In light ion beam therapy, positron (${\beta }^{+}$) emitters are produced by the tissue nuclei through nuclear interactions with the beam ions. They can be used for the verification of the delivered dose using positron emission tomography by comparing the spatial distribution of the ${\beta }^{+}$ emitters activity to a computer simulation taking into account the patient morphology and the treatment plan. However, the accuracy of the simulation greatly depends on the method used to generate the nuclear interactions producing these emitters. In the case of Monte Carlo (MC) simulations, the nuclear interaction models still lack the required accuracy due to insufficient experimental cross section data. This is particularly true for carbon therapy where literature data on fragmentation cross sections of a carbon beam with targets of medical interest are very scarce. Therefore, we performed at GANIL in July 2016 measurements on ${\beta }^{+}$ emitter production cross sections with a carbon beam at 25, 50, and 95 MeV/nucleon on thin targets (C, N, O, and PMMA). We extracted the production cross section of ${}^{10,11}\mathrm{C}, {}^{13}\mathrm{N}$, and ${}^{14,15}\mathrm{O}$ that are essential to constrain or develop MC nuclear fragmentation models.

The DUET Collaboration reports on the measurements of the absorption (${\sigma }_{\mathrm{ABS}}$) and charge exchange (${\sigma }_{\mathrm{CX}}$) cross sections of positively charged pions on carbon nuclei for the momentum range 201.6 to 295.1 $\mathrm{MeV}/c$. The uncertainties on the absorption and charge exchange cross sections are $\sim 9.5\%$ and $\sim 18\%$, respectively. The results are in good agreement with previous experiments. A covariance matrix correlating the five ${\sigma }_{\mathrm{ABS}}$ and five ${\sigma }_{\mathrm{CX}}$ measured data points is also reported.

In this paper we show that $ip-jn$ relations for nuclear masses and charge radii of four neighboring nuclei reconcile with Casten's $N_p{N}_n$ scheme.

A newly observed isomeric intruder ${\mathrm{½}}^{+}$ state $[T_{½}=3.5\left(6\right)\mathrm{ms}]$ is identified in ${}^{203}\mathrm{At}$ using a gas-filled recoil separator and fusion-evaporation reactions. The isomer is depopulated through a cascade of $E3$ and mixed $M1/E2$ transitions to the ${9/2}^{-}$ ground state, and it is suggested to originate from the $\pi {\left(s_{½}\right)}^{-1}$ configuration. In addition, the structures above the ${\mathrm{½}}^{+}$ state in ${}^{203}\mathrm{At}$ and ${}^{197}\mathrm{At}$ are studied using in-beam $\gamma$-ray spectroscopy, recoil-decay tagging, and recoil-isomer decay tagging methods. The ${\mathrm{½}}^{+}$ state is fed from ${3/2}^{+}$ and ${5/2}^{+}$ states, and the origin of these states are discussed.

We present a detailed discussion of the structure of the low-lying positive-parity energy spectrum of ${}^{12}\mathrm{C}$ from a no-core shell-model perspective. The approach utilizes a fraction of the usual shell-model space and extends its multishell reach via the symmetry-based no-core symplectic shell model (NCSpM) with a simple, physically informed effective interaction. We focus on the ground-state rotational band, the Hoyle state, and its $2^{+}$ and $4^{+}$ excitations, as well as the giant monopole $0^{+}$ resonance, which is a vibrational breathing mode of the ground state. This, in turn, allows us to address the open question about the structure of the Hoyle state and its rotational band. In particular, we find that the Hoyle state is best described through deformed prolate collective modes rather than vibrational modes, while we show that the higher lying giant monopole $0^{+}$ resonance resembles the oblate deformation of the ${}^{12}\mathrm{C}$ ground state. In addition, we identify the giant monopole $0^{+}$ and quadrupole $2^{+}$ resonances of selected light- and intermediate-mass nuclei, along with other observables of ${}^{12}\mathrm{C}$, including matter rms radii, electric quadrupole moments, and $E2$ and $E0$ transition rates.

The residual nuclei produced in the spallation reaction of ${}^{136}\mathrm{Xe}$ nuclei at $200A$ MeV on protons have been studied by measuring the isotopic distributions for the elements from cadmium ($Z=48$) to cesium ($Z=55$) by using the fragment separator (FRS) spectrometer at GSI and the inverse kinematics technique. This is one of the few measurements performed at such a low projectile energy, close to the validity limit for intranuclear cascade models such as incl or isabel. The experimental results have been compared to these intranuclear cascade codes coupled to the evaporation code abla. Both code combinations reproduce qualitatively the measured isotopic distributions; however, both underestimate the production of residues with mass numbers between 126 and 134. The measured cross sections are of interest for the planning of future radioactive beam or neutron source facilities.

The recent net-proton fluctuation results of the STAR (Solenoidal Tracker At RHIC) experiment from the beam energy scan (BES) program at the BNL Relativistic Heavy Ion Collider (RHIC) have drawn much attention to exploring the QCD critical point and the nature of deconfinement phase transition. There has been much speculation that the nonmonotonic behavior of $\kappa {\sigma }^2$ of the produced protons around $\sqrt{s_{NN}}$ = 19.6 GeV in the STAR results may be due to the existence of a QCD critical point. However, the experimentally measured proton distributions contain protons from heavy resonance decays, from baryon stopping, and from direct production processes. These proton distributions are used to estimate the net-proton number fluctuation. Because it is difficult to disentangle the protons from the above-mentioned sources, it is better to devise a method which will account for the directly produced baryons (protons) to study the dynamical fluctuation at different center-of-mass energies. This is because it is assumed that any associated criticality in the system could affect the particle production mechanism and hence the dynamical fluctuation in various conserved numbers. In the present work, we demonstrate a method to estimate the number of stopped protons at RHIC BES energies for central 0–5% $\mathrm{Au}+\mathrm{Au}$ collisions within STAR acceptance and discuss its implications on the net-proton fluctuation results.

The hadron-resonance gas (HRG) model with the mass-proportional eigenvolume (EV) corrections is employed to fit the hadron yield data of the NA49 Collaboration for central Pb+Pb collisions at $\sqrt{s_{NN}}=6.3$, 7.6, 8.8, 12.3, and 17.3 GeV, the hadron midrapidity yield data of the STAR Collaboration for Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV, and the hadron midrapidity yield data of the ALICE Collaboration for Pb+Pb collisions at $\sqrt{s_{NN}}=2760$ GeV. At given bombarding energy, for a given set of radii, the EV HRG model fits do not just yield a single $T-{\mu }_B$ pair, but a whole range of $T-{\mu }_B$ pairs, each with similarly good fit quality. These pairs form a valley in the $T-{\mu }_B$ plane along a line of nearly constant entropy per baryon, $S/A$, which increases nearly linearly with bombarding energy $E_{\mathrm{lab}}$. The entropy per baryon values extracted from the data at the different energies are a robust observable: it is almost independent of the details of the modeling of the eigenvolume interactions and of the specific $T-{\mu }_B$ values obtained. These results show that the extraction of the chemical freeze-out temperature and chemical potential is extremely sensitive to the modeling of the short-range repulsion between the hadrons. This implies that the ideal point-particle HRG values are not unique. The wide range of the extracted $T$ and ${\mu }_B$ values suggested by the eigenvolume HRG fits, as well as the approximately constant $S/A$ at freeze-out, are consistent with a nonequilibrium scenario of continuous freeze-out, where hadrons can be chemically frozen out throughout the extended space-time regions during the evolution of the system. Even when the EV HRG fits are restricted to modest temperatures suggested by lattice QCD, the strong systematic effects of EV interactions are observed.

The stiff equation of state (EoS) giving the neutron-star mass of $2M_{\odot }$ suggests the existence of strongly repulsive many-body effects (MBE) not only in nucleon channels but also in hyperonic ones. As a specific model for MBE, the repulsive multi-Pomeron exchange potential (MPP) is added to the two-body interaction together with the phenomenological three-body attraction. For various versions of the Nijmegen interaction models, the MBE parts are determined so as to reproduce the observed data of $B_{\mathrm{\Lambda }}$. The mass dependence of $B_{\mathrm{\Lambda }}$ values is shown to be reproduced well by adding MBE to the strong MPP repulsion, assuring the stiff EoS of hyperon-mixed neutron-star matter, in which $P$-state components of the adopted interaction model lead to almost vanishing contributions. The nuclear matter $\mathrm{\Lambda }NG$-matrix interactions are derived and used in $\mathrm{\Lambda }$ hypernuclei on the basis of the averaged-density approximation (ADA). The $B_{\mathrm{\Lambda }}$ values of hypernuclei with $9\le A\le 59$ are analyzed in the framework of antisymmetrized molecular dynamics with use of the two types of $\mathrm{\Lambda }NG$-matrix interactions including strong and weak MPP repulsions. The calculated values of $B_{\mathrm{\Lambda }}$ reproduce the experimental data well within a few hundred keV. The values of $B_{\mathrm{\Lambda }}$ in $p$ states also can be reproduced well, when the ADA is modified to be suitable also for weakly bound $\mathrm{\Lambda }$ states.

We investigate the problem of periodically modulated strongly interacting neutron matter. We carry out ab initio nonperturbative auxiliary-field diffusion Monte Carlo calculations using an external sinusoidal potential in addition to phenomenological two- and three-nucleon interactions. Several choices for the wave function ansatz are explored and special care is taken to extrapolate finite-sized results to the thermodynamic limit. We perform calculations at various densities as well as at different strengths and periodicities of the one-body potential. Our microscopic results are then used to constrain the isovector term from energy-density functional theories of nuclei at many different densities, while making sure to separate isovector contributions from bulk properties. Lastly, we use our results to extract the static density-density linear response function of neutron matter at different densities. Our findings provide insights into inhomogeneous neutron matter and are related to the physics of neutron-star crusts and neutron-rich nuclei.

We revisit antiproton-proton annihilation into light mesons in the energy domain relevant to the antiproton annihilation at Darmstadt (PANDA) experiment at the GSI Facility for Antiproton and Ion Research (FAIR) [$2.25\left(1.5\right)\le \sqrt{s}\left(p_L\right)\le 5.47\left(15\right) \mathrm{GeV} (\mathrm{GeV}/c)$ where $\sqrt{s}\left(p_L\right)$ is the total energy (the beam momentum in the laboratory frame)]. An effective meson model is developed, with mesonic and baryonic degrees of freedom. Form factors are added to take into account the composite nature of the interacting hadrons. A comparison is made with the existing data for charged pion pair production and predictions for angular distributions and energy dependence in the range $3.362\left(5\right)\le \sqrt{s}\left(p_L\right)\le 4.559\left(10.1\right) \mathrm{GeV} (\mathrm{GeV}/c)$. The model is applied to ${\pi }^{\pm }p$ elastic scattering, using crossing symmetry, and to charged kaon pair production, on the basis of SU(3) symmetry. In all cases the results illustrate a nice agreement with the data.

${}^{180m}\mathrm{Ta}$ is the rarest naturally occurring quasistable isotope and the longest lived metastable state which is known. Its possible decay via the ${\beta }^{-}$ or the electron capture channel has never been observed. This article presents a search for the decay of ${}^{180m}\mathrm{Ta}$ with an ultralow background Sandwich HPGe $\gamma$ spectrometry setup in the HADES underground laboratory. No signal is observed and improved lower partial half-life limits are set with a Bayesian analysis to $5.8\times {10}^{16}\mathrm{yr}$ for the ${\beta }^{-}$ channel and $2.0\times {10}^{17}\mathrm{yr}$ for the electron capture channel (90 % credibility). The total half-life of ${}^{180m}\mathrm{Ta}$ is longer than $4.5\times {10}^{16}\mathrm{yr}$. This is more than a factor of two improvement compared to previous searches.

The giant dipole resonance (GDR) in ${}^6\mathrm{Li}$ was investigated via the ${}^6\mathrm{Li}(\gamma ,xn)$ reactions by using quasi-mono-energy $\gamma$ rays in an energy range from 4.9 to 53.6 MeV. The $\gamma$ rays were generated via Compton backscattering of Nd laser photons with relativistic energy electrons in an electron storage ring, NewSUBARU. The energy resolution in a full width at half maximum of $\gamma$ ray was simulated to be $5\%$ at 50 MeV. Photoneutrons were detected with a $4\pi$-type neutron detector consisting of 41 ${}^3\mathrm{He}$-gas proportional counters. The $(\gamma ,n)$ cross sections were dominant, while the $(\gamma ,2n)$ and $(\gamma ,3n)$ cross sections were negligibly small. The energy integral of photoneutron cross sections up to 53.6 MeV was 59 $\mathrm{MeV}\mathrm{mb}$, which exhausted $65\%$ of the Thomas-Reiche-Kuhn sum rule. The GDR in ${}^6\mathrm{Li}$ was found to consist of mainly two components. The peak energy and the width for the low-energy component were $E_r=12\pm 1\mathrm{MeV}$ and $\mathrm{\Gamma }=21\pm 2\mathrm{MeV}$. Those for the high-energy component were $E_r=33\pm 2\mathrm{MeV}$ and $\mathrm{\Gamma }=30\pm 2$ MeV. The low-energy component corresponded to the GDR in ${}^6\mathrm{Li}$. The high-energy component was inferred to be the GDR owing to an $\alpha$-cluster excitation in ${}^6\mathrm{Li}$. The existence of this component was recently proposed and was suggested by the experimental studies of the $(p,p^{\prime })$, $({}^3\mathrm{He},t)$, and $({}^7\mathrm{Li},{}^7\mathrm{Be})$ reactions. The observed resonance shape of the high-energy component was well reproduced by modifying the GDR shape of a theoretical prediction for ${}^4\mathrm{He}$ at $E_r=26\mathrm{MeV}$ with $\mathrm{\Gamma }=20\mathrm{MeV}$; with increasing the excitation energy by 7 MeV ($Q$ value was more negative), widening the width by $1.5\pm 0.1$ times, and decreasing a peak height by $0.29\pm 0.02$ times. As a result, the magnitude of the energy integral of the cross sections for the high-energy component observed in the present work was $0.86\pm 0.06$ times that in the theoretical prediction of the ${}^4\mathrm{He}(\gamma ,n)$ reaction. It is a well-known fact that a frequency of a vibrating system is inversely proportional to the size of the system. We suggest that in excitation of the $\alpha$ cluster in ${}^6\mathrm{Li}$, the mass of the $\alpha$ cluster increases by $7\pm 2\mathrm{MeV}$, the size of the $\alpha$ cluster in ${}^6\mathrm{Li}$ is smaller than that of the free ${}^4\mathrm{He}$ by $\sim 20\%$, and the width of the GDR is broader than that of ${}^4\mathrm{He}$ by 1.5 times owing to the nuclear medium effect.

Background: Large $\alpha$ yields have been reported over the years in reactions with ${}^6\mathrm{Li}$ and ${}^7\mathrm{Li}$ projectiles. Previous theoretical analyses have shown that the elastic breakup (EBU) mechanism (i.e., projectile breakup leaving the target in its ground state) is able to account only for a small fraction of the total $\alpha$-inclusive breakup cross sections, pointing toward the dominance of nonelastic breakup (NEB) mechanisms.

Purpose: We aim to provide a systematic study of the $\alpha$-inclusive cross sections observed in nuclear reactions induced by ${}^6\mathrm{Li}$ projectiles. In addition to estimating the total $\alpha$ singles' cross sections, it is our goal to evaluate angular and energy distributions of these $\alpha$ particles and compare them with experimental data, when available.

Method: We compute separately the EBU and NEB components of the inclusive breakup cross sections. For the former, we use the continuum-discretized coupled-channels (CDCC) method, which treats this mechanism to all orders. For the NEB part, we employ the model proposed by Ichimura et al. [Phys. Rev. C 32, 431 (1985)], within the distorted-wave Born approximation (DWBA).

Results: Overall, the sum of the computed EBU and NEB cross sections is found to reproduce very well the measured singles' cross sections. In all cases analyzed, we find that the inclusive breakup cross section is largely dominated by the NEB component.

Conclusions: The presented method provides a global and systematic description of inclusive breakup reactions induced by ${}^6\mathrm{Li}$ projectiles. It provides also a natural explanation of the previously observed underestimation of the measured $\alpha$ yields by CDCC calculations. The method used here can be extended to other weakly bound projectiles, including halo nuclei.

Using the event-by-event viscous hydrodynamics VISH2+1 with MC-Glauber, MC-KLN, and AMPT initial conditions, we investigate the correlations of flow harmonics including the symmetric cumulants $S{C}^v(m,n)$ and the normalized symmetric cumulants $NSC(m,n)$ in $2.76A$ TeV Pb-Pb collisions. We find $S{C}^v(m,n)$ is sensitive to both initial conditions and the specific shear viscosity $\eta /s$. Comparisons with the recent ALICE data show that our hydrodynamic calculations can qualitatively describe the data of $S{C}^v(3,2)$ and $S{C}^v(4,2)$ for various initial conditions, which demonstrate that $v_2$ and $v_3$ are anticorrelated and $v_2$ and $v_4$ are correlated. Meanwhile, the predicted symmetric cumulants $S{C}^v(5,2)$, $S{C}^v(5,3)$, and $S{C}^v(4,3)$ reveal that $v_2$ and $v_5$ are correlated and $v_3$ and $v_5$ are correlated, while $v_3$ and $v_4$ are anticorrelated in most centrality classes. We also find that $NS{C}^v(3,2)$ is insensitive to $\eta /s$, and is mainly determined by corresponding $NS{C}^{\varepsilon }(3,2)$ from the initial state. In contrast, other $NS{C}^v(m,n)$ are influenced by both initial conditions and $\eta /s$, which illustrates the nonlinear mode couplings in higher flow harmonics with $n\ge 4$.

We study neutron-proton equilibration in dynamically deformed nuclear systems by investigating the correlations between the two largest fragments produced in collisions of ${}^{70}\mathrm{Zn}+{}^{70}\mathrm{Zn}$, ${}^{64}\mathrm{Zn}+{}^{64}\mathrm{Zn}$, ${}^{64}\mathrm{Ni}+{}^{64}\mathrm{Ni}$ and ${}^{64}\mathrm{Zn}+{}^{64}\mathrm{Ni}$ at $35\mathrm{MeV}$ per nucleon. The extent of equilibration is investigated using the rotation angle as a clock for the equilibration. The initially dissimilar fragments converge exponentially with consistent rate constants across a wide variety of reaction partners and systems, indicating that the equilibration follows first-order kinetics.

We present two new methods for performing ab initio calculations of excited states for closed-shell systems within the in-medium similarity renormalization group (IMSRG) framework. Both are based on combining the IMSRG with simple many-body methods commonly used to target excited states, such as the Tamm-Dancoff approximation (TDA) and equations-of-motion (EOM) techniques. In the first approach, a two-step sequential IMSRG transformation is used to drive the Hamiltonian to a form where a simple TDA calculation (i.e., diagonalization in the space of $1\mathrm{p}1\mathrm{h}$ excitations) becomes exact for a subset of eigenvalues. In the second approach, EOM techniques are applied to the IMSRG ground-state-decoupled Hamiltonian to access excited states. We perform proof-of-principle calculations for parabolic quantum dots in two dimensions and the closed-shell nuclei ${}^{16}\mathrm{O}$ and ${}^{22}\mathrm{O}$. We find that the TDA-IMSRG approach gives better accuracy than the EOM-IMSRG when calculations converge, but it is otherwise lacking the versatility and numerical stability of the latter. Our calculated spectra are in reasonable agreement with analogous EOM-coupled-cluster calculations. This work paves the way for more interesting applications of the EOM-IMSRG approach to calculations of consistently evolved observables such as electromagnetic strength functions and nuclear matrix elements, and extensions to nuclei within one or two nucleons of a closed shell by generalizing the EOM ladder operator to include particle-number nonconserving terms.