The recently discovered stellar system, Ursa Major III/UNIONS 1, may be the faintest and densest dwarf spheroidal satellite galaxy of the Milky Way. Owing to its close proximity and substantial dark matter (DM) component, Ursa Major III emerges as a highly promising target for DM indirect detection. It is known that electrons and positrons originating from DM annihilation can generate a broad radio spectrum through the processes of synchrotron radiation and inverse Compton scattering within galaxies. In this study, we investigate the potential of the Square Kilometre Array (SKA) in detecting radio signatures arising from DM annihilation in Ursa Major III over a 100 hour observation period. Our analysis indicates that the SKA has strong capabilities in detecting these signatures. For instance, the SKA sensitivity to the DM annihilation cross section is estimated to reach $\mathcal{O}({10}^{-30})-\mathcal{O}({10}^{-28}){\mathrm{cm}}^3{\mathrm{s}}^{-1}$ in the DM mass range from several GeV to $\sim 100\mathrm{GeV}$ for the $e^{+}{e}^{-}$ and ${\mu }^{+}{\mu }^{-}$ annihilation channels. The precise results are significantly influenced by various astrophysical factors, such as the strength of magnetic field, the diffusion coefficient, and the DM density profile in the dwarf galaxy. We discuss the impact of the uncertainties associated with these factors, and find that the SKA sensitivities have the potential to surpass the current constraints, even when considering these uncertainties.

We present a new method to search for long transient gravitational waves signals, like those expected from fast spinning newborn magnetars, in interferometric detector data. Standard search techniques are computationally unfeasible (matched filtering) or very demanding (suboptimal semicoherent methods). We explored a different approach by means of machine learning paradigms, to define a fast and inexpensive procedure. We used convolutional neural networks to develop a classifier that is able to discriminate between the presence or the absence of a signal. To complement the classification and enhance its effectiveness, we also developed a denoiser. We studied the performance of both networks with simulated colored noise, according to the design noise curve of LIGO interferometers. We show that the combination of the two models is crucial to increase the chance of detection. Indeed, as we decreased the signal initial amplitude (from ${10}^{-22}$ down to ${10}^{-23}$) the classification task became more difficult. In particular, we could not correctly tag signals with an initial amplitude of $2\times {10}^{-23}$ without using the denoiser. By studying the performance of the combined networks, we found a good compromise between the search false alarm rate (2%) and efficiency (90%) for a single interferometer. In addition, we demonstrated that our method is robust with respect to changes in the power law describing the time evolution of the signal frequency. Our results highlight the computationally low cost of this method to generate triggers for long transient signals. The study carried out in this work lays the foundations for further improvements, with the purpose of developing a pipeline able to perform systematic searches of long transient signals.

Numerous models of neutron star (NS) equation of state (EoS) exist based on different superdense-matter physics approaches. Nevertheless, some NS properties show universal (EoS-independent) relations. Here, we propose a novel class of such universalities. Despite different physics inputs, a wide class of realistic nucleonic, hyperonic, and hybrid EoS models can be accurately described using only three parameters. For a given EoS, these are the mass and radius of the maximum-mass NS (or pressure and density in its center) and the radius of a half-maximum-mass star. With such a parametrization, we build universal analytic expressions for mass-radius and pressure-density relations. They form a semianalytic mapping from the mass-radius relation to the EoS in NS cores (the so-called inverse Oppenheimer-Volkoff mapping). This mapping simplifies the process of inferring the EoS from observations of NS masses and radii. Applying it to current NS observations we set new limits on the high-density end of the EoS. Using this method we also present new estimates of the radii of NS with measured masses.

Quasinormal modes of neutron stars are an exciting prospect for analyzing the internal composition of neutron stars and studying matter at high densities. In this work, we focus on studying the $f$- and $p$-quadrupolar oscillation modes, which couple with gravitational waves. We construct two different equation of state ensembles, one without and one with a first-order phase transition, and examine how $f$ and $p$ modes might help us differentiate them. We find ensemble specific exclusion regions in the 65% and 95% confidence contours of the frequency-damping time relations. The exclusion regions become more prominent for the higher-order oscillation modes. However, these modes have higher frequencies, which are beyond the detection capabilities of present gravitational wave detectors. The quasiuniversal relations of dimensionless quantities prove to be ineffective in differentiating the equation of state ensembles, as they obscure the details of the equation of state.

We explore the contribution of hadronic final state interactions (FSI) to propose a production mechanism and interpret the puzzle on helicity angle distributions in $B^{+}\to p\overline{p}{\pi }^{+}$ and $B^{+}\to p\overline{p}{K}^{+}$ decays. Experimental results indicate opposite helicity angle ${\theta }_p$ distributions in those two channels with the difference presenting a remarkable linear dependence on $\cos {\theta }_p$. We assume the production mechanism is driven by $B^{+}\to xy{m}^{+}\to p\overline{p}{m}^{+}$, where $m=\pi$ or $K$, and $xy$ represents favorable mesonic decay channels producing $p\overline{p}$. We develop a model that includes a three-body final state interaction between the $p,\overline{p}$, and ${\pi }^{+}$ or $K^{+}$ considering the dominance of elastic channels ${\pi }^{+}p$ and $K^{+}\overline{p}$ interactions below $2\mathrm{GeV}/{\mathrm{c}}^2$. Our three-body framework with FSI explains qualitatively the observed opposite behavior of the helicity distributions and the observed linearity.

We present a comprehensive analysis of the dynamic process of quark spin polarization induced by magnetic fields at the prethermal stage in heavy-ion collisions by using the recently developed theoretical tool of chiral kinetic theory. Our findings demonstrate that the spin polarization of quarks is highly sensitive to the interactions between quarks. These interactions can delay the decay of early spin polarization vectors while accelerating the decay of later spin polarization vectors. Specifically, our simulations show the detailed process of how magnetic fields polarize quarks within the fireball and reveal that quark interactions lead to an acceleration effect on the average spin. Notably, the fireball of quark-gluon plasma in its early stages exhibits an incomplete electromagnetic response effect, which differs from the response predicted by Lenz’s law. This discrepancy arises from quantum corrections involving the interactions between quark spin and electromagnetic fields.

We develop an effective field theory for the description of high energetic or hard photons, the on-shell effective theory (OSEFT). The OSEFT describes the so-called eikonal or semiclassical optical limit, allowing for corrections organized in a systematic expansion on inverse powers of the photon energy. We derive the OSEFT from the Maxwell Lagrangian and study its different properties, such as the gauge symmetry and reparametrization invariance. The theory can be finally formulated in terms of a gauge invariant vector gauge field, without the need to introduce gauge-fixing. We then use the OSEFT to compute corrections to the Wigner photon function and derive its associated side jump effect from reparametrization invariance. Finally, we discuss how to properly define the Stokes parameters from transport theory once quantum effects are considered, so as to preserve their well-defined properties under Lorentz transformations.

While there is much indirect evidence for the existence of dark matter (DM), to date it has evaded detection. Current efforts focus on DM masses over $\sim \mathrm{GeV}$—to push the sensitivity of DM searches to lower masses, new DM targets and detection schemes are needed. In this work, we focus on the latter—a novel detection scheme recently proposed to detect 10–100 meV phonons in polar target materials. Previous work showed that well-motivated models of DM can interact with polar semiconductors to produce an athermal population of phonons. This new sensing scheme proposes that these phonons then facilitate quantum evaporation of ${}^3\mathrm{He}$ from a van der Waals film deposited on the target material. However, a fundamental understanding of the underlying process is still unclear, with several uncertainties related to the precise rate of evaporation and how it can be controlled. In this work, we use ab initio density functional theory calculations to compare the adsorption energies of helium atoms on a polar target material, sodium iodide, to understand the underlying evaporation physics. We explore the role of surface termination, monolayer coverage, and elemental species on the rate of He evaporation from the target material. Using this, we discuss the optimal target features for He-evaporation experiments and their range of tunability through chemical and physical modifications such as applied field and surface termination.

A derivative coupling of an axionlike particle (ALP) with a $B-L$ current may lead to the baryon asymmetry of the Universe via spontaneous leptogenesis provided a lepton number breaking interaction prevails in thermal equilibrium. Conventionally, such scenario works only for heavy ALPs and high reheating temperature due to the fact that the same lepton number breaking contribution is tied up with neutrino mass generation also. In this work, we propose inert Higgs doublet assisted lepton number violating operator to relieve such tension so as to generate lepton asymmetry (of freeze-in/out type) with a much lower reheating temperature that can accommodate light (sub-GeV) ALPs sensitive to current and future ALP searches.

In this paper we investigate the scattering amplitudes of spin-2 Kaluza-Klein (KK) states in Randall-Sundrum models with brane-localized curvature terms. We show that the presence of brane-localized curvature interactions modifies the properties of (4D) scalar fluctuations of the metric, resulting in scattering amplitudes of the massive spin-2 KK states which grow as $\mathcal{O}(s^3)$ instead of $\mathcal{O}(s)$. We discuss the constraints on the size of the brane-localized curvature interactions based on the consistency of the Sturm-Liouville mode systems of the spin-2 and spin-0 metric fluctuations. We connect the properties of the scattering amplitudes to the diffeomorphism invariance of the compactified KK theory with brane-localized curvature interactions. We verify that the scattering amplitudes involving brane-localized external sources (matter) are diffeomorphism-invariant, but show that those for matter localized at an arbitrary point in the bulk are not. We demonstrate that, in Feynman gauge, the spin-0 Goldstone bosons corresponding to helicity-0 states of the massive spin-2 KK bosons behave as a tower of Galileons, and that it is their interactions that produce the high-energy behavior of the scattering amplitudes. We also outline the correspondence between our results and those in the Dvali-Gabadadze-Porrati model. In an Appendix we discuss the analogous issue in extra-dimensional gauge theory, and show that the presence of a brane-localized gauge kinetic-energy term does not change the high-energy behavior of corresponding KK vector boson scattering amplitudes.

We discuss the possibility that the two nearby resonances observed by BESIII partially below the $p\overline{p}$ threshold might be due to mixing between two metastable states with the same $J^{PC}=0^{-+}$ quantum numbers, but rather different internal structure. One is a $p\overline{p}$ hadronic molecule and the other a bound state of a light-quark diquark and an antidiquark, both with spin 1 and isospin 0, a composite color antitriplet and triplet, respectively. The doubling of resonances, one of which may be interpreted as a hadronic molecule, while the other arises from $q\overline{q}$ annihilation in a state with vacuum quantum numbers, may be a more general feature than the specific case considered here.

Momentum exchange between a heavy quark and a hot quark-gluon medium can be characterized nonperturbatively in terms of field-strength field-strength ($E-E$ and $B-B$) correlators along a Polyakov loop. These can be studied on the lattice and analytically continued. However the lattice typically determines the correlators after the application of gradient flow. We investigate how gradient flow renormalizes these correlation functions by carrying out a next-to-leading order perturbative analysis of the correlators including gradient flow. This establishes a next-to-leading order renormalization matching between the correlators as measured on the lattice and the correlators relevant for momentum diffusion.

We investigate the high $Q^2$ (photon virtuality) limit of single-inclusive hadron production in deep inelastic scattering at small $x$, using the color glass condensate formalism at next-to-leading order. We focus on the ${\mathrm{\Lambda }}_{\mathrm{QCD}}^2\ll {\mathbf{p}}_h^2\ll Q^2$ kinematic regime, where ${\mathbf{p}}_h$ is the produced hadron transverse momentum, and extract the Sudakov double logarithms. We further argue that compatibility between the color glass condensate calculation and transverse momentum dependent distribution factorization at one-loop order can only be achieved if the small-x evolution is kinematically constrained.

Inspired by the recent considerations of parton momentum broadening in the glasma phase, we study the medium-induced soft gluon radiation of jet partons at early times in heavy-ion collisions. The glasma state is assumed to be comprised of independent color domains with homogenous longitudinal fields that vary event by event, and we further complete this model with an event-averaging procedure accounting for the finite correlation length. Using this description, we evaluate the rate of medium-induced radiation from an energetic parton at midrapidity in the glasma phase. We mainly focus on SU(2) color fields for simplicity, also referring to the U(1) case and comparing with the Baier, Dokshitzer, Mueller, Peigné, Schiff, and Zakharov rate to gain further insight. Our results show that there is an intricate interplay of the synchrotron-like radiation in a single color domain with the destructive interference between different color domains, after the medium averaging is performed. Thus, we find that the emission rate is sensitive to the matter structure, decreasing for a glasma state populated by smaller color domains—i.e., for a glasma with a larger characteristic saturation scale. Our approach can be applied to more realistic backgrounds, and it sets the stage for the modeling of jet evolution in the early stages of heavy-ion collisions.

Electron-neutrino charged-current interactions with xenon nuclei were modeled in the nEXO neutrinoless double-$\beta$ decay detector ($\sim 5$ metric ton, 90% ${}^{136}\mathrm{Xe}$, 10% ${}^{134}\mathrm{Xe}$) to evaluate its sensitivity to supernova neutrinos. Predictions for event rates and detectable signatures were modeled using the Model of Argon Reaction Low Energy Yields (MARLEY) event generator. We find good agreement between MARLEY’s predictions and existing theoretical calculations of the inclusive cross sections at supernova neutrino energies. The interactions modeled by MARLEY were simulated within the nEXO simulation framework and were run through an example reconstruction algorithm to determine the detector’s efficiency for reconstructing these events. The simulated data, incorporating the detector response, were used to study the ability of nEXO to reconstruct the incident electron-neutrino spectrum and these results were extended to a larger xenon detector of the same isotope enrichment. We estimate that nEXO will be able to observe electron-neutrino interactions with xenon from supernovae as far as 5–8 kpc from Earth, while the ability to reconstruct incident electron-neutrino spectrum parameters from observed interactions in nEXO is limited to closer supernovae.

We propose a microwave-laser-mixed three-beam stimulated resonant photon collider, which enables access to axionlike particles in the meV mass range. Collisions between a focused pulse laser beam and a focused microwave pulse beam directly produce axionlike particles (ALPs) and another focused pulse laser beam stimulates their decay. The expected sensitivity in the meV mass range has been evaluated. The result shows that the sensitivity can reach the ALP-photon coupling down to $\mathcal{O}({10}^{-13}){\mathrm{GeV}}^{-1}$ with ${10}^6$ shots if 10–100 TW class high-intensity lasers are properly combined with a conventional 100 MW class S-band klystron. This proposal paves the way for identifying the nature of ALPs as candidates for dark matter, independent of any cosmological and astrophysical models.

Experimental proposals for testing quantum gravity-induced entanglement of masses (QGEM) typically involve two interacting masses which are each in a spatial superposition state. Here, we propose instead a QGEM experiment with two particles which are each in a superposition of rotational states; this amounts to a superposition of mass through mass-energy equivalence. In sharp contrast to the typical protocols studied, our proposal is genuinely relativistic. It does not consider a quantum positional degree of freedom and but relies on the fact that rotational energy gravitates: the effect we consider disappears in the $c\to \infty$ limit. Furthermore, this approach would test a feature unique to gravity since it amounts to sourcing a spacetime in superposition due to a superposition of “charge.”

We present the first systematic study of the relativistic axial-vector four-current distributions inside a nucleon. We show in particular that the slope of the axial form factor $G_A(Q^2)$ in the forward limit—conventionally denoted as $R_A^2$ in the literature—does not represent the three-dimensional mean-square axial radius in the Breit frame, but corresponds instead to a contribution to the mean-square spin radius. We derive explicit expressions for the latter in different frames and find in general additional contributions that depend on both the nucleon mass and the forward values of the axial-vector form factors $G_A(0)$ and $G_P(0)$. This provides an additional key motivation for ongoing lattice quantum chromodynamics (QCD) calculations and future experimental measurements of the induced pseudoscalar form factor $G_P(Q^2)$.

One of the most wanted features of holography in its condensed matter physics application is to encode the structure of lattice, which is the most direct data of the material. In this paper, we propose a method to encode the lattice structure by embedding the tight binding data into the Dirac equation in the anti–de Sitter bulk. We explicitly worked out the idea for the graphene and Haldane models, and the result shows that some degrees of freedom escape the free-electron on-shell curve, and Green’s function loses the pole structure completely. It implies that the electronic structure is not described by the band structure only, which is consistent with what many angle-resolved photoemission spectroscopy data tell us, and it also implies that the system is in non-Fermi liquid even for the graphene, which is consistent with recent experiments for the clean graphene.

We study transitions from chaotic to integrable Hamiltonians in the double scaled Sachdev-Ye-Kitaev (SYK) and $p$-spin systems. The dynamics of our models is described by chord diagrams with two species. We begin by developing a path integral formalism of coarse graining chord diagrams with a single species of chords, which has the same equations of motion as the bilocal ($G\mathrm{\Sigma }$) Liouville action, yet appears otherwise to be different and in particular well defined. We then develop a similar formalism for two types of chords, allowing us to study different types of deformations of double scaled SYK and in particular a deformation by an integrable Hamiltonian. The system has two distinct thermodynamic phases: one is continuously connected to the chaotic SYK Hamiltonian, the other is continuously connected to the integrable Hamiltonian, separated at low temperature by a first order phase transition. We also analyze the phase diagram for generic deformations, which in some cases includes a zero-temperature phase transition.