${}^{25}\mathrm{Mg}(p,\gamma ){}^{26}\mathrm{Al}$ is the most important reaction in the Mg-Al cycle in the hydrogen burning regions of stars. Its cross sections at stellar energies are essential to understand the issues of radioactive ${}^{26}\mathrm{Al}$ in the galaxy and meteorites. The 57.7 keV resonance dominate the ${}^{25}\mathrm{Mg}(p,\gamma ){}^{26}\mathrm{Al}$ astrophysical reaction rates at relative low temperature, but it is very difficult to measure its resonance strength directly, and the indirect measurement results deviate by a factor of about 2 by far. In this work, the angular distributions of ${}^{25}\mathrm{Mg}({}^7\mathrm{Li},{}^6\mathrm{He}){}^{26}\mathrm{Al}$ leading to 6.364 MeV and eleven low-lying states in ${}^{26}\mathrm{Al}$ have been measured by the Q3D magnetic spectrometer of the HI-13 tandem accelerator. The spectroscopic factors were derived and used to deduce the proton width and 57.7 keV resonance strength. The astrophysical ${}^{25}\mathrm{Mg}(p,\gamma ){}^{26}\mathrm{Al}$ reaction rates at stellar energies have been updated by using the present result.

In this paper we study mass relations of mirror nuclei, with our focus on local correlations of deviations between theoretical nuclear masses and experimental data. With inclusion of such local correlations, we are able to construct very accurate mass formulas of mirror nuclei. The root-mean-square deviation (RMSD) of our formulas is $\sim 69$ keV for nuclei with $10\le Z\le 38$ and $Z>N+1$ in the AME2016 database, and, furthermore, the RMSD value becomes only 51 keV if one excludes three experimental data for which experimental uncertainties are larger than 150 keV. More than 240 proton-rich nuclear masses with mass number $A$ below 80 are predicted within the theoretical accuracy of 300 keV and are tabulated in the Supplemental Material of this paper. As a simple application, our predicted results are adopted to predict candidates with two-proton radioactivity.

The microscopic origin of the spin-orbit (SO) potential in terms of sub-baryonic degrees of freedom is explored and discussed for application to nuclei and hypernuclei. We thus develop a chiral relativistic approach where the coupling to the scalar- and vector-meson fields are controlled by the quark substructure. This approach suggests that the isoscalar and isovector density dependence of the SO potential can be used to test the microscopic ingredients which are implemented in the relativistic framework: the quark substructure of the nucleon in its ground state and its coupling to the rich meson sector where the $\rho$ meson plays a crucial role. This is also in line with the vector dominance model phenomenology and the known magnetic properties of the nucleons. We explore predictions based on Hartree and Hartree-Fock mean field, as well as various scenarios for the $\rho$-nucleon coupling, ranked as weak, medium, and strong, which impacts the isoscalar and isovector density dependence of the SO potential. We show that a medium-to-strong $\rho$ coupling is essential to reproduce Skyrme phenomenology in $N=Z$ nuclei as well as its isovector dependence. Assuming an SU(6) valence quark model, our approach is extended to hyperons and furnishes a microscopic understanding of the quenching of the $N\mathrm{\Lambda }$ spin-orbit potential in hypernuclei. It is also applied to other hyperons, such as $\mathrm{\Sigma }$, $\mathrm{\Xi }$, and $\mathrm{\Omega }$.

We investigate the measurement of Hanbury Brown–Twiss (HBT) photon correlations as an experimental tool to discriminate different sources of photon production. To showcase that HBT correlations can distinguish between such sources, we consider two different scenarios in which we enhance the yields from standard hydrodynamical simulations. In the first, additional photons are produced from the early preequilibrium stage computed from the “bottom-up” thermalization scenario. In the second, the thermal rates are enhanced close to the pseudocritical temperature $T_c\approx 155\text{MeV}$ using a phenomenological ansatz. We compute the correlators for relative momenta $q_{\mathrm{o}}$, $q_{\mathrm{s}}$, and $q_{\mathrm{l}}$ for different transverse pair momenta, $K_{\perp }$, and find that the longitudinal correlation is the most sensitive to different photon sources. Our results also demonstrate that including anisotropic preequilibrium rates enhances non-Gaussianities in the correlators, which can be quantified using the kurtosis of the correlators. Finally, we study the feasibility of measuring a direct photon HBT signal in the upcoming high-luminosity runs at the CERN Large Hadron Collider. Considering only statistical uncertainties, we find that with the projected $\approx {10}^{10}$ heavy-ion events a measurement of the HBT correlations for $K_{\perp }<1\text{GeV}$ is statistically significant.

In this work we analyze the effect of uncertainties in parton distribution functions upon the calculation of cross sections for ultrahigh-energy neutrinos. As a detector we choose ${}^{12}\mathrm{C}$. The elementary diagrams for the neutrino-proton and neutron interactions have been calculated at quark level using nuclear parton distribution functions and their corresponding error bars, as given by the Jyvaskyla group. The leptonic sector of the current-current interactions includes active-sterile neutrino mixing. From the calculated cross section we have set limits on the values of the mixing parameters.

In-beam spectroscopic technique using the fusion evaporation reaction ${}^{52}\mathrm{Cr}({}^{18}\mathrm{O},1p3n)$, at a beam energy of 72.5 MeV, was employed to explore the structural phenomena in ${}^{66}\mathrm{Ga}$, mainly at intermediate and high spins. The experimental setup involved an array of 14 Compton suppressed Ge clover detectors, placed around the target position to detect emitted $\gamma$ rays from excited states. A new level scheme has been proposed, which is enriched with more than 20 new transitions and is extended up to an excitation energy $\approx 12$ MeV. A few observed intermediate spin states of ${}^{66}\mathrm{Ga}$ are discussed in the framework of coupling of single-particle configurations with the vibrational core of ${}^{64}\mathrm{Zn}$. Shell model calculations have also been performed with two different interactions, viz., jj44bpn and jun45pn, for the interpretation of the observed level structure in ${}^{66}\mathrm{Ga}$.

The excited level structures of ${}^{202}\mathrm{Tl}$ and ${}^{203}\mathrm{Pb}$, above the $7^{+}$ and $29/2^{-}$ isomers, respectively, have been studied. An isomer with $I^{\pi }={20}^{+}$ and $T_{1/2}=215\left(10\right)\mu \mathrm{s}$ has been established in ${}^{202}\mathrm{Tl}$, and the level scheme extended from $I=10$ to $20\hslash$ with the placement of fifteen new transitions. In ${}^{203}\mathrm{Pb}$, the $I^{\pi }=37/2^{+}$ state is established to be metastable, with $T_{1/2}=2.5\left(3\right)\mathrm{ns}$. Levels in both nuclei arise from intrinsic excitations, with likely particle-hole character for the higher-lying states in ${}^{203}\mathrm{Pb}$. The ${20}^{+}$ isomer in ${}^{202}\mathrm{Tl}$ is most likely associated with a $\pi h_{11/2}^{-1}$ $\otimes$ $\nu (i_{13/2}^{-2},f_{5/2}^{-1})$ configuration, while the $37/2^{+}$ state in ${}^{203}\mathrm{Pb}$ results from the excitation of five neutrons. Calculations, using both an empirical approach and the oxbash code, have been performed to aid in the description of the excited level structure.

Light charged particles emitted by the compound nucleus ${}^{158}\mathrm{Er}$ produced in the reaction ${}^{32}\mathrm{S}$ $(180 \mathrm{MeV})+{}^{126}\mathrm{Te}$, at the excitation energy $E_x=92$ MeV, have been measured at Laboratori Nazionali di Legnaro in coincidence with fission fragments and evaporation residues. The $4\pi$ detector array $8\pi \mathrm{LP}$ coupled to a system of parallel-plate avalanche counters to detect evaporation residues has been used. Data have been analyzed in the framework of the statistical model of evaporation with the code pace2_n11. This enlarged version of the code pace2 has been used to reproduce the large set of observables measured in the fusion-evaporation and fusion-fission channels along with experimental prescission neutron multiplicity and fission cross section taken from literature. It is found that the simultaneous reproduction of the prescission neutron, proton, and $\alpha$-particle multiplicities can be obtained with zero fission delay without dynamical effects. However, the same set of model input parameters does not allow us to reproduce proton and $\alpha$-particle multiplicities in the evaporation channel. Extensive calculations, with different sets of parameters, show the limits of the statistical model in reproducing the whole set of data. This work evidences the importance of measuring a large set of observables in order to obtain a reliable description of the decay of the compound nucleus, and in particular of the fission process.

Spectroscopy of doubly magic ${}_{50}^{132}{\mathrm{Sn}}_{82}$ has been performed with the GRIFFIN spectrometer at TRIUMF-ISAC following the $\beta$ decay of ${}_{49}^{132}{\mathrm{In}}_{83}$. The analysis has allowed for the placement of a total of 70 transitions and 29 excited states in ${}^{132}\mathrm{Sn}$. Detailed spectroscopy has also been performed on ${}^{131}\mathrm{Sb}$, resulting from the $\beta$ decay of ${}^{131}\mathrm{Sn}$, produced from the $\beta$-delayed neutron decay of ${}^{132}\mathrm{In}$. Measurement of $\gamma$ rays in both ${}^{131}\mathrm{Sn}$ and ${}^{131}\mathrm{Sb}$ has led to the determination of the $\beta$-delayed neutron emission probability $P_n$ from ${}^{132}\mathrm{In}$. This is the first time that $P_n$ has been measured for this nucleus by using $\gamma$ spectroscopy, and the new value of 12.3(4)% is consistent with the most recent $\beta -n$ counting experiment. Additionally, $\gamma -\gamma$ angular correlations have been performed in ${}^{132}\mathrm{Sn}$, supporting the spin assignments of several excited states. Novel ab initio calculations are presented which describe several of the excited states, and these are compared with the experimental spectrum.

The lack of experimental data on the ${}^{35}\mathrm{Cl}(n,p){}^{35}\mathrm{S}$ reaction above 100 keV has led to nuclear data evaluations that are relatively unconstrained at fast neutron energies. As a result, efforts to explore, develop, and potentially certify next generation reactor designs that incorporate chloride salts as a coolant material have been hindered. In this paper, we report partial cross section data for the ${}^{35}\mathrm{Cl}(n,p){}^{35}\mathrm{S}$ and ${}^{35}\mathrm{Cl}(n,\alpha ){}^{32}\mathrm{P}$ reactions at incident neutron energies between 0.6 MeV and 6 MeV. The measurement was performed using the pulsed beam of neutrons at the unmoderated WNR spallation neutron source at the Los Alamos Neutron Science Center, with the outgoing charged particles detected by the LENZ experimental setup, consisting of annular silicon detectors. Nonstatistical fluctuations in the ${}^{35}\mathrm{Cl}(n,p_0)$ cross section were observed up to around 3 MeV, and the magnitude of the cross section was systematically lower than all available data evaluations at energies above 1 MeV. Modifications to the ENDF/B-VIII.0 data evaluation are suggested to better reproduce the energy averaged experimental data.

Recently it has been pointed out that in the two-baryon $N\mathrm{\Delta }$ or $\mathrm{\Delta }\mathrm{\Delta }$ system the width of the state is greatly diminished due to the relative kinetic energy of the two baryons, because the internal energy of the particles, available for pionic decay, is smaller. For nonzero orbital angular momenta this effect becomes state dependent. Also, the real part of the $N\mathrm{\Delta }$ energy can get contributions from the centrifugal barrier, leading to a rotational series of diffuse states. Obviously, these states may have an interpretation as isospin one dibaryons. Direct and explicit calculations for this are presented with some details of the coupled-state wave functions displayed. With finite expectation values of these repulsive effects, it may be possible to define state-dependent effective thresholds for $N\mathrm{\Delta }$ states and these, in turn, can show resonantlike behavior.

We calculate field isotope shifts for nobelium atoms using nuclear charge distributions which come from different nuclear models. We demonstrate that comparing calculated isotope shifts with experiment can serve as a testing ground for nuclear theories. It also provides a way of extracting parameters of nuclear charge distribution beyond nuclear root mean square (rms) radius, e.g., parameter of quadrupole deformation $\beta$. The measurements of at least two atomic transitions is needed to disentangle the contributions of the changes in deformation and nuclear rms radius into field isotopic shift. We argue that a previous interpretation of the isotope measurements in terms of $\delta \langle r^2\rangle$ between ${}^{252,254}\mathrm{No}$ isotopes should be amended when nuclear deformation is taken into account. We calculate isotope shifts for other known isotopes and for hypothetically metastable isotope ${}^{286}\mathrm{No}$ for which the predictions of nuclear models differ substantially.

We propose an arrangement of the most commonly invoked version of the two-nucleon chiral potential such that the low-lying amplitude zero of the ${}^1\mathrm{S}_0$ partial wave is captured at leading order of the effective expansion. Adopting other partial waves from the LENPIC interaction, we show how this modification yields an improved description of ground-state energies and point-proton radii of the ${}^3\mathrm{H}$, ${}^4\mathrm{He}$, and ${}^6\mathrm{He}$ nuclei.

The properties of the $\alpha +{}^{28}\mathrm{Si}$ and ${}^{16}\mathrm{O}+{}^{16}\mathrm{O}$ molecular states, which are embedded in the excited states of ${}^{32}\mathrm{S}$ and can have an impact on the stellar reactions, are investigated using antisymmetrized molecular dynamics. From the analysis of the cluster spectroscopic factors, the candidates of $\alpha +{}^{28}\mathrm{Si}$ and ${}^{16}\mathrm{O}+{}^{16}\mathrm{O}$ molecular states are identified close to and above the cluster threshold energies. The calculated properties of $\alpha +{}^{28}\mathrm{Si}$ molecular states are consistent with those reported by $\alpha +{}^{28}\mathrm{Si}$ resonant scattering experiments. On the other hand, the ${}^{16}\mathrm{O}+{}^{16}\mathrm{O}$ molecular state, which is predicted to be identical to the superdeformation of ${}^{32}\mathrm{S}$, is inconsistent with the assignment proposed by an $\alpha$ inelastic scattering experiment. Our calculation suggests that the monopole transition from the ground state to the ${}^{16}\mathrm{O}+{}^{16}\mathrm{O}$ molecular state is rather weak and is not strongly excited by $\alpha$ inelastic scattering.

The structure of ${}^{33}\mathrm{Si}$ was studied by a one-neutron knockout reaction from a ${}^{34}\mathrm{Si}$ beam at 98.5 MeV/u incident on a ${}^9\mathrm{Be}$ target. The prompt $\gamma$ rays following the de-excitation of ${}^{33}\mathrm{Si}$ were detected using the GRETINA $\gamma$-ray tracking array while the reaction residues were identified on an event-by-event basis in the focal plane of the S800 spectrometer at the National Superconducting Cyclotron Laboratory. The presently derived spectroscopic factor values, $C^{2}S$, for the $3/2^{+}$ and $1/2^{+}$ states, corresponding to a neutron removal from the $0d_{3/2}$ and $1s_{1/2}$ orbitals, agree with shell model calculations and point to a strong $N=20$ shell closure. Three states arising from the more bound $0d_{5/2}$ orbital are proposed, one of which is unbound by about 930 keV. The sensitivity of this experiment has also confirmed a weak population of $9/2^{-}$ and $11/2_{1,2}^{-}$ final states, which originate from a higher-order process. This mechanism may also have populated, to some fraction, the $3/2^{-}$ and $7/2^{-}$ negative-parity states, which hinders a determination of the $C^{2}S$ values for knockout from the normally unoccupied $1p_{3/2}$ and $0f_{7/2}$ orbits.

Decay spectroscopy of the long-lived states in ${}^{186}\mathrm{Tl}$ has been performed at the ISOLDE Decay Station at ISOLDE, CERN. The $\alpha$ decay from the low-spin $\left(2^{-}\right)$ state in ${}^{186}\mathrm{Tl}$ was observed for the first time and a half-life of $3.4_{-0.4}^{+0.5}$ s was determined. Based on the $\alpha$-decay energy, the relative positions of the long-lived states were fixed, with the $\left(2^{-}\right)$ state as the ground state, the $7^{(+)}$ state at 77(56) keV, and the ${10}^{(-)}$ state at 451(56) keV. The level scheme of the internal decay of the ${}^{186}\mathrm{Tl}$(${10}^{(-)}$) state [$T_{1/2}=3.40\left(9\right)$ s], which was known to decay solely through emission of 374-keV $\gamma$-ray transition, was extended and a lower limit for the $\beta$-decay branching $b_{\beta }>5.9\left(3\right)\%$ was determined. The extracted retardation factors for the $\gamma$ decay of the ${10}^{(-)}$ state were compared to the available data in neighboring odd-odd thallium isotopes indicating the importance of the $\pi d_{3/2}$ shell in the isomeric decay and significant structure differences between ${}^{184}\mathrm{Tl}$ and ${}^{186}\mathrm{Tl}$.

The low-lying structure of semimagic ${}^{118}\mathrm{Sn}$ has been investigated through the $\beta$ decay of ${}^{118}\mathrm{In}$ ($T_{1/2}=4.45$ min) to study shape coexistence via the reduced transition probabilities of states in the 2p-2h proton intruder band. This high-statistics study was carried out at TRIUMF-ISAC with the GRIFFIN spectrometer. In total, 99 transitions have been placed in the level scheme with 43 being newly observed. Three low-lying $\gamma$-ray transitions with energies near 285 keV have been resolved from which the $2_{\mathrm{intr}.}^{+}\to 0_{\mathrm{intr}.}^{+}$ 284.52-keV transition was determined to have half of the previous branching fraction leading to a $B(E2;2_2^{+}\to 0_2^{+})$ of 21(4) W.u. compared to 39(7) W.u. from the previous measurement. Calculations using $sd$ IBM-2 with mixing have also been made to compare the experimental $B\left(E2\right)$ values to the theoretical values and to make comparisons to the ${}^{114,116}\mathrm{Sn}$ isotopes previously studied using the same theoretical model.