Nonlocal gluon condensates are vacuum expectations of the product of gluon field strength tensors. Short-distance expansions of two-, three-, and four-gluon condensates are presented up to dimension-eight local operators. We propose a method for calculating the Wilson coefficients based on the presented expansions and the Feynman diagram technique in the background field approach. The method is demonstrated using the glueball current correlators as examples. Methodological aspects of the background field approach are discussed in relation to glueball studies within QCD sum rules. We confirm the results for operator product expansion of the two-gluon $0^{\pm +}$ glueball current correlators and calculate additional contributions coming from dimension-six four-quark condensate and dimension-eight mixed quark-gluon condensates. The operator product expansions used in QCD sum rules for three-gluon $0^{\pm +}$ glueballs are revisited up to dimension-six order.

Very recently, a substantial $7\sigma$ deviation of the $W$-boson mass from the Standard Model prediction has been reported by the CDF Collaboration. Furthermore, the Muon $g-2$ Experiment recently confirmed the long-standing tension in $(g-2{)}_{\mu }$. Besides, the updated result from the LHCb Collaboration found evidence for the breaking of lepton universality in beauty-quark decays, which shows a $3.1\sigma$ discrepancy and is consistent with their previous measurements. Motivated by several of these drawbacks of the Standard Model, in this work, we propose a model consisting of two scalar leptoquarks and a vectorlike quark to simultaneously address the $W$-boson mass shift, the $(g-2{)}_{\mu }$, and anomalies in the neutral current transitions of the $B$-meson decays. The proposed model also sheds light on the origin of neutrino mass and can be fully tested at the future colliders.

It has been recently pointed out that in certain axion models it is possible to suppress simultaneously both the axion couplings to nucleons and electrons, realizing the so-called astrophobic axion scenarios, wherein the tight bounds from SN1987A and from stellar evolution of red giants and white dwarfs are greatly relaxed. So far, however, the conditions for realizing astrophobia have only been set out in tree-level analyses. Here we study whether these conditions can still be consistently implemented once renormalization group effects are included in the running of axion couplings. We find that axion astrophobia keeps holding, albeit within fairly different parameter space regions, and we provide analytical insights into this result. Given that astrophobic axion models generally feature flavor-violating axion couplings, we also assess the impact of renormalization group effects on axion-mediated flavor-violating observables.

Very recently, the CMS Collaboration reported a peaking phenomenon existing in the di-$J/\psi$ invariant mass spectrum from $pp$ collision, by which the $X(6900)$ structure announced by the LHCb Collaboration was confirmed, but also more enhancement structures were discovered. Facing such a novel phenomenon, in this work we indicate that these new features reflected from the CMS measurement provide a good implication for a dynamical mechanism which reproduces the novel peaking phenomenon in the reported $J/\psi$-pair mass spectrum well. This mechanism is due to special reactions, where different charmonium pairs directly produced by $pp$ collision may transit into the final state of $J/\psi J/\psi$. The present work provides a special viewpoint to decode these observed fully charm structures in the $J/\psi$-pair invariant mass spectrum.

By using the cross sections of $e^{+}{e}^{-}\to p\overline{p}{\pi }^0$ measured at the center-of-mass energies from 3.65 to 4.60 GeV, we find that the line shape well agrees with pure continuum production parametrized by a power law function and the significance of both $\psi (3770)$ and $\psi (4230)\to p\overline{p}{\pi }^0$ is less than $0.4\sigma$. We set more stringent constraints on the charmless decays of the charmonium state, $\psi (3770)$, and the charmoniumlike state, $\psi (4230)$, to $p\overline{p}{\pi }^0$ than in previous measurements. The data are also used to estimate the cross sections of $p\overline{p}\to {\pi }^0\psi (3770)$ and $p\overline{p}\to {\pi }^0\psi (4230)$ that are essential for planning the data taking of the $\overline{\mathrm{P}}\mathrm{ANDA}$ experiment.

COSINE-100 is a direct detection dark matter experiment that aims to test DAMA/LIBRA’s claim of dark matter discovery by searching for a dark-matter-induced annual modulation signal with NaI(Tl) detectors. We present new constraints on the annual modulation signal from a dataset with a 2.82 yr livetime utilizing an active mass of 61.3 kg for a total exposure of $173\mathrm{kg}·\mathrm{yr}$. This new result features an improved event selection that allows for both lowering the energy threshold to 1 keV and a more precise time-dependent background model. In the 1–6 and 2–6 keV energy intervals, we observe best-fit values for the modulation amplitude of $0.0067\pm 0.0042$ and $0.0051\pm 0.0047\mathrm{counts}/(\mathrm{day}·\mathrm{kg}·\mathrm{keV})$, respectively, with a phase fixed at 152.5 days.

We use data from the COHERENT CsI[Na] scintillation detector to constrain sub-GeV leptophobic dark matter models. This detector was built to observe low-energy nuclear recoils from coherent elastic neutrino-nucleus scattering. These capabilities enable searches for dark matter particles produced at the Spallation Neutron Source mediated by a vector portal particle with masses between 2 and $400\mathrm{MeV}/{\mathrm{c}}^2$. No evidence for dark matter is observed and a limit on the mediator coupling to quarks is placed. This constraint improves upon previous results by two orders of magnitude. This newly explored parameter space probes the region where the dark matter relic abundance is explained by leptophobic dark matter when the mediator mass is roughly twice the dark matter mass. COHERENT sets the best constraint on leptophobic dark matter at these masses.

We provide a new extension to the geometric construction of six-dimensional (6D) (1,0) superconformal field theories (SCFTs) that encapsulates Higgs branch structures with identical global symmetry but different spectra. In particular, we find that there exist distinct 6D (1,0) SCFTs that may appear to share their tensor branch description, flavor symmetry algebras, and central charges. For example, such subtleties arise for the very even nilpotent Higgsing of $({\mathfrak{so}}_{4k},{\mathfrak{so}}_{4k})$ conformal matter; we propose a method to predict at which conformal dimension the Higgs branch operators of the two theories differ via augmenting the tensor branch description with the Higgs branch chiral ring generators of the building block theories. Torus compactifications of these 6D (1,0) SCFTs give rise to four-dimensional (4D) $\mathcal{N}=2$ SCFTs of class-$\mathcal{S}$, and the Higgs branch of such 4D theories are captured via the Hall-Littlewood index. We confirm that the resulting 4D theories indeed differ in their spectra in the predicted conformal dimension from their Hall-Littlewood indices. We highlight how this ambiguity in the tensor branch description arises beyond the very even nilpotent Higgsing of $({\mathfrak{so}}_{4k},{\mathfrak{so}}_{4k})$ conformal matter and hence should be understood for more general classes of 6D (1,0) SCFTs.

We study the generalized entanglement entropy in the higher-dimensional two-sided eternal black hole by double holography. By introducing an end of the world ETW brane, which defines the time-dependent effective Hawking radiation region, we find a new type of Ryu-Takayanagi surface besides the Hartman-Maldacena surface and the island Ryu-Takayanagi surface known previously. We study the phase transition among the three Ryu-Takayanagi surfaces at different temperatures and obtain the phase diagram as well as the Page curve.

Using an $O(N)$-symmetric toy model QFT in zero space-time dimensions we discuss several aspects and limitations of the $\frac{1}{N}$-expansion. We demonstrate how slight modifications in a classical UV action can lead the $\frac{1}{N}$-expansion astray and how the infinite-$N$ limit may alter fundamental properties of a QFT. Thereby we present the problem of calculating correlation functions from two totally different perspectives: First, we explicitly analyze our model within an $\frac{1}{N}$-saddle-point expansion and show its limitations. Second, we picture the same problem within the framework of the functional renormalization group. Applying novel analogies between (F)RG flow equations and numerical fluid dynamics from parts I and II of this series of publications, we recast the calculation of expectation values of our toy model into solving a highly nonlinear but exact advection(-diffusion) equation. In doing so, we find that the applicability of the $\frac{1}{N}$-expansion to our toy model is linked to freezing shock waves in field space in the FRG-fluid dynamic picture, while the failure of the $\frac{1}{N}$-expansion in this context is related to the annihilation of two opposing shock waves in field space.

We demonstrate that the reformulation of renormalization group (RG) flow equations as nonlinear heat equations has severe implications on the understanding of RG flows in general. We demonstrate by explicitly constructing an entropy function for a zero-dimensional ${\mathbb{Z}}_2$-symmetric model that the dissipative character of generic nonlinear diffusion equations is also hard-coded in the functional RG equation. This renders RG flows manifestly irreversible, revealing the semigroup property of RG transformations on the level of the flow equation itself. Additionally, we argue that the dissipative character of RG flows, its irreversibility and the entropy production during the RG flow may be linked to the existence of a so-called $\mathcal{C}\text{−}/\mathcal{A}$-function. In total, this introduces an asymmetry in the so-called RG time—in complete analogy to the thermodynamic arrow of time—and allows for an interpretation of infrared actions as equilibrium solutions of dissipative RG flows equations. The impossibility of resolving microphysics from macrophysics is evident in this framework. Furthermore, we directly link the irreversibility and the entropy production in RG flows to an explicit numerical entropy production, which is manifest in diffusive and non-linear partial differential equations (PDEs) and a standard mathematical tool for the analysis of PDEs. Using exactly solvable zero-dimensional ${\mathbb{Z}}_2$-symmetric models, we explicitly compute the (numerical) entropy production related to the total variation nonincreasing property of the PDE during RG flows toward the infrared limit. Finally, we discuss generalizations of our findings and relations to the $\mathcal{C}\text{−}/\mathcal{A}$-theorem as well as how our work may help to construct truncations of RG flow equations in the future, including numerically stable schemes for solving the corresponding PDEs.

The functional renormalization group (FRG) approach is a powerful tool for studies of a large variety of systems, ranging from statistical physics over the theory of the strong interaction to gravity. The practical application of this approach relies on the derivation of so-called flow equations, which describe the change of the quantum effective action under the variation of a coarse-graining parameter. In the present work, we discuss in detail a novel approach to solve such flow equations. This approach relies on the fact that RG equations can be rewritten such that they exhibit similarities with the conservation laws of fluid dynamics. This observation can be exploited in different ways. First of all, we show that this allows to employ powerful numerical techniques developed in the context of fluid dynamics to solve RG equations. In particular, it allows us to reliably treat the emergence of nonanalytic behavior in the RG flow of the effective action as it is expected to occur in studies of, e.g., spontaneous symmetry breaking. Second, the analogy between RG equations and fluid dynamics offers the opportunity to gain novel insights into RG flows and their interpretation in general, including the irreversibility of RG flows. We work out this connection in practice by applying it to zero-dimensional quantum-field theoretical models. The generalization to higher-dimensional models is also discussed. Our findings are expected to help improving future FRG studies of quantum field theories in higher dimensions both on a qualitative and quantitative level.

We give a general description of the evolving quantum state of a Schwarzschild black hole, in the quantum field theory approximation. Such a time-dependent description is based on introducing a choice of time slices. We in particular consider slices that smoothly cross the horizon, and introduction of “stationary” such slices simplifies the analysis. This analysis goes beyond standard derivations of Hawking radiation that focus on asymptotic excitations, and in particular gives an evolving state that is regular at the horizon, with no explicit trans-Planckian dependence, and that can in principle be generalized to incorporate interacting fields. It is also argued to be useful in connecting to information-theoretic investigation of black hole evolution. The description of the evolving state depends on the choice of slices as well as coordinates on the slices and mode bases; these choices give different “pictures” analogous to that of Schrödinger. Evolution does have a simpler appearance in an energy eigenbasis, but such a basis is also singular at the horizon; evolution of regular modes has a more complicated appearance, whose properties may be inferred by comparing with the energy eigenbasis. In a regular description, Hawking quanta are produced in a black hole atmosphere, at scales comparable to the horizon size. This approach is also argued to extend to more general asymptotics, such as that of anti de Sitter space. In the latter context, this analysis provides a description of the Hamiltonian and evolution of a black hole that may be compared to the large-$N$ dynamics of the proposed dual CFT.

In this paper we discuss the gravitational field of ultrarelativistic extended spinning objects. For this purpose, we use a solution of the linearized gravitational equations obtained in the frame where such an object is translationally at rest, and boost this solution close to the speed of light. In order to obtain a regular limiting metric for nonspinning matter, it is sufficient to keep the energy of the boosted body fixed. This process is known as the Penrose limit. We demonstrate that in the presence of rotation, an additional rescaling is required for the angular momentum density components in the directions orthogonal to the boost. As a result of the Lorentz contraction, the thickness of the body in the direction of the boost shrinks. The body takes the form of a pancake, and its gravitational field is localized in the null plane. We discuss light and particle scattering in this gravitational field, and calculate the scattering parameters associated with the gravitational memory effect. We also show that by taking the inverse of the Penrose transform, one can use the obtained scattering map to study the gravitational lensing effect in the rest frame of a massive spinning object.

We set up a general framework for systematically building and classifying, in the linear regime, causal and stable dissipative hydrodynamic theories that, alongside with the usual hydrodynamic modes, also allow for an arbitrary number of nonhydrodynamic modes with complex dispersion relation (such theories are often referred to as “quasihydrodynamic”). To increase the number of nonhydrodynamic modes, one needs to add more effective fields to the model. The system of equations governing this class of quasihydrodynamic theories is symmetric hyperbolic, thermodynamically consistent (i.e., the entropy is a Lyapunov function) and can be derived from an action principle. As a first application of the formalism, we prove that, in the linear regime, the Israel-Stewart theory in the Eckart frame and the Israel-Stewart theory in the Landau frame are exactly the same theory. In addition, with an Onsager-Casimir analysis, we show that in strongly coupled plasmas the nonequilibrium degrees of freedom typically appear in pairs, whose members acquire opposite phase under time reversal. We use this insight to modify Cattaneo’s model for diffusion, in a way to make its initial transient consistent with the transient dynamics of holographic plasmas.

We propose a novel scenario to explain the small cosmological constant (CC) by a peculiar inflaton potential. The shape almost satisfies the following conditions: The inflation is eternal if the CC is positive and not eternal if the CC is negative. Although realizing the peculiar shape has a similar amount of fine-tuning as the CC, the shape can be made stable under radiative corrections in the effective theory. By introducing a slowly varying CC from a positive value to a negative value, the dominant volume of the Universe after the inflation turns out to have a vanishingly small CC. The scenario does not require eternal inflation, but the $e$-folding number is exponentially large, and the inflation scale is low. The Hubble parameter during inflation, $H_{\inf }$, is required to be smaller than the present CC scale, and, thus, the CC relaxed during inflation with the low renormalization scale, $\sim H_{\inf }$, is safe from the radiative corrections from the standard model particles. The scenario can have a consistent thermal history, but the present equation of state of the Universe is predicted to slightly differ from the one for the $\mathrm{\Lambda }\mathrm{CDM}$ model. In a time-varying CC model, CC can be relaxed from $({10}^3\mathrm{GeV}{)}^4$, and in a model with a light scalar field scanning the CC during inflation, CC can be relaxed from $(10\mathrm{MeV}{)}^4$.

Motivated by the $\mathrm{AdS}/\mathrm{CFT}$ correspondence, we use Monte Carlo simulation to investigate the Ising model formulated on tessellations of the two-dimensional hyperbolic disk. We focus in particular on the behavior of boundary-boundary correlators, which exhibit power-law scaling both below and above the bulk critical temperature indicating scale invariance of the boundary theory at any temperature. This conclusion is strengthened by a finite-size scaling analysis of the boundary susceptibility which yields a scaling exponent consistent with the scaling dimension extracted from the boundary correlation function. This observation provides evidence that the connection between continuum boundary conformal symmetry and isometries of the bulk hyperbolic space survives for simple interacting field theories even when the bulk is approximated by a discrete tessellation.

We describe a broad class of 4D F-theory models in which an $E_7$ gauge group is broken through fluxes to the standard model gauge group. These models are ubiquitous in the 4D F-theory landscape and can arise from flux breaking of most models with $E_7$ factors. While in many cases the $E_7$ breaking leads to exotic matter, there are large families of models in which the standard model gauge group and chiral matter representations are obtained through an intermediate SU(5) group. The number of generations of matter appearing in these models can easily be small. We demonstrate the possibility of getting three generations of chiral matter as the preferred matter content.

The celebrated GKLS master equation, widely called just the Lindblad equation, is the universal dynamical equation of nonrelativistic open quantum systems in their Markovian approximation. It is not necessary and perhaps impossible that GKLS equations possess sensible relativistic forms. In 2017, in a lucid talk on black hole information loss paradox, David Poulin argued for a Lorentz invariant GKLS master equation proposed by Alicki, Fannes, and Verbeure in 1986. The equation is really puzzling. A closer look uncovers a smartly hidden defect that leaves us without Lorentz invariant Markovian master equations. They, in view of the present author, should not exist.

We study the effects of quantum corrections on transverse momentum broadening of a fast parton passing through dense QCD matter. We show that, at leading logarithmic accuracy the broadening distribution tends at late times or equivalently for large system sizes $L$ to a universal distribution that only depends on a single scaling variable $k_T^2/Q_s^2$ where the typical transverse momentum scale increases with time as $\ln Q_s^2\simeq (1+2\beta )\ln L-\frac{3}{2}(1+\beta )\ln \ln L$ up to nonuniversal terms, with an anomalous dimension $\beta \sim \sqrt{{\alpha }_s}$. This property is analogous to geometric scaling of gluon distributions in the saturation regime and traveling-wave solutions to reaction-diffusion processes. We note that since $\beta >0$ the process is super-diffusive, which is also reflected at large transverse momentum where the scaling distribution exhibits a heavy tail $k_T^{-4+2\beta }$ akin to Lévy random walks.