The STAR Collaboration presents measurements of the semi-inclusive distribution of charged-particle jets recoiling from energetic direct-photon (${\gamma }_{\mathrm{dir}}$) and neutral-pion (${\pi }^0$) triggers in $p+p$ and central $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=200\mathrm{GeV}$ over a broad kinematic range, for jet resolution parameters $R=0.2$ and 0.5. Medium-induced jet yield suppression is observed to be larger for $R=0.2$ than for 0.5, reflecting the angular range of jet energy redistribution due to quenching. The predictions of model calculations incorporating jet quenching are not fully consistent with the observations. These results provide new insight into the physical origins of jet quenching.

We present a study on neutron-rich tin ($Z=50$) isotopes beyond the doubly closed shell of $N=82$ through high-precision mass measurements, including the first-ever measurements of the masses of ${}^{136}\mathrm{Sn}$, ${}^{137}\mathrm{Sn}$, and ${}^{138}\mathrm{Sn}$ isotopes. These measurements enhance our understanding of the nuclear structure and astrophysical nucleosynthesis in this previously unexplored region. The new mass data are used for evaluation of the final abundances of mass numbers $A=135$ and 137 in $r$-process network calculations. Our findings reveal a notable change in the empirical pairing gap for tin isotopes beyond the $N=82$ closed shell and a shift in the two-neutron-separation energy slope compared to heavier elements above the shell closure. A new set of ab initio calculations effectively describes these observed trends.

The neutron-neutron ($nn$) correlation function has been measured in $25\mathrm{MeV}/\mathrm{u}{}^{124}\mathrm{Sn}+{}^{124}\mathrm{Sn}$ reactions. Using the Lednický-Lyuboshitz approach, the $nn$ scattering length and effective range ($f_0^{nn}$, $d_0^{nn}$), as well as the reduced space-time size $R^{(0)}$ of the neutron emission source are simultaneously extracted as (${18.9}_{-1.2}^{+1.3}\mathrm{fm}$, ${1.9}_{-1.0}^{+1.3}\mathrm{fm}$) and $4.12\pm 0.12\mathrm{fm}$, respectively. The measured $nn$ scattering length is consistent with the results obtained in the low-energy scattering ${}^2\mathrm{H}({\pi }^{-},\gamma )2n$, indicating heavy-ion collisions can serve as an effective approach for measuring $nn$ interactions and further investigating the charge symmetry breaking of nuclear force. The space-time size extracted from momentum-gated correlation functions exhibits clear dependence on the pair momentum, with $R^{(0)}=2.8\pm 0.1\mathrm{fm}$ and $4.9\pm 0.2\mathrm{fm}$ being determined for the high and low momentum neutrons, respectively.

Nuclear halos are exotic quantal structures observed far from stability. They are mostly studied through reactions. The ratio of angular cross sections for breakup and scattering is predicted to be independent of the reaction process and to be very sensitive to the halo structure. We test this new observable experimentally for the first time on the collision of ${}^{11}\mathrm{Be}$ on C at $22.8\mathrm{MeV}/\mathrm{nucleon}$ and using existing data on Pb at $19.1\mathrm{MeV}/\mathrm{nucleon}$. The theoretical predictions are verified, which offers the possibility of developing a new spectroscopic tool to study nuclear structure far from stability.

We present calculations of various electroweak response functions for the ${}^{16}\mathrm{O}$ nucleus obtained using coupled-cluster theory in conjunction with the Lorentz integral transform method. We employ nuclear forces derived at next-to-leading order and next-to-next-to-leading order in chiral effective field theory and perform a Bayesian analysis to assess uncertainties. Our results are in good agreement with available electron-scattering data at $|\mathbf{q}|\approx 326\mathrm{MeV}/\mathrm{c}$. Additionally, we provide several predictions for the weak response functions in the quasielastic peak region at $|\mathbf{q}|=300$ and $400\mathrm{MeV}/\mathrm{c}$, which are critical for long-baseline neutrino experiments.

The parity-violating asymmetry, including leading-order QED corrections to the Coulomb potential, is calculated nonperturbatively by solving the Dirac equation. At GeV collision energies and forward scattering angles, QED effects enhance the asymmetry by approximately 5% for the recently measured nuclei ${}^{27}\mathrm{Al}$, ${}^{48}\mathrm{Ca}$, and ${}^{208}\mathrm{Pb}$. The corrections result in a shift of the estimated neutron radius, leading to an increase in the inferred neutron skin thicknesses of these nuclei and, thus, to the pressure neutrons feel around nuclear saturation density.

We propose a general method embedded in the ab initio nuclear framework to reconstruct linear response functions and calculate sum rules. Within our approach, based on the Gaussian integral transform, we consistently treat the ground state and the excited spectrum. Crucially, the method allows for a robust uncertainty estimation of the spectral reconstruction. We employ it to obtain the spin response in neutron matter. Our calculations are performed using state-of-the-art many-body coupled-cluster method and Hamiltonians derived in the chiral effective field theory, emphasizing the analysis of finite-size effects. Our findings reveal that the spin response exhibits a strong dependence on both nuclear interactions and many-body wave functions, offering a new avenue for exploring nuclear correlations and dynamics in infinite systems. This work serves as a stepping stone toward further studies of neutrino interactions in astrophysical environments from first principles.

High-order virtual excitations play an important role in microscopic models of nuclear reactions at intermediate energies. However, the factorial growth of their complexity has prevented their consistent inclusion in ab initio many-body calculations. For infinite systems at finite temperature, such drawbacks can be overcome using diagrammatic Monte Carlo techniques to resum entire series of Feynman diagrams. We present a diagrammatic Monte Carlo algorithm that can be applied to self-bound systems with discrete energy levels at zero temperature, and demonstrate its potential for the Richardson model of nuclear pairing. We show that sampling the topological space of diagrams allows the inclusion of high-order excitations that are neglected in state-of-the-art approximations used in nuclear physics and quantum chemistry. We propose that sampling the diagrammatic space can overcome the long-standing gap between our microscopic understanding of structure and reactions in nuclear physics.

Nuclear charge radii of neutron-rich ${}^{47–49}\mathrm{Sc}$ isotopes were measured using collinear laser spectroscopy at CERN-ISOLDE. The new data reveal that the charge radii of scandium isotopes exhibit a distinct trend between $N=20$ and $N=28$, with ${}^{41}\mathrm{Sc}$ and ${}^{49}\mathrm{Sc}$ isotopes having similar values, mirroring the closeness of the charge radii of ${}^{40}\mathrm{Ca}$ and ${}^{48}\mathrm{Ca}$. Theoretical models that successfully interpret the radii of calcium isotopes could not account for the observed behavior in scandium radii, in particular the reduced odd-even staggering. Remarkably, the inclusion of the new ${}^{49}\mathrm{Sc}$ radius data has unveiled a similar trend in the charge radii of $N=28$ isotones and $Z=20$ isotopes when adding the protons atop the ${}^{48}\mathrm{Ca}$ core and the neutrons atop the ${}^{40}\mathrm{Ca}$ core, respectively. We demonstrate that this trend is consistent with the prediction of the seniority model.

Neutron emission probabilities and half-lives of 37 $\beta$-delayed neutron emitters from ${}^{75}\mathrm{Ni}$ to ${}^{92}\mathrm{Br}$ were measured at the RIKEN Nishina Center in Japan, including 11 one-neutron and 13 two-neutron emission probabilities and six half-lives for the first time that supersede theoretical estimates. These nuclei lie in the path of the weak $r$ process occurring in neutrino-driven winds from the accretion disk formed after the merger of two neutron stars synthesizing elements in the $A\sim 80$ abundance peak. The presence of such elements dominates the accompanying kilonova emission over the first few days and have been identified in the AT2017gfo event, associated to the gravitational wave detection GW170817. Abundance calculations based on over 17 000 simulated trajectories describing the evolution of matter properties in the merger outflows show that the new data lead to an increase of 50%–70% in the abundance of Y, Zr, Nb, and Mo. This enhancement is large compared to the scatter of relative abundances observed in old very metal poor stars and thus is significant in the comparison with other possible astrophysical processes contributing to the light-element production. These results underline the importance of including experimental decay data for very neutron-rich $\beta$-delayed neutron emitters into $r$-process models.

We use classical equations of motion for heavy quarks to show that the preequilibrium glasma phase of a heavy ion collision has an extremely strong effect on heavy quark angular correlations. At the same time the effect on the single inclusive spectrum is much more moderate. This suggests that $D\overline{D}$ meson angular correlations in future LHC measurements could provide a direct experimental access to the physics of the preequilibrium stage.

The mass of the electron-antineutrino can be determined in dedicated measurements of the $\beta$ spectral shape near the $\beta$ end point of a ${\beta }^{-}$ transition, with a low $Q$ value enhancing the sensitivity of the measurement. One such low $Q$ value candidate is the transition between the $6^{+}$ isomer of ${}^{110}\mathrm{Ag}$ and the $5_2^{+}$ state in ${}^{110}\mathrm{Cd}$ ($Q_{\beta ,m}^{*}=-0.12(131)\mathrm{keV}$). To reduce the uncertainty of the $Q$ value, we have used the phase-imaging ion-cyclotron-resonance technique with the JYFLTRAP double Penning trap and performed a high-precision atomic mass measurement of ${}^{109}\mathrm{Ag}$ with ${}^{110}\mathrm{Cd}$ as a reference. Combined with the known spectroscopic data, we obtain a reevaluated value $Q_{\beta ,m}^{*}=405(135)\mathrm{eV}$ for the ${}^{110}\mathrm{Ag}(6_{\mathrm{m}}^{+})\to {}^{110}\mathrm{Cd}(5_2^{+})$ transition. This represents the lowest $Q_{\beta }$ value for any allowed transition observed to date. In order to estimate the partial half-life ($t_{1/2}$) and branching ratio (Br) of the transition, nuclear shell model calculations were performed using the $jj45pnb$ Hamiltonian in combination with state-of-the-art atomic calculations. The computed values of $t_{1/2}=2.23_{-1.28}^{+5.24}\times {10}^7\mathrm{years}$ and $\mathrm{Br}=3.07_{-2.15}^{+4.16}\times {10}^{-8}$, along with the thermal-neutron capture on stable ${}^{109}\mathrm{Ag}$ as a viable production method, make ${}^{110}{\mathrm{Ag}}^m$ a promising candidate for future antineutrino mass measurements.

We present a systematic ab initio study of the low-lying states in beryllium isotopes from ${}^7\mathrm{Be}$ to ${}^{12}\mathrm{Be}$ using nuclear lattice effective field theory with the ${\mathrm{N}}^3\mathrm{LO}$ interaction. Our calculations achieve good agreement with experimental data for energies, radii, and electromagnetic properties. We introduce a novel, model-independent method to quantify nuclear shapes, uncovering a distinct pattern in the interplay between positive and negative parity states across the isotopic chain. By combining Monte Carlo sampling of the many-body density operator with a novel nucleon-grouping algorithm, the prominent two-center cluster structures, the emergence of one-neutron halo, complex nuclear molecular dynamics such as $\pi$ orbital and $\sigma$ orbital, emerge naturally.

We present the first measurement of the ${}^{47}\mathrm{K}(d,p\gamma ){}^{48}\mathrm{K}$ transfer reaction, performed in inverse kinematics using a reaccelerated beam of ${}^{47}\mathrm{K}$. The level scheme of ${}^{48}\mathrm{K}$ has been greatly extended, with nine new bound excited states identified and spectroscopic factors deduced. Uniquely, the ${}^{47}\mathrm{K}(d,p)$ reaction gives access to nuclear states that are sensitive to the interaction of protons and neutrons in the widely spaced $1s$ and $fp$ orbitals, respectively. Detailed comparisons with SDPF-U and SDPF-MU shell-model calculations reveal a number of discrepancies between theory and experiment. Intriguingly, a systematic overestimation of spectroscopic factors and a poor reproduction of the energies for $1^{-}$ states suggests that the mixing between the $\pi s_{1/2}^1{d}_{3/2}^4$ and $\pi s_{1/2}^2{d}_{3/2}^3$ proton configurations in ${}^{48}\mathrm{K}$ is not correctly described using current interactions, challenging our description of light nuclei around the $N=28$ island of inversion.

Isospin symmetry is a fundamental concept in nuclear physics. Even though isospin symmetry is partially broken, it holds approximately for most nuclear systems, which makes exceptions very interesting from the nuclear structure perspective. In this framework, it is expected that the spins and parities of the ground states of mirror nuclei should be the same, in particular for the simplest systems where a proton is exchanged with a neutron or vice versa. In this Letter, we present evidence that this assumption is broken in the mirror pair ${}^{71}\mathrm{Br}$ and ${}^{71}\mathrm{Kr}$ system. Our conclusions are based on a high-statistics $\beta$ decay study of ${}^{71}\mathrm{Kr}$ and on state-of-the-art shell model calculations. In our work, we also found evidence of a new state in ${}^{70}\mathrm{Se}$, populated in the $\beta$-delayed proton emission process which can be interpreted as the long sought coexisting $0^{+}$ state.

For the first time the neutron-rich hydrogen isotope ${}^6\mathrm{H}$ was produced in an electron scattering experiment in the reaction ${}^7\mathrm{Li}(\mathrm{e},{\mathrm{e}}^{\prime }\mathrm{p}{\pi }^{+}{)}^6\mathrm{H}$ using the spectrometer facility of the A1 Collaboration at the Mainz Microtron accelerator. By measuring the triple coincidence between the scattered electron, the produced proton, and ${\pi }^{+}$, the missing mass spectrum of ${}^6\mathrm{H}$ was obtained. A clear peak above ${}^3\mathrm{H}+\mathrm{n}+\mathrm{n}+\mathrm{n}$ energy threshold was seen resulting in a ground state energy of ${}^6\mathrm{H}$ at $2.3\pm 0.5(\mathrm{stat}.)\pm 0.4(\mathrm{syst}.)\mathrm{MeV}$ with a width of $1.9\pm 1.0(\mathrm{stat}.)\pm 0.4(\mathrm{syst}.)\mathrm{MeV}$. This Letter challenges the understandings of multinucleon interactions and presents a new method to study light neutron-rich nuclei with electron scattering experiments.

We present the first nuclear cross-section measurements of $(\mathrm{p},\gamma )$ and (p,n) reactions on ${}^{118}\mathrm{Te}$ at energies relevant for the $\gamma$-process nucleosynthesis. Absolute cross-section values for center-of-mass energies of 6, 7 and 10 MeV are provided, together with a theoretical extrapolation to the Gamow window. This experiment marks the first time that direct proton-induced reactions have been measured on a radioactive ion beam at the Experimental Storage Ring (ESR) at GSI, Darmstadt. This paves the way for a large variety of measurements, delivering new constraints for explosive nucleosynthesis and for physics beyond nuclear stability.