We derive fully general expressions for the inclusive (anti-)neutrino-induced nuclear quasielastic production of a strange or charmed baryon $Y$, considering all dimension-six new-physics operators relevant to the semileptonic $q\to q^{\prime }\ell {\nu }_{\ell }$ transition with both left- and right-handed neutrino fields. We illustrate the formalism by applying it to the ${\mathrm{\Lambda }}_c$ production in neutrino-nucleus scattering. The nuclear response is computed using a state-of-the-art ab initio spectral function, based on realistic nuclear many-body wave functions obtained via the coupled-cluster method and a nuclear Hamiltonian derived from chiral effective field theory. We also highlight the role played by the final state interactions between the produced $Y$ hyperon and the residual nuclear system, which can obscure potential new physics signals in this (anti-)neutrino–nucleus reaction. Our results improve upon previous studies that neglected nuclear corrections and uncertainties—effects we show to be comparable to, or even larger than, those expected from new physics.

We search for dark matter in the form of axionlike particles (ALPs) in the mass range $5.576741\mathrm{neV}/{\mathrm{c}}^2-5.577733\mathrm{neV}/{\mathrm{c}}^2$ by probing their possible coupling to fermion spins through the ALP field gradient. This is achieved by performing proton nuclear magnetic resonance spectroscopy on a sample of methanol as a technical demonstration of the Cosmic Axion Spin Precession Experiment Gradient (CASPEr-Gradient) Low-Field apparatus. Searching for spin-coupled ALP dark matter in this mass range with associated Compton frequencies in a 240 Hz window centered at 1.348570 MHZ resulted in a sensitivity to the ALP-proton coupling constant of $g_{\mathrm{ap}}\approx 3\times {10}^{-2}{\mathrm{GeV}}^{-1}$. This narrow-bandwidth search serves as a proof-of-principle and a commissioning measurement, validating our methodology and demonstrating the experiment’s capabilities. CASPEr-Gradient Low-Field will probe the mass range from $4.1\mathrm{peV}/{\mathrm{c}}^2$ to $17\mathrm{neV}/{\mathrm{c}}^2$ with hyperpolarized samples to boost the sensitivity beyond the astronomical limits.

We discuss the ’t Hooft-Polyakov (TP) monopole and then dyon in the framework of higher dimensional gauge theories, such as gauge-Higgs unification models. First, we point out that the Bogomol’nyi-Prasad-Sommerfield (BPS) monopole is nothing but a self-dual gauge field in the 4-dimensional (4D) space including the extra dimension, which is argued to lead to a consequence that the mass of the BPS monopole $M_{\mathrm{TPM}}$ and therefore the vacuum expectation value (VEV) of the Higgs field are topologically quantized. In literatures, there exist related arguments on the calorons, which may be understood to be a composition of a pair of constituent monopole and antimonopole, with each constituent carrying fractional topological charge, while the net topological charge carried by the caloron is unity. From the viewpoint of the caloron, our conclusion of the quantized monopole mass corresponds to the special case, where only a single monopole exists that carries the net topological charge. Next, the argument is generalized to the case of the dyon. The mass of the BPS dyon, $M_{\mathrm{BPS}}$, is still proportional to the quantized Higgs VEV, though it also depends on a parameter $\mu$, denoting the ratio of the electric and magnetic charges of the dyon. In the 5D gauge theories the Chern-Simons term is induced at the quantum level, which, after the extra space component of the gauge field is replaced by its VEV, produces the $\theta$ term. Then, through the Witten effect we reach to an interesting conclusion that the parameter $\mu$ and therefore $M_{\mathrm{BPS}}$ are discretized. In addition, we propose a numerical method to obtain the field configurations and the mass of the non-BPS dyons by use of “modified” gradient flow equations.

In this paper, quantum theory of a real massive scalar field in the background of a traversable wormhole is examined. The wormhole is supposed to connect two different universes; as a particular example the simplest Ellis wormhole is considered. It is shown that the resulting theory possesses a doubling of quantum states parametrized by the same value of asymptotic momentum; two different sets of such degenerate states are localized in different universes. This is a consequence of the topological structure of the wormhole spacetime, which is the same as the topological structure of the Schwarzschild spacetime providing a similar degeneracy of quantum states.

We investigate the rate of change of the mean atomic energy for centripetally accelerated atoms interacting with electromagnetic vacuum fluctuations near a reflecting boundary, using the Dalibard–Dupont-Roc–Cohen-Tannoudji formalism. The distinct contributions from vacuum fluctuations and radiation reaction are analyzed separately. Our results reveal that, when the centripetal acceleration significantly exceeds the characteristic acceleration set by the atomic transition frequency, vacuum fluctuations dominates over radiation reaction, irrespective of the atom-boundary distance and the atomic polarization. In the near-zone regime, where the atom-boundary distance is much smaller than both the characteristic length associated with the acceleration and the transition wavelength of the atom, the boundary introduces substantial corrections to the rate of change of the mean atomic energy. These corrections are comparable in magnitude to those in free space and exhibit strong dependence on the atomic polarization. Remarkably, in the intermediate and far regions, contributions stemming from the combined effects of the boundary and acceleration can become the leading and subleading terms, respectively. An acceleration-independent term also arises from their interplay. These findings highlight the significant interplay between acceleration and the presence of a boundary in shaping atomic radiative properties and may have potential implications for experimentally probing the circular Unruh effect.

It is apparent that a stationary spacetime does not admit gravitational radiation. But whether a spacetime without gravitational radiation is stationary is not clear. Especially when a spacetime holds matter such as electromagnetic field, gravitational radiation in general cannot determine the matter radiation and the matter behavior. In this paper we show that, remarkably, electrovac Robinson-Trautman spacetimes without gravitational radiation are necessarily stationary. More precisely, if the gravitational news function of a Robinson-Trautman spacetime containing a Maxwell field vanishes, the electromagnetic radiation must vanish as well. Furthermore, we prove that any Robinson-Trautman spacetime endowed with a Maxwell field and zero gravitational news is exactly the Reissner-Nordström solution. Our results provide a new perspective on the uniqueness of the Reissner-Nordström spacetime.

We investigate the gravitational impulse by using the generalized formulation of the quantum Boltzmann equation (QBE), wherein the initial states are taken as wave packets rather than plane waves. The QBE operates within an open quantum system framework. Using this approach, we can analyze the two-body gravitational scattering by considering one body as part of the environment and the other as the system. Through this procedure, we obtain the system’s impulse up to the second order for two massive objects. Similarly, we apply the forward scattering of the QBE to the gravitational impulse of a photon due to a massive object, during which we consider the photon as the system and the massive object as the environment. In this methodology, we use the QBE to compute the time evolution of the momentum operator associated with the system. While the forward scattering term vanishes when considering point particles, we demonstrate its persistence when using wave packets to describe both massive particles and the photon field. The results reported here are entirely consistent with the previous approaches.

The Einstein-Cartan theory of gravity can arise from a mechanism of spontaneous symmetry breaking within the context of pregeometric gauge theories. In this work, we develop the Hamiltonian analysis of such theories. By making contact with the Arnowitt-Deser-Misner formalism, we show that all the results of canonical General Relativity are correctly recovered in the IR limit of the spontaneously broken phase. We then apply Dirac’s algorithm to study the algebra of constraints and determine the number of degrees of freedom in the UV limit of the unbroken phase. We also discuss possible pathways toward a UV completion of General Relativity, including a pregeometric generalization of the Wheeler-DeWitt equation and an extended BF formulation of the pregeometric theory.

The field equations of pregeometric theories of gravity are derived and analyzed, both without and with matter. After the spontaneous symmetry breaking that reduces the gauge symmetry of these theories à la Yang-Mills, a metric structure for spacetime emerges and the field equations recover both the Einstein and the Cartan field equations for gravity. A first exact solution of the pregeometric field equations is also presented. This solution can be considered as a pregeometric de Sitter universe and provides a possible resolution for the problem of the big bang singularity.

We study the causal structure for spherically symmetric dust collapse within a model of effective loop quantum gravity in midisuperspace framework. We develop a general strategy (working beyond the dynamical model of our consideration) for constructing double null coordinates, allowing the extraction of conformal diagrams within single coordinate charts. With the methods introduced, we confirm that the homogeneous Oppenheimer-Snyder collapse scenario resembles the Reissner-Nordström-like picture. For the nonhomogeneous collapse scenario, we construct the conformal diagrams, subsequently, we study its relevant properties, in particular, dust particles’ trajectories, apparent horizons and shell-crossing singularities. We conclude that a significant region of spacetime remains inaccessible to the model’s dynamics due to the formation of the shell-crossing singularities. The question of whether a timelike singularity, similar to that in the homogeneous dust ball collapse scenario, arises in the nonhomogeneous case remains unresolved. Furthermore, we find that phenomena such as black hole explosions or gravitational shock waves cannot be witnessed by an external observer who does not cross any horizon. Indeed, the collapse cannot take place within single asymptotic region.

We study the greybody factor of charged hairy black holes (BHs) that arise due to the presence of an axion coupled to the electromagnetic field. Specifically, we consider spin-0 and spin-1 test particles propagating in the background of BHs with axion hair, where the spacetime geometry is modified compared to that of the Reissner-Nordström (RN) BH. In contrast to the RN solution, with a given total BH charge, the effective potential for test particles depends on the ratio of electric to magnetic charges. In other words, charged BHs with axion hair breaks the electric-magnetic duality present in the RN solution. We compute the transmission coefficient of test particles plunging into the charged hairy BH and find that the deviation from the RN solution is particularly evident for higher multipole moments. Precise measurements of greybody factors can, thus, serve as probes for the possible existence of axions coupled to the electromagnetic field, as well as potential signatures of magnetic monopoles.

We present the first search for evidence of neutrino self-interaction with two new, state-of-the-art likelihoods for eBOSS Lyman-$\alpha$ data. These are an effective field theory (EFT) likelihood with priors from the Sherwood simulation suite, and a compressed likelihood derived from an emulator built using the PRIYA simulation suite. Previous analyses that combined Planck measurements with eBOSS Lyman-$\alpha$ likelihoods based on earlier simulations found a preference for neutrino self-interactions. In contrast, using either of the new eBOSS Lyman-$\alpha$ likelihoods, we find that a joint analysis with the cosmic microwave background data from Planck prefers a negligible level of neutrino self-interaction, and derive new constraints on the neutrino self-coupling: ${\log }_{10}(G_{\mathrm{eff}}{\mathrm{MeV}}^2)=-5.57_{-0.58}^{+0.98}$ for $Planck+\mathrm{EFT}$ Lyman-$\alpha$, and ${\log }_{10}(G_{\mathrm{eff}}{\mathrm{MeV}}^2)=-5.16_{-0.67}^{+1.12}$ for $Planck+\mathrm{PRIYA}$ Lyman-$\alpha$, at 68% confidence. We also consider Planck in combination with DESI BAO data, and find that the latter does not provide significant constraining power for neutrino self-interactions.

Recent analyses from the Dark Energy Spectroscopic Instrument (DESI) collaboration suggest that the dark energy density of the Universe may be decreasing with time, slowing the acceleration of the scale factor $a$. Typically these studies are performed assuming an ansatz for the equation of state $w(a)$. In this work, we instead consider simple models of a scalar quintessence potential with linear and quadratic behavior, which could be more representative of real models than particular parametrizations of $w(a)$. We observe a significant preference for dynamical dark energy when using supernova data from the Dark Energy Survey year 5 along with DESI baryonic acoustic oscillation and Planck data, at the cost of slightly exacerbating the Hubble tension. However, when using supernova data from $\mathrm{Pantheon}+$ or Union3, we find only a mild preference for dynamical dark energy.

Many large scale structure surveys sort their observations into redshift bins and treat every tracer as being located at the mean redshift of its bin, a treatment which we refer to as the equal time approximation. Recently, a new method was developed which allows for the estimation and correction of errors introduced by this approximation, which we refer to as the unequal time correlator-level projection. For single tracer power spectra, corrections arise at second order and above in a series expansion, with first order terms surviving only in multitracer analyses. In this paper we develop a new method which we refer to as the unequal time field level projection. This formalism projects the fields individually onto the celestial sphere, displaced from individual reference times, before defining their correlators. This method introduces new, first order correction terms even in the case of single tracer power spectra. Specifically, new first order terms are introduced which apply to both cross-bin and single bin correlators. All of these new corrections originate with derivatives over combinations of a delta function, a cross-bin phase term, and the power spectrum itself and stem from the introduction of two unequal time Fourier transforms into the analysis. We analyze these corrections in the context of a linearly biased power spectrum divided between two redshift bins and find that they can lead to nontrivial corrections, particularly to cross-bin correlators. We also show that these terms can be replicated by appropriately extending the correlator-level analysis to include a second Fourier transform which allows for a full redshift bin integration.

The origin of magnetic fields observed on both astrophysical and cosmological scales is a compelling problem that has the potential to shed light on the early Universe. We analytically investigate inflationary magnetogenesis in scenarios where a brief departure from slow-roll inflation—akin to mechanisms proposed for primordial black hole formation—leads to enhanced magnetic field generation with a growing power spectrum. Focusing on the Ratra model, we derive an analytic bound on the growth of the magnetic field power spectrum in this context, showing that the spectral index can reach $d\ln {\mathcal{P}}_B/d\ln k=4.75$ during the growth phase. This growth enables amplification from cosmic-microwave-background-safe large-scale amplitudes to values of astrophysical relevance. We further compute the stochastic gravitational wave background sourced by the resulting magnetic fields, incorporating their rich spectral features. Under suitable conditions, the induced signal exhibits a characteristic frequency dependence and amplitude within reach of future gravitational wave observatories, providing a distinctive signature of this mechanism and a specific class of templates for upcoming gravitational wave searches.

Numerous observations confirm the existence of dark matter (DM) at astrophysical and cosmological scales, yet the fundamental nature of this elusive component of our Universe remains unknown. Theory and simulations of Galaxy formation predict that DM should cluster on small scales in bound structures called subhalos or DM clumps. While the most massive DM subhalos host baryonic matter and are observed as dwarf galaxies of the Milky Way (MW), less massive, unpopulated subhalos could be abundant in the Galaxy as well and yield high-energy gamma rays as final products of DM annihilation. Recently, it has been highlighted that the brightest halos should also have a sizeable extension in the sky. In this study, we examine the prospects offered by the Cherenkov Telescope Array Observatory (CTAO), a next-generation gamma-ray instrument, for detecting and characterizing such objects. Previous studies have primarily focused on high-latitude observations; here, we assess the potential impact of the CTAO’s Galactic Plane Survey, which will provide unprecedentedly deep survey data for the inner five degrees of the Galactic plane. Our modeling accounts for tidal effects on the subhalo population, examining the conditions under which DM subhalos can be detected and distinguished from conventional astrophysical sources. We find that regions a few degrees above or below the Galactic plane offer the highest likelihood for DM subhalo detection. For an individual subhalo—the brightest from among various realizations of the MW subhalo population—we find that detection at the $5\sigma$ level is achievable for an annihilation cross section of $⟨\sigma v⟩\sim 3\times {10}^{-25}{\mathrm{cm}}^3/\mathrm{s}$ for TeV-scale DM annihilating into $b\overline{b}$. For a full population study, depending on the distribution and luminosity model of Galactic subhalos, still unconstrained cross sections in the range $⟨\sigma v⟩\sim {10}^{-23}–{10}^{-22}{\mathrm{cm}}^3/\mathrm{s}$ for TeV DM candidates are necessary for the brightest subhalos to be detected.

Twin stars, characterized by identical stellar masses but distinct internal structures, can arise in dark matter admixed neutron stars (DANSs). This work will focus on one kind of special twin stars—ultimate twin stars (UTSs)—defined as DANSs with identical total masses and normal matter radii. Based on the two-fluid Tolman-Oppenheimer-Volkoff (TOV) equations, we model DANSs with normal matter described by APR3 and dark matter represented by ideal Fermi gas or self-interacting bosonic model. The results demonstrate that UTSs with canonical mass $1.4M_{\odot }$ emerge as the dark matter mass fraction varies, and their tidal deformabilities may differ by up to three orders of magnitude. The huge difference in tidal deformability provides a critical observable for distinguishing UTSs. Moreover, the tidal deformability exhibits correlation with dark matter mass fraction, offering a potential method to constrain dark matter parameters through gravitational wave observations.

We introduce $w_i{f}_i$ ensembles as a novel framework to obtain asymptotic frequentist uncertainties on density ratios, with a particular focus on neural ratio estimation in the context of high-energy physics. When the density ratio of interest is a likelihood ratio conditioned on parameters, $w_i{f}_i$ ensembles can be used to perform simulation-based inference on those parameters. After training the basis functions $f_i(x)$, uncertainties on the weights $w_i$ can be straightforwardly propagated to the estimated parameters without requiring extraneous bootstraps. To demonstrate this approach, we present an application in quantum chromodynamics at the Large Hadron Collider, using $w_i{f}_i$ ensembles to estimate the likelihood ratio between generated quark and gluon jets. We use this learned likelihood ratio to estimate the quark fraction in a synthetic mixed quark/gluon sample, showing that the resultant uncertainties empirically satisfy the desired coverage properties.

The isospin-singlet scalar meson $f_0(980)$ is hypothesized to consist of two energy eigenstates, forming a mixture of $\frac{1}{\sqrt{2}}(\overline{u}u+\overline{d}d)$ and $\overline{s}s$. Building on this framework, we apply the quantum chromodynamics (QCD) sum rules approach in the background field theory to compute the $f_0(980)$ decay constant, yielding $f_{f_0}({\mu }_0=1\mathrm{GeV})=0.386\pm 0.009\mathrm{GeV}$. Subsequently, we derive the first two $\xi$-moments of the leading-twist light-cone distribution amplitude ${\varphi }_{2;f_0}$. Using QCD light-cone sum rules, we then calculate the $D_s^{+}\to f_0(980)$ transition form factor (TFF) $f_{+}(q^2)$, obtaining $f_{+}(0)=0.516_{-0.024}^{+0.027}$ at the large-recoil region. We extend $f_{+}(q^2)$ to the full physical region via a simplified series expansion parametrization, enabling calculations of the differential decay widths and the branching fraction $\mathcal{B}(D_s^{+}\to f_0(980)(\to {\pi }^{+}{\pi }^{-})e^{+}{\nu }_e)=(1.783_{-0.189}^{+0.227})\times {10}^{-3}$. Our theoretical predictions align well with the latest BESIII Collaboration measurements within reasonable errors.