Supernova-neutrino-boosted dark matter ($\mathrm{SN}\nu$ BDM) has emerged as a promising portal for probing sub-GeV dark matter. In this work, we investigate the behavior of BDM signatures originating from core-collapse supernovae within the Milky Way (MW) over the past one hundred thousand years, examining both their temporal evolution and present-day spatial distributions. We show that while the MW BDM signature is approximately diffuse in the nonrelativistic regime, it exhibits significant temporal variation and spatial localization when the BDM is relativistic. Importantly, we compare these local MW signatures with the previously proposed diffuse $\mathrm{SN}\nu$ BDM (DBDM), which arises from the accumulated flux of all past supernovae in the Universe [Y.-H. Lin and M.-R. Wu, Phys. Rev. Lett. 133, 111004 (2024)]. In the nonrelativistic limit, DBDM consistently dominates over the local diffuse MW BDM signature. Only when the MW BDM becomes ultrarelativistic and transitions into a transient, highly localized signal can it potentially surpass the DBDM background. This work thus reinforces the importance of DBDM for $\mathrm{SN}\nu$ BDM searches until the next galactic SN offers new opportunities.

The absence of direct evidence for new physics at current collider energies motivates the study of indirect effects within the framework of the Standard Model effective field theory (SMEFT). In this work, we investigate the role of the $A_4$ discrete flavor symmetry in constraining the UV dynamics, giving rise to dimension-six SMEFT operators involving leptons. We consider renormalizable interactions between SM fields and heavy mediators, classified according to their $A_4$ transformation properties in the modular framework, where Yukawa structures are encoded in modular forms. Restricting our analysis to UV interactions with at most a single modular form insertion, we study the resulting classification of $A_4$ UV mediator irreducible representations and explore their implications across a range of observables, including both lepton-flavor-conserving and lepton-flavor-violating processes. A detailed phenomenological analysis is carried out, incorporating both tree-level and one-loop matching contributions for scalar and fermionic mediators, as well as leading-log renormalization group equation effects in case of vectors.

We illustrate how the future electron-ion collider (EIC) can be used to discover dark bosons with masses in the $\sim (10\mathrm{MeV}\text{−}10\mathrm{GeV})$ regime, having a wide range of properties. We only require that the dark bosons have a non-negligible weak coupling to electrons and decay with the $\mathcal{O}(1)$ branching fraction into invisible final states. Our signal selection takes advantage of the excellent electron beam kinematic measurements and the capability to tag incoherent scattering, as envisioned at the EIC. This makes the EIC a powerful tool for uncovering potential dark sector forces, for a variety of possibilities.

In this paper, we develop an approach to calculate the valence-quark quasiparton distribution amplitude (quasi-PDA) and quasiparton distribution function (quasi-PDF) for the pion with a large longitudinal momentum with the functional renormalization group (fRG). This is demonstrated in a low energy effective theory (LEFT) with four-quark scatterings. In the study of the complex structure of quasi-PDA, we introduce a deformed integration contour in the calculations of quasi-PDA or quasi-PDF, which allows us to obtain correct integrals for all momentum fractions. It is found that the pion light-front PDA extrapolated from quasi-PDA based on the large momentum effective theory in the LEFT is comparable with lattice QCD and Dyson-Schwinger equation. This work paves the way to study the PDA and PDF within the fRG approach to first-principles QCD.

We investigate energy bounds and the stability of stationary asymptotically flat spacetimes with an ergoregion and no future horizon in the context of Einstein-Maxwell-scalar field models that naturally arise in Kaluza-Klein and string theories. In order to do that, we consider scalar field perturbations nonminimally coupled to a background electromagnetic field. We show that there is compactly supported initial data such that the initial energy flux across the initial Cauchy hypersurface is negative and that the energy flux decreases with time. Then, considering arguments due to Friedman and Moschidis, this indicates that the energy flux diverges for those solutions and such spacetimes with an ergoregion are unstable.

Primordial black holes (PBHs) with masses between ${10}^{14}$ and ${10}^{20}\mathrm{kg}$ are candidates to contribute a substantial fraction of the total dark matter abundance. When in orbit around the center of a star, which can possibly be a completely interior orbit, such objects would emit gravitational waves, as predicted by general relativity. In this work, we examine the gravitational wave signals emitted by such objects when they orbit typical stars, such as the Sun. We show that the magnitude of the waves that could eventually be detected on Earth from a possible PBH orbiting the Sun or a neighboring Sun-like star within our Galaxy can be significantly stronger than those originating from a PBH orbiting a denser but more distant neutron star. Such signals may be detectable by the LISA gravitational wave detector. In addition, we estimate the contribution that a large collection of such PBH-star systems would make to the stochastic gravitational wave background within a range of frequencies to which pulsar timing arrays are sensitive.

Recently, there has been interest in the applicability of quantum statistics to distinguish Dirac from Majorana neutrinos in multineutrino final states. In particular, debate has arisen over the validity of the Dirac-Majorana confusion theorem in these processes, i.e., that any distinction between the Dirac and Majorana processes goes to zero as the neutrino mass goes to zero. Here we approach this problem equipped with spinor-helicity methods generalized for massive Dirac and Majorana fermions. We explicitly calculate all helicity amplitudes, and their squares, for the decay of a light scalar particle to two neutrinos and two oppositely charged leptons. This allows us to pinpoint the crucial steps which could lead to claims of a violation of the confusion theorem. We show that, if the correct antisymmetrization of Dirac to Majorana amplitudes is used, identification of which is clear in this framework, and all relevant contributions are appropriately summed, a scalar decay into two charged leptons and two neutrinos satisfies the Dirac-Majorana confusion theorem.

In the poltergeist mechanism the enhancement of induced gravitational waves (GWs) occurs due to a sudden transition from an early matter-dominated era to the radiation-dominated era. In this work, we calculate the bispectrum of induced GWs from the poltergeist mechanism by adopting the sudden transition approximation. We find that the tensor bispectrum peaks either in the equilateral or squeezed configurations, depending on scales. Such a characteristic behavior enables us to distinguish it from that from other GW generation mechanisms.

Recently, the wavefunction coefficients for conformally coupled scalars in an Friedmann-Robertson-Walker cosmology have been presented as a sum over amplitudelike functions known as amplitubes. In this work, we extend this analysis to full correlation functions. Remarkably, the amplitube expansion of the correlator exhibits many vanishing contributions that are otherwise present in the expansion of the wavefunction. Moreover, while the wavefunction coefficients suffer from relative minus signs between terms, the surviving terms in thte correlation function do not. These observations point to a hidden simplicity in the structure of the correlation function compared to that of the wavefunction coefficient.

This letter introduces a novel analytical approach to calculating phase-space integrals, crucial for precision in particle physics. We develop a method to compute angular components using multifold Mellin-Barnes integrals, yielding results in terms of Goncharov polylogarithms for integrals involving three denominators. Our results include expressions for massless momenta to $\mathcal{O}({\epsilon }^2)$ and for massive momentum to $\mathcal{O}(\epsilon )$. We derive recursion relations that reduce integrals with higher powers of denominators to simpler ones. We detail how to combine the angular part with the radial one which requires a careful handling of singularities.

The muon collider, recently highlighted as recommendation 1 in the U.S. National Academies report on elementary particle physics, offers a unique opportunity for fixed-target experiments with high energy and luminosity. This paper outlines some of the challenges and possibilities for fixed-target experiments to study the multidimensional structure of hadrons at the muon collider. We present a sketch of an experiment making use of the high-energy muon beam from the muon collider that could serve as the next-generation hadronic physics experiment after the Electron-Ion Collider.

We investigate the internal structure of the $\mathrm{\Omega }(2012{)}^{-}$ by analyzing lattice QCD simulation and experimental data within Hamiltonian effective field theory, considering both $J^P=1/2^{-}$ and $3/2^{-}$ assignments. The couplings to the dominant decay channel $\mathrm{\Xi }\overline{K}$ and the near-threshold channel $\mathrm{\Xi }(1530)\overline{K}$ are determined through the quark-pair-creation model. By studying the lattice QCD spectra in these two spin-parity scenarios, we extract the masses and widths of the resonances. We notice that the $J^P=3/2^{-}$ resonance is consistent with the observed $\mathrm{\Omega }(2012{)}^{-}$ while the recently reported $\mathrm{\Omega }(2109{)}^{-}$ may be a $J^P=1/2^{-}$ $\mathrm{\Omega }$.

Recent measurements of $J/\psi$ production as a function of event charged-particle multiplicity at the collision energies of both the Large Hadron Collider (LHC) and the Relativistic Heavy Ion Collider (RHIC) show enhanced $J/\psi$ production yields with increasing multiplicity. One potential explanation for this type of dependence is multiparton interactions (MPI). We present the first study of potential autocorrelations at RHIC energies and forward and backward rapidity of self-normalized $J/\psi$ yields and $\psi (2S)$ to $J/\psi$ ratio, as a function of self-normalized multiplicity in $p+p$ collisions. In addition, detailed pythia studies tuned to RHIC energies were performed to investigate the MPI impacts. We find that the PHENIX data at RHIC are consistent with recent LHC measurements and can only be described by pythia calculations that include MPI effects. The forward and backward $\psi (2S)$ to $J/\psi$ ratio is found to be less dependent on the charged-particle multiplicity.

The uniqueness and rigidity theorems assert that the asymptotically flat, vacuum, stationary rotating black hole solution in general relativity must be the Kerr solution exhibiting additional symmetries such as axisymmetry and circularity. In our analysis of the postmerger ringdown signal from coalescing black hole binary systems, we identify potential observational signatures for deviations from these Kerr symmetries. Utilizing ringdown data from the gravitational wave event GW150914, we place significant constraints on such deviations. Our analysis introduces a new and novel approach for testing spacetime symmetries through gravitational wave observations.

We propose that moments of time arise through the failed emergence of the temporal diffeomorphism as gauge symmetry, and that the passage of time is a continual process of an instantaneous state collapsing toward a gauge-invariant state. Unitarity and directedness of the resulting time evolution are demonstrated for a minisuperspace model of cosmology.

Radiative properties and images of the short-hairy black hole surrounded by a thin accretion disk are studied. After studying the geodesic motion of massive test particles in the equatorial plane of the short-hairy black hole, the radiative efficiency of the black hole is calculated, and it is found that the short hair term results in the increase of the radiative efficiency. Then, the radiative properties, such as radiative flux, effective temperature, and spectral luminosity, of the thin accretion disk around the short-hairy black hole are investigated and the impact of parameters $a$, $Q$, and $k$ on these properties is also discussed. Several examples with concrete black hole masses and accretion rates for the radiative properties are also illustrated and compared with the corresponding Kerr cases. Finally, by using the ray-tracing method, the observational appearance of the short-hairy black hole illuminated by the thin accretion disk is presented for various inclination angles. Compared with the Kerr case, the short hair term leads to tiny shrink of the black hole images.

In this work, based on the $3+1$ decomposition in Fecko and Löffler et al., we present a fully exterior calculus breakdown of spacetime and Einstein’s equations. Links to the orthonormal frame approach are drawn to help understand the variables in this context. Two formulations are derived, discretized, and tested using the exterior calculus discrete de Rham complex, and some discrete quantities are shown to be conserved in one of the cases.

The radiated energy and angular momentum from a point mass on a hyperboliclike orbit about a Schwarzschild black hole are computed for the first time in the framework of the first-order self-force theory. The analytical expressions for the fluxes are obtained through the standard method of Mano, Suzuki, and Takasugi in the form of combined post-Minkowskian (PM) and post-Newtonian (PN) expansions. The reached PM accuracy for the energy and angular momentum losses is $O(G^5)$ and $O(G^4)$, respectively, and 7PN for both. The radiative losses (energy, angular momentum, and linear momentum) are currently known in PN-expanded form up to the (fractional) 3PN order [D. Bini et al., [Phys. Rev. D 107, 024012 (2023)] ]. Exact PM results valid for arbitrary values of the velocity are limited to $O(G^4)$ for the energy and $O(G^3)$ for the angular momentum. An exact expression for the radiated energy at $O(G^5)$ has been recently obtained in M. Driesse et al., [Nature (London) 641, 603 (2025)] in the first-order self-force limit, whereas the $O(G^4)$ radiated angular momentum has been partially determined in C. Heissenberg, [Phys. Rev. D 111, 126012 (2025)]. The results of this work are in agreement with the state of the art of both energy and angular momentum losses, also completing the knowledge of the 4PM radiated angular momentum up to the reached PN accuracy. The expressions for radiative losses are then used to get the 5PM radiation-reacted scattering angle, which should also serve as a cross-check of ongoing calculations by other methods.

Todays precision in astrometry has reached a level of a few microarcseconds in the positional measurements of celestial objects. The next generations of astrometric facilities are aiming at the submicroarcsecond scale of accuracy. Submicroarcsecond astrometry requires a considerable improvement in the theory of light propagation in the curved space time of the solar system. In particular, it is indispensable to determine light trajectories to the second order of the post-Newtonian scheme, where the monopole and quadrupole structure of some solar system bodies need to be taken into account. In reality, both the light source as well as the observer are located at finite spatial distances from the gravitating body. This fact implies for the need to solve the boundary value problem of light propagation, where the light trajectory is fully determined by the spatial positions of source and observer and its unit direction at past infinity. This problem has been solved in a recent investigation. A practical relativistic model of observational data reduction necessitates the determination of the unit tangent vector along the light trajectory at the spatial position of the observer. In this investigation, the unit tangent vector at the observer’s position is determined by a sequence of several basic transformations. The light trajectory is then fully given by this unit tangent vector at the observer’s position and by the spatial positions of the celestial light source and observer. The determination of this unit tangent vector allows one to calculate the impact of the monopole and quadrupole structure of solar system bodies on light deflection on the submicroarcsecond level, both for stellar light sources as well as for light sources located in the solar system. Numerical values for the magnitude of light deflection, caused by the monopole and quadrupole structure of the gravitating bodies, are given for grazing light rays at the giant planets of the solar system. The general relativistic model (GREM) is presently used for data reduction of the European Space Agency astrometry mission Gaia. It is shown how the implementation of these basic transformations into GREM would proceed for possible future space astrometry missions like Theia or GaiaNIR.

Analog gravity experiments are making remarkable strides in unveiling both the classical and quantum nature of black holes. By harnessing diverse states of matter, contemporary tabletop setups now replicate strong-field phenomena typically confined to the enigmatic regions surrounding black holes. Through these modern gravity simulators, physical processes once considered elusive may finally be brought into experimental reach. In this work, we investigate the spectrum of massless scalar excitations propagating within the effective geometry of a rotating acoustic metric. Specifically, we build an analog vortexlike spacetime endowed with a tunable parameter that emulates the geometry of a rotating gravitational background. This model accommodates both the presence of a sonic horizon, characteristic of an acoustic black hole for nonzero tuning parameters, and its absence when the parameter vanishes, yielding a horizonless, purely rotational vortex flow devoid of radial inflow. We focus on the case where the vortex flow is purely rotational. The resulting spectral properties are found to be qualitatively consistent with that observed in recent experimental realizations of giant multiply quantum vortices featuring solid or hollow cores. This correspondence suggests that the analog spacetime used here holds significant potential to replicate, qualitatively, the phenomenology of cutting-edge laboratory experiments. In doing so, it offers new insight into the intricate landscape of analog black hole spectroscopy and, potentially, the resonant topography of bounded, rotating astrophysical environments around black holes.