The thermal evolution of neutron stars is affected by the elementary excitations that characterize the stellar matter. In particular, the low-energy excitations, with a spectrum linear in momentum, can play a major role in the emission and propagation of neutrinos. In this paper, we focus on the elementary modes in the region of proton superfluidity, where the neutron component is expected to have a very small or zero pairing gap. We study the overall spectral functions of protons, neutrons, and electrons on the basis of the Coulomb and nuclear interactions. This study is performed in the framework of the random phase approximation, generalized in order to describe the response of a superfluid system. The formalism we use ensures that the generalized Ward's identities are satisfied. Despite their relative small fraction, the protons turn out to modify the neutron spectral function as a consequence of the nuclear neutron-proton interaction. This effect is particularly evident at the lower density, just below the crust for a density close to the saturation value, while at increasing density the neutrons and the protons are mainly decoupled. The proton spectral function is characterized by a pseudo-Goldstone mode below $2\mathrm{\Delta }$, twice the pairing gap, and a pair-breaking mode above $2\mathrm{\Delta }$. The latter merges in the sound mode of the normal phase at higher momenta. The neutron spectral function develops a collective sound mode only at the higher density. The electrons have a strong screening effect on the proton-proton interaction at the lower momenta and decouple from the protons at higher momenta.

The present Rapid Communication reports conclusive evidence for an antimagnetic rotational band in the odd-odd ${}^{142}\mathrm{Eu}$ nucleus. The parity of the states of a quadrupole sequence in this nucleus is identified firmly from polarization measurements using the Indian National Gamma Array, and lifetimes of some of the states in the same structure are measured using the Doppler-shift attenuation method. The decreasing trends of the deduced quadrupole transition strength $B\left(E2\right)$ with spin in the sequence along with the increasing $J^{\left(2\right)}/B\left(E2\right)$ values conclusively establish the origin of these states as arising from antimagnetic rotation. The results are well reproduced by numerical calculations within the framework of a semiclassical geometric model.

Background: The study of deep-inelastic reactions of nuclei provides a vehicle to explore nuclear transport phenomena for a full range of equilibration dynamics. These investigations provide us the ingredients to model such phenomena and help answer important questions about the nuclear equation of state and its evolution as a function of neutron-to-proton ($N/Z$) ratio.

Purpose: The motivation is to examine the real-time dynamics of nuclear transport phenomena and its dependence on $N/Z$ asymmetry from a microscopic point of view to avoid any pre-conceived assumptions about the involved processes.

Method: The time-dependent Hartree-Fock (TDHF) method in full three dimensions is employed to calculate deep-inelastic reactions of ${}^{78}\mathrm{Kr}+{}^{208}\mathrm{Pb}$ and ${}^{92}\mathrm{Kr}+{}^{208}\mathrm{Pb}$ systems at 8.5 MeV/nucleon. The impact parameter and energy-loss dependence of relevant observables are calculated. In addition, the density-constrained TDHF method is used to compute excitation energies of the primary fragments. The statistical deexcitation code gemini is utilized to examine the final reaction products.

Results: The kinetic energy loss and sticking times as a function of impact parameter are calculated. The final properties of the fragments (charge, mass, scattering angle, and kinetic energy) are computed. Their evolution as a function of energy loss is studied and various intra-relations are investigated. The fragment excitation energy sharing is computed.

Conclusions: We find a smooth dependence of the energy loss, $E_{\mathrm{loss}}$, on the impact parameter for both systems. However, the transfer properties for low $E_{\mathrm{loss}}$ values are very different for the two systems but become similar in the higher $E_{\mathrm{loss}}$ regime. The mean lifetime of the charge equilibration process, obtained from the final $(N-Z)/A$ value of the fragments, is shown to be $\sim 0.5$ zs. This value is slightly larger than (but of the same order as) the value obtained from reactions at Fermi energies.

The role of different parts of the nucleon-nucleon (NN) interaction potential on the production of light- and intermediate-mass fragments in different mass asymmetric reactions ${}^{120}\mathrm{Sn}+{}^{120}\mathrm{Sn}$ ($\eta =0$), ${}^{82}\mathrm{Kr}+{}^{158}\mathrm{Gd}$ ($\eta =0.3$), ${}^{56}\mathrm{Fe}+{}^{184}\mathrm{W}$ ($\eta =0.5$), and ${}^{35}\mathrm{Cl}+{}^{205}\mathrm{Tl}$ ($\eta =0.7$) (with $A_{\text{total}}=240$ units) within different rapidity domains has been investigated using the isospin-dependent quantum molecular-dynamics model. The results indicate that the multiplicity of different fragments changes with the gradual addition of different parts of the NN interaction potential. The comparison between calculations and experimental data for the ${}^{120}\mathrm{Sn}+{}^{120}\mathrm{Sn}$ reaction reveals that both momentum dependent interactions (MDIs) and symmetry potential are indispensable to explain the charge distribution. The MDI plays a dominant role while the symmetry potential has minor influence on the fragment production, but both together lead to an increase in the multiplicity of light- and intermediate-mass fragments and hence show their significance in the fragment production at intermediate energies.

${}^4\mathrm{He}$ ions are considered to be used for hadron radiotherapy due to their favorable physical and radiobiological properties. For an accurate dose calculation the fragmentation of the primary ${}^4\mathrm{He}$ ions occurring as a result of nuclear collisions must be taken into account. Therefore precise nuclear reaction models need to be implemented in the radiation transport codes used for dose calculation. A fragmentation experiment using thin graphite targets was conducted at the Heidelberg Ion Beam Therapy Center (HIT) to obtain new and precise ${}^4\mathrm{He}$-nucleus cross section data in the clinically relevant energy range. Measured values for the charge-changing cross section, mass-changing cross section, as well as the inclusive ${}^3\mathrm{He}$ production cross section for ${}^4\mathrm{He}+{}^{12}\mathrm{C}$ collisions at energies between 80 and $220\mathrm{MeV}/\mathrm{u}$ are presented. These data are compared to the ${}^4\mathrm{He}$-nucleus reaction model by DeVries and Peng as well as to the parametrizations by Tripathi et al. and by Cucinotta et al., which are implemented in the treatment planning code trip98 and several other radiation transport codes.

Correlation femtoscopy allows one to measure the space-time characteristics of particle production in relativistic heavy-ion collisions due to the effects of quantum statistics (QS) and final state interactions (FSIs). The main features of the femtoscopy measurements at top RHIC and LHC energies are considered as a manifestation of strong collective flow and are well interpreted within hydrodynamic models employing equation of state (EoS) with a crossover type transition between quark-gluon plasma (QGP) and hadron gas phases. The femtoscopy at lower energies was intensively studied at AGS and SPS accelerators and is being studied now in the Beam Energy Scan program (BES) at the BNL Relativistic Heavy Ion Collider in the context of exploration of the QCD phase diagram. In this article we present femtoscopic observables calculated for Au-Au collisions at $\sqrt{s_{NN}}=7.7–62.4$ GeV in a viscous hydro + cascade model vHLLE+UrQMD and their dependence on the EoS of thermalized matter.

A new algorithm for the asymptotic nuclear coefficients calculation, which we call the $\mathrm{\Delta }$ method, is proved and developed. This method was proposed by Ramírez Suárez and Sparenberg (arXiv:1602.04082.) but no proof was given. We apply it to the bound state situated near the channel threshold when the Sommerfeld parameter is quite large within the experimental energy region. As a result, the value of the conventional effective-range function $K_l\left(k^2\right)$ is actually defined by the Coulomb term. One of the resulting effects is a wrong description of the energy behavior of the elastic scattering phase shift ${\delta }_l$ reproduced from the fitted total effective-range function $K_l\left(k^2\right)$. This leads to an improper value of the asymptotic normalization coefficient (ANC) value. No such problem arises if we fit only the nuclear term. The difference between the total effective-range function and the Coulomb part at real energies is the same as the nuclear term. Then we can proceed using just this $\mathrm{\Delta }$ method to calculate the pole position values and the ANC. We apply it to the vertices ${}^4\mathrm{He}+{}^{12}\mathrm{C}\leftrightarrow {}^{16}\mathrm{O}$ and ${}^3\mathrm{He}+{}^4\mathrm{He}\leftrightarrow {}^7\mathrm{Be}$. The calculated ANCs can be used to find the radiative capture reaction cross sections of the transfers to the ${}^{16}\mathrm{O}$ bound final states as well as to the ${}^7\mathrm{Be}$.

We present calculations for the $c$ coefficients of the isobaric mass multiplet equation for nuclei from $A=42$ to $A=54$ based on input from three realistic nucleon-nucleon interactions. We demonstrate that there is a clear dependence on the short-range charge-symmetry-breaking (CSB) part of the strong interaction and that there is significant disagreement in the CSB part between the commonly used CD-Bonn, chiral effective field theory at next-to-next-to-next-to-leading-order, and Argonne V18 nucleon-nucleon interactions. In addition, we show that all three interactions give a CSB contribution to the $c$ coefficient that is too large when compared to experiment.

Lifetimes of excited states of ${}^{157}\mathrm{Dy}$ were measured by recoil distance Doppler-shift (RDDS) and Doppler-shift attenuation (DSAM) methods. The $\gamma$-ray coincidence data were analyzed by the differential decay curve method. The level scheme and the newly deduced transition strengths were simultaneously described in the framework of the particle plus triaxial rotor model (PTRM) and the rigid-rotor model.

At the National Ignition Facility, experiments are being performed to measure charged-particle stopping powers in the previously unexplored warm dense plasma regime. These measurements are done using reaction-in-flight (RIF) neutrons from an inertial confinement fusion system. RIF neutrons are produced with a continuum of energies up to 30 MeV. By making activation measurements utilizing threshold reactions for neutrons in the energy range of $15<E_n<30\mathrm{MeV}$, the number of RIF neutrons can be determined and from this the stopping power of the deuterium and tritium ions that produced the RIF neutrons can be inferred. Currently, the ${}^{169}\mathrm{Tm}(n,3n){}^{167}\mathrm{Tm}$ reaction has been used. However, in an effort to provide a secondary complimentary measurement, efforts are underway to make use of the ${}^{209}\mathrm{Bi}(n,4n){}^{206}\mathrm{Bi}$ reaction, with a threshold of 22.5 MeV. The cross sections were measured at the 10 MV tandem Van De Graaff accelerator at the Triangle Universities Nuclear Laboratory with quasimonoenergetic neutrons between 23.5 and 30.5 MeV, where few previous measurements have been made. Cross-section data are compared to calculations and other available measurements.

In this paper we discuss the $R$-matrix approach to treat the subthreshold resonances for the single-level and one-channel and for the single-level and two-channel cases. In particular, the expression relating the asymptotic normalization coefficient (ANC) with the observable reduced width, when the subthreshold bound state is the only channel or coupled with an open channel, which is a resonance, is formulated. Since the ANC plays a very important role in nuclear astrophysics, these relations significantly enhance the power of the derived equations. We present the relationship between the resonance width and the ANC for the general case and consider two limiting cases: wide and narrow resonances. Different equations for the astrophysical $S$ factors in the $R$-matrix approach are presented. After that we discuss the Trojan horse method (THM) formalism. The developed equations are obtained using the surface-integral formalism and the generalized $R$-matrix approach for the three-body resonant reactions. It is shown how the Trojan horse (TH) double-differential cross section can be expressed in terms of the on-the-energy-shell astrophysical $S$ factor for the binary subreaction. Finally, we demonstrate how the THM can be used to calculate the astrophysical $S$ factor for the neutron generator ${}^{13}\mathrm{C}(\alpha ,n){}^{16}\mathrm{O}$ in low-mass AGB stars. At astrophysically relevant energies this astrophysical $S$ factor is controlled by the threshold level $1/2^{+},E_x=6356$ keV. Here, we reanalyzed recent TH data taking into account more accurately the three-body effects and using both assumptions that the threshold level is a subthreshold bound state or it is a resonance state.

We compare the methods of amplitude reconstruction, for a complete experiment and a truncated partial-wave analysis, applied to the electroproduction of pseudoscalar mesons off nucleon targets. We give examples which show, in detail, how the amplitude reconstruction (observables measured at a single energy and angle) is related to a truncated partial-wave analysis (observables measured at a single energy and a number of angles). A connection is made to existing data.

Background: The Anderson-Bogoliubov (AB) phonon, called also the superfluid phonon, has attracted attentions since it may influence the thermal conductivity and other properties of the inner crust of neutron stars. However, there are a limited number of microscopic studies of the AB phonon where the presence of clusters is explicitly taken into account.

Purpose: We intend to clarify how the presence of clusters affects the AB phonon in order to obtain microscopic information relevant to the coupling between the AB phonon and the lattice phonon.

Methods: The Hartree-Fock-Bogoliubov model and the quasiparticle random-phase approximation formulated in a spherical Wigner-Seitz cell are adopted to describe neutron superfluidity and associated collective excitations. We perform systematic numerical calculations for dipole excitation by varying the neutron chemical potential and the number of protons in a cell.

Results: The model predicts systematic emergence of the dipole AB phonon mode, which, however, exhibits strong suppression of phonon amplitude inside the cluster. We find also that the phonon amplitude around the cluster surface varies with the neutron density. At higher neutron densities ($\gtrsim 0.006$ ${\mathrm{fm}}^{-3}$) the AB phonon mode exhibits behavior similar to the pygmy dipole resonance in neutron-rich nuclei.

Conclusions: The dipole AB phonon mode does not penetrate into the clusters. This suggests that the coupling between the AB phonon and the lattice phonon may be weak.

Two-proton decay of the ${}^{17}\mathrm{Ne}$ low-lying states populated in the ${}^1\mathrm{H}({}^{18}\mathrm{Ne},d){}^{17}\mathrm{Ne}$ transfer reaction is studied. The two-proton width ${\mathrm{\Gamma }}_{2p}$ of the ${}^{17}\mathrm{Ne}$ first excited $3/2^{-}$ state at $E^{*}=1.288$ MeV is of importance for the two-proton radioactivity theory and nuclear-astrophysics applications. A dedicated search for the two-proton emission of this state was performed leading to the new upper limit obtained for the width ratio ${\mathrm{\Gamma }}_{2p}/{\mathrm{\Gamma }}_{\gamma }<1.6\left(3\right)\times {10}^{-4}$. An original, “combined mass” method is suggested and tested as capable of improving the resolution of the experiment, which is a prime significance for the study of nuclear states with extremely small particle-to-gamma width ratios ${\mathrm{\Gamma }}_{\mathrm{part}}/{\mathrm{\Gamma }}_{\gamma }$. The condition ${\mathrm{\Gamma }}_{\mathrm{part}}\ll {\mathrm{\Gamma }}_{\gamma }$ is quite common for the states of astrophysical interest, which makes the proposed approach promising in this field.

Accelerator mass spectrometry (AMS) represents a complementary approach for precise measurements of neutron capture cross sections, e.g., for nuclear astrophysics. This technique, completely independent of previous experimental methods, was applied for the measurement of the ${}^{54}\mathrm{Fe}(n,\gamma ){}^{55}\mathrm{Fe}$ reaction. Following a series of irradiations with neutrons from cold and thermal to keV energies, the produced long-lived ${}^{55}\mathrm{Fe}$ nuclei ($t_{1/2}=2.744+-0.009)$ yr) were analyzed at the Vienna Environmental Research Accelerator. A reproducibility of about 1% could be achieved for the detection of ${}^{55}\mathrm{Fe}$, yielding cross-section uncertainties of less than 3%. Thus, this method produces new and precise data that can serve as anchor points for time-of-flight experiments. We report significantly improved neutron capture cross sections at thermal energy (${\sigma }_{\mathrm{th}}=2.30\pm 0.07$ b) as well as for a quasi-Maxwellian spectrum of $kT=25$ keV ($\sigma =30.3\pm 1.2$ mb) and for $E_n=481\pm 53$ keV ($\sigma =6.01\pm 0.23$ mb). The new experimental cross sections have been used to deduce improved Maxwellian-averaged cross sections in the temperature regime of the common $s$-process scenarios. The astrophysical impact is discussed by using stellar models for low-mass asymptotic giant branch stars.

The giant dipole resonance (GDR) observables are calculated within the thermal shape fluctuation model by considering the probability distributions of different angular momentum ($I$) and temperature ($T$) values estimated recently in the deexcitation process of the compound nucleus ${}^{88}\mathrm{Mo}$. These results are found to be very similar to the results obtained with the average $T$ ($T_{\mathrm{ave}}$) and average $I$ ($I_{\mathrm{ave}}$) corresponding to those distributions. The shape transitions in ${}^{88}\mathrm{Mo}$ at different $T$ and $I$ are also studied through the free energy surfaces calculated within the microscopic-macroscopic approach. The deformation of ${}^{88}\mathrm{Mo}$ is found to increase considerably with $T$ and $I$, leading to the Jacobi shape transition at $I\sim 50\hslash$. The combined effect of increasing deformation, larger fluctuations at higher $T$, and larger Coriolis splitting of GDR components at higher $I$, leads to a rapid increase in the GDR width.

The extended Skyrme interaction involving additional momentum- and density-dependent terms is adopted to uniformly describe the properties of nuclear matter and finite nuclei, as well as the nuclear reaction properties. A new set of extended Skyrme interaction parameters is constructed by simultaneously fitting the properties of nuclear matter and the experimental data of finite nuclei and neutron-nucleus scattering observables. These data include the binding energies and charge rms radii of some spherical even-even nuclei, the total cross sections, nonelastic cross sections, elastic-scattering angular distributions, and analyzing powers. Compared with the existing Skyrme interactions, the obtained extended Skyrme interaction has a significantly improvement in the agreement with corresponding experimental data, together with some additional constraints on nuclear matter.

We discuss properties and applications of factorial cumulants of various particle numbers and for their mixed channels measured by event-by-event analysis in relativistic heavy-ion collisions. After introducing the factorial cumulants for systems with multiparticle species, their properties are described. The uses of factorial cumulants in the study of critical fluctuations are discussed. We point out that factorial cumulants play useful roles in understanding fluctuation observables when they have underlying physics approximately described by the binomial distribution. As examples, we suggest novel utilization methods of the factorial cumulants in the study of the momentum cut and rapidity window dependences of fluctuation observables.

I have used a potential model and results from an earlier shell-model calculation to compute expected widths for decays of the first three states of ${}^{17}\mathrm{Na}$. I compare them with a recent experiment that observed a large peak near the region of the predicted $3/2^{+}$ and $5/2^{+}$ states.

The transitional nuclei ${}^{132}\mathrm{Xe}$ and ${}^{133}\mathrm{Xe}$ are investigated after multinucleon-transfer (MNT) and fusion-evaporation reactions. Both nuclei are populated (i) in ${}^{136}\mathrm{Xe}+{}^{208}\mathrm{Pb}$ MNT reactions employing the high-resolution Advanced GAmma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA, (ii) in the ${}^{136}\mathrm{Xe}+{}^{198}\mathrm{Pt}$ MNT reaction employing the GAMMASPHERE spectrometer in combination with the gas-detector array CHICO, and (iii) as an evaporation residue after a ${}^{130}\mathrm{Te}(\alpha ,xn){}^{134-xn}\mathrm{Xe}$ fusion-evaporation reaction employing the HORUS $\gamma$-ray array at the University of Cologne. The high-spin level schemes are considerably extended above the $J^{\pi }=\left(7^{-}\right)$ and $\left({10}^{+}\right)$ isomers in ${}^{132}\mathrm{Xe}$ and above the $11/2^{-}$ isomer in ${}^{133}\mathrm{Xe}$. The results are compared to the high-spin systematics of the $Z=54$ as well as the $N=78$ and $N=79$ chains. Furthermore, evidence is found for a long-lived ($T_{1/2}\gg 1\mu \mathrm{s}$) isomer in ${}^{133}\mathrm{Xe}$ which closes a gap along the $N=79$ isotones. Shell-model calculations employing the SN100PN and PQM130 effective interactions reproduce the experimental findings and provide guidance to the interpretation of the observed high-spin features.