The half-life of the ${}^{249}\mathrm{Bk}$ ground state was determined by means of $\gamma$-ray spectroscopy, following for 728 days the growth of its $\alpha$-decaying daughter nuclide ${}^{249}\mathrm{Cf}$. Using a chemically purified source containing ${}^{249}\mathrm{Bk}$ and ${}^{137}\mathrm{Cs}$ nuclides, $\gamma$-ray singles measurements were carried out using a 25% coaxial Ge detector. The areas of the strongest 333.37- and 388.17-keV $\gamma$-ray peaks, produced in the $\alpha$ decay of ${}^{249}\mathrm{Cf}$, and the 661.66-keV peak, produced in the ${\beta }^{-}$ decay of ${}^{137}\mathrm{Cs}$, were determined. The measured activity of the latter was used to account for geometrical and dead-time corrections to the efficiency of the spectrometer, thus minimizing the systematic uncertainties associated with long-time, $\gamma$-ray counting measurements. Using the growth with time of the ratio of the 388.17- and 661.66-keV $\gamma$-ray peaks, a value of $T_{1/2}=327.2\pm 0.3$ d (the uncertainty quoted is one standard deviation, $1\sigma$) for the half-life of the ${}^{249}\mathrm{Bk}$ ground state was determined. The ${\beta }^{-}$-decay end-point energy of ${}^{249}\mathrm{Bk}$ was measured with a passivated implanted planar silicon detector to be $123.6\pm 0.4$ keV.

Experimental elastic scattering and double differential cross sections of ${}^{89}\mathrm{Y}\left(d,n\right)$ and ${}^{89}\mathrm{Y}\left(d,p\right)$ reactions have been measured with 5, 6, and 7.44 MeV deuteron beams. It was found that about 76% of the total reaction cross sections are determined by the compound mechanism and the rest is due to direct and preequilibrium interactions. Cross sections measured at backward angles were compared with calculations based on the compound nuclear Hauser-Feshbach model. It was found that it is possible to reproduce the backward angle neutron cross sections by the compound model, but it fails to describe proton cross sections. A pronounced peak is observed in neutron differential cross section which might result from strongly populated states $0^{+},4^{-}$, and $5^{-}$ of ${}^{90}\mathrm{Zr}$ via direct stripping reactions. The level density of ${}^{90}\mathrm{Zr}$ has been obtained from neutron cross sections measured at backward angles. It is best described with the constant-temperature level density model versus the traditional Fermi-gas one.

The propagation of heavy quarks in the quark-gluon plasma was often treated within the framework of the Langevin equation (LV), i.e., assuming the momentum transfer is small or the scatterings are sufficiently forward peaked, small screening mass $m_D$. We address a direct comparison between the Langevin dynamics and the Boltzmann collisional integral (BM) when a bulk medium is in equilibrium at fixed temperature. We show that unless the cross section is quite forward peaked $\left(m_D\cong T\right)$ or the mass to temperature ratio is quite large $\left(M_{\mathrm{HQ}}/T\gtrsim 8–10\right)$ there are significant differences in the evolution of the $p$ spectra and consequently on the nuclear modification factor $R_{AA}\left(p_T\right)$. However, for charm quark we find that very similar $R_{AA}\left(p_T\right)$ between the LV and BM can be obtained, but with a modified diffusion coefficient of about $\sim 15\%–50\%$ depending on the angular dependence of the cross section which regulates the momentum transfer. Studying also the momentum spread suffered by the single heavy quarks we see that at temperatures $T\gtrsim 250\mathrm{MeV}$ the dynamics of the scatterings is far from being of Brownian type for charm quarks. In the case of bottom quarks we essentially find no differences in the time evolution of the momentum spectra between the LV and the BM dynamics independently of the angular dependence of the cross section, at least in the range of temperature relevant for ultrarelativistic heavy-ion collisions (HICs). Finally, we have shown the possible impact of this study on $R_{AA}\left(p_T\right)$ and $v_2\left(p_T\right)$ for a realistic simulation of relativistic HICs. For larger $m_D$ the elliptic flow can be about $50\%$ larger for the Boltzmann dynamics with respect to the Langevin. This is helpful for a simultaneous reproduction of $R_{AA}\left(p_T\right)$ and $v_2\left(p_T\right)$.

The photoabsorption cross section of ${}^{181}\mathrm{Ta}$ up to the neutron-separation energy is deduced using bremsstrahlung produced with an electron beam of 9.6 MeV energy. The analysis of the measured $\gamma$-ray spectra includes the quasicontinuum of levels at high energy. Simulations of $\gamma$-ray cascades are performed to estimate intensities of inelastic transitions and branching ratios of the ground-state transitions. The resulting photoabsorption cross section shows enhanced dipole strength in the energy range from 5 to 8 MeV, which may be related to a pygmy dipole resonance. The results of the present experiment are compared with predictions of a quasiparticle-random-phase approximation in a deformed basis. A combination of the present experimental data and $(\gamma ,n)$ data is used as an input to the statistical code talys applied to calculate cross sections and reaction rates of photonuclear reactions that are important for the nucleosynthesis of ${}^{180}\mathrm{Ta}$.

Background: Formal optical model theory shows that coupling to vibrational nuclear states generates a nonlocal and $l$-dependent dynamical polarization potential (DPP). Little is established concerning the DPP, yet its properties are crucial for explaining the departures of optical model potentials (OMPs) from global behavior and for the rigorous extraction of spectroscopic information from direct reactions.

Purpose: To appraise the application of channel coupling followed by $S$-matrix inversion for the systematic exploration of the contribution of the coupling of collective states to the nucleon OMP and to identify properties of nuclear potentials indicative of $l$-dependence.

Methods: $S$-matrix to potential, $S_{lj}\to V\left(r\right)+\mathbf{l}·\mathbf{s}{V}_{\mathrm{SO}}\left(r\right)$, inversion provides local potentials that precisely reproduce the elastic channel $S$-matrix from coupled channel (CC) calculations. Subtracting the elastic channel uncoupled (bare) potential yields a local and $l$-independent representation of the DPP. The dependence of this local DPP upon the nature of the coupled states and upon other parameters can be studied.

Results: All components of the DPP arising from coupling to vibrational states are substantially undulatory with a point-by-point magnitude therefore disproportionate to their contribution to volume integrals. Information relating to dynamical nonlocality is found. The proton charge leads to a substantial difference between DPPs for protons and neutrons.

Conclusions: Undulatory features in potentials found in precision fits to elastic scattering data are significant, are a consequence of coupling to inelastic channels and must be allowed for in phenomenology; they are indirect evidence of $l$-dependence. Within the model, coupling to excited states magnifies the effect of the proton charge on the difference between proton-nucleus and neutron-nucleus interactions. Coupled channel plus inversion is a procedure of wide applicability, complementary to evaluation of the Feshbach formalism.

Background: Of the two sources of nonlocality in nucleon-nucleus and nucleus-nucleus interactions, knock-on exchange and dynamically generated, almost all papers referring to nonlocality mention only the first.

Purpose: Our purpose is threefold: to demonstrate a method for including dynamical nonlocality, for which a simple prescription (like the Perey factor for exchange nonlocality) is unknown, within distorted wave Born approximation (DWBA) calculations; to identify signatures of dynamic nonlocality and illuminate the extent to which the presence of such nonlocality can influence the extraction of spectroscopic information from direct reactions, and more generally, to increase our understanding of nucleus-nucleus interactions.

Methods: After reviewing existing indications of dynamically induced nonlocality, DWBA transfer calculations are presented which compare results involving dynamically nonlocal potentials with those involving their local equivalents. The dynamical nonlocal potentials are generated in situ by the presence of channel coupling and the local equivalents are generated by inversion of the corresponding coupled channel elastic $S$ matrix. This method obviates the need for solving integro-differential equations for including nonlocal potentials in DWBA.

Results: The coupling of nucleons to collective states of the target nucleus induces dynamical nonlocality in the nucleon-nucleus interaction that has a significant effect on $\left(p,d\right)$ reactions at energies relevant to spectroscopic studies.

Conclusions: A method for studying the contribution of dynamically induced nonlocality in nuclear interactions has been demonstrated. Dynamically induced nonlocality should not be overlooked in the analysis of direct reactions. The method can also be applied to dynamic nonlocality due to projectile excitation.

We investigate the sensitivity of the medium effect in the high-density region on nucleus-nucleus elastic scattering in the framework of the double-folding (DF) model with the complex $G$-matrix interaction. The medium effect including the three-body-force (TBF) effect is investigated with two methods. In both methods, the medium effect is clearly seen on the potential and the elastic cross section. Finally, we make clear the crucial role of the TBF effect up to $k_F=1.6$ ${\mathrm{fm}}^{-1}$ in nucleus-nucleus elastic scattering.

The role of antikaons in the symmetry energy to be determined in heavy-ion collisions as, for instance, in such observables as the ${\pi }^{-}/{\pi }^{+}$ ratio is discussed using a simple chiral Lagrangian. It is shown, with some mild assumptions, that kaons, when present in the system, can affect the equation of state appreciably for both symmetric and asymmetric nuclear matter. For nuclear matter with small asymmetry, with which heavy-ion collisions are studied, it may be difficult to distinguish a stiff symmetry energy and the supersoft symmetry energy, even with kaons present. However, the effect of kaon is found to be significant such that ${\mu }_n-{\mu }_p\ne 0$ near $x=1/2$, at which the chemical potential difference is 0 without kaon amplitude. We present arguments that, in order to make a more reliable calculation relevant for heavy-ion collisions, a much deeper understanding of how the strangeness degrees of freedom such as kaons, hyperons, etc., figure in dense baryonic matter than is presently available in the literature is needed.

The angular dependence of surface diffuseness is further discussed. The results of self-consistent calculations are compared with those obtained with the phenomenological mean-field potential. The rather simple parametrizations are suggested. The effects of surface polarization and hexadecapole deformation on the height of the Coulomb barrier are revealed.

We argue that the transverse shape of the fireball created in the heavy-ion collision could be strongly influenced by event-by-event fluctuations of the eccentricity vectors for the forward-going and backward-going wounded nucleons: ${\vec{\epsilon }}_n^{\mathrm{F}}\equiv {\epsilon }_n^{\mathrm{F}}{e}^{in{\Phi }_n^{*\mathrm{F}}}$ and ${\vec{\epsilon }}_n^{\mathrm{B}}\equiv {\epsilon }_n^{\mathrm{B}}{e}^{in{\Phi }_n^{*\mathrm{B}}}$. Due to the asymmetric energy deposition of each wounded nucleon along its direction of motion, the eccentricity vector of the produced fireball is expected to interpolate between ${\vec{\epsilon }}_n^{\mathrm{F}}$ and ${\vec{\epsilon }}_n^{\mathrm{B}}$ along the pseudorapidity, and hence exhibits sizable forward-backward (FB) asymmetry (${\epsilon }_n^{\mathrm{B}}\ne {\epsilon }_n^{\mathrm{F}}$) and/or FB twist (${\Phi }_n^{*\mathrm{F}}\ne {\Phi }_n^{*\mathrm{B}}$). A transport model calculation shows that these initial-state longitudinal fluctuations for $n=2$ and 3 survive the collective expansion, and result in similar FB asymmetry and/or a twist in the final-state event-plane angles. These novel event-by-event longitudinal flow fluctuations should be accessible at RHIC and the LHC using the event-shape selection technique proposed in earlier papers. If these effects are observed experimentally, it could improve our understanding of the initial-state fluctuations, particle production, and collective expansion dynamics of the heavy-ion collision.

We study the role of different entrance channels and model ingredients on the composite particle yield ratios and entropy production. We find that the composite particle yield ratios show some sensitivity towards equation of state. The Gaussian width of the nucleons affects the production of light charged particles significantly.

$L=0$ proton-neutron $\left(pn\right)$ pair-addition and pair-removal strengths in ${}^{40}\mathrm{Ca}$ and ${}^{56}\mathrm{Ni}$ are investigated by means of the $pn$ particle-particle random-phase approximation employing a Skyrme energy-density functional. It is found that the collectivity of the lowest $J^{\pi }=1^{+}$ state in the adjacent odd-odd nuclei becomes stronger as the strength of the isoscalar $\left(T=0\right)$ pairing interaction increases. The results suggest the emergence of the $T=0$ $pn$-pairing vibrational mode as a possible critical phenomenon toward the $T=0$ pairing condensation.

Background: Ground-state spins and magnetic moments are sensitive to the nuclear wave function, thus they are powerful probes to study the nuclear structure of isotopes far from stability.

Purpose: Extend our knowledge about the evolution of the $1/2^{+}$ and $3/2^{+}$ states for K isotopes beyond the $N=28$ shell gap.

Method: High-resolution collinear laser spectroscopy on bunched atomic beams.

Results: From measured hyperfine structure spectra of K isotopes, nuclear spins, and magnetic moments of the ground states were obtained for isotopes from $N=19$ up to $N=32$. In order to draw conclusions about the composition of the wave functions and the occupation of the levels, the experimental data were compared to shell-model calculations using SDPF-NR and SDPF-U effective interactions. In addition, a detailed discussion about the evolution of the gap between proton $1d_{3/2}$ and $2s_{1/2}$ in the shell model and ab initio framework is also presented.

Conclusions: The dominant component of the wave function for the odd-$A$ isotopes up to ${}^{45}\mathrm{K}$ is a $\pi 1d_{3/2}^{-1}$ hole. For ${}^{47,49}\mathrm{K}$, the main component originates from a $\pi 2s_{1/2}^{-1}$ hole configuration and it inverts back to the $\pi 1d_{3/2}^{-1}$ in ${}^{51}\mathrm{K}$. For all even-$A$ isotopes, the dominant configuration arises from a $\pi 1d_{3/2}^{-1}$ hole coupled to a neutron in the $\nu 1f_{7/2}$ or $\nu 2p_{3/2}$ orbitals. Only for ${}^{48}\mathrm{K}$, a significant amount of mixing with $\pi 2s_{1/2}^{-1}\otimes \nu \left(pf\right)$ is observed leading to a $I^{\pi }=1^{-}$ ground state. For ${}^{50}\mathrm{K}$, the ground-state spin-parity is $0^{-}$ with leading configuration $\pi 1d_{3/2}^{-1}\otimes \nu 2p_{3/2}^{-1}$.

It is a well-observed result that different nuclear input models sensitively affect Hauser-Feshbach (HF) cross-section calculations. Less well-known, however, are the effects on calculations originating from nonmodel aspects, such as experimental data truncation and transmission function energy binning, as well as code-dependent aspects, such as the definition of level-density matching energy and the inclusion of shell correction terms in the level-density parameter. To investigate these aspects, Maxwellian-averaged neutron capture cross sections (MACS) at 30 keV have been calculated using the well-established statistical Hauser-Feshbach model codes talys and non-smoker for approximately 340 nuclei. For the same nuclei, MACS predictions have also been obtained using two new HF codes, cigar and sapphire. Details of these two codes, which have been developed to contain an overlapping set of identically implemented nuclear physics input models, are presented. It is generally accepted that HF calculations are valid to within a factor of 3. It was found that this factor is dependent on both model and nonmodel details, such as the coarseness of the transmission function energy binning and data truncation, as well as variances in details regarding the implementation of level-density parameter, backshift, matching energy, and giant dipole strength function parameters.

We calculate the rates of (i) the continuum- and bound-state ${\beta }^{-}$ decays of the bare ${}^{108}\mathrm{Ag}^{47+}$ ions and (ii) the continuum-state ${\beta }^{-}$ decays, the $K$-shell electron capture (EC) decays, and bound-state ${\beta }^{-}$ decays of the hydrogen-like (H-like) ${}^{108}\mathrm{Ag}^{46+}$ ions. The obtained results are compared with the experimental data on the neutral ${}_{47}{}^{108}\mathrm{Ag}^{0+}$ atoms.

Using the high-energy color fluctuation formalism to include inelastic diffractive processes and taking into account the collision geometry and short-range nucleon-nucleon correlations in nuclei, we assess various manifestations of “flickering” of the parton wave function of a rapid proton in $pA$ interactions focusing at energies available at the CERN Large Hadron Collider (LHC) in soft QCD processes and in the special soft QCD processes accompanying hard processes. We evaluate the number of wounded nucleons, $N_{\text{coll}}$—the number of inelastic collisions of projectiles—in these processes and find a nontrivial relation between the hard collision rate and centrality. We study the distribution over $N_{\text{coll}}$ for a hard trigger selecting configurations in the nucleon with the strength larger or smaller than the average one and argue that the pattern observed in the LHC $pA$ measurements by CMS and ATLAS for jets carrying a large fraction of the proton momentum, $x_p$, is consistent with the expectation that these configurations interact with the strength which is significantly smaller than the average one, a factor of two smaller for $x_p\sim 0.5$. We also study the leading twist shadowing and the European Muon Collaboration effects for superdense nuclear matter configurations probed in the events with a larger-than-average number of wounded nucleons. We also argue that taking into account energy-momentum conservation does not change the distribution over $N_{\text{coll}}$ but suppresses hadron production at central rapidities.

Plasmons of quark-gluon plasma, or gluon collective modes, are systematically studied. The plasma is, in general, nonequilibrium but homogeneous. We consider anisotropic momentum distributions of plasma constituents which are obtained from the isotropic one by stretching or squeezing in one direction. This leads to prolate or oblate distributions, respectively. We study all possible degrees of one-dimensional deformation from the extremely prolate case, when the momentum distribution is infinitely elongated in one direction to the extremely oblate distribution, which is infinitely squeezed in the same direction. In between these extremes we discuss arbitrarily prolate, weakly prolate, isotropic, weakly oblate, and arbitrarily oblate distributions. For each case, the number of modes is determined using a Nyquist analysis and the complete spectrum of plasmons is found analytically if possible and numerically when not. Unstable modes are shown to exist in all cases except that of isotropic plasma. We derive conditions on the wave vectors for the existence of these instabilities. We also discuss stable modes which are not limited to small domains of wave vectors and therefore have an important influence on the system's dynamics.

A chirally-motivated coupled-channel $\overline{K}N$ potential, reproducing all low-energy experimental data on $K^{-}p$ scattering and kaonic hydrogen and suitable for using in accurate few-body calculations, was constructed. The potential was used for calculations of low-energy amplitudes of elastic $K^{-}d$ scattering using Faddeev-type Alt-Grassberger-Sandhas (AGS) equations with coupled $\overline{K}NN$ and $\pi \Sigma N$ channels. A complex $K^{-}-d$ potential reproducing the three-body $K^{-}d$ amplitudes was constructed and used for calculation of the $1s$ level shift and the width of kaonic deuterium. The predicted shift $\Delta E_{1s}^{K^{-}d}\sim -830$ eV and width ${\Gamma }_{1s}^{K^{-}d}\approx 1055$ eV are close to our previous results obtained with phenomenological $\overline{K}N$ potentials. No quasi-bound states in the $K^{-}d$ system were found.

New calculations of the quasibound state in the $K{}^{-}pp$ system using Faddeev-type equations in Alt-Grassberger-Sandhas (AGS) form with coupled $\overline{K}NN$ and $\pi \Sigma N$ channels were performed. A chirally motivated $\overline{K}N$ potential together with phenomenological models of $\overline{K}N$ interaction with one- and two-pole structure of the $\Lambda \left(1405\right)$ resonance were used. All three potentials reproduce experimental data on low-energy $K{}^{-}p$ scattering and kaonic hydrogen with the same level of accuracy. A new method of calculating the subthreshold resonance position and width in a three-body system was proposed and used together with the direct search of the resonance pole. We obtained binding energy of the $K{}^{-}pp$ quasibound state $\approx 32$ MeV with the chirally motivated and $47–54$ MeV with the phenomenological $\overline{K}N$ potentials. The width is about 50 MeV for the two-pole models of the interaction, while the one-pole potential gives $\approx 65$ MeV width. The question of using an energy-dependent potential in few-body calculations is discussed in detail. It is shown that “self-consistent” variational calculations using such a potential are unable to produce a reasonable approximation to the exact result.

We present a fully perturbative calculation of the quartet-channel proton-deuteron scattering length up to next-to-next-to-leading order in pionless effective field theory. We use a framework that consistently extracts the Coulomb-modified effective-range function for a screened Coulomb potential in momentum space and allows for a clear linear extrapolation back to the physical limit without screening. Our result of ${{}^{4}a}_{p\text{−}d}=(10.9\pm 0.4)$ fm agrees with older experimental determinations of this quantity but deviates from potential-model calculations and a more recent result from Black et al., which find larger values around 14 fm. As a possible resolution to this discrepancy, we discuss the scheme dependence of Coulomb subtractions in a three-body system.