69\pm 7\%$ was deduced for ${}^{82}\mathrm{Zn}$ and revised $\beta$-decay half-life values of ${}^{82}\mathrm{Zn}$ [155(17)(20) ms] and ${}^{83}\mathrm{Zn}$ [122(28) ms] were determined.

The $\alpha$ preformation factors of medium-mass nuclei as well as their behavior in the vicinity of $Z=82$ shell closure are systematically investigated by using the cluster-formation model (CFM). The recently proposed CFM was proven to be effective in the evaluation of $\alpha$ preformation factors in the heavy-mass region, and we find that it is also valid for medium-mass nuclei because it reproduces reasonable features of the variation of $\alpha$ preformation probability, especially the $Z=82$ shell effects which are made evident in a recent experiment. A total of 363 nuclides (including even-even, odd-$A$ and odd-odd nuclei) with $72\le Z\le 88$ and $84\le N\le 117$ are included in our calculation. Through a comparison between $Z=82$ and $N=126$ shell effects, the structural effects inside the observed different behavior of preformation factors are discussed in detail. As an extended application to medium-mass nuclei, the CFM provides a convenient and effective way to extract nuclear structure information from the $\alpha$ preformation factor. The results in this work can be a useful reference for future analysis in the microscopic calculation of $\alpha$ decay.

Low-lying excited states of the neutron-rich calcium isotopes ${}^{48\text{–}52}\mathrm{Ca}$ have been studied via $\gamma$-ray spectroscopy following inverse-kinematics proton scattering on a liquid hydrogen target using the GRETINA $\gamma$-ray tracking array. The energies and strengths of the octupole states in these isotopes are remarkably constant, indicating that these states are dominated by proton excitations.

Heavy-quark observables in ultrarelativistic heavy-ion collisions, like the nuclear modification factor and the elliptic flow, give insight into the mechanisms of high-momentum suppression and low-momentum thermalization of heavy quarks. Here, we present a global study of these two observables within a coupled approach of the heavy-quark propagation in a realistic fluid dynamical medium, $\text{MC@sHQ}+\text{EPOS2}$, and compare with experimental data from the BNL Relativistic Heavy Ion Collider and the CERN Large Hadron Collider experiments. The heavy quarks scatter elastically and inelastically with the quasiparticles of the quark-gluon plasma (QGP), which are represented consistently with the underlying equation of state. We examine two scenarios: first, we interpret the lattice QCD equation of state as a sum of partonic and hadronic contributions and, second, as a gas of massive partonic quasiparticles. It is observed that, independent of their momentum, the energy loss of heavy quarks depends strongly on how the lattice QCD equation of state is translated into degrees of freedom of the QGP.

Recent analyses of small collision systems, namely $p+p$ and $p+\mathrm{Pb}$ at the LHC, and $p+\mathrm{Au}$, $d+\mathrm{Au}$, and ${}^3\mathrm{He}+\mathrm{Au}$ at RHIC, have revealed azimuthal momentum anisotropies commonly associated with collective flow in larger systems. Viscous hydrodynamics and parton cascade calculations have proven successful at describing some flow-like observables in these systems. These two classes of calculations also confirm these observables to be directly related to the initial geometry of the created system. Describing data at the highest RHIC and LHC energies requires a quark-gluon plasma or partonic rescattering stage, which raises the question of how small and low in energy can one push the system before only hadronic interactions are required for a full description. Hence, a beam-energy scan of small systems—that amounts to varying the initial temperature and the lifetime of the medium—can provide valuable information to shed light on these issues. In this paper, we present predictions from viscous hydrodynamics (sonic and supersonic), and partonic (ampt) and hadronic (urmqd) cascade calculations for elliptic $\left(v_2\right)$ and triangular $\left(v_3\right)$ anisotropy coefficients in $d$ + Au collisions at $\sqrt{s_{{}_{NN}}}=7.7$, 20, 39, 62.4, 200 GeV and 5.02 TeV.

Formulas connecting cumulants of particle numbers observed with efficiency losses with the original ones are derived based on the binomial model. These formulas can be applied to quantities given by a linear combination of particle numbers observed with different efficiencies in a compact form. Compared with the presently suggested ones based on factorial moments, these formulas would drastically reduce the numerical cost for the efficiency corrections when the order of the cumulant and the number of different efficiencies are large. The efficiency correction with realistic $p_T$-dependent efficiency would be carried out with the aid of these formulas.

The Pauli exclusion principle plays an important role in many-body fermion systems, preventing them from collapsing by repulsion. For example, the Pauli principle causes a repulsive potential at short distances between two $\alpha$ particles. On the other hand, the existence of nuclear rainbows demonstrates that the internuclear potential is sufficiently attractive in the internal region to cause refraction. The two concepts of repulsion and attraction are seemingly irreconcilable. Contrary to traditional understanding, it is shown that the Pauli principle causes a universal structural Pauli attraction between nuclei rather than a structural repulsive core. Through systematic studies of $\alpha +\alpha ,\alpha +{}^{16}\mathrm{O},\alpha +{}^{40}\mathrm{Ca}$, and ${}^{16}\mathrm{O}+{}^{16}\mathrm{O}$ systems, it is shown that the emergence of cluster structures near the threshold energy at low energies and nuclear rainbows at high energies is a direct consequence of the Pauli principle.

We apply improved nucleon-nucleon potentials up to fifth order in chiral effective field theory, along with a new analysis of the theoretical truncation errors to study nucleon-deuteron $\left(\mathrm{N}d\right)$ scattering and selected low-energy observables in ${}^3\mathrm{H},{}^4\mathrm{He}$, and ${}^6\mathrm{Li}$. Calculations beyond second order differ from experiment well outside the range of quantified uncertainties, providing truly unambiguous evidence for missing three-nucleon forces within the employed framework. The sizes of the required three-nucleon-force contributions agree well with expectations based on Weinberg's power counting. We identify the energy range in elastic $\mathrm{N}d$ scattering best suited to study three-nucleon-force effects and estimate the achievable accuracy of theoretical predictions for various observables.

A simple model is used to compute $B\left(E2\right)$'s in several nuclei that have one or two $sd$-shell neutrons and no $sd$-shell protons. The model works well for all six nuclei if I use later experimental values for ${}^{16}\mathrm{C}$ for which the measured $B\left(E2\right)$ is about four to eight times earlier values.

We have studied the ${}^{14,15}\mathrm{C}(d,{}^3\mathrm{He}){}^{13,14}\mathrm{B}$ proton-removing reactions in inverse kinematics. The $\left(d,{}^3\mathrm{He}\right)$ reaction probes the proton occupation of the target ground state, and also provides spectroscopic information about the final states in ${}^{13,14}\mathrm{B}$. The experiments were performed using ${}^{14,15}\mathrm{C}$ beams from the ATLAS accelerator at Argonne National Laboratory. The reaction products were analyzed with the HELIOS device. Angular distributions were obtained for transitions from both reactions. The ${}^{14}\mathrm{C}$-beam data reveal transitions to excited states in ${}^{13}\mathrm{B}$ that suggest configurations with protons outside the $\pi \left(0p_{3/2}\right)$ orbital, and some possibility of proton cross-shell $0p\text{−}1s0d$ excitations, in the ${}^{14}\mathrm{C}$ ground state. The ${}^{15}\mathrm{C}$-beam data confirm the existence of a broad $2^{-}$ excited state in ${}^{14}\mathrm{B}$. The experimental data are compared to the results of shell-model calculations.

Strength distributions for isoscalar giant resonances with multipolarity $L\le 2$ have been determined in ${}^{24}\mathrm{Mg}$ from “instrumental background-free” inelastic scattering of 386-MeV $\alpha$ particles at extreme forward angles, including $0^{\circ }$. The isoscalar $E0, E1$, and $E2$ strengths are observed to be $57\pm 7\%, 111.1_{-7.2}^{+10.9}\%$, and $148.6\pm 7.3\%$, respectively, of their energy-weighted sum rules in the excitation energy range of 6 to 35 MeV. The isoscalar giant monopole (ISGMR) and quadrupole (ISGQR) resonances exhibit a prominent $K$ splitting which is consistent with microscopic theory for a prolate-deformed ground state of ${}^{24}\mathrm{Mg}$. For the ISGQR it is due to splitting of the three $K$ components, whereas for the ISGMR it is due to its coupling to the $K=0$ component of the ISGQR. Deformation effects on the isoscalar giant dipole resonance are less pronounced, however.