The Nilsson mean-field plus extended-pairing model for deformed nuclei is applied to describe the ground-state properties of selected rare-earth nuclei. Binding energies, even-odd mass differences, energies of the first pairing excitation states, and moments of inertia for the ground-state band of ${}^{152-164}\mathrm{Er}$, ${}^{154-166}\mathrm{Yb}$, and ${}^{156-168}\mathrm{Hf}$ are calculated systematically in the model employing both proton-proton and neutron-neutron pairing interactions. The pairing interaction strengths are determined as a function of the mass number in the isotopic chains. In comparison with the corresponding experimental data, it is shown that pairing interaction is crucial in elucidating the properties of both the ground state and the first pairing excitation state of these rare-earth nuclei. With model parameters determined by fitting the energies of these states, ground-state occupation probabilities of valence nucleon pairs with angular momentum $J=0,1,\cdots ,12$ for even-even ${}^{156-162}\mathrm{Yb}$ are calculated. It is inferred that the occupation probabilities of valence nucleon pairs with even angular momenta are much higher than those of valence nucleon pairs with odd angular momenta. The results clearly indicate that $S, D$, and $G$ valence nucleon pairs dominate in the ground state of these nuclei.

We study momentum imbalance as a function of jet asymmetry in high-energy heavy-ion collisions. To implement parton production during the collision, we include all leading order (LO) $2\to 2$ and $2\to 3$ parton processes in pQCD. The produced partons lose energy within the quark gluon plasma and hadronize collinearly when they leave it. The energy and momentum deposited into the plasma is described using linear viscous hydrodynamics with a constant energy loss per unit length and a total energy loss given by a Gaussian probability centered around a mean value $\overline{\mathcal{E}}$ and a half-width $\mathrm{\Delta }\mathcal{E}$. We argue that the shape of the asymmetry observed by the CERN-CMS Collaboration can indeed be attributed to parton energy loss in the medium and that a good description of data is achieved when one includes a slight enhancement coming from the contribution of $2\to 3$ parton processes that modifies the asymmetry distribution of the dijet events. We compare our results to CMS data for the most central collisions and study different values for $\overline{\mathcal{E}}$ and $\mathrm{\Delta }\mathcal{E}$.

Determination of the accurate astrophysical $S$ factor of ${}^{12}\text{C}(\alpha ,\gamma ){}^{16}\text{O}$ reaction has been regarded as the holy grail of nuclear astrophysics for decades. In current stellar models, a knowledge of that value to better than 10% is desirable. Due to the practical issues, tremendous experimental and theoretical efforts over nearly 50 years are not able to reach this goal, and the published values contradicted with each other strongly and their uncertainties are two times larger than the required precision. To this end we have developed a reduced $R\text{-matrix}$ theory based on the classical $R\text{-matrix}$ theory of Lane and Thomas, which treats primary transitions to the ground state and four bound states as the independent reaction channels in the channel spin representation. With the coordination of covariance statistics and error-propagation theory, a global fitting for almost all available experimental data of ${}^{16}\mathrm{O}$ system has been multi-iteratively analyzed by our powerful code. A reliable, accurate, and self-consistent astrophysical $S$ factor of ${}^{12}\text{C}(\alpha ,\gamma ){}^{16}\text{O}$ was obtained with a recommended value $S_{\mathrm{tot}}\left(0.3\mathrm{MeV}\right)=162.7\pm 7.3$ keV b (4.5%) which could meet the required precision.

The ground state spin and parity of a daughter formed in a radioactive $\alpha$ emitter are expected to influence the preformation probability of the $\alpha$ and daughter clusters inside it. We investigate the $\alpha$ and daughter preformation probability inside odd-$A$ and doubly odd radioactive nuclei when the daughter and parent are of different spin and/or parity. We consider only the ground state to ground state unfavored decays. This is to extract precise information about the effect of the difference in the spin-parity of the ground states of the involved nuclei far away from any influence from the excitation energy, if the decays are coming from isomeric states. The calculations are done for $161\alpha$ emitters, with $65\le Z\le 112$ and $84\le N\le 173$, in the framework of the extended cluster model, with the Wentzel-Kramers-Brillouin penetrability and assault frequency. We used a Hamiltonian energy density scheme based on the Skyrme SLy4 interaction to compute the interaction potential. The $\alpha$-plus-cluster preformation probability is extracted from the calculated decay width and the experimental half-life time. We discussed in detailed steps the effect of the angular momentum of the emitted $\alpha$ particle on the various physical quantities involved in the unfavored decay process and how it finally increases the half-life time. We found that if the ground state spin and/or parity of parent and daughter nuclei are different, then the preformation probability of the $\alpha$ cluster inside the parent is less than it would be if they had similar spin-parity. We modified the formula that gives the $\alpha$ preformation probability in terms of the numbers of protons and neutrons outside the shell closures of the parent, to account for this hindrance in the preformation probability for the unfavored decays between ground states.

The article presents analysis of the single top quark production in PbPb collisions at the CERN Large Hadron Collider at center-of-mass energy 5.5 TeV per nucleon pair. The analysis is performed with CompHEP and PYQUEN event generators. The neutron and proton content in the nuclei is taken into account. NLO precision has been implemented to simulate kinematic properties and rate of single top production. The modification of different characteristics of single top quark decay products due to interactions of jet partons in quark-gluon medium, and the specific charge asymmetry of top/antitop quark yields due to the isospin effect are evaluated.

We argue that the full conversion of a hadronic star into a quark or a hybrid star occurs within two different regimes separated by a critical value of the density of the hadronic phase $\overline{n_h}$. The first stage, occurring for $n_h>\overline{n_h}$, is characterized by turbulent combustion and lasts typically a few ms. During this short time scale, neutrino cooling is basically inactive and the star heats up due to the heat released in the conversion. In the second stage, occurring for $n_h<\overline{n_h}$, turbulence is not active anymore, and the conversion proceeds on a much longer time scale (of the order of tens of seconds), with a velocity regulated by the diffusion and the production of strange quarks. At the same time, neutrino cooling is also active. The interplay between the heating of the star due to the slow conversion of its outer layers (with densities smaller than $\overline{n_h}$) and the neutrino cooling of the forming quark star leads to a quasiplateau in the neutrino luminosity which, if observed, would possibly represent a unique signature for the existence of quark matter inside compact stars. We will discuss the phenomenological implications of this scenario, in particular in connection with the time structure of long gamma-ray bursts.

In this work, we calculate the matrix elements for the $0\nu \beta \beta$ decay of ${}^{150}\mathrm{Nd}$ using the deformed quasiparticle random-phase approximation $(pn$-QRPA) method. We adopted the approach introduced by Rodin and Faessler [Phys. Rev. C 84, 014322 (2011)] and Simkovic et al. [Phys. Rev. C 87, 045501 (2013)] to restore the isospin symmetry by enforcing $M_F^{2\nu }=0$. We found that with this restoration, the Fermi matrix elements are reduced in the strongly deformed ${}^{150}\mathrm{Nd}$ by about 15 to 20%, while the more important Gamow-Teller matrix elements remain the same. The results of an enlarged model space are also presented. This enlargement increases the total (Fermi plus Gamow-Teller) matrix elements by less than 10%.

The first excited, $J^{\pi }=2^{+}$ state of ${}^{16}\mathrm{Ne}$ at $E^{*}=1.69\left(2\right)$ MeV is well populated in neutron knockout reactions with a ${}^{17}\mathrm{Ne}$ beam and the correlations between the momenta of the three final fragments following $2p$ decay were measured. The correlation pattern showed aspects of both sequential and diprotonlike decay, which were reproduced in three-body ${}^{14}\mathrm{O}$ + $p+p$ calculations. These calculations suggest that interference between these processes is responsible for the observed features which can be described in terms of a “tethered decay mechanism.” The intrinsic width of this state was constrained to be from 100 to 250 keV. Higher excited states populating the ${}^{13}\mathrm{N}$ + $p+p+p$ exit channel were found at $E^{*}=8.37\left(10\right)$ and 10.76(20) MeV.

This paper presents the first application of the shell-model-based source-term approach (STA) to calculations of widths of neutron and proton resonances for some $0p$-shell nuclei. The STA widths are compared to (i) the popular standard approach that uses the product of shell-model spectroscopic factors and single-particle widths obtained from a potential model with standard potential well geometry, (ii) available predictions from a similar approach with variational Monte Carlo (VMC) wave functions, and (iii) experimental data. It is found out that the STA predictions are often smaller than those made within the widely used standard practice (ii), thus indicating that reduction of spectroscopic strength, known in bound states, persists in the continuum. In most cases the STA gives better agreement with experiment than the standard approach does and is comparable to results obtained from the VMC-based integral equations approach. The agreement of the STA widths with experimental values is of quality similar to that seen in predictions of asymptotic normalization coefficients made in the same approach.

We present an improved variant of the in-medium similarity renormalization group (IM-SRG) based on the Magnus expansion. In the new formulation, one solves flow equations for the anti-Hermitian operator that, upon exponentiation, yields the unitary transformation of the IM-SRG. The resulting flow equations can be solved using a first-order Euler method without any loss of accuracy, resulting in substantial memory savings and modest computational speedups. Since one obtains the unitary transformation directly, the transformation of additional operators beyond the Hamiltonian can be accomplished with little additional cost, in sharp contrast to the standard formulation of the IM-SRG. Ground state calculations of the homogeneous electron gas (HEG) and ${}^{16}\mathrm{O}$ nucleus are used as test beds to illustrate the efficacy of the Magnus expansion.

Prompt fission $\gamma$-ray (PFG) spectra have been measured in a recent experiment with the novel directional fast-neutron source LICORNE at the ALTO facility of the IPN Orsay. These first results from the facility involve the comparative measurement of prompt $\gamma$ emission in fast-neutron-induced fission of ${}^{235}\mathrm{U}$ and ${}^{238}\mathrm{U}$. Characteristics such as $\gamma$ multiplicity and total and average radiation energy are determined in terms of ratios between the two systems. Additionally, the average photon energies were determined and compared with recent data on thermal-neutron-induced fission of ${}^{235}\mathrm{U}$. PFG spectra are shown to be similar within the precision of the present measurement, suggesting that the extra incident energy does not significantly impact the energy released by prompt $\gamma$ rays. The origins of some small differences, depending on either the incident energy or the target mass, are discussed. This study demonstrates the potential of the present approach, combining an innovative neutron source and new-generation detectors, for fundamental and applied research on fission in the near future.

Background: Near-barrier fusion can be strongly affected by the coupling between relative motion and internal degrees of freedom of the collision partners. The coupled channels (CC) method is a usual way of describing the reaction dynamics in this energy region. In the standard approach in the CC method only strong reaction channels (collective excitations) are taken into account. However, in some cases this approach fails to describe experimentally obtained barrier height distributions.

Purpose: The influence of weak (noncollective) reaction channels on barrier height distributions was studied.

Method: The barrier height distributions were determined from quasielastic scattering of ${}^{20}\mathrm{Ne}$ on ${}^{58,60,61}\mathrm{Ni}$ targets. The scattered ions were registered at backward angles (130–150 degrees).

Results: In the ${}^{58}\mathrm{Ni}$ and ${}^{60}\mathrm{Ni}$ cases one observes a “structure” (two peaks) in the barrier height distribution which is completely smoothed out for ${}^{61}\mathrm{Ni}$.

Conclusions: The results support the hypothesis that noncollective excitations of the target nuclei, much more numerous in ${}^{61}\mathrm{Ni}$ than in ${}^{58}\mathrm{Ni}$ and ${}^{60}\mathrm{Ni}$, influence the barrier height distribution and are responsible for smoothing out the structure.

Lepton-nucleon elastic scattering, using the one-photon and one-scalar-boson exchange mechanisms considering all possible polarizations, is used to study searches for a new scalar boson and suggest new measurements of the nucleon form factors. A new light scalar boson, which feebly couples to leptons and nucleons, may account for the proton radius and muon $g-2$ puzzles. We show that the scalar boson produces relatively large effects in a certain kinematic region when using sufficient control of lepton and nucleon spin polarization. We generalize current techniques to measure the ratio $G_E:G_M$ and present a new method to separately measure $G_M^2$ and $G_E^2$ using polarized incoming and outgoing muons.

The effective baryon-baryon interaction is studied in the refined quark delocalization color screening model (QDCSM), in which the different quark clusterings are fully taken into account, instead of controlling by a variational delocalization parameter $\epsilon \left(s\right)$ between two three-quark clusters. The symmetry bases are employed to do the calculation, all possible configurations for two-quark clusters are considered. The results obtained are very similar to those of QDCSM. It is inferred that the delocalization parameter $\epsilon \left(s\right)$ used in QDCSM is an economic and effective way to describe the mixing of quarks between baryons. The relativized quark model is also employed to study the relativistic effect on the effective potentials between two baryons.

The magnetic-dipole form factor and the ratios $R_{EM}$ and $R_{SM}$ for the ${\gamma }^{*}N\to \mathrm{\Delta }\left(1232\right){\frac{3}{2}}^{+}$ transition are predicted within the light-front relativistic quark model up to photon virtuality $Q^2=12{\mathrm{GeV}}^2$. We also predict the helicity amplitudes of the ${\gamma }^{*}N\to \mathrm{\Delta }\left(1600\right){\frac{3}{2}}^{+}$ transition assuming that the $\mathrm{\Delta }\left(1600\right){\frac{3}{2}}^{+}$ is the first radial excitation of the ground state $\mathrm{\Delta }\left(1232\right){\frac{3}{2}}^{+}$.

Properties of excited states in ${}^{147}\mathrm{Nd}$ have been studied with the multispectra and $\gamma \gamma$ coincidence measurements. Twenty-four new $\gamma$ lines and three new levels have been introduced into the level scheme of ${}^{147}\mathrm{Nd}$. Using the advanced time-delayed $\beta \gamma \gamma$($t$) method, we measured lifetimes of eight excited levels in ${}^{147}\mathrm{Nd}$, populated via the $\beta$ decay of ${}^{147}\mathrm{Pr}$. We have determined reduced transition probabilities for 30 $\gamma$ transitions. Multidimensional potential energy surface calculations performed for ${}^{147}\mathrm{Nd}$ suggest two single-quasiparticle configurations with nonzero octupole deformation, with $K=1/2$ and $K=5/2$. Our calculations also predict a sizable value of the electric dipole moment $|D_0|=0.26e$ fm for this nucleus, while experimentally, a lower limit of $|D_0|\ge 0.02e$ fm has been evaluated for the supposed $K=1/2$ parity doublet. In contrast to the theoretical results, we do not observe the parity doublet bands with $K=5/2$. This, and the lack of theoretically expected $E1$ strength in ${}^{147,149}\mathrm{Nd}$ may signal some poorly understood structural effect in the odd-$N$ lanthanides.

The electric dipole strength distribution in ${}^{120}\mathrm{Sn}$ between 5 and 22 MeV has been determined at the Research Center for Nuclear Physics, Osaka, from polarization transfer observables measured in proton inelastic scattering at $E_0=295$ MeV and forward angles including $0^{\circ }$. Combined with photoabsorption data, a highly precise electric dipole polarizability ${\alpha }_{\mathrm{D}}\left({}^{120}\mathrm{Sn}\right)=8.93\left(36\right){\mathrm{fm}}^3$ is extracted. The dipole polarizability as isovector observable par excellence carries direct information on nuclear symmetry energy and its density dependence. The correlation of the new value with the well-established ${\alpha }_{\mathrm{D}}\left({}^{208}\mathrm{Pb}\right)$ serves as a test of its prediction by nuclear energy density functionals. Models based on modern Skyrme interactions describe the data fairly well while most calculations based on relativistic Hamiltonians cannot.

The one-body density-matrix elements obtained from the USDA Hamiltonian are used to calculate the electron-nucleus scattering form factors for the ${}^{25}\mathrm{Mg}$ nucleus. The longitudinal form factor calculations produce good agreements for all states in the first sequence whereas the shell-model predictions show a variation in results for the excitation states in the second sequence. The wave functions of radial single-particle matrix elements have been calculated with the Woods-Saxon, harmonic-oscillator, and Skyrme (Sk42) potentials. The results of the inelastic transverse form factors are in good agreement with the experimental data when using the Sk42 potential whereas the elastic magnetic scattering results show a significant difference in values compared with the experimental data. However the overall shape and other features of the form factors are satisfactory when using the harmonic-oscillator potential. The effective $g$ factors were used as adjustable parameters in the oxbash code to describe the core-polarization effects in the transverse form factor calculations with the use of a harmonic-oscillator size parameter in the elastic magnetic scattering.

The development of high performance computing facilities makes possible a massive production of nuclear data in a full microscopic framework. Taking advantage of the individual potential calculations of more than 7000 nuclei, a new statistical scission-point model, called SPY, has been developed. It gives access to the absolute available energy at the scission point, which allows the use of a parameter-free microcanonical statistical description to calculate the distributions and the mean values of all fission observables. SPY uses the richness of microscopy in a rather simple theoretical framework, without any parameter except the scission-point definition, to draw clear answers based on perfect knowledge of the ingredients involved in the model, with very limited computing cost.