We analyze the confinement/deconfinement transition of pure Yang-Mills theories within the framework of the center-symmetric Landau gauge supplemented by a Curci-Ferrari mass term that models the effect of the associated Gribov copies in the infrared. In addition to providing details for earlier one-loop calculations in that framework, we explore how the results depend on the renormalization scale and/or on the renormalization scheme. We find that the predicted values for the transition temperatures of SU(2) and SU(3) Yang-Mills theories are similar in both schemes and are little sensitive to the renormalization scale $\mu$ over a wide range of values including the standard range $\mu \in [\pi T,4\pi T]$. These values are also close both to those obtained from a minimal sensitivity principle and to those of lattice simulations, especially in the SU(3) case. These results further confirm the good behavior of perturbative calculations within the Curci-Ferrari model and support the adequacy of the latter as an effective description of Yang-Mills theories in the infrared. We perform a similar analysis for the spinodal temperatures in the SU(3) case and for the Polyakov loop, the order parameter associated with the breaking of center symmetry.

This paper employs the $H+b+\text{jets}$ signature in proton-proton collisions to explore the structure of the $Hb\overline{b}$ couplings. The focus of the analysis lies in the decay of the Higgs boson into a photon pair, taking into account both reducible and irreducible backgrounds and a realistic simulation of the detector effects. To enhance the discrimination between signal and background, a multivariate analysis is employed to analyze the kinematic variables and optimise the signal-to-background ratio. The results indicate that the $H+b+\text{jets}$ process can significantly contribute to the precise measurement of $CP$-even and $CP$-odd couplings between the bottom quark and the Higgs boson at the LHC and FCC-hh. Finally, a novel asymmetry is introduced for the purpose of probing $CP$ violation within the $Hb\overline{b}$ coupling, formulated exclusively based on lab-frame momenta.

The nonlinear character of general relativity leaves its imprint in the coalescence of two black holes, from the inspiral to the final ringdown stage. To quantify the impact of nonlinearities, we work at second order in black hole perturbation theory and we study the excitation of second-order modes relative to the first-order modes that drive them as we vary the black hole spin and the initial data for the perturbations. The relative amplitude of second-order modes is only mildly dependent on the initial data that we consider, but it strongly decreases for large black hole spins. This implies that the extrapolation of calculations based on the Kerr–conformal field theory correspondence to subextremal Kerr black holes should be viewed with caution.

We investigate possible configurations for vacuum multiblack holes that maintain static equilibrium in expanding bubbles. Our analysis assumes a five-dimensional Weyl metric to describe the spacetime, facilitating the derivation of solutions based on the provided rod structure. We consider a spacetime having expanding bubbles caused by one or two acceleration horizons, and show that various configurations such as two bubbles, four bubbles devoid of horizons, a black saturn, a black di-ring, a bicycling black ring (orthogonal black di-ring), and a five-dimensional black hole binary can achieve equilibrium within expanding bubbles. Specifically, we demonstrate that equilibrium requires two acceleration horizons on both sides for the bicycling ring and the five-dimensional black hole binary. However, only one acceleration horizon is necessary for achieving equilibrium in the case of the black saturn and the black di-ring.

The Hawking process results in a monotonic decrease of the black hole mass, but a biased random walk of the black hole angular momentum. We demonstrate that this stochastic process leads to a significant fraction of primordial black holes becoming extremal Kerr black holes (EKBHs) of one to a few Planck masses regardless of their initial mass. For these EKBHs, the probability of ever absorbing a photon or other particle from the cosmic environment is small, even in the cores of galaxies. Assuming that EKBHs are stable, they behave as cold dark matter, and can comprise all of the dark matter if they are formed with the correct initial abundance.

A dark matter (DM) having feeble interaction with the visible sector can thermalize via substantial interaction with a weakly interacting massive particle (WIMP). Such DM candidates can be categorized as pseudofeebly interacting massive particles (pFIMPs). pFIMPs have both direct and indirect search prospects via a WIMP loop. This work focuses on such possibilities. We provide all such one loop graphs stemming from pFIMP-WIMP interactions involving scalar, fermion, and vector boson particles, assuming both of them are stabilized via ${\mathbb{Z}}_2\otimes {\mathbb{Z}}_2^{\prime }$ symmetries. We elaborate upon a model where a fermionic WIMP has a significant Yukawa interaction with a scalar pFIMP with negligible Higgs portal coupling. We study, in detail, the loop induced direct and indirect search prospects of the pFIMP in the relic density allowed region of the model along with collider expectations at the LHC.

Multiquark systems appear less frequently than mesons and baryons despite the enormous worldwide experimental effort that has been made during the last two decades. In this work, we propose a possible explanation for that fact, restricting ourselves to the case of sets including only $c$ and $\overline{c}$ quarks. We show that those multiquarks can be thought as different combinations of smaller units that associate together to produce colorless assemblies with a definite value of the total spin. For instance, for the $cccccc$ hexaquark with spin $S=0$, we have three possibilities; a set of six undistinguishable $c$ quarks, an association of two $ccc$ baryons, or a set of three $cc$ diquarks close together. This means we can have three different values for the mass of an open-charm hexaquark with $S=0$. Using the diffusion Monte Carlo method, we calculate all possible combinations compatible with tetraquark $cc\overline{c}\overline{c}$, pentaquark $cccc\overline{c}$, open-charm $cccccc$, and hidden-charm $ccc\overline{c}\overline{c}\overline{c}$ hexaquark structures with the minimum value of total spin ($S=0$ or $S=1/2$). We consider compact structures with radial wave functions including pair interactions between all the quarks in the cluster. We find that, in all cases, the mass of the multiquark decreases with the number of small units that conform the set of quarks. For instance, an open charm hexaquark made up of three diquarks has a smaller mass than a set of six $c$ undistinguishable units. When the pieces that conform the multiquark are themselves colorless with a definite value of the total spin, the cluster splits into those smaller units that separate infinitely from each other.

We study the nonleptonic three-body charmed baryon weak decays of ${\mathbf{B}}_c\to {\mathbf{B}}_{n}P{P}^{\prime }$ under the $SU(3{)}_F$ flavor symmetry, where ${\mathbf{B}}_c$ denotes the antitriplet charmed baryon, comprising $({\mathrm{\Xi }}_c^0,-{\mathrm{\Xi }}_c^{+},{\mathrm{\Lambda }}_c^{+})$, and ${\mathbf{B}}_n$ and $P(P^{\prime })$ represent octet baryon and pseudoscalar meson states, respectively. In addition to 12 parameters from the contributions of the color-antisymmetric part of the effective Hamiltonian, denoted as $H(\overline{\mathbf{6}})$, there are 4 parameters from the color-symmetric one, $H(\mathbf{15})$, which were not included in the previous study. With 16 parameters in total and 28 experimental data points, we obtain the minimal ${\chi }^2$ over degree of freedom of ${\chi }^2/\mathrm{d}.\mathrm{o}.\mathrm{f}=1.5$, which is a great improvement comparing to that without $H(\mathbf{15})$. With the better fitting values, we evaluate the branching ratios and up-down asymmetries of ${\mathbf{B}}_c\to {\mathbf{B}}_{n}P{P}^{\prime }$, which present some interesting results such as $\mathcal{B}({\mathrm{\Lambda }}_c^{+}\to (\mathrm{\Xi }(1690{)}^0\to {\mathrm{\Sigma }}^{+}{K}^{-})K^{+})\equiv (1.5\pm 0.4)\times {10}^{-3}$ and potential $SU(3)$ breaking effects in ${\mathrm{\Xi }}_c^{+}\to p{\pi }^{+}{K}^{-}$ and ${\mathrm{\Lambda }}_c^{+}\to {\mathrm{\Sigma }}^{+}{\pi }^{-}{K}^{+}$ to be verified by the experiments at BESIII, Belle-II, and LHCb.

The general form of a 2D conformal field theory (CFT) correlator on a Euclidean Riemann surface, Lorentzian plane or Lorentzian cylinder is well known. This paper describes the general form of 2- and 3-point CFT correlators on the Lorentzian torus ${\mathcal{LT}}^2$ which arises as the conformal boundary of the group manifold $\mathrm{SL}(2,\mathbb{R})\simeq {\mathrm{AdS}}_3/\mathbb{Z}$. We consider only generic points, thereby omitting an analysis of contact terms, which already exhibits a surprisingly rich structure. The results are relevant to celestial holography, for which the ${\mathcal{LT}}^2$ at the boundary of Klein space is the home of the putative celestial CFT.

The nanohertz stochastic gravitational wave background (SGWB) is an excellent early universe laboratory for testing the fundamental properties of gravity. In this paper, we elucidate on the full potential of pulsar timing array (PTA) by utilizing cosmic variance-limited, or rather experimental noise-free, correlation measurements to understand the SGWB and by extension gravity. We show that measurements of the angular power spectrum play a pivotal role in the PTA precision era for scientific inferencing. In particular, we illustrate that cosmic variance-limited measurements of the first few power spectrum multipoles enable us to clearly set apart general relativity from alternative theories of gravity. This ultimately conveys that PTAs can be most ambitious for testing gravity in the nanohertz GW regime by zeroing in on the power spectrum.

We consider the frequency-domain leading order and next-to-leading order post-Minkowskian waveforms obtained from the tree-level and one-loop amplitudes describing the scattering of two massive scalar objects and the emission of one graviton. We explicitly calculate their post-Newtonian (PN) limit obtaining an expansion up to the third subleading PN order in all ingredients: the tree-level amplitude, the odd and even parts of the real one-loop kernel, and the Compton or “rescattering” cuts, thus reaching 3PN precision for the latter. We provide explicit expressions for the multipole decomposition of these results in the center-of-mass frame and compare them with the results obtained from the classical multipolar post-Minkowskian method. We find perfect agreement between the two, once the Bondi-Metzner-Sachs supertranslation frame is properly adjusted and the infrared divergences due to rescattering are suitably subtracted in dimensional regularization. This shows that the approach proposed in Georgoudis et al. [An eikonal-inspired approach to the gravitational scattering waveform, J. High Energy Phys. 03 (2024) 089] can be applied beyond the soft-regime ensuring the agreement between amplitude-based and multipolar post-Minkowskian results for generic frequencies.

We examine a specific category of eigenfunctions of the lattice Laplacian on $\{p,q\}$-tessellations of the Poincaré disk that bear resemblance to plane waves in the continuum case. Our investigation reveals that the lattice eigenmodes deviate from the continuum solutions by a factor that depends solely on the local inclination of the vertex in relation to the wave’s propagation direction. This allows us to compute certain eigenfunctions by numerical and analytical methods. For various special cases we find explicit exact eigenfunctions and their eigenvalues on the infinite lattice.

We formulate a model for quantum gravity based on the local Lorentz symmetry and general-coordinate invariance. A key idea is the irreversible vierbein postulate that a tree-level action for the model at a certain energy scale does not contain an inverse vierbein. Under this postulate, only the spinor becomes a dynamical field, and no gravitational background field is introduced in the tree-level action. In this paper, after explaining the transformation rules of the local Lorentz and general-coordinate transformations in detail, a tree-level action is defined. We show that fermionic fluctuations can induce a nonvanishing gravitational background field.

Many theories of nonlinear electrodynamics (NLED) that have been proposed in physical contexts involving strong fields are causal for weak fields but acausal for strong fields. We show that for any such theory there is a unique causal and self-dual (electromagnetic duality invariant) theory with the same Lagrangian at zero magnetic field. This follows from a construction of the general causal self-dual NLED, which shows that strong-field causality is implied by weak-field causality for self-dual theories. We illustrate our results with explicit examples.

We introduce a machine learning model designed to rapidly and accurately predict the time domain gravitational wave emission of nonprecessing binary black hole coalescences, incorporating the effects of higher order modes of the multipole expansion of the waveform. Expanding on our prior work [Phys. Rev. D 103, 043020 (2021)], we decompose each mode by amplitude and phase and reduce dimensionality using principal component analysis. An ensemble of artificial neural networks is trained to learn the relationship between orbital parameters and the low-dimensional representation of each mode. Our model is trained with $\sim {10}^5$ signals with mass ratio $q\in [1,10]$ and dimensionless spins ${\chi }_i\in [-0.9,0.9]$, generated with the state-of-the-art approximant seobnrv4hm, and it is able to generate waveforms up to $\sim 4\times {10}^{5}M$ long. We find that it achieves a median faithfulness of ${10}^{-4}$ averaged across the parameter space. We show that our model generates a single waveform 2 orders of magnitude faster than the training model, with the speedup increasing when waveforms are generated in batches. This framework is entirely general and can be applied to any other time domain approximant capable of generating waveforms from aligned spin circular binaries, possibly incorporating higher order modes.

Accurately modeling the tidal response of neutron stars is crucial to connecting gravitational wave observations of binaries to ultradense nuclear physics. Most current models of the tidal response of relativistic stars either assume a static response model, or use phenomenological models inspired by Newtonian gravity. In this work, we present a general formalism for computing the linear dynamical tidal response function of relativistic, spherically symmetric stars. Our formalism incorporates stratification due to thermal and chemical imbalances, allowing one to study the effects of $g$ modes on the tidal response function. We also describe how to incorporate sources of dissipation due to shear and bulk viscosity. To showcase the utility of our approach, we present several applications for polytropic stars in general relativity. We show how our formalism can capture the dynamical tidal resonance due to the $f$ and $g$ modes of inviscid stars and explore the sensitivity of the dynamical tidal response to the compactness of the star. We also compute the dissipative tidal deformability due to bulk and shear viscous dissipation assuming a simple viscous profile for the bulk and shear viscosity.

We investigate the classical symmetries of the dynamics of the null-dust spherically symmetric Vaidya spacetime. Einstein’s equations for this model can be obtained as equations of motion of a two-dimensional field theory. We discuss the transformations leaving invariant such equations of motion. These are given by two distinct sets, the residual diffeomorphisms coming from general relativity and the generalization of the Schrödinger symmetry, recently found for the static Schwarzschild black holes. Surprisingly, these two sets represent the symmetries of two different action functionals, leading to the same equations of motion, but with different phase spaces.

In this paper, we analyze parity-violating effects in the propagation of gravitational waves (GWs). For this purpose, we adopt a newly proposed parametrized post-Einsteinian (PPE) formalism, which encodes modified gravity corrections to the phase and amplitude of GW waveforms. In particular, we focus our study on three well-known examples of parity-violating theories, namely Chern-Simons, symmetric teleparallel, and Horăva-Lishitz gravity. For each model, we identify the PPE parameters emerging from the inclusion of parity-violating terms in the gravitational Lagrangian. Thus, we use the simulated sensitivities of third-generation GW interferometers, such as the Einstein Telescope and Cosmic Explorer, to obtain numerical bounds on the PPE coefficients and the physical parameters of binary systems. In so doing, we find that deviations from general relativity cannot be excluded within given confidence limits. Moreover, our results show an improvement of 1 order of magnitude in the relative accuracy of the GW parameters compared to the values inferred from the LIGO-Virgo-KAGRA network. In this respect, the present work demonstrates the power of next-generation GW detectors to probe fundamental physics with unprecedented precision.