This study introduces a novel set of variables, namely the centre-of-momentum variables, ${\theta }_{\mathrm{c}.\mathrm{m}.}$ and $E_{\mathrm{c}.\mathrm{m}.}$, designed to isolate final-state interactions (FSI) from other aspects of neutrino-nucleus interactions. Through detailed simulation studies, this work demonstrates the ability of these variables to distinguish FSI contributions with minimal dependence on the nuclear initial state and, practically, on the neutrino flux, highlighting their potential for advancing FSI modeling. With high-purity neutrino-hydrogen interaction selections, ${\theta }_{\mathrm{c}.\mathrm{m}.}$ offers the first opportunity for a direct cross-comparison among different neutrino cross-section experiments.

The eikonal limit of black hole quasinormal modes (the large multipole limit $\ell \gg 1$) can be realized geometrically as a next-to-leading order solution to the geometric optics approximation, and also as linear fluctuations about the Penrose limit plane wave adapted to the light ring. Extending this interpretation beyond the linear order in perturbation theory requires a robust understanding of quadratic quasinormal modes for large values of $\ell$. We analyze numerically the relative excitation of quadratic to linear quasinormal modes of Schwarzschild black holes, with two independent methods. Our results suggest that the ratio of quadratic to linear amplitudes for the $\ell \times \ell \to 2\ell$ channel converges towards a finite value for large $\ell$, in sharp contrast with a recent proposal inspired by the Penrose limit perspective. On the other hand, the $2\times \ell \to \ell +2$ channel seems to have a linearly growing ratio. Nevertheless, we show that there is no breakdown of black hole perturbation theory for physically realistic initial data.

We extend all known area inequalities obeyed by Ryu-Takayanagi surfaces of anti–de Sitter boundary regions—the holographic entropy cone—to static generalized entanglement wedges of bulk regions in arbitrary spacetimes. The generalized holographic entropy cone is subject to a mutual independence condition on the bulk regions: each bulk input region must be outside the entanglement wedge of the union of all others. The condition captures when gravitating regions involve fundamentally distinct degrees of freedom despite the nonlocality inherent in the holographic principle.

We present a study of energy density and pressure of a free real scalar quantum field after its decoupling from a thermal bath in the spatially flat Friedman-Lemaître-Robertson-Walker spacetime by solving the Klein-Gordon equation both analytically and numerically for different predetermined scale factor functions $a(t)$. The energy density and pressure, defined by subtracting the vacuum expectation values at the decoupling time, feature corrections with respect to the classical free-streaming solution of the relativistic Boltzmann equation. We show that if the expansion rate is comparable or larger than $m{c}^2/\hslash$ or $K{T}_0/\hslash$ where $m$ is the mass and $T_0$ the decoupling temperature, both energy density and pressure gets strong quantum corrections which substantially modify their classical dependence on the scale factor $a(t)$ and drive pressure to large negative values. For a minimally coupled field with a very low mass in an expanding de Sitter universe quantum corrections are dominant driving pressure and energy density to become asymptotically constant with an equation of state $p/ϵ\simeq -1$, thereby mimicking a cosmological constant. For a minimally coupled massless field, quantum corrections are asymptotically dominant for any accelerated expansion.

We construct the analog of the Dirac-Born-Infeld (DBI) action in Weyl conformal geometry in $d$ dimensions and obtain a general theory of gravity with Weyl gauge symmetry of dilatations (Weyl-DBI). This is done in the Weyl gauge covariant formulation of conformal geometry in $d$ dimensions, suitable for a gauge theory, in which this geometry is metric. The Weyl-DBI action is a special gauge theory in that it has the same gauge invariant expression with dimensionless couplings in any dimension $d$, so it has no need for a UV regulator (be it an additional field, higher derivative operator or DR subtraction scale) for which reason we argue it is Weyl-anomaly free. For $d=4$, the leading order of a series expansion of the Weyl-DBI action recovers exactly the gauge invariant Weyl quadratic gravity action associated to this geometry, that is Weyl anomaly-free; this is broken spontaneously and Einstein-Hilbert gravity is recovered in the broken phase, with $\mathrm{\Lambda }>0$. The rest of the terms in the series expansion of the Weyl-DBI action are of nonperturbative nature and can, in principle, be recovered by quantum corrections in Weyl quadratic gravity in $d=4$ in a gauge invariant (geometric) regularization automatically provided by the Weyl-DBI action. If the Weyl gauge boson is not dynamical the Weyl-DBI action recovers in the leading order the conformal gravity action. All fields and scales have geometric origin, with no added matter, scalar field compensators or UV regulators.

We study the homogeneous breaking of spatial translation symmetry concomitantly with the spontaneous breaking of other internal and spacetime symmetries, including dilations. We use the symmetry-breaking pattern as the only input to derive, via the coset construction, general effective field theories for the symmetry-originated modes associated with Goldstone’s theorem, namely the Nambu-Goldstone candidates. Through explicit computations, we show that integrating out the explicit massive Nambu-Goldstone candidates or imposing symmetric constraints, namely the inverse Higgs constraints, to express massive modes in terms of the massless ones leads to physically distinct effective field theories. This sensitivity to the chosen method can be traced back to the homogeneous breaking of translations, the homogeneous aspect of the breaking induces a mixing between internal and spacetime symmetries at the level of the Lie algebra. This, in turn, leads to subtle discussions about the inverse Higgs constraints, in particular that they lead to a loss of generality in our specific examples. The derived general effective field theories also give rise to a broad class of theories exhibiting emergent enhanced shift symmetries, which constrain the mobility of the modes. The latter are referred to as fractonic modes.

We define and calculate the mass multipole moments of a material body of mass $M$ and electric charge $Q$ tidally deformed by a particle of mass $m\ll M$ and charge $q\ll Q$ placed at a distance $r_0$ from the body. Given $Q/M$ and $r_0$, we choose $q/m$ so that the gravitational attraction between body and particle is balanced by the electrostatic repulsion; the system can then be maintained in a static state. The multipole moments are defined in a setting in which the body’s self-gravity is allowed to be strong, but the mutual gravity between body and companion is required to be weak. In this setting, the body is described in full general relativity, in terms of a perturbed metric and electromagnetic potential characterized by tidal constants, and the mutual gravity is described within the post-Newtonian approximation to general relativity, in terms of objects with a multipole structure. Matching the different descriptions of the same field delivers a relation between the tidal constants and the multipole moments. In our implementation of this program, the calculation is performed in full Einstein-Maxwell theory (as a linearized perturbation of the unperturbed field), without appeal to a post-Newtonian approximation. After the fact we take $M/r_0$ to be small and carry out an expansion of the metric in powers of $M/r$ to obtain the multipole moments and associated Love numbers. The calculations are performed for a body made up of a perfect fluid with a uniform ratio of charge to mass densities, governed by a polytropic equation of state. We show that the Love numbers of a charged body in a situation of balanced gravitational and electrostatic forces are negative. The statement remains true even when $Q/M$ is very small, and we conclude that the tidal deformability of a charged body is radically different from that of an uncharged object, for which the Love numbers are positive.

We present a numerical and analytical study of the so-called “toron” solution of the stationary axisymmetric Einstein equations in vacuum expressed in terms of elliptic functions. The asymptotic behavior of this solution coincides with the one of the Newman-Unti-Tamburino (NUT) solution, i.e., it has a “gravimagnetic” mass known as the NUT parameter while the ordinary mass vanishes. The physical properties of this spacetime are studied via ray tracing. The results are compared to known geodesic flows in Schwarzschild, Kerr, and NUT spacetimes to discuss similarities and differences, with a particular emphasis on the comparison of NUT and toron spacetimes.

Cosmic-ray (CR) positrons are relatively rare due to their secondary origin and thus sensitive to exotic contributions. Primordial black holes (PBHs) with masses above $\sim 5\times {10}^{14}\mathrm{g}$ can be stable sources of CR positrons due to Hawking radiation. The energies of the evaporated positrons can increase significantly through scattering with the Galactic random magnetic fields during the propagation in the Galaxy, which is a generic feature in diffusive reacceleration CR propagation models. We show that, in well-constrained diffusive reacceleration models, a significant portion of CR positron flux can enter the energy region of $\mathcal{O}(\mathrm{GeV})$ and can be constrained by the current AMS-02 data. As an example, we show that in the galprop+helmod model for CR propagation in the Galaxy and heliosphere, an upper limit of $f_{\mathrm{PBH}}\lesssim 2.15\times {10}^{-4}$ at PBH mass $2\times {10}^{16}\mathrm{g}$ can be obtained, which improves the previous constraints from the Voyager CR all-electron data by around an order of magnitude.

The Feynman path integral has revolutionized modern approaches to quantum physics. Although the path integral formalism has proven very successful and spawned several approximation schemes, the direct evaluation of real-time path integrals is still extremely expensive and numerically delicate due to its high-dimensional and oscillatory nature. We propose an efficient method for the numerical evaluation of the real-time world-line path integral for theories where the potential is dominated by a quadratic at infinity. This is done by rewriting the high-dimensional oscillatory integral in terms of a series of low-dimensional oscillatory integrals, that we efficiently evaluate with Picard-Lefschetz theory or approximate with the eikonal approximation. Subsequently, these integrals are stitched together with a series of fast Fourier transformations to recover the lattice regularized Feynman path integral. Our method directly applies to problems in quantum mechanics, the word-line quantization of quantum field theory, and quantum gravity.

We discuss the implications of the DESI 2024 baryon acoustic oscillation (BAO) data on scalar-tensor models of gravity. We consider four representative models: induced gravity (equivalent to Jordan-Brans-Dicke), where we either fix today’s value of the effective gravitational constant on cosmological scales to the Newton’s constant or allow them to differ, Jordan-Brans-Dicke supplemented with a Galileon term (BDG), and early modified gravity with a conformal coupling. In this way it is possible to investigate how different modified gravity models compare with each other when confronted with DESI 2024 BAO data. Compared to previous analyses, for all of these models, the combination of Planck and DESI data favors a larger value of the key parameter of the theory, such as the nonminimal coupling to gravity or the Galileon term, leading also to a larger value of $H_0$, due to the known degeneracy between these parameters. These new results are mainly driven by the first two redshift bins of DESI. In BDG, in which we find the largest value for $H_0$ among the models considered, the combination of Planck and DESI is consistent with Chicago-Carnegie Hubble prograaringm results and reduces the $H_0$ tension with the SH0ES measurement to $1.2\sigma$ (compared to $4.5\sigma$ of $\mathrm{\Lambda }\mathrm{CDM}$ in our $\mathrm{Planck}+\mathrm{DESI}$ analysis).

Although the QCD phase transition is a crossover in the standard model, nonstandard effects such as a large lepton asymmetry are known to make it first order, with possible applications to gravitational wave production. This process is sensitive to the speed of the bubble walls during the phase transition, which is difficult to compute from first principles. We take advantage of recent progress on wall speed determinations to provide a simple estimate valid in the small supercooling regime that constrains the wall speed to be significantly lower than what has been used in previous literature. This in turn strongly suppresses the production of gravitational waves, to a level that is just out of reach of the most sensitive projected experiment for this signal, $\mu \mathrm{Ares}$. While our analysis approximates the equation of state using the template model, we demonstrate that our conclusions remain robust when incorporating state-of-the-art QCD equation of state data.

We revisit the question of how generic is the formation of primordial black holes via self-resonant growth of inflaton fluctuations in the postinflationary, preheating phase. Using analytical and lattice calculations, we find that primordial black hole production is far from being a generic outcome. Also, in most of the parameter space of viable inflationary models, the metric preheating term is subleading to the anharmonic terms and the approximation of a quadratic potential for describing the resonance dynamics is inadequate. Nonetheless, the anharmonicity of the potential cannot be used to rescue the mechanism: The generic outcome of the nonlinear evolution of the scalar field in this case is the formation of metastable transients or oscillons, that do not generically collapse into black holes.

Neutrino transport in compact objects is an inherently challenging multidimensional problem. This difficulty is compounded if one includes flavor transformation—an intrinsically quantum phenomenon requiring one to follow the coherence between flavors and thus necessitating the introduction of complex numbers. To reduce the computational burden, simulations of compact objects that include neutrino transport often make use of momentum-angle-integrated moments (the lowest order ones being commonly referred to as the energy density and flux) and these quantities can be generalized to include neutrino flavor, i.e., they become quantum moments. Numerous finite-volume approaches to solving the moment evolution equations for classical neutrino transport have been developed based on solving a Riemann problem at cell interfaces. In this paper we describe our generalization of a Riemann solver for quantum moments, specifically decomposing complex numbers in terms of a (signed) magnitude and phase instead of real and imaginary parts. We then test our new algorithm in numerous cases showing a neutrino fast flavor instability, varying from toy models with analytic solutions to snapshots from neutron star merger simulations. Compared to previous algorithms for neutrino transport with flavor mixing, we find uniformly smaller growth rates of the flavor transformation along with concomitantly larger length-scales, and that the results are a better match with the growth rates seen from multiangle codes.

Vortex states of particles—nonplane-wave solutions of the corresponding wave equation with a helicoidal wave front—open new opportunities for particle physics, unavailable in plane wave scattering. Here we demonstrate that $p\overline{p}$ annihilation with a vortex proton and antiproton provides access to the phase of proton electromagnetic form factors even in unpolarized scattering.

There have been many applications of deep neural networks to detector calibrations and a growing number of studies that propose deep generative models as automated fast detector simulators. We show that these two tasks can be unified by using maximum likelihood estimation (MLE) from conditional generative models for energy regression. Unlike direct regression techniques, the MLE approach is prior independent and non-Gaussian resolutions can be determined from the shape of the likelihood near the maximum. Using an ATLAS-like calorimeter simulation, we demonstrate this concept in the context of calorimeter energy calibration.

We propose a dark matter (DM) model with a complex scalar charged under a hidden gauge symmetry denoted as $\mathrm{U}(1{)}_{\mathrm{D}}$. The scalar field is the DM candidate while the $\mathrm{U}(1{)}_{\mathrm{D}}$ gauge field $A^{\prime }$ plays the role of a mediator, which connects the dark sector to the standard model (SM) sector via a tiny kinetic mixing. We find that both the secluded and catalyzed-annihilation scenarios can be realized in this model. The phenomenology of DM, including relic density, indirect detection (Fermi-LAT), and cosmic microwave background (CMB; Planck) constraints, is discussed. We also extend our discussion to DM with other spins, including the Dirac fermion and vector boson. Our analysis is carried out in two models denoted as $\mathrm{U}(1{)}_{\mathrm{D}}\times \mathrm{U}(1{)}_{\mathrm{Y}}$ and $\mathrm{U}(1{)}_{\mathrm{D}}\times \mathrm{U}(1{)}_{L_{\mu }-L_{\tau }}$, with the former corresponding to $A^{\prime }$ kinetically mixing with the $\mathrm{U}(1{)}_{\mathrm{Y}}$ gauge field $B$ and the latter corresponding to $A^{\prime }$ mixing with the $\mathrm{U}(1{)}_{L_{\mu }-L_{\tau }}$ gauge field $Z^{\prime }$. We find that in previous studies of catalyzed-annihilation scenarios, the indirect detection limits were overly restrictive because they only considered the simplified $2\mathrm{DM}\to 2\mathrm{SM}$ annihilation channel. In contrast, by performing a complete calculation of the gamma-ray and CMB constraints from the process $2\mathrm{DM}\to 2A^{\prime }\to 4\mathrm{SM}$ in the models we consider, we observe weaker constraints in both the $\mathrm{U}(1{)}_{\mathrm{D}}\times \mathrm{U}(1{)}_{\mathrm{Y}}$ and $\mathrm{U}(1{)}_{\mathrm{D}}\times \mathrm{U}(1{)}_{L_{\mu }-L_{\tau }}$ models, with the $\mathrm{U}(1{)}_{\mathrm{D}}\times \mathrm{U}(1{)}_{L_{\mu }-L_{\tau }}$ model being subject to the weakest constraints overall since it involves fewer hadronic decay processes.

In a previous work, Buttazzo and Paradisi [Phys. Rev. D 104, 075021 (2021)], pointed out that heavy new physics (NP) contributions to lepton dipole moments and high-energy cross sections of lepton pairs into Higgs and $\gamma /Z$ bosons are connected, if the electroweak symmetry breaking is realized linearly. As a consequence, a multi-TeV muon collider would provide a unique test of NP in the muon $g\text{−}2$ through the study of high-energy processes such as ${\mu }^{+}{\mu }^{-}\to h+\gamma /Z$. Since the analysis involved a Standard Model effective field theory (SMEFT) approach to Higgs processes, it could also be studied by the more general Higgs EFT (HEFT) formulation. We compute the modification of the high-energy cross section ${\mu }^{+}{\mu }^{-}\to h+\gamma /Z$ and $h\to {\mu }^{+}{\mu }^{-}+\gamma /Z$ decay using the dimension-6 HEFT Lagrangian and compare them with the SMEFT analysis. We find that, within the current HEFT analysis, there are plausible scenarios where the HEFT approach could lead to a higher sensitivity to test the NP contributions in the muon $g\text{−}2$. However, a more precise knowledge of the new HEFT parameters is needed for a definite conclusion, which motivates the search for complementary measurements.

We study lattice two-color QCD with two flavors of staggered fermions at imaginary and real quark chemical potential ${\mu }_q$ and $T>T_c$. We employ various methods of extrapolation of the quark number density from imaginary to real quark chemical potentials ${\mu }_q$, including series expansions as well as analytic continuation based on phenomenological models, and study their accuracy by comparing the results to the lattice data. Below the Roberge-Weiss temperature, $T<T_{\mathrm{RW}}$, we find that the cluster expansion model provides an accurate analytic continuation of the baryon number density in the studied range of chemical potentials. On the other hand, the behavior of the reconstructed canonical partition functions indicates that the available models may require corrections at high quark densities. At $T>T_{\mathrm{RW}}$ we show that the analytic continuation to the real values of ${\mu }_q$ based on trigonometric functions works equally well with the conventional method based on the Taylor expansion in powers of ${\mu }_q$.