Fission energy is one of the basic parameters needed in the calculation of antineutrino flux from nuclear reactors. Improving the precision of fission energy calculations is useful for current and future reactor neutrino experiments, which are aimed at more precise determinations of neutrino oscillation parameters. In this article, we give new values for fission energies of some common thermal reactor fuel isotopes, with improvements on three aspects. One improvement is more recent input data acquired from updated nuclear databases. The second improvement is a consideration of the production yields of fission fragments from both thermal and fast incident neutrons for each of the four main fuel isotopes. The third improvement is a more careful calculation of the average energy taken away by antineutrinos in thermal fission involving a comparison of antineutrino spectra from different models. The change in calculated antineutrino flux due to the new values of fission energy is about 0.32$\%$, and the uncertainties of the new values are about 50$\%$ smaller.

In order to study the Gamow-Teller (GT) transitions from the $T_z=+2$ nucleus ${}^{44}$Ca to the $T_z=+1$ nucleus ${}^{44}$Sc, where $T_z$ is the $z$ component of isospin $T$, we performed the ($p,n$)-type (${}^3\mathrm{He},t$) charge-exchange (CE) reaction at 140 MeV/nucleon and the scattering angles $0^{\circ }$ and $2.5^{\circ }$. An energy resolution of 28 keV, that was realized by applying matching techniques to the magnetic spectrometer system, allowed the study of fragmented states. The GT transition strengths, $B$(GT), were derived up to the excitation energy ($E_x$) of 13.7 MeV assuming the proportionality between cross sections and $B$(GT) values. The total sum of $B$(GT) values in discrete states was 3.7, which was 31$\%$ of the sum-rule-limit value of 12. Shell model calculations using the GXPF1J interaction could reproduce the gross features of the experimental $B$(GT) distribution, but not the fragmentation of the strength. By introducing the concepts of isospin, properties of isospin analogous transitions and states were investigated. (i) Assuming isospin symmetry, the $T_z=+2\to +1$ and $T_z=-2\to -1$ mirror GT transitions should have the same properties, where the latter can be studied in the $\beta$ decay of ${}^{44}$Cr to ${}^{44}$V. First, we confirmed that the $\beta$-decay half-life $T_{1/2}$ of ${}^{44}$Cr can be reproduced using the $B$(GT) distribution from the ${}^{44}$Ca(${}^3\mathrm{He},t$) measurement. Then, the $0^{\circ }$, (${}^3\mathrm{He},t$) spectrum was modified to deduce the “$\beta$-decay spectrum” and it was compared with the delayed-proton spectrum from the ${}^{44}$Cr $\beta$ decay. The two spectra were mostly in agreement for the GT excitations, but suppression of the proton decay was found for the $T=2$ isobaric analog state (IAS). (ii) Starting from the $T=2$ ground state of ${}^{44}$Ca, the (${}^3\mathrm{He},t$) can excite GT states (state populated by GT transitions) with $T=1$, 2, and 3. On the other hand, the ${}^{44}$Ca($p,p^{\prime }$) reaction can excite spin-$M1$ states (states populated by spin-$M1$ transitions) with $T=2$ and 3 that are analogous to the $T=2$ and 3 GT states, respectively. By comparing the spectra from these two reactions, a $T$ value of 2 is suggested for several GT states in the $E_x=11.5$–13.7 MeV region. (iii) It has been suggested that the $T=2$, $J^{\pi }=0^{+}$ double isobaric analog state (DIAS) at 9.338 MeV in the $T_z=0$ nucleus ${}^{44}$Ti forms an isospin-mixed doublet with a subsidiary $0^{+}$ state at 9.298 MeV. Since no corresponding state was found in the $T_z=+1$ nucleus ${}^{44}$Sc, we suggest $T=0$ for the subsidiary state.

Nuclear formation cross sections are reported for 65 nuclides produced from 800-MeV proton irradiation of thorium foils. These data are useful as benchmarks for computational predictions in the ongoing process of theoretical code development and also in the design of spallation-based radioisotope production currently being considered for multiple radiotherapeutic pharmaceutical agents. Measured data are compared with the predictions of three mcnp6 event generators and used to evaluate the potential for 800-MeV productions of radioisotopes of interest for medical radiotherapy. In only a few instances code predictions are discrepant from measured values by more than a factor of 2, demonstrating satisfactory predictive power across a large mass range. Similarly, agreement between measurements presented here and those previously reported is good, lending credibility to predictions of target yields and radioimpurities for high-energy accelerator-produced radionuclides.

The three-body force (TBF) effect on the neutrino emissivity in neutron star matter and the total neutrino emissivity of neutron stars have been investigated within the framework of the Brueckner-Hartree-Fock approach by adopting the AV18 two-body interaction plus a microscopic TBF. The neutrino emissivity from the direct Urca process turns out to be much larger than that from the modified Urca process. Inclusion of the TBF reduces strongly the density thresholds of the direct Urca processes involving electrons and muons. The TBF effect on the total neutrino emissivity of neutron stars is shown to be negligibly weak for neutron stars with small masses. For neutron stars with large masses, the TBF effect becomes visible and inclusion of the TBF may enhance the total neutrino emissivity by about $50\%$ for neutron stars with a given mass of $M=1.6M_{\odot }$.

The core excitation, being an important reaction mechanism, so far is not properly included in most calculations of three-body nuclear reactions. We aim to include the excitation of the core nucleus using an exact Faddeev-type framework for nuclear reactions in the three-body (core+neutron+proton) system. We employ Alt, Grassberger, and Sandhas (AGS) integral equations for the three-particle transition operators and solve them in the momentum-space framework. The Coulomb interaction is included via the method of screening and renormalization. We calculate elastic, inelastic, and transfer reactions involving ${}^{10}\mathrm{Be}$ and ${}^{24}\mathrm{Mg}$ nuclear cores. Important effects of the core excitation are found, often improving the description of the experimental data. In the neutron transfer reactions the core excitation effect is by far not just a simple reduction of the cross section by the respective spectroscopic factor. This indicates that widely used extraction of the spectroscopic factors from the ratio of the experimental and theoretical transfer cross sections is an unreliable approach.

A detailed $\beta$-decay study of ${}^{61}$Mn is presented, yielding extended information on the level structure of ${}^{61}$Fe. Pure beams were obtained at ISOLDE, CERN, after selective laser ionization and mass separation of fission products from the bombardment of a UC${}_x$ target by 1.4-GeV protons. The $\beta$ and $\gamma$ information was detected by two MiniBall clusters and three $\Delta$$E$ plastic scintillators. The new ${}^{61}$Mn decay scheme reveals 48 $\gamma$ transitions, distributed over 20 excited states. A comparison to the decay scheme of ${}^{59}$Mn and excited states in ${}^{59}$Fe is made. Shell-model calculations with two different interactions are performed in order to compare the nuclear structure of the two neighboring odd-$A$ iron isotopes. Tentative spin and parities of several excited states in ${}^{61}$Fe are assigned on the basis of $\beta$-decay feeding patterns in both ${}^{59,61}$Fe and of results from the theoretical shell-model calculations.

It is argued that the fine tuning due to the unnaturally large, generalized effective range in the ${}^1{S}_0$ channel of $\mathit{NN}$ scattering must be incorporated in order for one to obtain satisfactory convergence for chiral effective field theory. Without the proposition of perturbative one-pion exchange, an effective field theory with the spin-0, isospin-1 dibaryon is developed to account for this fine tuning and is demonstrated up to $O\left(Q^1\right)$, where the leading irreducible two-pion exchange arises. The approach shown in the paper results in rapid convergence of the ${}^1{S}_0$ partial-wave amplitude, though at the cost of an additional parameter at each order.

The coupled dynamics of low-lying modes and various giant resonances are studied with the help of the Wigner function moments method on the basis of time-dependent Hartree-Fock equations in the harmonic oscillator model including spin-orbit potential plus quadrupole-quadrupole and spin-spin residual interactions. New low-lying spin-dependent modes are analyzed. Special attention is paid to the spin scissors mode.

The transverse spin correlations $A_{x,x}$ and $A_{y,y}$ have been measured in the $\vec{d}\vec{p}\to p_{\text{spec}}{\left\{pp\right\}}_s{\pi }^{-}$ reaction at COSY-ANKE at 353 MeV per nucleon. Here ${\left\{pp\right\}}_s$ denotes a proton-proton pair with low excitation energy, which is dominantly in the ${}^1{S}_0$ state. By measuring three protons in the final state it was possible to extract events where there was a spectator proton $p_{\text{spec}}$ so that the reaction could be interpreted in terms of quasifree $\vec{n}\vec{p}\to {\left\{pp\right\}}_s{\pi }^{-}$. The proton and neutron analyzing powers in this reaction were also deduced from this data set by averaging over the polarizations of the deuteron beam and hydrogen target, respectively. The values of $A_y$ were shown to be consistent with a refined analysis of our earlier results obtained with a polarized proton incident on a deuterium target. Taking these data in combination with our previous measurements of the differential cross sections and analyzing powers in the $\vec{p}p\to {\left\{pp\right\}}_s{\pi }^0$ reaction, a more robust partial wave decomposition was achieved. Three different acceptable solutions were found, and the only way of resolving this ambiguity without further theoretical input would be through a measurement of the mixed spin-correlation parameter $A_{x,z}$.

The shape phase transition and the associated phase coexistence in the odd Sm isotopes are investigated. Through analyzing two-neutron separation energies and the low-lying spectra of the odd Sm isotopes, it is found that the spherical to axially deformed shape phase transition does occur in the odd Sm nuclei just as their neighboring even Sm nuclei. The phase coexistence in ${}^{151}$Sm, which lies close to the critical point, is revealed.

The two-rotor model predicts two levels above the scissors modes with degenerate intrinsic energy. They have $J^{\pi }=0^{+},2^{+}$ and are referred to as overtones. Their energy is below the threshold for nucleon emission, which should make them observable. The $J^{\pi }=0^{+}$ overtone, which has the structure of an isovector breathing mode, has vanishing $E0$ amplitude so that it cannot be directly excited, but it could be reached in the decay of the $J=2^{+}$ overtone. We discuss such a process and evaluate the $B\left(E2\right)$ strength, which turns out to be very small.

We analyze the proton-lead collisions at the CERN Large Hadron Collider energy of $\sqrt{s_{NN}}=5.02$ TeV in the three-stage approach, previously used to successfully describe the relativistic $A$-$A$ collisions. The approach consists of the early phase, modeled with the Glauber model, the event-by-event viscous 3+1 dimensional (3+1 D) relativistic hydrodynamics, and the statistical hadronization at freeze-out. We show that features typical of collective dynamics, such as the harmonic flow and the ridge structures in the two-particle correlations in relative azimuth and pseudorapidity, may be naturally explained in our framework. In the proton-nucleus system the harmonic flow is generated from an initially event-by-event deformed system and is entirely due to these initial fluctuations. Notably, fluctuations of strength of the initial Glauber sources which yield the observed distribution of hadron multiplicities and, at the same time, lead to correct values of the elliptic flow coefficients both from the two- and four-particle cumulant method, as measured by the ATLAS collaboration. The azimuthally asymmetric flow is not modified significantly when changing the viscosity coefficient, the initial time for the collective expansion, or the initial size of the fireball. The results present an estimate of the collective component in the two-particle correlations measured experimentally. We demonstrate that the harmonic flow coefficients can be experimentally measured with methods based on large rapidity gaps which reduce some of the other sources of correlations.

For the 90-keV resonance in ${}^{18}$O($p$,γ), I have combined the measured value of ωγ ($p$,α) $=$ 0.16(5) μeV and the spectroscopic strength (2$J$+1) $C^{2}S$ $=$ 0.097 from ${}^{18}$O(${}^3$He,$d$) to compute the ($p$,γ) resonance-strength parameter. The result is ωγ ($p$,γ) $=$ 0.70(28) μeV, which is about 90(36) times the most recent upper limit.

Using several relativistic mean-field models (such as GM1, GM3, NL3, TM1, FSUGold, and IU-FSU) as well as the quark-meson coupling model, we calculate the particle fractions, the equation of state, the maximum mass, and radius of a neutron star within relativistic Hartree approximation. We also discuss in detail the role of nonlinear potentials involved in the mean-field models. In determining the couplings of the isoscalar, vector mesons to the octet baryons, we examine the extension of SU(6) spin-flavor symmetry to SU(3) flavor symmetry. Furthermore, we consider the strange (${\sigma }^{*}$ and $\varphi$) mesons and study how they affect the equation of state. We find that the equation of state in SU(3) symmetry can sustain a neutron star with mass of $(1.8\sim 2.1)M_{\odot }$, even if hyperons exist inside the core. It is noticeable that the strange vector ($\varphi$) meson and the variation of baryon substructure in matter also play important roles in supporting a massive neutron star.

We study the role of higher order couplings in extended relativistic mean-field models, along with the condensation of antikaons and hyperons, on neutron star properties. Though this approach seems to be better and inclusive, the results are sensitive to the hyperon-nucleon and antikaon-nucleon coupling constants, which are poorly known. Despite this aspect, we find that both the hyperons and the antikaons can play a significant role, even in extended relativistic mean-field models which yield softer equations of state. We find that there is a strong interplay between antikaons and hyperons affecting each other's influence on neutron star properties. We discuss the implications of our results in light of the recently observed pulsar with $1.97\pm 0.04$ solar masses.

We solve the Hartree-Fock-Bogoliubov (HFB) equations for a spherical mean field and a pairing potential with the inverse Hamiltonian method, which we have developed for the solution of the Dirac equation. This method is based on the variational principle for the inverse Hamiltonian and is applicable to Hamiltonians that are not bound from above or below. We demonstrate that the method works well not only for the Dirac, but also for the HFB equations.

Background: The interplay between single-particle and collective excitations in the 30 $\le Z\le$ 40 and 30 $\le N\le$ 50 even-even isotopes has been examined in light of recent new measurements of magnetic moments of 4${}_1^{+}$, 2${}_2^{+}$, and 2${}_1^{+}$ states.

Purpose: The $g$ factors of the 4${}_1^{+}$ and 2${}_2^{+}$ states in the ${}^{72,74,76}$Ge isotopes have been measured for the first time and the $g\left(2_1^{+}\right)$ values have been remeasured.

Methods: The transient field (TF) technique in inverse kinematics with a variety of targets has been applied, following Coulomb excitation of the relevant states. The data have been analyzed within the framework of the IBA-II model. Large-scale shell-model calculations have been performed within the $p_{3/2},p_{1/2},f_{5/2},g_{9/2}$ orbital space for both protons and neutrons with the JUN45 and JJ4B interactions.

Results: The measured Ge $g$ factors were compared to the $g$ factors of the low-lying states of the neighboring Zn, Ge, Se, Kr, and Sr isotopes. The results were evaluated in the context of the systematics of $g$ factors in the $A\sim 80$ region.

Conclusions: The predictions based on the classic collective model and the interacting boson model IBA-II agree with the experimental results. No evidence for shell closure was found for neutrons at $N=38$ or $N=40$.

The mass-dependent symmetry energy coefficients $a_{\text{sym}}\left(A\right)$ are extracted with the ${\beta }^{-}$-decay energies $Q_{{\beta }^{-}}$ of heavy odd-$A$ nuclei. The dominant position of this approach is that only the Coulomb energy survives in $Q_{{\beta }^{-}}$ to determine the unknown $a_{\text{sym}}\left(A\right)$. The obtained $a_{\text{sym}}\left(A\right)$ is employed to analyze the density dependence of the nuclear matter symmetry energy around the saturation density. The estimated $a_{\text{sym}}\left(A\right)$ of ${}^{208}\text{Pb}$ is 22.1–22.7 MeV. The slope parameter of the symmetry energy is found to be $50\pm 15$ MeV, with the symmetry energy $S_0=32.3\pm 1.3$ MeV at saturation density obtained from the analysis of pygmy dipole resonance (PDR) [Carbone et al., Phys. Rev. C 81, 041301(R) (2010)] as input. Furthermore, the corresponding neutron skin thickness in ${}^{208}\text{Pb}$ is estimated to be $\Delta R_{np}=0.174\pm 0.022$ fm.

Measurements of the elliptic flow, $v_2$, of identified hadrons (${\pi }^{\pm }$, $K^{\pm }$, $K_s^0$, $p$, $\overline{p}$, $\varphi$, $\Lambda$, $\overline{\Lambda }$, ${\Xi }^{-}$, ${\overline{\Xi }}^{+}$, ${\Omega }^{-}$, ${\overline{\Omega }}^{+}$) in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{\mathit{NN}}}=7.7$, 11.5, 19.6, 27, 39, and 62.4 GeV are presented. The measurements were done at midrapidity using the time-projection chamber and the time-of-flight detectors of the Solenoidal Tracker at RHIC experiment during the beam-energy scan program at Relativistic Heavy Ion Collider. A significant difference in the $v_2$ values for particles and the corresponding antiparticles was observed at all transverse momenta for the first time. The difference increases with decreasing center-of-mass energy, $\sqrt{s_{\mathit{NN}}}$ (or increasing baryon chemical potential, ${\mu }_B$), and is larger for the baryons as compared to the mesons. This implies that particles and antiparticles are no longer consistent with the universal number-of-constituent quark (NCQ) scaling of $v_2$ that was observed at $\sqrt{s_{\mathit{NN}}}=200$ GeV. However, for the selected group of particles (${\pi }^{+}$, $K^{+}$, $K_s^0$, $p$, $\Lambda$, ${\Xi }^{-}$, ${\Omega }^{-}$) NCQ scaling at $(m_T-m_0)/n_q>0.4$ GeV/$c^2$ is not violated within $\pm 10\%$. The $v_2$ values for $\varphi$ mesons at 7.7 and 11.5 GeV are approximately two standard deviations from the trend defined by the other hadrons at the highest measured $p_T$ values.