It has been suggested that the density of dark matter (DM) halo can be highly enhanced around supermassive black holes at the centers of massive galaxies. If real, these DM spikes would offer new opportunities to probe the properties of DM. In this work, we point out that DM spikes can significantly impact the composition and survivability of ultrahigh-energy cosmic rays accelerated near supermassive black holes. A large DM-nucleon cross section would fragment heavy nuclei into lighter elements and prevent them from attaining the energies observed at Earth. While the origin of cosmic rays remains a mystery, we show that if the highest-energy cosmic rays on Earth come from sources like NGC 1068, then cross sections of size ${\sigma }_{\chi p}\le {10}^{-33}(\frac{m_{\chi }}{\mathrm{GeV}}){\mathrm{cm}}^2$ would be excluded by cosmic ray data. These bounds can be competitive with other existing probes and rule out new parameter space in the DM mass region $m_{\chi }\in [3\mathrm{MeV},30\mathrm{MeV}]$. While the uncertainties on the acceleration mechanism of cosmic rays prevent us from setting robust limits, our study highlights an important connection between DM spikes and cosmic ray physics that is complementary to existing cosmological and direct detection constraints.

The quantitative impact of strong rotation on the amplitudes and frequencies of the postbounce gravitational wave (GW) signal from core-collapse supernovae (CCSNe) is still not fully understood. To study trends in frequencies and amplitudes, and possibly spectacular phenomena like resonant amplification, we perform a series of axisymmetric long-duration magnetohydrodynamic CCSN simulations of a $17M_{\odot }$ progenitor using a finely spaced grid in initial rotation rate from $0.29\mathrm{rad}{\mathrm{s}}^{-1}$ to $3.48\mathrm{rad}{\mathrm{s}}^{-1}$. We find that these rotating models produce GWs at frequencies of up to 3 kHz, higher than in typical nonrotating models in the literature. The high frequencies arise due to small polar radii of rapidly rotating protoneutron stars and stabilization by angular momentum gradients at lower latitude. GW frequencies and amplitudes tend to decrease with faster rotation. Different from two complementary simulations without magnetic fields, the magnetohydrodynamic models are characterized by an absence of $p$-modes above the dominant high-frequency emission band. We find no indication of resonant mode amplification for any rotation rate, although a temporospatial and space-frequency analysis reveals some interesting couplings of quadrupolar motions across the protoneutron star and the gain region. We find that linear mode analysis based on the spherically averaged structure becomes unsuitable in this regime of rapid rotation. Generalized, multidimensional perturbative techniques need to be developed to study the mode structure and mode interaction in the collapse of rapidly rotating massive stars.

We present the first general relativistic, neutrino-radiation hydrodynamics simulations of accretion-induced collapse (AIC) extending to seconds after core bounce, using realistic hadron–quark hybrid equations of state (EOSs). A first-order QCD phase transition (PT) triggers a second dynamical collapse and the formation of a quasistable protohybrid star (PHS) with a deconfined quark core and a distinctive second neutrino burst. We find that the thermally suppressed onset of the mixed phase allows low-mass protoneutron stars to enter the hadron-quark mixed phase during long-term evolution, even for hybrid EOSs with high onset densities. In contrast to core-collapse supernovae (CCSNe), AIC models exhibit a tightly constrained onset mass with minimal EOS dependence, owing to the absence of a massive envelope and thus the reduced postbounce accretion. This enhances the sensitivity of neutrino observables in AIC to hybrid EOS properties. We establish empirical relations between PT onset density and neutrino signatures, revealing a distinct behavior in AIC not seen in CCSNe. Our results suggest that a single Galactic AIC neutrino detection could place strong constraints on QCD PT thresholds, hybrid EOS characteristics, and the existence of PHSs. PT in AIC may also produce gravitational waves, gamma-ray bursts, and $r$-process elements, motivating multidimensional simulations with rotation, magnetic fields, and improved microphysics for realistic multimessenger predictions.

If a strong first-order phase transition takes place at sufficiently high rest-mass densities in the equation of state (EOS) modeling compact stars, a new branch will appear in the mass-radius sequence of stable equilibria. This branch will be populated by stars comprising a quark-matter core and a hadronic-matter envelope, i.e., hybrid stars, which represent “twin-star” solutions to equilibria having the same mass but a fully hadronic EOS. While both branches are stable to linear perturbations, it is unclear which of the twin solutions is the “favored” one, that is, which of the two configurations is expected to be found in nature. We assess this point by performing a large campaign of general-relativistic simulations aimed at assessing the response of compact stars on the two branches to perturbations of various strength. In this way, we find that, independently of whether the stars populate the hadronic or the twin branch, their response is characterized by a critical-perturbation strength such that the star will oscillate on the original branch for subcritical perturbations and migrate to the neighboring branch for supercritical perturbations while conserving rest mass. Because the critical values are different for stars with the same rest mass but sitting on either branch, it is possible to define as favored the part of the branch that has the largest critical perturbation, thus correcting the common wisdom that stellar models on the twin branch are the favored ones. Interestingly, we show that the binding energies on the two branches can be used to deduce without simulations which of the stellar configurations is more likely to be found in nature.

Recent experimental data from $\mathrm{MINER}\nu \mathrm{A}$ on transverse kinematics observables across four different nuclear targets—carbon, oxygen, iron, and lead—have been utilized to refine the modeling of final state interaction effects in the nuwro Monte Carlo neutrino event generator. For this purpose, we have developed an event reweighting tool for future applications to adjust the strength of final-state interactions. This study highlights the requirement for stronger nucleon reinteractions than previously assumed, but it still falls within the uncertainty range observed in a study comparing proton transparency measurements. This conclusion has significant implications for both experimental and theoretical work involving nuwro.

The left-right symmetric model (LRSM) could not only restore parity of the weak interaction, but also provide natural explanations of the tiny active neutrino masses via the seesaw mechanisms. The $SU(2{)}_R$-breaking scalar $H_3$ can induce lepton flavor violating (LFV) effects in the minimal version of LRSM at the 1-loop order, originating from the mixing of heavy right-handed neutrinos (RHNs). If $H_3$ is light, say below the GeV scale, it will lead to rich signals, e.g., the LFV muon and tauon decays ${\ell }_{\beta }\to {\ell }_{\alpha }+X$ ($X$ being either visible or invisible final states) and the anomalous supernova signatures. Combined with the diphoton coupling of $H_3$, and recasting the existing constraints onto the light $H_3$ scenario, the right-handed scale $v_R$ is excluded up to $2\times {10}^9\mathrm{GeV}$. In the future, the $v_R$ scale can be probed up to $5\times {10}^9\mathrm{GeV}$ in high-precision muon experiments, if the Yukwa couplings for RHN masses are of order one and the RHN mixing is maximal, and further up to $6\times {10}^{11}\mathrm{GeV}$ by supernova observations, reaching the nonresonant leptogenesis scale in the LRSM.

The renormalization group running of fermion mixing matrices in the Standard Model and beyond is studied. For the massless one-loop running with three generations, six fixed points are found. Their associated anomalous dimension matrices are calculated and the nature of each fixed point, whether attractive, repulsive, or mixed, is determined. An argument is given that the fixed points found at one loop must remain fixed points to all orders in perturbation theory and even nonperturbatively, as they are associated with certain differential geometric properties of vector fields on the space of mixing matrices. With $N_g$ dark or sterile neutrinos there are at least $N_g!$ fixed points of the fermion mixing matrix.

We investigate string configurations in the deconfined phase of SU(3) gauge theory, which arise from the spontaneous breaking of the $Z_3$ center symmetry. These configurations form at the junctions of domain walls of the theory. The complex phase of the Polyakov loop changes by multiples of $2\pi$ on large spatial loops around the string, rendering them topologically stable. Using the Monte Carlo simulations of the partition function, we compute the free energy associated with these configurations. The simulations are performed on lattices with spatial dimensions $N_{x,y}=60,N_z=4$, and temporal extent $N_{\tau }=2$, 4. Our results show that the free energy of the $Z_3$ strings is dominated by the domain walls. Further near the transition point, thermal fluctuations cause the decay of domain walls as well as the $Z_3$ strings into confined-deconfined interfaces.

Simulating fermions coupled to spin degrees of freedom, relevant for a range of quantum field theories, represents a promising application for quantum simulators. Mapping fermions to qubits is challenging in $2+1$ and higher spacetime dimensions, and mapping bosons demands substantial quantum-computational overhead. These features complicate the realization of mixed fermion-boson quantum systems in digital quantum computers. We propose a native fermion-(large-)spin analog quantum simulator by utilizing dopant arrays in silicon. Specifically, we show how to use a dynamical lattice of coupled nuclear spins and conduction-band electrons to realize a quantum field theory: an extended Jackiw–Rebbi model involving coupled fermions and quantum rotors. We demonstrate the feasibility of observing dynamical mass generation and a confinement-deconfinement quantum phase transition in $1+1$ dimensions on this platform, even in the presence of strong long-range Coulomb interactions. Furthermore, we employ finite-temperature Hartree–Fock–Bogoliubov simulations to investigate the dynamics of mass generation in two-dimensional square and honeycomb arrays, showing that this phenomenon can be simulated with realistic experimental parameters. Our findings reveal two distinct phases and demonstrate robustness against the addition of Coulomb interactions. Finally, we discuss experimental signatures of the phases through transport and local charge sensing in dopant arrays. This study lays the foundation for quantum simulations of quantum field theories exhibiting fermions coupled to spin degrees of freedom using donors in silicon.

Functional approaches are the only first principle quantum chromodynamics (QCD) setup to date that allow for direct computations in the strongly correlated finite density regime of QCD. Predictive power and quantitative reliability of the respective results can only be obtained within a systematic expansion scheme with controlled systematic error estimates. Here we set up such a scheme within the functional renormalization group (fRG) approach to QCD, aiming for full apparent convergence. In the current work we test this setup, using correlation functions and observables in $2+1$ flavor vacuum QCD as a natural benchmark case. While the current work includes many evolutionary improvements collected over the past two decades, we also report on three novel important developments: (i) comprehensive systematic error analysis based on the modular nature of the fRG approach. (ii) The introduction of a fully automated computational framework, allowing for unprecedented access and improvement of the fRG approach to QCD. (iii) The inclusion of the full effective potential of the chiral order parameter. This also gives access to all-order scattering events of pions and to the full momentum dependence of correlation functions, which is a first application of the automated computational framework (ii). The results compare very well to other state-of-the-art results both from functional approaches and lattice simulations, and provide data on general multiscattering events of pions and the sigma mode for the first time.

Many theories of physics beyond the Standard Model predict particles with nonhelical trajectories in a uniform magnetic field, but standard tracking algorithms assume helical paths and so are incapable of discovering nonhelical tracks. While alternative algorithms have been developed for specific trajectories, unforeseen physics could lead to unanticipated behavior, and such unexpected tracks are largely invisible to current algorithms, despite being potentially striking to the naked eye. A model-agnostic tracking algorithm is presented, capable of reconstructing a broad class of smooth nonhelical tracks without requiring explicit specification of particle trajectories, instead defining the target trajectories implicitly in the training sample. The network exhibits strong performance, even outside of the trajectories defined by the training sample. This proof-of-principle study takes the first step towards searches for unexpected tracks which may await discovery in current data.

The polarization of $\mathrm{\Lambda }$ hyperons is preserved in the angular distribution of their decay products. This property allows one to study the spin structure of the $\mathrm{\Lambda }$. In semi-inclusive deep inelastic scattering where a high energy lepton interacts with a nucleon target and one or more hadrons and the scattered lepton are detected in the final state, the probability for a struck quark to impart the polarization of the lepton to the $\mathrm{\Lambda }$ may be measured. In particular, in electron-proton scattering this quantity may be related to the longitudinal light quark polarization of the $\mathrm{\Lambda }$. Currently, limited experimental data cannot discriminate between different models of $\mathrm{\Lambda }$ spin structure. This work reports on the measurement of the longitudinal spin transfer $D_{L{L}^{\prime }}^{\mathrm{\Lambda }}$ to the $\mathrm{\Lambda }$ using data taken by the CLAS12 spectrometer at Jefferson Lab with a 10.6 GeV longitudinally polarized electron beam and an unpolarized hydrogen target. This measurement is the most precise to date, and, in comparison with theory predictions, it offers valuable insight into the relative dominance of current and target fragmentation in $\mathrm{\Lambda }$ production.

Using a sample of $(2712.4\pm 14.3)\times {10}^6\psi (3686)$ events collected by the BESIII detector at the BEPCII collider, we measure the branching fractions of the decays ${\chi }_{cJ}\to \varphi \varphi \eta ,\varphi \varphi {\eta }^{\prime }$, and $\varphi K^{+}{K}^{-}\eta$ ($J=0$, 1, 2). The obtained branching fractions are $\mathcal{B}({\chi }_{c0}\to \varphi \varphi \eta )=(7.40\pm 0.23\pm 0.55)\times {10}^{-4}$, $\mathcal{B}({\chi }_{c1}\to \varphi \varphi \eta )=(3.33\pm 0.14\pm 0.25)\times {10}^{-4}$, $\mathcal{B}({\chi }_{c2}\to \varphi \varphi \eta )=(5.46\pm 0.17\pm 0.40)\times {10}^{-4}$, $\mathcal{B}({\chi }_{c0}\to \varphi \varphi {\eta }^{\prime })=(2.96\pm 0.23\pm 0.29)\times {10}^{-4}$, $\mathcal{B}({\chi }_{c1}\to \varphi \varphi {\eta }^{\prime })=(0.69\pm 0.10\pm 0.08)\times {10}^{-4}$, $\mathcal{B}({\chi }_{c2}\to \varphi \varphi {\eta }^{\prime })=(0.65\pm 0.09\pm 0.07)\times {10}^{-4}$, $\mathcal{B}({\chi }_{c0}\to \varphi K^{+}{K}^{-}\eta )=(1.23\pm 0.08\pm 0.10)\times {10}^{-4}$, $\mathcal{B}({\chi }_{c1}\to \varphi K^{+}{K}^{-}\eta )=(1.00\pm 0.07\pm 0.07)\times {10}^{-4}$, and $\mathcal{B}({\chi }_{c2}\to \varphi K^{+}{K}^{-}\eta )=(1.82\pm 0.09\pm 0.14)\times {10}^{-4}$, where $K^{+}{K}^{-}$ is not from the decay of a $\varphi$ meson, the first uncertainties are statistical and the second systematic. The branching fractions of ${\chi }_{cJ}\to \varphi \varphi \eta$ are measured with precision improved by factors of 1.5–1.9, and those of ${\chi }_{cJ}\to \varphi \varphi {\eta }^{\prime }$ and $\varphi K^{+}{K}^{-}\eta$ are measured for the first time.

The Coherent Neutrino-Nucleus Interaction Experiment (CONNIE) aims to detect the coherent scattering ($\mathrm{CE}\nu \mathrm{NS}$) of reactor antineutrinos off silicon nuclei using thick fully depleted high-resistivity silicon CCDs. Two Skipper-CCD sensors with subelectron readout noise capability were installed at the experiment next to the Angra-2 reactor in 2021, making CONNIE the first experiment to employ Skipper-CCDs for reactor neutrino detection. We report on the performance of the Skipper-CCDs, the new data processing, data quality, and event selection for $\mathrm{CE}\nu \mathrm{NS}$ interactions, which enable CONNIE to reach a record low detection threshold of 15 eV. The data were collected over 300 days in 2021–2022 and correspond to exposures of 14.9 g-days with the reactor-on and 3.5 g-days with the reactor-off. The difference between the reactor-on and off event rates shows no excess and yields upper limits for the neutrino interaction rates, comparable with previous CONNIE limits from standard CCDs and higher exposures. Searches for new neutrino interactions beyond the Standard Model improve the previous CONNIE limit on a simplified model with light vector mediators. A first dark matter (DM) search by diurnal modulation by CONNIE obtains the best limits on the DM-electron scattering cross section by a surface-level experiment. These promising results, obtained using a very small-mass sensor, illustrate the potential of Skipper-CCDs to probe rare neutrino interactions and motivate the plans to increase the detector mass in the near future.

We uncover a cascade of exceptional points (EPs) in the quasinormal mode spectrum of massive scalar perturbations of Kerr black holes, revealing an intricate non-Hermitian structure underlying their linear response. The cascade originates from a single damped mode that enters the extremal spectrum for sufficiently large field masses. We obtain evidence for an infinite sequence of EPs in the $(\ell ,m)=(1,1)$ and (2, 2) sectors near the extremal limit, mediating the transition between damped and zero-damping modes. Each EP carries a geometric phase that enables adiabatic mode mixing across the entire overtone spectrum, a phenomenon we refer to as adiabatic ergodicity.

We propose and calculate a holographic Krylov complexity in $\mathcal{N}=4$ SYM theory via the proper momentum for motion in ${\mathrm{AdS}}_5$ sliced by ${\mathrm{AdS}}_3$. The motion in an ${\mathrm{AdS}}_3$ subgroup corresponds to the Krylov complexity of the $Sl(2)$ subsector. The general motion corresponds to the Krylov complexity of the $\mathcal{N}=4$ SYM.

We calculate Euclidean correlation functions through next-to-leading order in the low-energy effective theory of gravity. We focus on correlation functions of curvature and volume operators, calculating these functions through one-loop order. We show that quantum fluctuations of the background spacetime must be taken into account in order to obtain gauge invariant expressions, and we point out a subtlety associated with the analytic continuation of the conformal mode. Our final expressions for the correlation functions involve only Newton’s constant and the source-sink separation, and they are a universal prediction of the low-energy effective theory. Thus, they serve as a useful point of comparison for nonperturbative lattice formulations of gravity.

We provide some up-to-date discussions related to cosmological event horizon and entropy of our Universe, then introduce an intriguing idea that there may be a universal finite upper bound for entropy accessible to an observer in consistent theories of quantum gravity. We argue that the Berenstein-Maldacena-Nastase (BMN) strings provide a test of the idea. More speculatively, in an optimistic scenario, this also provides a possible estimate of the cosmological constant.

Through the Hamilton-Jacobi equation of classical mechanics, BPS magnetized baryonic layers (possessing both baryonic charge and magnetic flux) have been constructed in the gauged nonlinear sigma model (G-NLSM) minimally coupled to Maxwell theory. This is one of the most relevant effective theories for quantum chromodynamics (QCD) in the strongly interacting low-energy limit, which also accounts for electromagnetic interactions. Since the topological charge that naturally appears on the right-hand side of the BPS bound is a nonlinear function of the baryonic charge, the thermodynamics of these magnetized baryonic layers is highly nontrivial. In this work, using tools from the theory of the Casimir effect, we derive analytical relationships between baryonic charge, topological charge, magnetic flux, and relevant thermodynamic quantities (such as pressure, specific heat, and magnetic susceptibility) for these layers. The critical baryonic chemical potential is identified. Interestingly, the grand canonical partition function can be related to the Riemann zeta function. On the technical side, it is a remarkable result to derive explicit expressions for all these thermodynamic quantities for a strongly interacting magnetized system at finite baryon density. Moreover, thanks to the BPS property of these configurations, we are also able to analytically determine both the equation of state and the speed of sound. The effects of the isospin chemical potential can also be included; specifically, we are able to explicitly construct the BPS bound and the corresponding BPS configurations even when the isospin chemical potential is nonzero. The physical interpretations of our analytical results are discussed.

This work investigates the geometrical properties of self-gravitating $N$-body systems from the perspective established by Henri Poincaré and Albert Einstein concerning the operational nature of measured geometry. Utilizing recent numerical analyses of central configurations (special equilibrium solutions to the Newtonian $N$-body problem), we uncover systematic spatial variations in nearest-neighbor particle separations correlated with the radial distance from the system’s center of mass. We argue that these variations reflect a context-dependent, emergent effective geometry shaped by gravitational interactions, in accordance with Poincaré’s assertion that measured geometry depends on the forces influencing measuring devices, and Einstein’s view that rods and clocks define physical geometry through their local dynamics. By revisiting these foundational insights within a modern computational framework, we provide evidence that geometry in self-gravitating Newtonian systems is not a fixed background but an emergent construct arising from internal physical interactions.