The rate of energy exchange of spatially localized and gravitationally bound axion configurations with electromagnetic radiation is investigated in the presence of strong static magnetic fields. A fully analytic treatment is achieved based on variationally optimized separable spatiotemporal clump profiles. For dilute axion stars the equation of the energy variation is reinterpreted as a rate equation of the axion number. Its solutions hints at an asymptotic $\sim t^{1/5}$ increase of the clump size.

The energy-momentum tensor (EMT) of the ’t Hooft-Polyakov monopole and the Julia-Zee dyon are studied. This tensor contains important information about the pressure and the shear force distributions which define mechanical properties of systems. Obtaining the violation of the local stability criterion for the magnetic monopole and dyon we decompose the EMTs into the long- and short-range parts. This decomposition depends on the Abelian field strength tensor which cannot be uniquely defined. We suggest to use the modified ’t Hooft definition for the tensor. Finally, the long- and short-range parts of the EMTs are computed and new equilibrium equations are obtained. Numerical values for masses, $D$-terms, and various mean square radii for the monopole and the dyon are also computed.

We study modular symmetric quark flavor models without fine-tuning. Mass matrices are written in terms of modular forms, and modular forms in the vicinity of the modular fixed points become hierarchical depending on their residual charges. Thus modular symmetric flavor models in the vicinity of the modular fixed points have a possibility to describe mass hierarchies without fine-tuning. Since describing quark hierarchies without fine-tuning requires $Z_n$ residual symmetry with $n\ge 6$, we focus on ${\mathrm{\Gamma }}_6$ modular symmetry in the vicinity of the cusp $\tau =i\infty$ where $Z_6$ residual symmetry remains. We use only modular forms belonging to singlet representations of ${\mathrm{\Gamma }}_6$ to make our analysis simple. Consequently, viable quark flavor models are obtained without fine-tuning.

We present the first calculation of the Mellin moments of the transverse quark spin densities in the nucleon using lattice QCD simulations with physical values of the pion mass and in the continuum limit. Specifically, we use three $N_f=2+1+1$ twisted mass fermion gauge ensembles each at different lattice spacings. The densities are extracted from the unpolarized and transversity generalized form factors. The first moment of transversely polarized quarks in an unpolarized nucleon shows an interesting distortion, which can be traced back to the sharp falloff of the transversity generalized form factor ${\overline{B}}_{Tn0}(Q^2)$. The isovector tensor anomalous magnetic moment is determined to be ${\kappa }_T=1.051(94)$, which confirms a negative and large Boer-Mulders function, $h_1^{\perp }$, in the nucleon.

We present a simultaneous extraction of the moments of $F_2$ and $F_L$ structure functions of the proton for a range of photon virtuality, $Q^2$. This is achieved by computing the forward Compton amplitude on the lattice utilizing the second-order Feynman-Hellmann theorem. Our calculations are performed on configurations with two different lattice spacings and volumes, all at the $SU(3)$ symmetric point. We find the moments of $F_2$ and $F_L$ in good agreement with experiment. Power corrections turn out to be significant. This is the first time the $Q^2$ dependence of the lowest moment of $F_2$ has been quantified.

We employ the comparatively minimal extension of hard-wall AdS/QCD due to Katz and Schwartz which takes into account the ${\mathrm{U}(1)}_A$ anomaly for computing hadronic light-by-light scattering contributions of pseudoscalar and axial-vector mesons to the anomalous magnetic moment of the muon $a_{\mu }$. By including a gluon condensate as one extra tunable parameter besides those fixed by $f_{\pi }$ and the pion, kaon, and rho masses, we obtain remarkably accurate fits for $\eta$ and ${\eta }^{\prime }$ masses and their decay rates to photons, leading to $a_{\mu }$ contributions in complete agreement with the Standard Model result by the Muon $g-2$ Theory Initiative. Turning to the less well understood axial-vector contributions, we update our previous predictions obtained in flavor-symmetric hard-wall AdS/QCD models without ${\mathrm{U}(1)}_A$ breaking.

We show that the momentum sum rule is a necessary condition for factorization of double parton distributions into a product of two single parton distributions for small values of the parton momentum fractions $x$ and large enough values of the evolution scale $Q^2$. This is a somewhat surprising result since the momentum sum rule involves integration over all values of the momentum fraction. In essence, the momentum sum rule provides a proper relation between the double and single parton distributions, which is necessary for the small $x$ factorization at large $Q^2$.

In the present work, the triply heavy tetraquarks states $QQ\overline{Q}\overline{q}$ with $Q=(c,b)$ and $q=(u,d,s)$ with all possible quantum numbers are systematically investigated in the framework of the chiral quark model with the resonating ground method. Two kinds of structures, including the meson-meson configuration (the color-singlet channels and the hidden-color channels) and the diquark-antidiquark configuration (the color sextet-antisextet and the color triplet-antitriplet), are considered. In the considered system, several bound states are obtained for the $cc\overline{c}\overline{q^{\prime }}$, $bb\overline{c}\overline{q^{\prime }}$, and $bc\overline{c}\overline{q}$ tetraquarks. From the present estimations, we find that the coupled-channel effect is of great significance for forming below-threshold tetraquark states, which are stable for strong decays.

We investigate the double-charm and hidden-charm hexaquarks as molecules in the framework of the one-boson-exchange potential model. The multichannel coupling and $S-D$ wave mixing are taken into account carefully. We adopt the complex scaling method to investigate the possible quasibound states, whose widths are from the three-body decay channel ${\mathrm{\Lambda }}_c{\mathrm{\Lambda }}_c\pi$ or ${\mathrm{\Lambda }}_c{\overline{\mathrm{\Lambda }}}_c\pi$. For the double-charm system of $I(J^P)=1(1^{+})$, we obtain a quasibound state, whose width is 0.50 MeV if the binding energy is $-14.27\mathrm{MeV}$, and the $S$-wave ${\mathrm{\Lambda }}_c{\mathrm{\Sigma }}_c$ and ${\mathrm{\Lambda }}_c{\mathrm{\Sigma }}_c^{*}$ components give the dominant contributions. For the $1(0^{+})$ double-charm hexaquark system, we do not find a pole. We find more poles in the hidden-charm hexaquark system. We obtain one pole as a quasibound state in the $I^G(J^{PC})=1^{+}(0^{--})$ system, which only has one channel $({\mathrm{\Lambda }}_c{\overline{\mathrm{\Sigma }}}_c+{\mathrm{\Sigma }}_c{\overline{\mathrm{\Lambda }}}_c)/\sqrt{2}$. Its width is 1.72 MeV with a binding energy of $-5.37\mathrm{MeV}$, but we do not find a pole for the scalar $1^{-}(0^{-+})$ system. For the vector $1^{-}(1^{-+})$ system, we find a quasibound state. Its energies, widths, and constituents are very similar to those of the $1(1^{+})$ double-charm case. In the vector $1^{+}(1^{--})$ system, we get two poles—a quasibound state and a resonance. The quasibound state has a width of 0.38 MeV with a binding energy of $-16.79\mathrm{MeV}$. For the resonance, its width is 4.06 MeV with an energy of 60.78 MeV relative to the ${\mathrm{\Lambda }}_c{\overline{\mathrm{\Sigma }}}_c$ threshold, and its partial width from the two-body decay channel $({\mathrm{\Lambda }}_c{\overline{\mathrm{\Sigma }}}_c-{\mathrm{\Sigma }}_c{\overline{\mathrm{\Lambda }}}_c)/\sqrt{2}$ is apparently larger than the partial width from the three-body decay channel ${\mathrm{\Lambda }}_c{\overline{\mathrm{\Lambda }}}_c\pi$. In particular, the $1^{+}(0^{--})$ and $1^{-}(1^{-+})$ hidden-charm hexaquark molecular states are very interesting. These isovector mesons have exotic $J^{PC}$ quantum numbers which are not accessible to the conventional $q\overline{q}$ mesons.

We investigate features of the hidden charm-strange scalar tetraquark $c\overline{c}s\overline{s}$ by calculating its spectral parameters and width, and we compare the obtained results with the mass and width of the resonance $X(3960)$ discovered recently in the LHCb experiment. We model the tetraquark as a diquark-antidiquark state $X=[cs][\overline{c}\overline{s}]$ with spin-parities $J^{\mathrm{PC}}=0^{++}$. The mass and current coupling of $X$ are calculated using the QCD two-point sum rules by taking into account various vacuum condensates up to dimension 10. The width of the tetraquark $X$ is estimated via the decay channels $X\to D_s^{+}{D}_s^{-}$ and $X\to {\eta }_c{\eta }^{(\prime )}$. The partial widths of these processes are expressed in terms of couplings $G$, $g_1$, and $g_2$, which describe the strong interactions of particles at the vertices $X{D}_s^{+}{D}_s^{-}$, $X{\eta }_c{\eta }^{\prime }$, and $X{\eta }_c\eta$, respectively. Numerical values of $G$, $g_1$, and $g_2$ are evaluated by employing the three-point sum rule method. Comparing the results $m=(3976\pm 85)\mathrm{MeV}$ and ${\mathrm{\Gamma }}_{\mathrm{X}}=(42.2\pm 12.0)\mathrm{MeV}$ obtained for parameters of the tetraquark $X$ and experimental data of the LHCb Collaboration, we conclude that the resonance $X(3960)$ can be considered as a candidate to a scalar diquark-antidiquark state.

Recently, the BESIII Collaboration published the Born cross section of $e^{+}{e}^{-}\to K^{+}{K}^{-}J/\psi$, in which a new vector enhancement structure $Y(4500)$ was observed for the first time. The mass of the $Y(4500)$ resonance structure is in good agreement with our previous prediction for a $5S\text{−}4D$ mixing charmonium candidate $\psi (4500)$, while the measured width is $2\sigma$ larger than the theoretical estimate. In this work, we reanalyzed the cross section of $e^{+}{e}^{-}\to K^{+}{K}^{-}J/\psi$ by introducing two theoretically predicted charmonium states $\psi (4220)$ and $\psi (4500)$ as intermediate resonances, and found that this width deviation problem can be resolved. Meanwhile, we found that the inclusion of two established charmonium states $\psi (4160)$ and $\psi (4415)$ can further improve the fit quality, with four sets of widely different solutions to ${\mathrm{\Gamma }}_{e^{+}{e}^{-}}\mathcal{B}(\psi \to K^{+}{K}^{-}J/\psi )$. In order to better identify the properties of the $Y(4500)$, we calculated the charmonium hadronic transition to final states $K^{+}{K}^{-}J/\psi$ within the charmed meson loop mechanism, where the fitted branching ratio of $\psi (4500)\to K^{+}{K}^{-}J/\psi$ can be well explained by the theoretical calculation, further supporting the new enhancement structure around 4.5 GeV as a higher charmonium $\psi (4500)$ that we predicted. Finally, we also discussed the possible signal of another predicted charmonium candidate $\psi (4380)$ in $e^{+}{e}^{-}\to K^{+}{K}^{-}J/\psi$. These research results should be an important step in constructing the charmonium family and thoroughly solving the charmoniumlike $Y$ problem.

I obtain identities satisfied by the three-loop self-energy master integrals with four or five propagators with generic masses, including the derivatives with respect to each of the squared masses and the external momentum invariant. These identities are then recast in terms of the corresponding renormalized master integrals, enabling straightforward numerical evaluation of them by the differential equations approach. Some benchmark examples are provided. The method used to obtain the derivative identities relies only on the general form implied by integration by parts relations, without actually following the usual integration by parts reduction procedure. As a byproduct, I find a simple formula giving the expansion of the master integrals to arbitrary order in the external momentum invariant, in terms of known derivatives of the corresponding vacuum integrals.

Understanding the polarization structure and providing precise predictions for multiboson processes at the LHC is becoming urgent in the light of the upcoming run-3 and high-luminosity data. The CMS and ATLAS collaborations have already started using polarized predictions to perform template fits of the data, getting access to the polarization of W and Z bosons. So far, only fully leptonic decay channels have been considered in this perspective. The natural step forward is the investigation of hadronic decays of electroweak bosons. In this work, we compute NLO QCD corrections to the production and decay of WZ pairs at the LHC in final states with two charged leptons and jets. The calculation relies on the double-pole approximation and the separation of polarized states at the level of Standard Model amplitudes. The presented NLO-accurate results are necessary building blocks for a broad understanding and precise modeling of polarized diboson production in semileptonic decay channels.

We introduce a class of states characterized by proposed conditions of homogeneity and isotropy in loop quantum gravity and construct concrete examples given by Bell-network states on a special class of homogeneous graphs. Such states provide new representations of cosmological spaces that can be explored for the formulation of cosmological models in the context of loop quantum gravity. We show that their local geometry is described in an automorphism-invariant manner by one-node observables analogous to the one-body observables used in many-body quantum mechanics, and compute the density matrix representing the restriction of global states to the algebra of one-node observables. The von Neumann entropy of this density matrix provides a notion of entanglement entropy of a local region that is invariant under automorphisms and can be applied to states involving superpositions of distinct graphs.

Spacetime emergence from entanglement proposes an alternative to quantizing gravity and typically derives a notion of distance based on the amount of mutual information shared across subsystems. Albeit promising, this program still faces challenges to describe simple physical systems, such as a maximally entangled Bell pair that is taken apart while preserving its entanglement. We propose a solution to this problem: a reminder that quantum systems can have multiple sectors of independent degrees of freedom, and that each sector can be entangled. Thus, while one sector can decohere, and decrease the amount of total mutual information within the system, another sector, e.g. spin, can remain entangled. We illustrate this with a toy model, showing that only within the particles’ momentum uncertainty there can be considerably more entanglement than in the spin sector for a single Bell pair. We finish by introducing some considerations about how spacetime could be tested in the lab in the future.

Spectral rigidity in Hermitian quantum chaotic systems signals the presence of dynamical universal features at timescales that can be much shorter than the Heisenberg time. We study the analog of this timescale in many-body non-Hermitian quantum chaos by a detailed analysis of long-range spectral correlators. For that purpose, we investigate the number variance and the spectral form factor of a non-Hermitian $q$-body Sachdev-Ye-Kitaev (nHSYK) model, which describes $N$ fermions in zero spatial dimensions. After an analytical and numerical analysis of these spectral observables for non-Hermitian random matrices, and a careful unfolding, we find good agreement with the nHSYK model for $q>2$ starting at a timescale that decreases sharply with $q$. The source of deviation from universality, identified analytically, is ensemble fluctuations not related to the quantum dynamics. For fixed $q$ and large enough $N$, these fluctuations become dominant up until after the Heisenberg time, so that the spectral form factor is no longer useful for the study of quantum chaos. In all cases, our results point to a weakened or vanishing spectral rigidity that effectively delays the observation of full quantum ergodicity. We also show that the number variance displays nonstationary spectral correlations for both the nHSYK model and random matrices. This nonstationarity, also not related to the quantum dynamics, points to intrinsic limitations of these observables to describe the quantum chaotic motion. On the other hand, we introduce the local spectral form factor, which is shown to be stationary and not affected by collective fluctuations, and propose it as an effective diagnostic of non-Hermitian quantum chaos. For $q=2$, we find saturation to Poisson statistics at a timescale of $\log D$, compared to a scale of $\sqrt{D}$ for $q>2$, with $D$ the total number of states.

We explore the chaotic dynamics of the mass-deformed Aharony-Bergman-Jafferis-Maldacena model. To do so, we first perform a dimensional reduction of this model from $2+1$ to $0+1$ dimensions, considering that the fields are spatially uniform. Working in the ’t Hooft limit and tracing over ansatz configurations involving fuzzy 2-spheres, which are described in terms of the Gomis–Rodriguez-Gomez–Van Raamsdonk–Verlinde matrices with collective time dependence, we obtain a family of reduced effective Lagrangians and demonstrate that they have chaotic dynamics by computing the associated Lyapunov exponents. In particular, we focus on how the largest Lyapunov exponent, ${\lambda }_L$, changes as a function of $E/N^2$. Depending on the structure of the effective potentials, we find either ${\lambda }_L\propto (E/N^2{)}^{1/3}$ or ${\lambda }_L\propto (E/N^2-{\gamma }_N{)}^{1/3}$, where ${\gamma }_N(k,\mu )$ are constants determined in terms of the Chern-Simons coupling $k$, the mass $\mu$, and the matrix level $N$. Noting that the classical dynamics approximates the quantum theory only in the high-temperature regime, we investigate the temperature dependence of the largest Lyapunov exponents and give upper bounds on the temperature above which ${\lambda }_L$ values comply with the Maldacena-Shenker-Stanford bound, ${\lambda }_L\le 2\pi T$, and below which it will eventually be not obeyed.

The origin and formation of stellar-mass binary black holes remains an open question that can be addressed by precise measurements of the binary and orbital parameters from their gravitational wave signal. Such binaries are expected to circularize due to the emission of gravitational waves as they approach merger. However, depending on their formation channel, some binaries could retain a non-negligible eccentricity when entering the frequency band of current gravitational wave detectors, which will decay as the binary inspirals. In order to meaningfully measure the eccentricity in an observed gravitational wave signal, two main ingredients are then necessary; an accurate waveform model that describes binaries on eccentric orbits, and an estimator to measure the noncircularity of the orbit as a function of frequency. In this work we first demonstrate the efficacy of the improved TEOBResumS waveform model for eccentric coalescing binaries with aligned spins. We validate the model against mock signals of aligned-spin binary black hole mergers and quantify the impact of eccentricity on the estimation of other intrinsic binary parameters. We then perform a fully Bayesian reanalysis of GW150914 with the eccentric waveform model. We find (i) that the model is reliable for aligned-spin binary black holes and (ii) that GW150914 is consistent with a noneccentric merger although we cannot rule out small values of initial eccentricity at a reference frequency of 20 Hz. Secondly, we present a systematic, model-agnostic method to measure the orbital eccentricity and its evolution directly from the gravitational-wave posterior samples. This method mitigates against the contamination of eccentricity measurements through the use of gauge-dependent quantities and has the advantage of allowing for the direct comparison between different analyses, as the definition of eccentricity may differ between models. Our scheme can be applied even in the case of small eccentricities and can be adopted straightforwardly in postprocessing to allow for direct comparison between analyses.

In the recent proposal [S. W. Wei et al., Black Hole Solutions as Topological Thermodynamic Defects, Phys. Rev. Lett. 129, 191101 (2022).], the black holes were viewed as topological thermodynamic defects by using the generalized off shell free energy. In this paper, we follow such proposal to study the local and global topological natures of the Gauss-Bonnet black holes in anti–de Sitter (AdS) space. The local topological natures are reflected by the winding numbers, where the positive and negative winding numbers correspond to the stable and unstable black hole branches. The global topological natures are reflected by the topological numbers, which are defined as the sum of the winding numbers for all black hole branches and can be used to classify the black holes into different classes. When the charge is present, we find that the topological number is independent on the values of the parameters, and the charged Gauss-Bonnet AdS black holes can be divided into the same class of the Reissner-Nordström anti-de Sitter black hole black holes with the same topological number 1. However, when the charge is absent, we find that the topological number has certain dimensional dependence. This is different from the previous studies, where the topological number is found to be a universal number independent of the black hole parameters. Furthermore, the asymptotic behaviors of curve $\tau (r_h)$ in small and large radii limit can be a simple criterion to distinguish the different topological number. We find a new asymptotic behavior as $\tau (r_h\to 0)=0$ and $\tau (r_h\to \infty )=0$ in the black hole system, which shows topological equivalency with the asymptotic behaviors $\tau (r_h\to 0)=\infty$ and $\tau (r_h\to \infty )=\infty$. We also give an intuitional proof of why there are only three topological classes in the black hole system under the condition $({\partial }_{r_h}S{)}_P>0$.

We investigate solutions of the five-dimensional rotating Einstein-Vlasov system with an $R\times SU(2)\times U(1)$ isometry group. In a five-dimensional spacetime, there are two independent planes of rotation; thus, considering $U(1)$ symmetry on each rotation plane, we may impose an $R\times U(1)\times U(1)$ isometry to a stationary spacetime. Furthermore, when the values of the two angular momenta are equal to each other, the spatial symmetry gets enhanced to $R\times SU(2)\times U(1)$ symmetry, and the spacetime has a cohomogeneity-1 structure. Imposing the same symmetry to the distribution function of the particles of which the Vlasov system consists, the distribution function can be dependent on three mutually independent and commutative conserved charges for particle motion [energy, total angular momentum on $SU(2)$ and $U(1)$ angular momentum]. We consider the distribution function which exponentially depends on the $U(1)$ angular momentum and reduces to the thermal equilibrium state in spherical symmetry. Then, in this paper, we numerically construct solutions of the asymptotically anti–de Sitter Einstein-Vlasov system.