Despite direct searches at the LHC excluding tripletlike Higgs bosons up to several hundred GeV over much of the type-II seesaw model parameter space, parts of it—most notably those featuring “cascade decays” of the charged Higgs bosons into their neutral partners and off-shell $W$ bosons—still remain unconstrained. Meanwhile, measurements of the diphoton signal strength of the Standard Model (SM) Higgs boson—potentially modified by loop contributions from tripletlike Higgs states—are in good agreement with the SM expectation, with combined experimental uncertainties currently at approximately 8%. Given the trend in previous measurements, it is expected that future precision Higgs measurements at the HL-LHC and a future lepton collider such as the Circular Electron Positron Collider, Future Circular Collider, or Muon Collider will be consistent the standard diphoton signal strength, albeit with significantly reduced uncertainties, down to about 0.7%. Presuming this and considering all relevant constraints, we explore whether such increasingly precise diphoton measurements can indirectly probe the parameter space that currently evades direct searches. We find that subpercent-level determinations of the diphoton rate will decisively probe a substantial fraction of this otherwise elusive region.

We thoroughly investigate nonanalytic terms in the finite-temperature effective potential in one-loop approximation on a $D$-dimensional spacetime, $S_{\tau }\times R^{D-(p+1)}\times {\prod }_{i=1}^p{S}_i^1$, using a mode recombination formula. Such nonanalytic terms cannot be expressed as positive powers of field-dependent mass squared. The formula provides a clear separation of the effective potential into a part that contains the nonanalytic terms and a part that is purely analytic, and clarifies the origin of the nonanalytic terms. We obtain all the nonanalytic terms and show that only two types of nonanalytic terms arise from the modes with zero Matsubara frequency. For a real scalar field with periodic boundary conditions, if the number of noncompacted spatial dimensions is odd (even), there are odd powers of $M$ ($\log M$ terms) but no $\log M$ terms (no odd powers of $M$). For fermions with general boundary conditions, we find that neither of the two types appears. These results clarify the nonanalytic structure of the finite-temperature effective potential on the spacetime with compactified spatial dimensions.

The massless $S$ matrix of the pure Ramond-Ramond sector of string theory on three-dimensional Anti de Sitter times a four-torus is very similar but also crucially distinct from Fendley-Intriligator’s model famous $\mathcal{N}=2$ $S$-matrix, in turn related to Sine-Gordon model taken at a special coupling. In this article we review the reason why supersymmetry emerges but with a fractional statistics of the particles. We then use this to obtain an interpolating $S$ matrix between massless ${\mathrm{AdS}}_3$ and Sine-Gordon model, and further find two interpolating $S$ matrices between these and the mixed-flux relativistic $S$ matrix, solving the Yang-Baxter equation all the way in between. They are all relativistic invariant and braiding unitary, can be written in terms of particles with fractional statistics, and embed all the ${\mathrm{AdS}}_3$ models into a parent integrable system. This also achieves the reformulation of all the ${\mathrm{AdS}}_3$ integrable scattering problems in the domain of fractional statistics.

Recent studies have shown that quantum gravity introduces important corrections to the process of spherically symmetric gravitational collapse expected from general relativity. In particular, instead of falling into a central singularity, the collapsing body undergoes a bounce and eventually exits its Schwarzschild radius, and this entire process of collapse and rebound can occur in a single asymptotic region. In this paper, particle creation during such nonsingular gravitational collapse is studied. It is shown that the probability of spontaneous emission of particles differs from the well-known probability of Hawking radiation from classical gravitational collapse. It is argued that the different result implies a deviation from thermality. Some arguments are also adduced concerning how the Hawking process during nonsingular dust collapse could potentially remove shell crossing singularities.

Induced gravity, defined as a globally scale-invariant “first-generation” scalar-tensor theory, is investigated within the framework of the thermodynamics of modified gravity theories. The “temperature of gravity” and its evolution equation are derived for this model, and the resulting expressions are used to analyze general relativity equilibrium states and to investigate the possible existence of an attractor mechanism toward Einstein’s theory with a cosmological constant.

Interacting dark energy (IDE) models offer a promising avenue to explore possible exchanges of energy and momentum between dark matter and dark energy, providing a dynamical extension of the standard $\mathrm{\Lambda }$ cold dark matter ($\mathrm{\Lambda }\mathrm{CDM}$) paradigm. Such interactions modify the growth of cosmic structures, imprinting distinctive signatures on the matter power spectrum that can be tested through large-scale structure (LSS) observations. In this work, we compute the one-loop corrections to the matter power spectrum in IDE models. We then reinterpret these results within the standard framework of the effective field theory of large-scale structure (EFTofLSS), which provides a consistent description of mildly nonlinear scales and allows for reliable comparisons with observational data. We investigate two commonly studied forms of the coupling function, $Q$, namely $Q=\xi \mathcal{H}{\rho }_{\mathrm{m}}$ and $Q=\xi \mathcal{H}{\rho }_{\mathrm{DE}}$, and introduce a novel interaction term, $Q=\mathrm{\Gamma }{\rho }_{\mathrm{m}}{\rho }_{\mathrm{DE}}{\theta }_{\mathrm{m}}$, characterized by the nonlinear coupling constant $\mathrm{\Gamma }$, which links the interaction strength to the velocity divergence of dark matter. This coupling function is proposed to isolate the effects solely of the IDE model on mildly nonlinear scales. Using full-shape (FS) measurements of the galaxy power spectrum from BOSS DR12, we constrain the interaction rate $\mathrm{\Gamma }$, the cosmological parameters, and the bias parameters. We find $\mathrm{\Gamma }=0.0039\pm 0.0082$, which is highly consistent with the $\mathrm{\Lambda }\mathrm{CDM}$ model. This work opens the possibility of testing IDE models at mildly nonlinear scales, potentially providing new insights for this class of models beyond the standard $\mathrm{\Lambda }\mathrm{CDM}$ framework.

The Lorentzian path integral for the wave function of the Universe is only conditionally convergent and thus requires a well-defined prescription. The Picard-Lefschetz approach ensures convergence through contour deformation, but it has been argued that this leads to unsuppressed perturbations due to relevant saddle points residing in the region $\mathrm{Im}N>0$. As an alternative, we propose a simple regulator for the lapse integral in minisuperspace. Specifically, we impose the vanishing initial size of the Universe via a delta function, represented as a narrow Gaussian of width $\sigma$, and take the limit $\sigma \to 0$ only after performing the functional integrations. This regulator has a clear physical interpretation: it corresponds to a vanishingly small quantum uncertainty in the initial size of the Universe. For any fixed $\sigma >0$, the lapse integral is absolutely convergent along (or slightly below) the real axis, and no excursion into the region $\mathrm{Im}N>0$ is required. We further argue that the initial wave function for scalar and tensor perturbations should be incorporated in the Lorentzian path integral formalism, and we show that these perturbations are then appropriately suppressed. A purely Lorentzian path integral thus yields the tunneling wave function with suppressed perturbations. We also demonstrate that the Hartle-Hawking wave function can be reproduced by choosing a contour for the lapse integral extending from $-\infty$ to $+\infty$ that passes below the singularity near the origin.

We study a simple setup with dark matter halos in real space, with the amplitude of the linear density field $A$ as the only free cosmological parameter. We show that Eulerian perturbation theory is adequate for describing this system on large scales, compute the leading $n$-point functions and perform a joint power spectrum, bispectrum, and trispectrum analysis. Beyond the bispectrum, which is crucial for breaking the degeneracy between $A$ and the linear bias, we find that addition of the trispectrum reduces the error on $A$ by only 20%–30%. Our results for the joint analysis are in good agreement with recent field-level analyses in the same setup. This implies that the field-level inference on large scales does not get significant information from large displacements beyond those in Eulerian kernels or higher-order $n$-point functions beyond the trispectrum. We provide further evidence for this showing that the dependence of the error bars on the maximum wave numbers used in the analysis is the same in the two approaches. Our results are in disagreement with some of the recent joint power spectrum and bispectrum analyses using likelihood-free inference based on perturbative forward modeling. We discuss a possible origin of this discrepancy and highlight the importance of resolving it in order to have the optimal results in cosmological analyses based on perturbation theory.

The remote dipole and quadrupole fields (RDF/RQF) encode information about the observable universe as seen from remote places within our past light cone. Sensitive to the superhorizon inhomogeneities, they provide a unique way to probe physics at the largest scales, bypassing the limitations of cosmic variance inherent in the primary cosmic microwave background (CMB). In this work, we focus on the bubble collision predicted by the eternal inflation theory, which can leave distinct azimuthally symmetric patterns on the superhorizon scales, potentially detectable through the RDF and RQF. We present the first analytic expression of the RQF signal induced by bubble collision and validate it against numerical calculations performed with remotefield, a new public software tool we developed, finding excellent agreement between the two. Combining our new RQF calculation with the corresponding RDF signal calculated by prior work, we forecast the constraining power on bubble collision parameters using RDF/RQF reconstruction. We find that, for a CMB-S4-like and a LSST-like experiment, the RDF reconstruction can provide comparable constraining power as that from the primary CMB alone; and the RQF reconstruction can improve the constraining power by about an order of magnitude. We argue that these constraints can be improved further by including more RDF/RQF multipoles and by using tomographic techniques to mitigate the standard $\mathrm{\Lambda }\mathrm{CDM}$ signal. We anticipate the framework we developed in this work to be broadly applicable to probe other superhorizon-scale physics, such as cosmic topology and domain walls.

Modern cosmological surveys cover extremely large volumes and map fluctuations on scales reaching gigaparsecs. As a result, it is no longer a valid assumption to ignore cosmological evolution along the line of sight from one end of the survey to the other. When extracting cosmological information, the power spectrum becomes suboptimal because it relies on the assumption of translational invariance of the observed field. For example, during the epoch of reionization, the 21 cm brightness temperature field on the nearby (low-redshift) end of a large survey volume exhibits statistical properties that differ significantly from those at the far (high-redshift) end. To overcome these limitations, we have developed an eigen decomposition-inspired non-Fourier basis that captures evolution effects. Our work demonstrates that using this new basis integrated in a new summary statistic yields tighter constraints on astrophysical parameters compared to the traditional power spectrum. Additionally, we provide an illustrative example and a practical guide for applying this basis in the context of a realistic forecast for interferometers such as the Hydrogen Epoch of Reionization Array.

In this work, we perform a simulation-based forecasting analysis to compare the cosmological constraining power of higher-order summary statistics of the large-scale structure (LSS)—the Minkowski functionals (MFs) and a class weighted morphological measure known as the conditional moments of derivatives (CMD)—with that of the redshift-space halo power spectrum multipoles (PS), with a particular focus on their sensitivity to nonlinear and anisotropic features in redshift space. Our analysis relies on halo catalogs from the big Sobol sequence (BSQ) simulations at redshift $z=0.5$, employing a likelihood-free inference framework implemented via neural posterior estimation. At the fiducial Quijote cosmology $({\mathrm{\Omega }}_{\mathrm{m}}=0.3175,{\sigma }_8=0.834)$ and for a Gaussian smoothing scale of $R=15h^{-1}\mathrm{Mpc}$, CMD provide systematically tighter constraints than MFs. Combining MFs and CMD into a joint estimator improves the precision by $27{\%}_{-5\%}^{+9\%}$ for ${\sigma }_8$ and $26{\%}_{-5\%}^{+7\%}$ for ${\mathrm{\Omega }}_{\mathrm{m}}$ relative to MFs alone, highlighting the complementary anisotropy-sensitive information captured by the CMD in contrast to the scalar morphological content encapsulated by the MFs. We compare the combined statistic $\mathrm{MFs}+\mathrm{CMD}$ with the PS at matched effective scales ($k_{\max }\simeq 0.16h{\mathrm{Mpc}}^{-1}$) under three halo-selection conditions: (i) all halos, (ii) fixed number density, and (iii) mass-selected ($M>3\times {10}^{13}{h}^{-1}{M}_{\odot }$). In the mass-selected configuration, the (weighted) morphological estimator outperforms the power spectrum by $45{\%}_{-9\%}^{+20\%}$ for ${\sigma }_8$ and $43{\%}_{-7\%}^{+10\%}$ for ${\mathrm{\Omega }}_{\mathrm{m}}$. We also extend the simulation-based forecast analysis across a continuous range of cosmological parameters and multiple smoothing scales for (weighted) morphological measures. While the absolute uncertainties depend on parameter values and smoothing scale, the relative constraining power of the summary statistics remains nearly constant.

Primordial black holes (PBHs) are theorized to form from the collapse of overdensities in the very early Universe. PBHs in the asteroid-mass range ${10}^{17}\mathrm{g}\lesssim M\lesssim {10}^{23}\mathrm{g}$ could serve as all or most of the dark matter today, but are particularly difficult to detect due to their modest rates of Hawking emission and sub-micron Schwarzschild radii. We consider whether the steep gradients of a PBH’s gravitational field could generate tidal forces strong enough to disrupt atoms and nuclei. Such phenomena may yield new observables that could uniquely distinguish a PBH from a macroscopic object of the same mass. We first consider the gravitational ionization of ambient neutral hydrogen and evaluate prospects for detecting photon radiation from the recombination of ionized atoms. During the present epoch, this effect would be swamped by Hawking radiation—which would itself be difficult to detect for PBHs at the upper end of the asteroid-mass window. We then consider the gravitational ionization and heating of neutral hydrogen immediately following recombination at $z\simeq 1090$ and identify a broad class of PBH distributions with typical mass $5\times {10}^{21}\mathrm{g}\lesssim M\lesssim {10}^{23}\mathrm{g}$ within which gravitational interactions would have been the dominant form of energy deposition to the medium. We also identify conditions under which tidal forces from a transiting PBH could overcome the strong nuclear force, either by dissociating deuterons, which would be relevant during big bang nucleosynthesis, or by inducing fission of heavy nuclei. We find that gravitational dissociation of deuterons dominates photodissociation rates due to Hawking radiation for PBHs with masses ${10}^{14}\mathrm{g}\lesssim M\lesssim {10}^{16}\mathrm{g}$. We additionally identify the phenomenon of gravitationally induced fission of heavy nuclei via tidal deformation.

We investigate the internal structure of the pion, including the contributions from one dynamical gluon, using the basis light-front quantization approach. By solving a light-front QCD Hamiltonian with a three-dimensional confining potential, we obtain the light-front wave functions for both the quark-antiquark and quark-antiquark-gluon Fock sectors. These wave functions are then employed to compute the unpolarized generalized parton distributions and the transverse momentum–dependent parton distributions of valence quarks and gluons. We also extract the transverse spatial distributions, providing the squared radii of quark and gluon densities in the impact parameter space. This work contributes toward a three-dimensional understanding of the pion’s internal structure in both momentum and coordinate space.

Quantum field theories containing fields with the same quantum numbers allow for mixed kinetic terms in the Lagrangian, leading to off-diagonal elements in the tree-level two-point function. After removing the mixing by a field rotation, the off-diagonal UV divergences cannot be subtracted by a counterterm, still, one can show that the theory is renormalizable. We study kinetic mixing of $U(1)$ gauge bosons in an extension of quantum electrodynamics with a massive “dark” photon at one-loop order. In the general covariant $R_{\xi }$-gauge, the gauge fixing function naively obstructs the removal of tree-level mixing, but we show that these off-diagonal gauge-dependent contributions cancel. We compare two renormalization schemes: one with and one without kinetic mixing, and relate them via a scale-dependent field transformation, showing that the schemes are equivalent.

We propose a method to explore the flavor structure of leptons using diffusion models, which are known as one of generative artificial intelligence (generative AI). We consider a simple extension of the Standard Model with the type I seesaw mechanism and train a neural network to generate the neutrino mass matrix. By utilizing transfer learning, the diffusion model generates 104 solutions that are consistent with the neutrino mass squared differences and the leptonic mixing angles. The distributions of the $CP$ phases and the sums of neutrino masses, which are not included in the conditional labels but are calculated from the solutions, exhibit nontrivial tendencies. In addition, the effective mass in neutrinoless double beta decay is concentrated near the boundaries of the existing confidence intervals, allowing us to verify the obtained solutions through future experiments. An inverse approach using the diffusion model is expected to facilitate the experimental verification of flavor models from a perspective distinct from conventional analytical methods.

In the ongoing broad search for dark matter, axions and axionlike particles have attracted considerable attention due to their potential to simultaneously resolve the strong $CP$ problem and serve as viable candidates for cold dark matter. These light bosons can mediate novel spin-dependent forces over macroscopic distance, providing a promising pathway for the indirect detection of dark matter. In this work, we propose an experimental scheme to search for the axion-mediated spin-mass interaction. The setup employs a closed-loop magnetic array to generate a highly spin-polarized electron ensemble and utilizes a gold microsphere probe that serves both as a source of unpolarized nucleons and as a high-sensitivity force sensor, enabling sensitive probing of electron-nucleon interactions at the micrometer scale. By systematically analyzing the spurious forces, we optimize the experimental parameters to maximize the exotic force signal. Based on the preliminary design parameters, with the force sensitivity achievable at low temperature, this experiment is expected to explore a parameter space with a coupling constant smaller than the current stringent constraints from micrometer to millimeter interaction range. The minimum detectable coupling constant is expected to $g_S^N{g}_P^e/\hslash c=9.4\times {10}^{-20}$ at $\lambda =5\mathrm{\mu }\mathrm{m}$. Specifically, the lower bound of the parameter space explored in this study will be an order of magnitude lower than the most stringent existing constraints for axion-mediated spin-mass interactions.

Recent experimental hints from the Large Hadron Collider (LHC) in diphoton and partially in the ${\tau }^{+}{\tau }^{-}$ final states suggest the possible existence of an additional Higgs boson with a mass around 95 GeV. Interestingly, these observations are consistent with earlier results from the Large Electron-Positron collider, which pointed to an excess in $b\overline{b}$ final states within a similar mass range. Additionally, CMS has observed an excess in the $\gamma \gamma b\overline{b}$ final state, indicating a possible resonance near 650 GeV decaying into a pair of Standard Model (SM)-like Higgs bosons or into a SM-like Higgs boson accompanied by a lighter scalar with mass near 95 GeV. In this work, we investigate whether these anomalies can be simultaneously explained within the next-to-two-Higgs-doublet model (N2HDM), an extension of the SM scalar sector featuring two complex Higgs doublets and an additional real singlet. Assuming the existence of a $CP$-even Higgs state compatible with the 95 GeV excesses (restricted to the $\gamma \gamma$ and $b\overline{b}$ channels), we analyze the Type-II and Type-Y Yukawa structures, taking the observed 650 GeV resonance to be a $CP$-even Higgs state. An extensive parameter scan is performed, incorporating the latest constraints from the properties of the observed 125 GeV Higgs boson, direct searches for additional Higgs states, flavor physics data, and electroweak precision observables. Our results show that a heavy $CP$-even Higgs resonance around 650 GeV, produced predominantly via gluon-gluon fusion and subsequently decaying into a 125 GeV Higgs boson together with another scalar at approximately 95 GeV, can be simultaneously accommodated within both the N2HDM Type-II and Type-Y frameworks in parameter regions that remain consistent with the relevant experimental $2\sigma$ intervals for the reported excesses, once all theoretical and experimental constraints are imposed. This interpretation leads to distinctive and testable predictions for the ongoing LHC Run 3 and the forthcoming high-luminosity LHC phase, in particular through correlated rates in the $\gamma \gamma b\overline{b}$, ${\tau }^{+}{\tau }^{-}b\overline{b}$, $b\overline{b}\gamma \gamma$, and $\gamma \gamma {\tau }^{+}{\tau }^{-}$ final states.

We analyze the interaction of photons with a scalar dark matter field $\varphi$, and we propose to use a single arm interferometer to reveal this interaction and constrain the parameters of the scalar dark matter model. By considering a beam of coherent light and two spatially separated squeezing operations, we show that the interaction of photons with scalar dark matter leads to an observable deviation in the outgoing light state, with respect to free evolution. Therefore the single-arm interferometer may yield a novel revelation method for scalar dark matter.

We present a high-precision study of the topological susceptibility in SU(3) pure gauge theory in four space-time dimensions. The result is based on ensembles at seven lattice spacings and in seven physical volumes to facilitate a controlled continuum and infinite-volume extrapolation. We use a gluonic topological charge measurement, with gradient flow smoothing in the operator. Two complementary smoothing strategies are used (one keeps the flow time fixed in lattice units, one in physical units). Our data support the idea that both strategies yield a universal continuum limit; we find ${\chi }_{\mathrm{top}}^{1/4}{r}_0=0.4775(14)(11)$ or ${\chi }_{\mathrm{top}}^{1/4}=198.1(0.7)(2.7)\mathrm{MeV}$. Our Appendix data suggest that the excess kurtosis $⟨q^4⟩/⟨q^2{⟩}^2-3$ decreases $\propto L^{-2}$ for large box sizes $L$.

We study the $J/\psi \to \varphi \eta {\pi }^0$ reaction measured recently by the BESIII Collaboration with high precision, paying attention to three important aspects: (1) the production of the $a_0(980)$ in the ${\pi }^0\eta$ mass distributions, with the typical narrow width observed in isospin violating processes; (2) the origin of two peaks in the $\varphi {\pi }^0$ mass distributions that were branded as “non-$\varphi$” contribution in the experimental analysis; (3) the existence of two triangle mechanisms developing a triangle singularity at the same energy where the non-$\varphi$ contribution peaks in the experiment. However, we also show that the strength of these peaks is very small relative to the observed ones, a feature that is tied to the experimental technique used to identify the $\varphi$ looking at $K^{+}{K}^{-}$ in a narrow window of invariant mass around the $\varphi$ mass. We suggest that these triangle singularities could be observed with other methods to identify the $\varphi$.