In this work we consider a dark matter candidate described by an ultralight vector field, whose mass is in principle in the range $H_{\mathrm{eq}}\sim {10}^{-28}\mathrm{eV}\ll m<\mathrm{eV}$. The homogeneous background vector field is assumed to point in a given direction. We present a numerical implementation of cosmological perturbations in a Bianchi type I geometry with vector field dark matter in a modified version of the Cosmic Linear Anisotropy Solving System. We study the evolution of large-scale cosmological perturbations in the linear regime. We compute the matter power spectrums defined for Fourier modes pointing in a given direction. We obtain interesting features in the power spectrums whose observational significance depends on the field mass. We compare the results with the standard $\mathrm{\Lambda }$ cold dark matter and with the corresponding well-studied ultralight scalar field dark matter case. As for the scalar case we obtain a suppression in the power spectrums at small scales characterized by the same scale, namely the Jeans scale. The main characteristic feature of the vector field model we notice here for first time is that the amplitude of the suppression effect depends on the direction of the Fourier modes with respect to the background vector field, leaving eventually a possible anisotropic imprint in structure formation at small scales.

We propose an emergent cosmological model rooted in the asymptotically safe antiscreening behavior of the Newton constant at Planckian energies. Distinguishing itself from prior approaches, our model encapsulates the variable nature of $G$ through a multiplicative coupling within the matter Lagrangian, characterized by a conserved energy-momentum tensor. The Universe emerges from a quasi–de Sitter phase, transitioning to standard cosmological evolution post-Planck era. Our analysis demonstrates the feasibility of constraining the transition scale to nearly classical cosmology using cosmic microwave background data and the potential to empirically probe the antiscreening trait of Newton’s constant, as predicted by asymptotic safety.

Intrinsic alignments (IAs) of galaxies/halos observed via galaxy imaging survey, combined with redshift information, offer a novel probe of cosmology as a tracer of the tidal force field of a large-scale structure. In this paper, we present a perturbation theory based model for the redshift-space power spectra of galaxy/halo IAs that can keep the impact of the Fingers-of-God damping effect, known as a nonlinear systematics of redshift-space distortions, under control. Focusing particularly on galaxy/halo density and an IA cross power spectrum, we derive analytically the explicit expressions for the next-to-leading order corrections. Comparing the model predictions with $N$-body simulations, we show that these corrections indeed play an important role for an unbiased determination of the growth-rate parameter, and hence the model proposed here can be used for a precision test of gravity on cosmological scales.

Big bounce cosmology provides a solution to the Universe’s initial singularity, and stochastic gravitational wave background (SGWB) searches offer a promising avenue for testing this paradigm. In this work, we establish an analytical relation between the bouncing energy scale, ${\rho }_{s\downarrow }^{1/4}$, and SGWB spectrum, ${\mathrm{\Omega }}_{\mathrm{GW}}(f)h^2$, for big bounce cosmology in the framework of standard general relativity (GR). By combining sensitivities from major GW detectors (e.g., Planck/BICEP, PTA, and LIGO/Virgo across low, medium, and high frequencies, respectively), we provide the first systematic GW constraint on ${\rho }_{s\downarrow }^{1/4}$. Our results show that the region $-\frac{1}{3}<w_1<-0.17$ is excluded by current SGWB searches, given the constraint ${\rho }_{s\downarrow }^{1/4}>1\mathrm{TeV}$, where $w_1$ is the contraction-phase equation of state parameter. Additionally, no detectable SGWB can be generated for $0.038<w_1<\infty$ with ${\rho }_{s\downarrow }^{1/4}<{10}^{16}\mathrm{TeV}$. We identify a window, $-0.17<w_1<0.038$, in which a detectable SGWB can be produced, disfavoring many GR-based bounce models, with the matter-dominated contraction ($w_1\simeq 0$) remaining viable. We prospect that future work could extend our analysis to bounce models incorporating modified gravity.

We compute the spectral distortions of the cosmic microwave background (CMB) created by an exotic process that extracts or injects photons of a particular frequency into the CMB. Such signatures are a natural prediction of a class of composite dark matter models characterized by electrically neutral states but with nonzero higher order electromagnetic moments. We consider a simplified model where dark matter exists as a two state system separated by a fixed transition frequency, which can range from radio waves to gamma rays. The electromagnetic transitions between the two states due to CMB photons give rise to thermal distortions, namely, the $\mu$-type distortion in the redshift range ${10}^5\lesssim z\lesssim 2\times {10}^6$ and the $y$-type distortion as well as nonthermal distortions at redshifts $z\lesssim {10}^5$. The nature of spectral distortions depends sensitively on the dark matter transition frequency and the strength of couplings of dark matter with visible sector particles as well as its self-interactions, thus opening a new window to probe the nature of dark matter. Nonthermal distortions have unique spectral shapes making them distinguishable from the standard $\mu$ and $y$-type distortions and potentially detectable in the next-generation experiments such as Primordial Inflation Explorer (PIXIE). We also find that the spectral distortion limits from the cosmic background explorer/far-infrared absolute spectrophotometer (COBE/FIRAS) already give a constraint on the electromagnetic coupling of dark matter, which is 3 orders of magnitude stronger compared to the current direct detection limits for $\sim \mathrm{MeV}$ mass dark matter with transition energy in $\sim 1–10\mathrm{eV}$ range.

Several pulsar timing array (PTA) missions have reported convincing evidence of a stochastic gravitational wave background within their latest datasets. This background could originate from an astrophysical source, though there are multiple possibilities for its origin to be cosmological. Focusing on the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) signal, which was in good agreement with other PTAs, we evaluate the possibility of an inflationary source for the background. However, we will consider a time-dependent minimal theory of massive gravity instead of standard general relativity for our analysis. We find that an inflationary interpretation will require a strongly blue spectrum, characterized by $n_T=1.8\pm 0.54$, while big bang nucleosynthesis limits will require a low reheating scale of $T_{\mathrm{rh}}\simeq 4000\mathrm{GeV}$. Although these constraints make it difficult for inflation to be the source of the NANOGrav signal, we find that the massive gravity model allows for a greater reheating temperature than standard general relativity, making an inflationary interpretation slightly less cumbersome.

It has recently been pointed out that rotation in internal space can induce superradiance. We explore this effect in non-topological solitons of the two-field Friedberg-Lee-Sirlin model. This renormalizable model admits very large solitons, making the perturbative scattering equations highly sensitive to boundary conditions and requiring a relaxation method for their solution. We find that the energy extraction rate is strongly influenced by the mass hierarchy of the two scalars, and solitons with lower internal frequencies lead to more peaks in the spectra of the amplification factors. Additionally, we derive absolute bounds on the amplification factors for general ingoing modes using a linear fractional optimization algorithm and establish analytical bounds near the mass gap.

In the field of modern high-energy physics research, there is a growing emphasis on utilizing deep learning techniques to optimize event simulation, thereby expanding the statistical sample size for more accurate physical analysis. Traditional simulation methods often encounter challenges when dealing with complex physical processes and high-dimensional data distributions, resulting in slow performance. To overcome these limitations, we propose a solution based on deep learning with the sliced Wasserstein distance as the loss function. By employing an advanced transformer learning architecture, we initiate the learning process from a Monte Carlo sample and generate high-dimensional data. Through the integration of the sliced Wasserstein distance with the permutation test, we introduce a novel, statistically rigorous, and more sensitive metric for assessing the distribution differences, which significantly outperforms other metrics in detecting subtle distributional shifts, further validating its effectiveness for precise evaluation in high-energy physics generative models and high-dimensional consistency test. The generated data samples maintain all the original distribution features from a limited number of training samples, as evidenced by their successful passage of all common consistency tests using a test sample size of the same order of statistical magnitude. This development opens up new possibilities for improving event simulation and high-dimensional consistency tests in high-energy physics research.

We study in detail the relativistic distributions of energy, longitudinal momentum, longitudinal energy flux, and axial momentum flux inside nucleons based on the quantum phase-space formalism. Similar to recent studies on the electromagnetic current, we include the effects of the nucleon polarization and show that the latter are essential for understanding how the Breit frame distributions transform under a longitudinal Lorentz boost. We also explicitly demonstrate that, in the infinite-momentum frame, these distributions allow one to recover not only the “good” but also the “bad” components of the light-front energy-momentum tensor distributions.

Through a holographic model of QCD, we present a phenomenological approach to study the running of the strong coupling constant ${\alpha }_s$ in both nonperturbative and perturbative regimes. The renormalization of the metric tensor, driven by the Ricci Flow, and the breaking of conformal and chiral symmetries—thanks to introducing a double dilaton model and large-$N_c$ corrections—allows us to relate the existence of an infrared fixed point in the coupling constant with a smooth matching to perturbative QCD well above 2 GeV. This is done through a model with two fit parameters and one matching point. The proposed dilaton model yields linear Regge trajectories and decay constants for scalar, vector, and tensor meson families similar to their experimental counterparts.

Within the framework of nonrelativistic quantum chromodynamics factorization, we calculate the next-to-leading order (NLO) perturbative QCD corrections to the form factors for the semileptonic decays of $B_c^{*}$ into $J/\psi$ via (axial-)vector and (axial-)tensor currents. We obtain the complete analytical results for the form factors up to NLO, and provide their asymptotic expressions in the hierarchical heavy quark limit. The NLO corrections are found to be both significant and convergent in the relatively small squared transfer momentum ($q^2$) region, while also reducing the dependence on the renormalization scale $\mu$. Finally, the theoretical predictions for $B_c^{*}\to J/\psi$ form factors over the full $q^2$ range are provided.

The branching fraction of the decay $B^{+}\to \psi (2S)\varphi (1020)K^{+}$, relative to the topologically similar decay $B^{+}\to J/\psi \varphi (1020)K^{+}$, is measured using proton-proton collision data collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of $9{\mathrm{fb}}^{-1}$. The ratio is found to be $0.061\pm 0.004\pm 0.009$, where the first uncertainty is statistical and the second systematic. Using the world-average branching fraction for $B^{+}\to J/\psi \varphi (1020)K^{+}$, the branching fraction for the decay $B^{+}\to \psi (2S)\varphi (1020)K^{+}$ is found to be $(3.0\pm 0.2\pm 0.5\pm 0.2)\times {10}^{-6}$, where the first uncertainty is statistical, the second systematic, and the third is due to the branching fraction of the normalization channel.

In strongly deformed planar $\mathcal{N}=4$ super-Yang-Mills theory, or fishnet theory, a point-split single-trace correlation function of four dimension-$m$ scalar operators is given by a single Feynman integral, which involves integrating over locations of a $m\times m$ grid of points. We show that for any integer $m$ this square fishnet graph is invariant under the combined action of a kinematic map and the antipode map of the Hopf algebra on multiple polylogarithms; i.e. it possesses an antipodal self-duality.

The first measurement of the $CP$ asymmetry of the decay rate ($A_{CP}$) and the $CP$ average ($\mathrm{\Sigma }{A}_{\mathrm{FB}}$) and $CP$ asymmetry ($\mathrm{\Delta }{A}_{\mathrm{FB}}$) of the forward-backward asymmetry in the muon system of ${\mathrm{\Lambda }}_c^{+}\to p{\mu }^{+}{\mu }^{-}$ decays is reported. The measurement is performed using a data sample of proton-proton collisions, recorded by the LHCb experiment from 2016 to 2018 at a center-of-mass energy of 13 TeV, which corresponds to an integrated luminosity of $5.4{\mathrm{fb}}^{-1}$. The asymmetries are measured in two regions of dimuon mass near the $\varphi$-meson mass peak. The dimuon-mass integrated results are $A_{CP}=(-1.1\pm 4.0\pm 0.5)\%$, $\mathrm{\Sigma }{A}_{\mathrm{FB}}=(3.9\pm 4.0\pm 0.6)\%$, $\mathrm{\Delta }{A}_{\mathrm{FB}}=(3.1\pm 4.0\pm 0.4)\%$, where the first uncertainty is statistical and the second systematic. The results are consistent with the conservation of $CP$ symmetry and the Standard Model expectations.

In this letter, we explore different aspects of a $3+1$ strongly coupled superconductor in the presence of an intense magnetic field. In order to study this interesting and highly complicated system, we make use of the holographic correspondence. We construct a gravitational solution incorporating a fully backreacted Maxwell field while treating a charged scalar field as a perturbation propagating on this background. Our work focuses on the implications of intense magnetic fields on superconductivity in the strongly coupled regime, offering insights into the modifications that such a field induces on key aspects of the superconducting phase, particularly near the critical value where the superconducting phase is broken, which has not been explored by previous perturbative methods. Through rigorous numerical analysis of the holographic model, we uncover intriguing effects arising from the interplay between the magnetic field and the superconducting condensate.

Asymptotic safety constitutes a promising mechanism for a consistent and predictive high-energy completion of the gravitational interactions. To date, most results on the interacting renormalization group fixed point underlying the construction are obtained for Euclidean signature spacetimes. In this work, we use the Arnowitt-Deser-Misner decomposition of the metric degrees of freedom and investigate the relations between the Euclidean and Lorentzian renormalization group flows resulting from the analytic continuation of the lapse function. We discuss the general conditions that guarantee the equivalence of the beta functions. These insights are illustrated based on the flow of the graviton two-point function within the Einstein-Hilbert truncation, demonstrating agreement of the Euclidean and Lorentzian settings. Hence, the UV and IR completions identified in the Euclidean case are robust when changing the spacetime signature. We take this as an important indicator that the Euclidean asymptotic safety mechanism carries over to Lorentzian signature spacetimes.

In this paper, we obtain a formula for time in general relativity from solutions of the Einstein-Hamilton-Jacobi equation along paths of steepest descent in the configuration space of general relativity. The formula for time emerges from the geometry of configuration space via the length of the steepest descent paths which is measured with respect to the de Witt metric on configuration space. The consequences of the indefinite signature of the de Witt metric are discussed in detail. We illustrate the general formula for time in various examples including de Sitter spacetime and asymptotically anti–de Sitter spacetimes.

We study the electron-positron to muon–anti-muon cross section in the asymptotically safe Standard Model. In particular, we include the graviton contributions to the scattering amplitude, which is computed from momentum-dependent timelike one-particle-irreducible correlation functions. Specifically, we employ reconstruction techniques for the graviton spectral functions. We find that the full asymptotically safe quantum cross section decreases in the ultraviolet with the center-of-mass energy, and is compatible with unitarity bounds. Importantly, our findings provide nontrivial evidence for the unitarity of the asymptotically safe Standard Model.

We show that Poincaré invariance directly implies the existence of a complexified Minkowski space whose real and imaginary directions unify spacetime and spin, which we dub spinspacetime. Despite the intrinsic noncommutativity of spin, spinspacetime exhibits mutually commuting holomorphic coordinates. Its twistorial construction derives the Newman-Janis shift property of spinning black holes by massive half-Fourier transforming complexified on shell kinematics, which encode a spinning analog of equivalence principle.

We propose a new way to perform path integrals in quantum mechanics by using a quantum version of Hamilton-Jacobi (HJ) theory. In classical mechanics, Hamilton-Jacobi theory is a powerful formalism, however, its utility is not explored in quantum theory beyond approximation schemes. The canonical transformation enables one to set the new Hamiltonian to constant or zero, but keeps the information about solution in Hamilton’s characteristic function. To benefit from this in quantum theory, one must work with a formulation in which classical Hamiltonian is used. This uniquely points to phase space path integral. However, the main variable in HJ formalism is energy, not time. Thus, we are led to consider the Fourier transform of the path integral, the spectral path integral $\tilde{Z}(E)$. The evaluation of path integrals reduces to determining the quantum Hamilton characteristic functions (which can be achieved via an asymptotic analysis) and a discrete sum over the quantum period lattice, generalizing Gutzwiller’s sum.