Two- and three-point functions of composite operators are analyzed with regard to (logarithmically) divergent contact terms. Using the renormalization group of dimensional regularization it is established that the divergences are governed by the anomalous dimensions of the operators and the leading UV behavior of the $1/\epsilon$ coefficient. Explicit examples are given by the $⟨G^2{G}^2⟩$, $⟨\mathrm{\Theta }\mathrm{\Theta }⟩$ (trace of the energy momentum tensor) and $⟨\overline{q}q\overline{q}q⟩$ correlators in QCD-like theories. The former two are convergent when the $1/\epsilon$ poles are resummed but divergent at fixed order implying that perturbation theory and the $\epsilon \to 0$ limit do not generally commute. Finite correlation functions obey unsubtracted dispersion relations which is of importance when they are directly related to physical observables. As a by-product the $R^2$ term of the trace anomaly is extended to next-to-next-to-leading order [$\mathcal{O}(a_s^5)$], in the minimal subtraction scheme, using a recent $⟨G^2{G}^2⟩$ computation.

We obtain the Buchdahl compactness limit for a pure Lovelock static fluid star and verify that the limit following from the uniform-density Schwarzschild’s interior solution, which is universal irrespective of the gravitational theory (Einstein or Lovelock), is true in general. In terms of surface potential $\mathrm{\Phi }(r)$, it means at the surface of the star $r=r_0$, $\mathrm{\Phi }(r_0)<2N(d-N-1)/(d-1{)}^2$, where $d$ and $N$ indicate spacetime dimensions and Lovelock order, respectively. For a given $N$, $\mathrm{\Phi }(r_0)$ is maximum for $d=2N+2$, while it is always $4/9$, Buchdahl’s limit, for $d=3N+1$. It is also remarkable that for $N=1$ Einstein gravity, or for pure Lovelock in $d=3N+1$, Buchdahl’s limit is equivalent to the criterion that gravitational field energy exterior to the star must be less than half its gravitational mass, having no reference to the interior at all.

Contrary to the general consensus in the literature that Friedmann-Lemaître-Robertson-Walker (FLRW) geometries are of embedding class one (i.e., embeddable in one higher dimensional pseudo-Euclidean spaces), we show that the most general $k=0$ and $k=-1$ FLRW geometries are of embedding class two, and their corresponding pseudo-Euclidean spaces have strictly one and two negative eigenvalues, respectively. These are particular results that follow from the new perspective on FLRW embedding that we develop in this paper, namely, that these embeddings are equivalent to unit-speed parametrized curves in two or three dimensions. A careful analysis of appropriate tensor fields then gives identical results and further explains why the class-two geometries remained hidden. However, the signatures of the embedding spaces, as well as the explicit embedding formulas, follow only from the curve picture. This also streamlines the comparatively difficult $k=0$ class and provides new explicit embedding formulas for it and reproduces known embedding formulas for the $k=1,-1$ classes. Embedding into anti–de Sitter space in one higher dimension can likewise be done by constructing associated curves. In particular, we find that all $k=1$ and mildly restricted subclasses of $k=0,-1$ geometries are embeddable in anti–de Sitter space in one higher dimension.

Assuming only a smooth and slow change of spacetime dimensionality at large scales, we find, in a background- and model-independent way, the general profile of the Hausdorff and the spectral dimension of multiscale geometries such as those found in all known quantum gravities. Examples of various scenarios are given. In particular, we derive uniquely the multiscale measure with log oscillations of theories of multifractional geometry. Predictivity of this class of models and falsifiability of their abundant phenomenology are thus established.

Gravitational wave searches to date have largely focused on nonprecessing systems. Including precession effects greatly increases the number of templates to be searched over. This leads to a corresponding increase in the computational cost and can increase the false alarm rate of a realistic search. On the other hand, there might be astrophysical systems that are entirely missed by nonprecessing searches. In this paper we consider the problem of constructing a template bank using stochastic methods for neutron star–black hole binaries allowing for precession, toward but with the restrictions that the orientation of the total angular momentum of the binary is pointing toward the detector and that the neutron star spin is negligible relative to that of the black hole. We quantify the number of templates required for the search, and we explicitly construct the template bank. We show that despite the large number of templates, stochastic methods can be adapted to solve the problem. We quantify the parameter space region over which the nonprecessing search might miss signals.

Using numerical and perturbative methods, we construct the first examples of black hole solutions in Einsteinian cubic gravity and study their thermodynamics. Focusing first on four-dimensional solutions, we show that these black holes have a novel equation of state in which the pressure is a quadratic function of the temperature. Despite this, they undergo a first order phase transition with associated van der Waals behavior. We then construct perturbative solutions for general $D\ge 5$ and study the properties of these solutions for $D=5$ and $D=6$ in particular. We note that for $D>4$ the solutions are described by two independent metric functions. We find novel examples of super-entropic behavior over a large portion of the parameter space. We analyze the specific heat, determining that the black holes are thermodynamically stable over large regions of parameter space.

We explore the use of galaxy bispectra with the multitracer technique as a possible probe of primordial non-Gaussianities. We forecast future constraints on non-linearity parameters, $f_{\mathrm{NL}}^{\mathrm{eq}}$ and $f_{\mathrm{NL}}^{\mathrm{orth}}$, which, respectively, characterize the equilateral- and orthogonal-type primordial bispectra, and show that the multitracer analysis would be effective with reducing the cosmic-variance noise if the number density of galaxies is high enough. We find that the measurement of the galaxy bispectrum by future galaxy surveys can reach the constraints on the nonlocal-type primordial non-Gaussianities to the level more severe than current one which has been obtained by cosmic microwave background observations.

We study particle production at the end of inflation in a kinetically driven $G$ inflation model and show that, in spite of the fact that there are no inflaton oscillations and hence no parametric resonance instabilities, the production of matter particles due to a coupling to the evolving inflaton field can be more efficient than pure gravitational Parker particle production.

Cosmic voids found in galaxy surveys are defined based on the galaxy distribution in redshift space. We show that the large scale distribution of voids in redshift space traces the fluctuations in the dark matter density field $\widehat{\delta }(\mathit{k})$ (in Fourier space with $\mu$ being the line-of-sight projected $\mathit{k}$ vector), ${\widehat{\delta }}_{\mathrm{v}}^s(\mathit{k})=(1+{\beta }_{\mathrm{v}}{\mu }^2)b_{\mathrm{v}}^s\widehat{\delta }(\mathit{k})$, with a beta factor that will be, in general, different than the one describing the distribution of galaxies. Only if voids are assumed to be quasilocal transformations of the linear (Gaussian) galaxy redshift space field does one get equal beta factors ${\beta }_{\mathrm{v}}={\beta }_{\mathrm{g}}=f/b_{\mathrm{g}}$ with $f$ being the growth rate and $b_{\mathrm{g}}$, $b_{\mathrm{v}}^s$ being the galaxy and void bias on large scales defined in redshift space. Indeed, in our mock void catalogs, we measure void beta factors in good agreement with the galaxy one. Further work needs to be done to confirm the level of accuracy of the beta factor equality between voids and galaxies, but in general the void beta factor needs to be considered as a free parameter for linear RSD studies.

We compute the generation of vorticity from velocity dispersion in the dark matter fluid. For dark matter at zero temperature Helmholtz’s theorem dictates that no vorticity is generated and we therefore allow the dark matter fluid to have a nonvanishing velocity dispersion. This implies a modification to the usual hydrodynamical system (continuity and Euler equations): we have to consider the Boltzmann hierarchy up to the second moment. This means that the Euler equation is modified with a source term that describes the effect of nonzero velocity dispersion. We write an equation for the Eulerian vorticity in Lagrangian coordinates and show that it has a growing mode already at second order in perturbation theory. We compute the power spectrum of the vorticity and the rotational velocity at second order in perturbation theory.

Thirty years after the discovery of the fundamental plane, explanations of the tilt of the fundamental plane with respect to the virial plane are still in need of fine-tuning. In this paper, we try to explore the origin of this tilt from the perspective of modified Newtonian dynamics (MOND) by applying the 16 Coma galaxies available in J. Thomas et al. [Mon. Not. R. Astron. Soc. 415, 545 (2011)]. Based on the mass models that can reproduce de Vaucouleurs’ law closely, we find that the tilt of the traditional fundamental plane is naturally explained by the simple form of the MONDian interpolating function, if we assume a well motivated choice of anisotropic velocity distribution, and adopt the Kroupa or Salpeter stellar mass-to-light ratio. Our analysis does not necessarily rule out a varying stellar mass-to-light ratio.

Simplified dark matter models have been recently advocated as a powerful tool to exploit the complementarity between dark matter direct detection, indirect detection and LHC experimental probes. Focusing on pseudoscalar mediators between the dark and visible sectors, we show that the simplified dark matter model phenomenology departs significantly from that of consistent $SU(2{)}_{\mathrm{L}}\times U(1{)}_{\mathrm{Y}}$ gauge invariant completions. We discuss the key physics that simplified models fail to capture, and its impact on LHC searches. Notably, we show that resonant mono-Z searches provide competitive sensitivities to standard mono-jet analyses at 13 TeV LHC.

We employ a mathematical framework based on rational approximants in order to calculate the pseudoscalar-pole piece of the hadronic light-by-light contribution to the anomalous magnetic moment of the muon, $a_{\mu }^{\mathrm{HLbL};P}$. The method is systematic and data based, profiting from over 13 different collaborations, and able to ascribe, for the first time, a systematic uncertainty which provides for the model independence. As a result, we obtain $a_{\mu }^{\mathrm{HLbL};P}=94.3(5.3)\times {10}^{-11}$, whose uncertainty is well below the one foreseen at future experiments measuring the $(g_{\mu }-2)$.

We investigate the possible existence of spin polarization and color superconductivity in the Nambu–Jona-Lasinio model with a tensor-type interaction at finite density and temperature. The thermodynamic potential is calculated by the functional integral method. Numerical results indicate that at low temperature and quark chemical potential the chiral condensed phase exists, and at intermediate chemical potential the color superconducting phase appears. In addition, depending on the magnitude of the tensor coupling, at large chemical potential and low temperature, a color superconducting phase and a spin polarized phase may coexist while at intermediate temperatures only the spin polarized phase occurs.

Standard QCD resummation techniques provide precise predictions for the spectrum and the cumulant of a given observable. The integrated spectrum and the cumulant differ by higher-order terms which, however, can be numerically significant. In this paper we propose a method, which we call the $\sigma$-improved scheme, to resolve this issue. It consists of two steps: (i) include higher-order terms in the spectrum to improve the agreement with the cumulant central value, and (ii) employ profile scales that encode correlations between different points to give robust uncertainty estimates for the integrated spectrum. We provide a generic algorithm for determining such profile scales, and show the application to the thrust distribution in $e^{+}{e}^{-}$ collisions at ${\mathrm{NLL}}^{\prime }+\mathrm{NLO}$ and ${\mathrm{NNLL}}^{\prime }+\mathrm{NNLO}$.

The framework under which decays ${\mathrm{\Lambda }}_b({\frac{1}{2}}^{+})\to B({\frac{1}{2}}^{+})+M$ are analyzed is not applicable for the decays ${\mathrm{\Lambda }}_b({\frac{1}{2}}^{+})\to B^{*}({\frac{3}{2}}^{+})+M$. These decays occur through a baryon pole ${\mathrm{\Sigma }}_c^0$ which is generated by the W-exchange diagram in the process $b+u\stackrel{W}{\to }c+d$. The effective Hamiltonian which arises from the W-exchange diagram is expressed in the nonrelativistic limit. Since ${\mathrm{\Sigma }}_c^0$ belongs to representation 6 of SU(3), it contributes to two sets of decays: ${\mathrm{\Lambda }}_b\to {\mathrm{\Delta }}^0{D}^0,{\mathrm{\Delta }}^{-}{D}^{+},{\mathrm{\Sigma }}^{*-}{D}_s^{+}$ and ${\mathrm{\Lambda }}_b\to {\mathrm{\Sigma }}_c^{*-}{\pi }^{+},{\mathrm{\Sigma }}_c^{*0}{\pi }^0,{\mathrm{\Xi }}_c^{*0}{K}^0$. The branching ratios for these decays are evaluated and can be compared with their experimental values when the data become available. Another prediction of the model is that asymmetry parameter $\alpha =0$ since the baryon pole contributes to the parity conserving ($p$-wave) amplitude and does not contribute to the parity violating ($d$-wave) amplitude.

We report the results of searches for solar axions and galactic dark matter axions or axionlike particles with the CDEX-1 experiment at the China Jinping Underground Laboratory, using 335.6 kg days of data from a $p$-type point-contact germanium detector. The data are compatible with the background model, and no excess signals are observed. Limits of solar axions on the model-independent coupling $g_{Ae}<2.5\times {10}^{-11}$ from Compton, bremsstrahlung, atomic-recombination, and deexcitation channels and $g_{AN}^{\text{eff}}\times g_{Ae}<6.4\times {10}^{-17}$ from a ${}^{57}\mathrm{Fe}$ M1 transition at 90% confidence level are derived. Within the framework of the Dine-Fischler-Srednicki-Zhitnitskiy and Kim-Shifman-Vainshtein-Zakharov models, our results exclude the axion mass heavier than 0.9 and $177\mathrm{eV}/{\mathrm{c}}^2$, respectively. The derived constraints for dark matter axions below 1 keV improve over the previous results.

Semiholography has been proposed as an effective nonperturbative framework which can consistently combine perturbative and nonperturbative effects for theories like QCD. It is postulated that the strongly coupled nonperturbative sector has a holographic dual in the form of a classical gravity theory in the large N limit, and the perturbative fields determine the gravitational boundary conditions. In this work, we pursue a fundamental derivation of this framework particularly showing how perturbative physics by itself can determine the holographic dual of the infrared, and also the interactions between the perturbative and the holographic sectors. We firstly demonstrate that the interactions between the two sectors can be constrained through the existence of a conserved local energy-momentum tensor for the full system up to hard-soft coupling constants. As an illustration, we set up a biholographic toy theory where both the UV and IR sectors are strongly coupled and holographic with distinct classical gravity duals. In this construction, the requirement that an appropriate gluing can cure the singularities (geodetic incompleteness) of the respective geometries leads us to determine the parameters of the IR theory and the hard-soft couplings in terms of those of the UV theory. The high energy scale behavior of the hard-soft couplings is state-independent but their runnings turn out to be state-dependent. We discuss how our approach can be adapted to the construction of the semiholographic framework for QCD.