A joint fit to neutrino-nucleon scattering and pion electroproduction data is performed to evaluate the nucleon axial form factor in the two-component model consisting of a three-quark intrinsic structure surrounded by a meson cloud. Further constraints on the model are obtained by re-evaluating the electromagnetic form factor using electron scattering data. The results of the axial form factor show sizable differences with respect to the widely used dipole model. The impact of such changes on the charged-current quasielastic neutrino-nucleus cross-section is evaluated in the SuSAv2 nuclear model, based on the relativistic mean field and including the contribution of two-body currents. How the different parametrizations of the axial form factor affect the cross-section prediction is assessed in full detail and comparisons to recent T2K and MINERvA data are presented.

The observation of multiparticle azimuthal correlations in high-energy small-system collisions has led to intense debate on its origin and the possible coexistence from two competing theoretical scenarios: one based on initial-state intrinsic momentum anisotropy, and the other based on final-state interaction model (FSM) collective response to the collision geometry. To complement the previous scan of asymmetric collision systems ($p+\mathrm{Au},d+\mathrm{Au}$, and $\mathrm{He}+\mathrm{Au}$), we propose a scan of small symmetric collision systems at the Brookhaven National Laboratory Relativistic Heavy Ion Collider, such as $\mathrm{C}+\mathrm{C}, \mathrm{O}+\mathrm{O}, \mathrm{Al}+\mathrm{Al}$, and $\mathrm{Ar}+\mathrm{Ar}\sqrt{s_{\mathrm{NN}}}=0.2\mathrm{TeV}$, to provide further insights in disentangling contributions from these two scenarios. These symmetric small systems have the advantage of providing a better controlled initial geometry dominated by the average shape of the overlap region as opposed to fluctuation-driven geometries in asymmetric systems. A transport model is employed to investigate the expected geometry response in the FSM scenario. Different trends of elliptic flow with increasing charge particle multiplicity are observed between symmetric and asymmetric systems, whereas triangular flow appears to show a similar behavior. Furthermore, a comparison of $\mathrm{O}+\mathrm{O}$ collisions at $\sqrt{s_{\mathrm{NN}}}=0.2\mathrm{TeV}$ and at $\sqrt{s_{\mathrm{NN}}}=2.76-7\mathrm{TeV}$ as proposed at the CERN Large Hadron Collider, provides a unique opportunity to disentangle the collision geometry effects at the nucleon level from those arising from subnucleon fluctuations.

We have identified an isomeric state in ${}^{201}\mathrm{Fr}$ for which we propose a spin and parity of $13/2^{+}$, and interpret it as arising from the $\pi \left(i_{13/2}\right)$ configuration. A half-life of 720(40) ns was measured, corresponding to $B\left(M2\right)=0.17\left(2\right)$ W.u., in good agreement with those of other $13/2^{+}\to 9/2^{-} [\pi \left(i_{13/2}\right)\to \pi \left(h_{9/2}\right)]$ transitions observed in other nuclei in the region. The nuclei of interest were produced in a fusion-evaporation reaction and their decay properties were investigated using the GREAT spectrometer at the focal plane of the RITU gas-filled recoil separator.

Fusion-evaporation reactions of carbon and oxygen isotopes at near-Coulomb-barrier energies are important subjects in nuclear-reaction studies. They are closely related to nucleosynthesis in astrophysics and may provide novel opportunities to study the $\alpha$-clustering effect in light nuclei. In this work, the ${}^{16-18}\mathrm{O}+{}^{16}\mathrm{O}$ and ${}^{16,18}\mathrm{O}+{}^{12,13}\mathrm{C}$ fusion-evaporation reactions are studied by using the statistical model based on the Hauser-Feshbach formalism. It is found that the statistical model with the original Gilbert-Cameron level-density formula typically underestimates the $\alpha$-emission cross sections. To overcome this problem, we introduce for the residual nuclei a new level-density formula with the correction term inspired by theoretical considerations on the $\alpha$-clustering effect. Compared with the original Gilbert-Cameron level-density formula, our statistical-model calculations with the new level-density formula show significant improvements.

The $\alpha$- and cluster-decay half-lives for the two superheavy nuclei (SHN) with $Z=121$ and 122 have been calculated within the density-dependent cluster model. The $\alpha$-nucleus potential was constructed by employing the double-folding model with a realistic $NN$ interaction whose exchange part has a finite range. We considered five isotopes for each one of the two SHN, $Z=121$ and 122, and compared the calculated $\alpha$-decay half-lives with those obtained from three semiempirical formulas, namely, the Viola-Seaborg-Sobiczewski formula, the modified Brown formula, and the semiempirical formula based on fission theory. The calculated $\alpha$-decay half-lives are in good agreement with their counterparts. We studied the competition between $\alpha$-decay and spontaneous fission and predicted possible decay modes for the SHN ${}^{300–304}121$ and ${}^{302–306}122$. The cluster decays for ${}^{300}121$ and ${}^{302}122$ have been studied within the double folding model, the unified formula, the scaling law of Horoi, and the universal decay law (UDL). We found that the UDL model predicts the possibility of heavy cluster emission from ${}^{300}121$ and ${}^{302}122$. We found that the proton and neutron numbers in the emitted clusters and their residual daughter nuclei are magic or near to the magic numbers. We hope that the theoretical prediction of $\alpha$-decay chains and cluster radioactivity could be helpful for future investigation in this field.

Different modes of fusion phenomena observed in the isolated experiments are not yet fully understood. To comprehend these fusion mechanisms, more experimental studies are necessary. In view of this, a new measurement of residual cross sections from the ${}^7\mathrm{Li}$-induced reaction on ${}^{89}\mathrm{Y}$ has been reported in this article within the 2.7–5.7 MeV/nucleon energy range. The $\gamma$-ray spectrometry has been used to identify the residues ${}^{93m}\mathrm{Mo}, {}^{92m}\mathrm{Nb}, {}^{89}\mathrm{Zr}, {}^{91m}\mathrm{Y}$, and ${}^{90m}\mathrm{Y}$ produced in the reaction. A systematic analysis of the complete and incomplete fusion dynamics has been carried out by comparing the measured excitation functions with the equilibrium and pre-equilibrium reaction models in the framework of empire3.2.2 and alice19. A strong indication of the occurrence of incomplete fusion has been realized within the energy range considered; hence the incomplete fusion strength is discussed in detail. The product yield of ${}^{93m}\mathrm{Mo}$, which is a candidate radionuclide for radiopharmaceuticals, has been estimated.

We study the production of charmed hadrons $D^0$ and ${\mathrm{\Lambda }}_c^{+}$ in relativistic heavy ion collisions using the charm quark coalescence. Besides taking into consideration changing hadron sizes in a hot dense medium, which results in an enhanced coalescence probability for charm quarks of very low transverse momenta, we also include the collective flow effect on heavier resonances, which leads to a shift of massive charmed resonances to larger transverse momenta. Including the conversion of charm quarks not undergoing coalescence to hadrons by independent fragmentation, we obtain a good description of the measured yield ratio ${\mathrm{\Lambda }}_c^{+}/D^0$ as a function of transverse momentum in $\mathrm{Au}+\mathrm{Au}$ collisions at ${\sqrt{s_{\mathrm{NN}}}}^{}=200$ GeV by the STAR Collaboration at the Relativistic Heavy Ion Collider.

Background: The LHCb Collaboration has studied a number of kinematic correlations between $B$-hadron pairs through their subsequent decays to $J/\psi$ pairs in $p+p$ collisions at 7 and 8 TeV for four minimum values of the $J/\psi p_T$.

Purpose: In this work, these measurements are compared to calculations of $b\overline{b}$ pairs and their hadronization and inclusive decays to $J/\psi J/\psi$ are compared to the same observables. Potential cold matter effects on the $b\overline{b}$ pair observables are discussed to determine which are most likely to provide insights about the system and why.

Methods: The calculations, employing the exclusive HVQMNR code, assume the same intrinsic $k_T$-broadening and fragmentation as in [R. Vogt, Phys. Rev. C 98, 034907 (2018)]. The pair distributions presented by LHCb are calculated in this approach, both for the parent $b\overline{b}$ and the $J/\psi J/\psi$ pairs produced in their decays. The sensitivity of the results to the intrinsic $k_T$ broadening is shown. The theoretical uncertainties due to the $b$ quark mass and scale variations on both the initial $b\overline{b}$ pairs and the resulting $J/\psi$ pairs are also shown, as is the dependence of the results on the rapidity range of the measurement. Possible effects due to the presence of the nucleus are studied by increasing the size of the $k_T$ broadening and modifying the fragmentation function.

Results: Good agreement with the LHCb data is found for all observables. The parent $b\overline{b}$ distributions are more sensitive to the $k_T$ broadening than are the final-state $J/\psi$ pairs.

Conclusions: Next-to-leading order calculations with $k_T$ broadening, as in [R. Vogt, Phys. Rev. C 98, 034907 (2018)], can describe all correlated observables. Multiple measurements of correlated observables are sensitive to different nuclear effects which can help distinguish between them.

Extensively applied to both light and heavy meson decay and standing as one of the most successful strong decay models is the ${}^{3}P_0$ model, in which $q\overline{q}$ pair production is the dominant mechanism. In this paper we evaluate strong decay amplitudes and partial widths of strange $S$ and $D$ state mesons, namely $\varphi \left(1020\right), \varphi \left(1680\right), \varphi \left(2050\right), {\varphi }_1\left(1850\right), {\varphi }_2\left(1850\right)$, and ${\varphi }_3\left(1850\right)$, in the bound-state corrected ${}^{3}P_0$ decay model ($\mathrm{C}{}^{3}P_0$). The $\mathrm{C}{}^{3}P_0$ model is obtained in the context of the Fock-Tani formalism, which is a mapping technique.

The $\beta$ decay of ${}^{26}\mathrm{P}$ was used to populate the astrophysically important $E_x=5929.4\left(8\right)$ keV, $J^{\pi }=3{}^{+}$ state of ${}^{26}\mathrm{Si}$. Both $\beta$-delayed protons at 418(8) keV and $\gamma$ rays at 1742(2) keV emitted from this state were measured simultaneously for the first time, and the corresponding absolute intensities have been estimated as 11.1(12)% and 0.59(44)%, respectively. The half-life of ${}^{26}\mathrm{P}$ has been determined to be 43.6(3) ms, which is in good agreement with previous experimental results. Besides, shell-model calculations with weakly bound effects were performed to investigate the decay properties of other resonant states and a spin-parity of $4^{+}$ rather than $0^{+}$ is favored for the $E_x=5945.9\left(40\right)$ keV state. Combining the experimental results and theoretical calculations, the ${}^{25}\mathrm{Al}(p,\gamma ){}^{26}\mathrm{Si}$ reaction rate in explosive hydrogen burning environments was calculated. The new determined total reaction rate is consistent with previous studies at $T>0.2$ GK.

We investigate the impact of charged-current–neutrino processes on the formation and evolution of neutrino spectra during the deleptonization of proto-neutron stars. To this end we develop the full kinematics of these reaction rates consistent with the nuclear equation of state, including weak magnetism contributions. This allows us to systematically study the impact of inelastic contributions and weak magnetism on the ${\nu }_e$ and ${\overline{\nu }}_e$ luminosities and average energies. Furthermore, we explore the role of the inverse neutron decay, also known as the direct Urca process, on the emitted spectra of ${\overline{\nu }}_e$. This process is commonly considered in the cooling scenario of cold neutron stars but has so far been neglected in the evolution of hot proto-neutron stars. We find that the inverse neutron decay becomes the dominating opacity source for low-energy ${\overline{\nu }}_e$. Accurate three-flavor Boltzmann neutrino transport enables us to relate the magnitude of neutrino fluxes and spectra to details of the treatment of weak processes. This allows us to quantify the corresponding impact on the conditions relevant for the nucleosynthesis in the neutrino-driven wind, which is ejected from the proto-neutron star surface during the deleptonization phase.

We have calculated electron-capture rates for neutron-rich $N=50$ nuclei (${}^{78}\mathrm{Ni}, {}^{82}\mathrm{Ge}, {}^{86}\mathrm{Kr}, {}^{88}\mathrm{Sr}$) within the thermal quasiparticle random-phase approximation approach at temperatures $T=0$, corresponding to capture on the ground state, and at $T=10\mathrm{GK}$ (0.86 MeV), which is a typical temperature at which the $N=50$ nuclei are abundant during a supernova collapse. In agreement with recent experiments, we find no Gamow-Teller (${\mathrm{GT}}_{+}$) strength at low excitation energies, $E<7\mathrm{MeV}$, caused by Pauli blocking induced by the $N=50$ shell gap. At the astrophysically relevant temperatures, this Pauli blocking of the ${\mathrm{GT}}_{+}$ strength is overcome by thermal excitations across the $Z=40$ proton and $N=50$ neutron shell gaps, leading to a sizable GT contribution to the electron capture. At the high densities, at which the $N=50$ nuclei are important for stellar electron capture, forbidden transitions contribute noticeably to the capture rate. Our results indicate that the neutron-rich $N=50$ nuclei do not serve as an obstacle of electron capture during supernova collapse.

Background: The scarce data systematics and complexity of deuteron interactions demand an updated experimental database and theoretical frame of deuteron activation cross sections. Various reactions induced by neutrons and protons following the deuteron breakup (BU) should be also taken into account. On the other hand, deuteron reaction cross sections recommended recently for high-priority elements are still based on data fit without predictive power.

Purpose: Accurate new measurements of low-energy deuteron-induced reaction cross sections for monoisotopic $\left({}^{55}\mathrm{Mn}\right)$ natural manganese target enhance the related database and provide the opportunity for a consistent account of the related reaction mechanisms.

Methods: Activation cross sections of ${}^{54,56}\mathrm{Mn}$ and ${}^{51}\mathrm{Cr}$ nuclei by deuterons on ${}^{55}\mathrm{Mn}$ were measured at energies $\le 20$ MeV by the stacked-foil technique and high-resolution $\gamma$ spectrometry at the U-120M cyclotron of NPI CAS. Then all available data for deuterons on ${}^{55}\mathrm{Mn}$ up to 50 MeV are analyzed, with particular attention to BU and direct reaction (DR) mechanisms.

Results: Newly measured activation cross sections strengthen the deuteron database at low energies with a detailed theoretical treatment of each reaction mechanism and consistent account for all available data.

Conclusions: The overall agreement between the measured data and model calculations of deuteron-induced reactions on ${}^{55}\mathrm{Mn}$, including particularly the experimental data at low energies, supports the fact that major discrepancies shown by the current evaluations are due to missing the proper account of direct interactions.

Inspired by the reconstituted similarity renormalization group method, the reconstituted Foldy-Wouthuysen (FW) transformation is proposed. Applied to the Dirac equation in the covariant density functional theory, the reconstituted FW transformation shows a fast convergence of the spectrum of the single-particle energy. The single-particle densities and the single-particle scalar densities obtained by this new method are also investigated. In particular, the relativistic corrections to the densities from the picture-change error between the Schrödinger and Dirac pictures are discussed in detail. Taking these relativistic corrections into account, both the single-particle densities and the single-particle scalar densities are almost identical to their exact values.

Experiments at the Relativistic Heavy Ion Collider have measured the net polarization of $\mathrm{\Lambda }$ and $\overline{\mathrm{\Lambda }}$ hyperons and attributed it to a coupling between their spin and the vorticity of the fluid created in heavy-ion collisions. Equipartition of energy is generally assumed, but the dynamical mechanism which polarizes them has yet to be determined. We consider two such mechanisms: vorticity fluctuations and helicity flip in scatterings between strange quarks and light quarks and gluons. With reasonable parameters both mechanisms lead to equilibration times orders of magnitude too large to be relevant to heavy-ion collisions. Our conclusion is that strange quark spin or helicity is unchanged from the time they are created to the time they hadronize. A corollary is that vorticity fluctuations do not affect the hyperon spin, either.

We use a simple coalescence model to generate $f_0$(980) particles for three configurations: a $s\overline{s}$ meson, a $u\overline{u}s\overline{s}$ tetraquark, and a $K^{+}{K}^{-}$ molecule. The phase-space information of the coalescing constituents is taken from a multiphase transport (AMPT) simulation of heavy-ion collisions. It is shown that the number of constituent quarks scaling of the elliptic flow anisotropy can be used to discern $s\overline{s}$ from $u\overline{u}s\overline{s}$ and $K^{+}{K}^{-}$ configurations.

The quark mean-field (QMF) model is applied to study the single-${\mathrm{\Lambda }}_c^{+}$ hypernuclei. The charm baryon ${\mathrm{\Lambda }}_c^{+}$ is constructed by three constituent quarks, $u,d$, and $c$, confined by central harmonic oscillator potentials. The confinement potential strength of charm quark is determined by fitting the experimental masses of charm baryons, ${\mathrm{\Lambda }}_c^{+},{\mathrm{\Sigma }}_c^{+}$, and ${\mathrm{\Xi }}_{cc}^{++}$. The effects of pions and gluons are also considered to describe the baryons at the quark level. The baryons in ${\mathrm{\Lambda }}_c^{+}$ hypernuclei interact with each other through exchanging the $\sigma ,\omega$, and $\rho$ mesons between the quarks confined in different baryons. The ${\mathrm{\Lambda }}_c^{+}N$ potential in the QMF model is strongly dependent on the coupling constant between $\omega$ meson and ${\mathrm{\Lambda }}_c^{+}$, $g_{\omega {\mathrm{\Lambda }}_c^{+}}$. When the conventional quark counting rule is used, i.e., $g_{\omega {\mathrm{\Lambda }}_c^{+}}=2/3g_{\omega N}$, the massive ${\mathrm{\Lambda }}_c^{+}$ hypernucleus can exist, whose single-${\mathrm{\Lambda }}_c^{+}$ binding energy is smaller with the mass number increasing because of the strong Coulomb repulsion between ${\mathrm{\Lambda }}_c^{+}$ and protons. When $g_{\omega {\mathrm{\Lambda }}_c^{+}}$ is fixed by the latest lattice ${\mathrm{\Lambda }}_c^{+}N$ potential, the ${\mathrm{\Lambda }}_c^{+}$ hypernuclei only can exist up to $A\approx 50$.

This paper reports cross-section measurements of the ($n,n^{\prime }$) and ($p,p^{\prime }$) reactions on ${}^{16}\mathrm{O}$ and ${}^{28}\mathrm{Si}$ at Geel Electron Linear Accelerator and at the 9-MV Tandem Accelerator of Horia Hulubei National Institute for Physics and Nuclear Engineering, respectively. The main purpose was to measure the neutron- and proton-induced inelastic $\gamma$-production cross sections for all observed transitions in ${}^{16}\mathrm{O}$ and ${}^{28}\mathrm{Si}$, followed by the calculation of the corresponding total inelastic cross section. The results are compared with theoretical calculations performed using the talys 1.9 code, evaluated nuclear data, and previously reported experimental data. The broader goal of this work is to study whether and to what extent the neutron-induced inelastic cross sections of these nuclei can be inferred from those obtained using suitable charged particle reactions. We show that, by making use of the formal similarities between the neutron- and the proton-target optical model potentials and isospin symmetry in mirror nuclei, one can develop a procedure that combines experimental proton-induced inelastic cross sections with theoretical calculations to infer neutron inelastic cross sections. For ${}^{16}\mathrm{O}$ and ${}^{28}\mathrm{Si}$, the precision associated with this procedure is around 10–20% for most of the incident energy range.

This paper describes the measurements of flow harmonics $v_2$–$v_6$ in $3\mu {\mathrm{b}}^{-1}$ of $\mathrm{Xe}+\mathrm{Xe}$ collisions at $\sqrt{s_{NN}}=5.44$ TeV performed using the ATLAS detector at the Large Hadron Collider (LHC). Measurements of the centrality, multiplicity, and $p_{\mathrm{T}}$ dependence of the $v_n$ obtained using two-particle correlations and the scalar product technique are presented. The measurements are also performed using a template-fit procedure, which was developed to remove nonflow correlations in small collision systems. This nonflow removal is shown to have a significant influence on the measured $v_n$ at high $p_{\mathrm{T}}$, especially in peripheral events. Comparisons of the measured $v_n$ with measurements in $\mathrm{Pb}+\mathrm{Pb}$ collisions and $p+\mathrm{Pb}$ collisions at $\sqrt{s_{NN}}=5.02$ TeV are also presented. The $v_n$ values in $\mathrm{Xe}+\mathrm{Xe}$ collisions are observed to be larger than those in $\mathrm{Pb}+\mathrm{Pb}$ collisions for $n=2$, 3, and 4 in the most central events. However, with decreasing centrality or increasing harmonic order $n$, the $v_n$ values in $\mathrm{Xe}+\mathrm{Xe}$ collisions become smaller than those in $\mathrm{Pb}+\mathrm{Pb}$ collisions. The $v_n$ in $\mathrm{Xe}+\mathrm{Xe}$ and $\mathrm{Pb}+\mathrm{Pb}$ collisions are also compared as a function of the mean number of participating nucleons, $\langle N_{\mathrm{part}}\rangle$, and the measured charged-particle multiplicity in the detector. The $v_3$ values in $\mathrm{Xe}+\mathrm{Xe}$ and $\mathrm{Pb}+\mathrm{Pb}$ collisions are observed to be similar at the same $\langle N_{\mathrm{part}}\rangle$ or multiplicity, but the other harmonics are significantly different. The ratios of the measured $v_n$ in $\mathrm{Xe}+\mathrm{Xe}$ and $\mathrm{Pb}+\mathrm{Pb}$ collisions, as a function of centrality, are also compared to theoretical calculations.

We report mass measurements of neutron-rich Ga isotopes ${}^{80-85}\mathrm{Ga}$ with TRIUMF's Ion Trap for Atomic and Nuclear science. The measurements determine the masses of ${}^{80-83}\mathrm{Ga}$ in good agreement with previous measurements. The masses of ${}^{84}\mathrm{Ga}$ and ${}^{85}\mathrm{Ga}$ were measured for the first time. Uncertainties between 25 and 48 keV were reached. The new mass values reduce the nuclear uncertainties associated with the production of $A\approx 84$ isotopes by the $r$-process for astrophysical conditions that might be consistent with a binary neutron star (BNS) merger producing a blue kilonova. Our nucleosynthesis simulations confirm that BNS merger may contribute to the first abundance peak under moderate neutron-rich conditions with electron fractions $Y_e=0.35-0.38$.