We analyze holographic field theory dual to Lovelock Chern-Simons anti–de Sitter (AdS) gravity in higher dimensions using first order formalism. We first find asymptotic symmetries in the AdS sector showing that they consist of local translations, local Lorentz rotations, dilatations and non-Abelian gauge transformations. Then, we compute 1-point functions of energy-momentum and spin currents in a dual conformal field theory and write Ward identities. We find that the holographic theory possesses Weyl anomaly and also breaks non-Abelian gauge symmetry at the quantum level.

An important class of observables for gravitational waves consists of the fluxes of energy, momentum, and angular momentum carried away by them and are well understood for weak gravitational waves in Minkowski background. In de Sitter background, the future null infinity, ${\mathcal{J}}^{+}$, is spacelike, which makes the meaning of these observables subtle. A spatially compact source in de Sitter background also provides a distinguished null hypersurface, its cosmological horizon, ${\mathcal{H}}^{+}$. For sources supporting the short wavelength approximation, we adopt the Isaacson prescription to define an effective gravitational stress tensor. We show that the fluxes computed using this effective stress tensor can be evaluated at ${\mathcal{H}}^{+}$, match with those computed at ${\mathcal{J}}^{+}$, and also match with those given by Ashtekar et al. at ${\mathcal{J}}^{+}$ at a coarse grained level.

The spacetime evolution of massless spinning particles in a Robertson-Walker background is derived using the deterministic system of equations of motion from Papapetrou, Souriau and Saturnini. A numerical integration of this system of differential equations in the case of the standard model of cosmology is performed. The deviation of the photon worldlines from the null geodesics is of the order of the wavelength. Perturbative solutions are also worked out in a more general case. An experimental measurement of this deviation would test the acceleration of our expanding Universe.

Non-Gaussianity generated in inflation can be contributed by two parts. The first part, denoted by $f_{NL}^{\delta N}$, is the contribution from the four-point correlation of the inflaton field which can be calculated using $\delta N$ formalism, and the second part, denoted by $f_{NL}^{\mathrm{int}}$, is the contribution from the three-point correlation function of the inflaton field. We consider the two contributions to the non-Gaussianity in noncanonical warm inflation throughout (noncanonical warm inflation is a new inflationary model which is proposed in X. M. Zhang and J. Y. Zhu, Phys. Rev. D 90, 123519 (2014)). We find the two contributions are complementary to each other. The four-point correlation contribution to the non-Gaussianity is overwhelmed by the three-point one in the strong noncanonical limit, while the conclusion is the opposite in the canonical case. We also discuss the influence of the field redefinition, thermal dissipative effect and noncanonical effect to the non-Gaussianity in noncanonical warm inflation.

The so-called GeV excess of the diffuse Galactic gamma-ray emission, as observed by the Fermi-LAT satellite, is studied with a spectral template fit based on energy spectra for each relevant process of gamma-ray emission. This has the advantage over “conventional” analysis because one includes the spectral knowledge of physical processes into the fit, which allows one to determine simultaneously the standard background processes and contributions from nonstandard processes, like the Fermi bubbles or the GeV excess, in each sky direction. The spectral templates can be obtained in a data-driven way from the gamma-ray data, which avoids the use of emissivity models to subtract the standard background processes from the data. Instead, one can determine these backgrounds simultaneously with any “signals” in any sky direction, including the Galactic disk and the Galactic center. Using the spectral template fit, two hypothesis of the GeV excess were tested: the dark matter (DM) hypothesis assuming the excess is caused by DM annihilation, and the molecular cloud hypothesis assuming the GeV excess is related to a depletion of gamma rays below 2 GeV, as is directly observed in the Central Molecular Zone. The origin of the depletion below 2 GeV is not important but is most likely caused by a magnetic cutoff of cosmic rays approaching molecular clouds (MCs), as will be discussed later. Both hypotheses provide acceptable fits, if one considers a limited field of view centered within 20° around the Galactic center and applies cuts on the energy range and/or excludes low latitudes, cuts typically applied by the proponents of the DM hypothesis. However, if one considers the whole gamma-ray sky and includes gamma-ray energies up to 100 GeV, one can find that the MC hypothesis is preferred over the DM hypothesis for several reasons: i) the MC hypothesis provides significantly better fits; ii) the morphology of the GeV excess follows the morphology of the Carbon-monoxide maps, a tracer of MCs, i.e., there exists a strong GeV excess in the Galactic disk also at large longitudes; iii) the massive Central Molecular Zone with a rectangular field of view of $l\times b\simeq 3.5°\times 0.5°$ shows the maximum of the energy flux per log bin in the diffuse gamma-ray spectrum at 2 GeV, i.e., the GeV excess, already in the raw data without any analysis. The rectangular profile contradicts the spherical morphology expected for DM annihilation.

The process of superradiance can extract angular momentum and energy from astrophysical black holes (BHs) to populate gravitationally bound states with an exponentially large number of light bosons. We analytically calculate superradiant growth rates for vectors around rotating BHs in the regime where the vector Compton wavelength is much larger than the BH size. Spin-1 bound states have superradiance times as short as a second around stellar BHs, growing up to a thousand times faster than their spin-0 counterparts. The fast rates allow us to use measurements of rapidly spinning BHs in x-ray binaries to exclude a wide range of masses for weakly coupled spin-1 particles, $5\times {10}^{-14}-2\times {10}^{-11}\mathrm{eV}$; lighter masses in the range $6\times {10}^{-20}-2\times {10}^{-17}\mathrm{eV}$ start to be constrained by supermassive BH spin measurements at a lower level of confidence. We also explore routes to detection of new vector particles possible with the advent of gravitational wave (GW) astronomy. The LIGO-Virgo Collaboration could discover hints of a new light vector particle in statistical analyses of masses and spins of merging BHs. Vector annihilations source continuous monochromatic gravitational radiation which could be observed by current GW observatories. At design sensitivity, Advanced LIGO may measure up to thousands of annihilation signals from within the Milky Way, while hundreds of BHs born in binary mergers across the observable Universe may superradiate vector bound states and become new beacons of monochromatic gravitational waves.

We explore ways of creating cold keV-scale dark matter by means of decays and scatterings. The main observation is that certain thermal freeze-in processes can lead to a cold dark matter distribution in regions with a small available phase space. In this way the free-streaming length of keV particles can be suppressed without decoupling them too much from the Standard Model. In all cases, dark matter needs to be produced together with a heavy particle that carries away most of the initial momentum. For decays, this simply requires an off-diagonal dark matter (DM) coupling to two heavy particles; for scatterings, the coupling of soft DM to two heavy particles needs to be diagonal, in particular in spin space. Decays can thus lead to cold light DM of any spin, while scatterings only work for bosons with specific couplings. We explore a number of simple models and also comment on the connection to the tentative 3.5 keV line.

We determine the contribution to the anomalous magnetic moment of the muon from the ${\alpha }_{\mathrm{QED}}^2$ hadronic vacuum polarization diagram using full lattice QCD and including $u/d$ quarks with physical masses for the first time. We use gluon field configurations that include $u$, $d$, $s$ and $c$ quarks in the sea at multiple values of the lattice spacing, multiple $u/d$ masses and multiple volumes that allow us to include an analysis of finite-volume effects. We obtain a result for $a_{\mu }^{\mathrm{HVP},\mathrm{LO}}$ of $667(6)(12)\times {10}^{-10}$, where the first error is from the lattice calculation and the second includes systematic errors from missing QED and isospin-breaking effects and from quark-line disconnected diagrams. Our result implies a discrepancy between the experimental determination of $a_{\mu }$ and the Standard Model of $3\sigma$.

In our previous work, Blum et al. [Phys. Rev. Lett. 118, 022005 (2017)], the connected and leading disconnected hadronic light-by-light contributions to the muon anomalous magnetic moment ($g-2$) have been computed using lattice QCD ensembles corresponding to physical pion mass generated by the RBC/UKQCD Collaboration. However, the calculation is expected to suffer from a significant finite-volume error that scales like $1/L^2$ where $L$ is the spatial size of the lattice. In this paper, we demonstrate that this problem is cured by treating the muon and photons in infinite-volume, continuum QED, resulting in a weighting function that is precomputed and saved with affordable cost and sufficient accuracy. We present numerical results for the case when the quark loop is replaced by a muon loop, finding the expected exponential approach to the infinite volume limit and consistency with the known analytic result. We have implemented an improved weighting function which reduces both discretization and finite-volume effects arising from the hadronic part of the amplitude.

We use the very forward neutron energy spectra measured by the LHC forward experiment at 7 TeV to extract the ${\pi }^{+}p$ total cross section at center-of-mass energies in the range $2.3–3.5\mathrm{TeV}$. To do this, we have to first isolate the $\pi$-exchange pole in forward neutron production in $pp$ collisions, by evaluating other possible contributions, namely, those from $\rho$ and $a_2$ exchange, from both eikonal and enhanced screening effects, from migration, from neutron production by $\mathrm{\Delta }$-isobar decay and from diffractive nucleon excitations. We discuss the possible theoretical uncertainties due to the fact that the data do not exactly reach the $\pi$ pole. We choose the kinematical domain where the pion contribution dominates and demonstrate the role of the different corrections which could affect the final result.

In this work, the pion-induced $f_1(1285)$ production off a nucleon target is investigated in an effective Lagrangian approach with an interpolating Reggeized treatment in a large range of the pion-beam momentum from threshold up to several tens of GeV. The $s$-channel, $u$-channel, and $t$-channel Born terms are included to calculate production cross sections. An interpolating Reggeized treatment is applied to the $t$ channel, which is found to be important to reproduce the behavior of the existent experimental total cross sections at both low ($\lesssim 8\mathrm{GeV}$) and high pion-beam momenta ($\gtrsim 8\mathrm{GeV}$). It is found that the $t$-channel contribution is dominant in the pion-induced $f_1(1285)$ production at low beam momentum and still dominant at very forward angles at high momentum. The interpolated Reggeized treatment of the $u$ channel is also discussed. The $u$-channel contribution is small and negligible at low momentum, and it becomes dominant at backward angles at momenta higher than 10 GeV. The differential cross sections are predicted with the model fixed by the fitting existent experimental data. The results are helpful to the possible experiments at J-PARC and COMPASS.

In this research paper, we evaluate the strong coupling constants of the $K^{*}K\pi$, $\varphi KK$, $\varphi K^{*}{K}^{*}$ and $\rho K^{*}{K}^{*}$ vertices in the framework of the three-point QCD sum rules. In each vertex two different off-shell particles are considered and the final results are compared to the other existing predictions. We study the decay width of $K^{*}\to K\pi$ and $\varphi \to KK$ and obtain the values $\mathrm{\Gamma }(K^{*}\to K\pi )=46.8$ and $\mathrm{\Gamma }(\varphi \to KK)=5.58$, which have good agreement with experimental values.

A measurement of the top quark mass ($M_t$) in the dileptonic $t\overline{t}$ decay channel is performed using data from proton-proton collisions at a center-of-mass energy of 8 TeV. The data was recorded by the CMS experiment at the LHC and corresponds to an integrated luminosity of $19.7\pm 0.5{\mathrm{fb}}^{-1}$. Events are selected with two oppositely charged leptons ($\ell =e$, $\mu$) and two jets identified as originating from $b$ quarks. The analysis is based on three kinematic observables whose distributions are sensitive to the value of $M_t$. An invariant mass observable, $M_{b\ell }$, and a “stransverse mass” observable, $M_{\mathrm{T}2}$, are employed in a simultaneous fit to determine the value of $M_t$ and an overall jet energy scale factor (JSF). A complementary approach is used to construct an invariant mass observable, $M_{b\ell \nu }$, that is combined with $M_{\mathrm{T}2}$ to measure $M_t$. The shapes of the observables, along with their evolutions in $M_t$ and JSF, are modeled by a nonparametric Gaussian process regression technique. The sensitivity of the observables to the value of $M_t$ is investigated using a Fisher information density method. The top quark mass is measured to be $172.22\pm 0.18(\mathrm{stat}){}_{-0.93}^{+0.89}(\mathrm{syst})\mathrm{GeV}$.

We systematically present a new approach for studying the coupled linear transport of holographic systems. In this approach, the set of equations for the linear perturbations can be reduced to a first-order nonlinear ordinary differential equation expressed as the radial (renormalization group) flow equation of the transport matrices. As an important application, we use this approach to compute the dc and ac conductivities of a holographic model with momentum dissipation, which can be easily read off from the nonlinear flow equations. This method also works for transport in the presence of an external magnetic field.

In this paper, the four-dimensional nonlinearly charged black hole solutions have been considered in the presence of the power Maxwell invariant electrodynamics. Two new classes of anti–de Sitter (AdS) black hole solutions have been introduced according to different amounts of the parameters in the nonlinear theory of electrodynamics. The conserved and thermodynamical quantities of either of the black hole classes have been calculated from geometrical and thermodynamical approaches, separately. It has been shown that the first law of black hole thermodynamics is satisfied for either of the AdS black hole solutions we just obtained. Through the canonical and grand canonical ensemble methods, the black hole thermal stability or phase transitions have been analyzed by considering the heat capacities with the fixed black hole charge and fixed electric potential, respectively. It has been found that the new AdS black holes are stable if some simple conditions are satisfied.

We present an expression for the gravitational self-force correction to the geodetic spin precession of a spinning compact object with small, but non-negligible mass in a bound, equatorial orbit around a Kerr black hole. We consider only conservative backreaction effects due to the mass of the compact object ($m_1$), thus neglecting the effects of its spin $s_1$ on its motion; i.e., we impose $s_1\ll G{m}_1^2/c$ and $m_1\ll m_2$, where $m_2$ is the mass parameter of the background Kerr spacetime. We encapsulate the correction to the spin precession in $\psi$, the ratio of the accumulated spin-precession angle to the total azimuthal angle over one radial orbit in the equatorial plane. Our formulation considers the gauge-invariant $\mathcal{O}(m_1)$ part of the correction to $\psi$, denoted by $\mathrm{\Delta }\psi$, and is a generalization of the results of Akcay et al. [Classical Quantum Gravity 34, 084001 (2017)] to Kerr spacetime. Additionally, we compute the zero-eccentricity limit of $\mathrm{\Delta }\psi$ and show that this quantity differs from the circular orbit $\mathrm{\Delta }{\psi }^{\text{circ}}$ by a gauge-invariant quantity containing the gravitational self-force correction to general relativistic periapsis advance in Kerr spacetime. Our result for $\mathrm{\Delta }\psi$ is expressed in a manner that readily accommodates numerical/analytical self-force computations, e.g., in the radiation gauge, and paves the way for the computation of a new eccentric-orbit Kerr gauge invariant beyond the generalized redshift.

The Cygnus X region contains giant molecular cloud complexes and populous associates of massive young stars. The discovery of spatially extended, hard $\gamma$-ray emission in Cygnus X by both Milagro and Fermi indicates that Cygnus X is also a potential source of high-energy Galactic neutrinos. Here, we adapt our single-zone model for cosmic ray interactions in the central molecular zones of starburst galaxies for use in Cygnus X. We calculate the potential neutrino flux corresponding to the hard $\gamma$-ray emission from the “Cygnus Cocoon” and to the soft, diffuse interstellar $\gamma$-ray emission. We check our results by comparing the corresponding $\gamma$-ray emission against the Fermi interstellar emission model and Milagro, ARGO-YBJ, and HAWC observations. In comparing our results against a recent IceCube analysis and the current sensitivity limits, we find that neutrino emission from the Cocoon has a large enough flux that it could plausibly be detected, provided hadronic interactions are occurring at sufficiently high energies. High-energy neutrinos from Cygnus X would provide direct evidence for the presence of as yet unidentified PeV energy accelerators in the Galactic disk.

It is argued that the multiplicity distribution in proton-proton ($pp$) collisions, which is often parametrized by the negative binomial distribution, may result from the multiplicity distribution measured in electron-positron ($e^{+}{e}^{-}$) collisions, once the fluctuating energy carried by two leading protons in $pp$ is taken into account.

Constraints on couplings of several beyond-Standard-Model-physics scenarios, mediated by massive intermediate particles including (1) an extra Z-prime, (2) a new light spin-1 boson, and (3) a charged Higgs boson, are placed via the neutrino-electron scattering channel to test the Standard Model at a low energy-momentum transfer regime. Data on ${\overline{\nu }}_{\mathrm{e}}-\mathrm{e}$ and ${\nu }_{\mathrm{e}}-\mathrm{e}$ scattering from the TEXONO and LSND, respectively, are used. Upper bounds to coupling constants of the flavor-conserving and flavor-violating new light spin-1 boson and the charged Higgs boson with respect to different mediator masses are determined. The relevant parameter spaces are extended by allowing light mediators. New lower mass limits for extra Z-prime gauge boson models are also placed.

We study the $t\overline{t}b\overline{b}$ final state at the LHC as a probe of new physics that couples mainly to the third generation of quarks. We analyze new physics simplified models with resonances of spin-0, -1 and -2. The sensitivity of the final states $t\overline{t}b\overline{b}$, $t\overline{t}t\overline{t}$, $b\overline{b}b\overline{b}$ and $t\overline{t}$ on each of these models is used to identify an important region in parameter space that is still not excluded and where $t\overline{t}b\overline{b}$ is the most sensitive final state. We indicate possible experimental hints and discuss potential issues of observables that rely mainly on Monte Carlo predictions. A new observable is proposed that, at the price of requiring more statistics, reduces the impact of Monte Carlo predictions. We use preliminary 13 TeV results to give a raw estimate on the discovery reach and propose simple improvements on the observables.