Continuing our analytic computation of the first-order self-force contribution to the “geodetic” spin precession frequency of a small spinning body orbiting a large (nonspinning) body, we provide the exact expressions of the 10 and 10.5 post-Newtonian terms. We also introduce a new approach to the analytic computation of self-force regularization parameters based on a WKB analysis of the radial and angular equations satisfied by the metric perturbations.

We study motion around a static Einstein and pure Lovelock black hole in higher dimensions. It is known that in higher dimensions bound orbits exist only for a pure Lovelock black hole in all even dimensions, $D=2N+2$, where $N$ is the degree of Lovelock polynomial action. In particular, we compute periastron shift and light bending, and the latter is given by one of the transverse spatial components of the Riemann curvature tensor. We also consider the pseudo-Newtonian potentials and Kruskal coordinates.

We investigate the cosmological evolution of a mimetic matter model with arbitrary scalar potential. The cosmological reconstruction—which is the method for constructing a model for an arbitrary evolution of the scale factor—is explicitly performed for different choices of potential. The cases where the mimetic matter model shows the evolution as cold dark matter (CDM), the $w\mathrm{CDM}$ model, dark matter and dark energy with a dynamical $Om(z)$ [where $Om(z)\equiv [(H(z)/H_0{)}^2-1]/[(1+z{)}^3-1]$], and phantom dark energy with a phantom-nonphantom crossing are presented in detail. The cosmological perturbations for such evolutions are studied in the mimetic matter model. For instance, the evolution behavior of the matter density contrast (which is different than the usual one, i.e., $\ddot{\delta }+2H\dot{\delta }-{\kappa }^2\rho \delta /2=0$) is investigated. The possibility of a peculiar evolution of $\delta$ in the model under consideration is shown. Special attention is paid to the behavior of the matter density contrast near the future singularity, where the decay of perturbations may occur much earlier than the singularity.

When the predecoupling plasma is thermodynamically reversible its fluctuations are classified in terms of the adiabatic and entropic modes. A different category of physical solutions, so far unexplored, arises when the inhomogeneities of the viscosity coefficients induce computable curvature perturbations. The viscous modes are explicitly illustrated and compared with the conventional isocurvature solutions.

In technicolor theories using a $\mathrm{SU}(N_{\mathrm{TC}})$ gauge group, the value of $N_{\mathrm{TC}}$ is not, a priori, determined and is typically chosen by phenomenological criteria. Here we present a novel way to determine $N_{\mathrm{TC}}$ from the embedding of a one-family technicolor model, with fermions in the fundamental represention of $\mathrm{SU}(N_{\mathrm{TC}})$, in an extended technicolor theory, and use it to deduce that $N_{\mathrm{TC}}=4$ in this framework.

The Bethe-Salpeter wave functions of $SU(3)$ pure gauge glueballs are revisited in this study. The ground and the first excited states of the scalar and tensor glueballs are identified unambiguously through the variational method. We calculate the wave functions in the Coulomb gauge and use two lattice spacings to check the discretization artifacts. For the ground states, the radial wave functions are approximately Gaussian, and the size of the tensor glueball is roughly twice as large as that of the scalar glueball. For the first excited states, the radial nodes are clearly observed for both the scalar and the tensor glueballs, such that they can be interpreted as the first radial excitations. These observations may shed light on the theoretical understanding of the inner structure of glueballs.

This study is part of a research program aimed to investigate the relations between instantons, monopoles, and chiral symmetry breaking. Monopoles are important three-dimensional topological configurations existing in QCD, which are believed to produce color confinement. Instantons are four-dimensional topological configurations and are known to be related to chiral symmetry breaking. To study the relation between monopoles and instantons we generate configurations which add static monopole-antimonopole pairs of opposite charges to the vacuum state by use of a monopole creation operator. We observe that the monopole creation operator only adds long monopole loops to the configurations. We then count the number of fermion zero modes using overlap fermions as a tool. As a result we find that each monopole-antimonopole pair of magnetic charge one adds one zero mode of chirality $\pm 1$, i.e. one instanton of topological charge $\pm 1$.

The signature produced by the Standard Model Higgs boson in the vector boson fusion (VBF) mechanism is usually pinpointed by requiring two well separated hadronic jets, one of which (at least) tends to be in the forward direction. With the increase of instantaneous luminosity at the LHC, the isolation of the Higgs boson produced with the VBF mechanism is rendered more challenging. In this paper the feasibility of single jet tagging is explored in a high-luminosity scenario. It is demonstrated that the separation in rapidity between the tagging jet and the Higgs boson can be effectively used to isolate the VBF signal. This variable is robust from the experimental and QCD standpoints. Single jet tagging allows us to probe the spin-CP quantum numbers of the Higgs boson.

We demonstrate that the spectacular structures discovered recently in various experiments and named as $X$, $Y$ and $Z$ states cannot be purely kinematic effects. Their existence necessarily calls for nearby poles in the $S$ matrix and they therefore qualify as states. We propose a way of distinguishing kinematic cusp effects from genuine $S$-matrix poles: the kinematic threshold cusp cannot produce a narrow peak in the invariant mass distribution in the elastic channel in contrast with a genuine $S$-matrix pole.

In gauge-gravity duality, heavy quark potential at finite temperature is usually calculated with the pure AdS background, which does not capture the renormalisation group (RG) running in the gauge theory part and the potential also does not contain any confining term in the deconfined phase. Following the developments on the Klebanov-Strassler geometry, we employ a geometry which captures the RG flow similar to QCD, to obtain the heavy quark potential by analytically continuing the string configurations into the complex plane. In addition to the attractive terms, the obtained potential has confining terms both at $T=0$ and $T\ne 0$, compared to the calculations usually done in the literature, where only Coulomb like term is present in the deconfined phase. The potential also develops an (negative) imaginary part above a critical separation, $r_c(=0.53z_h)$. Moreover our potential exhibits a behaviour, different from the usual Debye screening obtained from the perturbation theory.

We derive a system of coupled flow equations for the proper vertices of the background effective average action and we give an explicit representation of these by means of diagrammatic and momentum space techniques. This explicit representation can be used as a new computational technique that enables the projection of the flow of a large new class of truncations of the background effective average action. In particular, these can be single- or bifield truncations of local or nonlocal character. As an application we study non-Abelian gauge theories. We show how to use this new technique to calculate the beta function of the gauge coupling (without employing the heat kernel expansion) under various approximations. In particular, one of these approximations leads to a derivation of beta functions similar to those proposed as candidates for an “all-orders” beta function. Finally, we discuss some possible phenomenology related to these flows.

In this work we analyze the properties of the gravitational Kaluza-Klein (KK) modes in two stringlike braneworlds, the thin Gherghetta-Shaposhnikov (GS) model and the thick string-cigar model. The string-cigar model is a smooth generalization of the GS model that undergoes a Ricci geometrical flow. We find a new massless mode in both models satisfying the respective Schrödinger equations. By means of a numerical analysis, we obtain the complete graviton spectrum and its respective eigenfunctions. The KK spectrum exhibits the usual linear regime for large discrete index $n$ and we find a new decreasing regime for small $n$. Moreover, there is an asymmetric mass gap between the massless mode and the massive KK tower. The mass gap in the GS model is bigger than in the string-cigar model. In addition, the mass gap remains invariant upon the geometrical flow. It turns out that in the string-cigar model the brane structure smoothes and amplifies the KK modes near the brane core. The presence of a potential well in the string-cigar scenario allows the existence of resonant massive gravitons for small masses.

We perform new long-term (15–16 orbits) simulations of coalescing binary neutron stars in numerical relativity using an updated Einstein equation solver, employing low-eccentricity initial data, and modeling the neutron stars by a piecewise polytropic equation of state. A convergence study shows that our new results converge more rapidly than the third order, and using the determined convergence order, we construct an extrapolated waveform for which the estimated total phase error should be less than one radian. We then compare the extrapolated waveforms with those calculated by the latest effective-one-body (EOB) formalism in which the so-called tidal deformability, higher post-Newtonian corrections, and gravitational self-force effects are taken into account. We show that for a binary of compact neutron stars with their radius 11.1 km, the waveform by the EOB formalism agrees quite well with the numerical waveform so that the total phase error is smaller than one radian for the total phase of $\sim 200$ radian up to the merger. By contrast, for a binary of less compact neutron stars with their radius 13.6 km, the EOB and numerical waveforms disagree with each other in the last few wave cycles, resulting in the total phase error of approximately three radian.

We perform radiation-hydrodynamics simulations of binary neutron-star mergers in numerical relativity on the Japanese “K” supercomputer, taking into account neutrino cooling and heating by an updated leakage-plus-transfer scheme for the first time. Neutron stars are modeled by three modern finite-temperature equations of state (EOS) developed by Hempel and his collaborators. We find that the properties of the dynamical ejecta of the merger such as total mass, average electron fraction, and thermal energy depend strongly on the EOS. Only for a soft EOS (the so-called SFHo), the ejecta mass exceeds $0.01M_{\odot }$. In this case, the distribution of the electron fraction of the ejecta becomes broad due to the shock heating during the merger. These properties are well-suited for the production of the solar-like $r$-process abundance. For the other stiff EOS (DD2 and TM1), for which a long-lived massive neutron star is formed after the merger, the ejecta mass is smaller than $0.01M_{\odot }$, although broad electron-fraction distributions are achieved by the positron capture and the neutrino heating.

This paper is devoted to the Hamiltonian analysis of the unimodular gravity. We treat the unimodular gravity as the general relativity action with the unimodular constraint imposed with the help of the Lagrange multiplier. We perform the canonical analysis of the given theory and determine its constraint structure.

Most searches for continuous gravitational waves from pulsars use Taylor expansions in the phase to model the spin-down of neutron stars. Studies of pulsars demonstrate that their electromagnetic (EM) emissions suffer from timing noise, small deviations in the phase from Taylor expansion models. How the mechanism producing EM emission is related to any continuous gravitational-wave (CW) emission is unknown; if they either interact or are locked in phase, then the CW will also experience timing noise. Any disparity between the signal and the search template used in matched filtering methods will result in a loss of signal-to-noise ratio, referred to as “mismatch.” In this work we assume the CW suffers a level of timing noise similar to its EM counterpart. We inject and recover fake CW signals, which include timing noise generated from observational data on the Crab pulsar. Measuring the mismatch over durations of order $\sim 10$ months, the effect is, for the most part, found to be small. This suggests recent so-called “narrow-band” searches which placed upper limits on the signals from the Crab and Vela pulsars will not be significantly affected. At a fixed observation time, we find the mismatch depends upon the observation epoch. Considering the averaged mismatch as a function of observation time, we find that it increases as a power law with time, and so may become relevant in long baseline searches.

We present results of a search for continuously emitted gravitational radiation, directed at the brightest low-mass x-ray binary, Scorpius X-1. Our semicoherent analysis covers 10 days of LIGO S5 data ranging from 50–550 Hz, and performs an incoherent sum of coherent $\mathcal{F}$-statistic power distributed amongst frequency-modulated orbital sidebands. All candidates not removed at the veto stage were found to be consistent with noise at a 1% false alarm rate. We present Bayesian 95% confidence upper limits on gravitational-wave strain amplitude using two different prior distributions: a standard one, with no a priori assumptions about the orientation of Scorpius X-1; and an angle-restricted one, using a prior derived from electromagnetic observations. Median strain upper limits of $1.3\times {10}^{-24}$ and $8\times {10}^{-25}$ are reported at 150 Hz for the standard and angle-restricted searches respectively. This proof-of-principle analysis was limited to a short observation time by unknown effects of accretion on the intrinsic spin frequency of the neutron star, but improves upon previous upper limits by factors of $\sim 1.4$ for the standard, and 2.3 for the angle-restricted search at the sensitive region of the detector.

The hierarchy of scales which would allow dimension-six contact interactions to parametrize new physics may not be verified at colliders. Instead, we explore the feasibility and usefulness of parametrizing the high-energy tail of distributions at the LHC using form factors. We focus on the process $pp\to \ell \overline{\ell }$ in the presence of $t$- (or $s$)-channel new physics, guess a form factor from the partonic cross section, and attempt to use data to constrain its coefficients, and the coefficients to constrain models. We find that our choice of form factor describes $t$-channel exchange better than a contact interaction, and the coefficients in a particular model can be obtained from the partonic cross section. We estimate bounds on the coefficients by fitting the form factors to available data. For the parametrization corresponding to the contact interaction approximation, our expected bounds on the scale $\mathrm{\Lambda }$ are within $\sim 15\%$ of the latest limits from the LHC experiments.

In some supersymmetric models like split supersymmetry or models with nonuniversal gaugino mass, ‘bino [lightest sparticle (LSP)] and wino [next-to-lightest sparticle (NLSP)] may have rather small mass splitting in order to provide the correct dark matter relic density through bino/wino coannihilation. Such a scenario with the compressed bino/wino is difficult to explore at the LHC. In this work we propose to probe this scenario from $pp\to j{\tilde{\chi }}_2^0{\tilde{\chi }}_1^{\pm }$ followed by ${\tilde{\chi }}_2^0\to \gamma {\tilde{\chi }}_1^0$ and ${\tilde{\chi }}_1^{\pm }\to W^{*}{\tilde{\chi }}_1^0\to {\ell }^{\pm }\nu {\tilde{\chi }}_1^0$ (this method is also applicable to the compressed bino/Higgsino scenario). Through a detailed Monte Carlo simulation for both the signal and the backgrounds, we find that for a mass splitting $\mathrm{\Delta }M\sim 10–15\mathrm{GeV}$ between bino (LSP) and wino (NLSP), the 14 TeV LHC with a luminosity of $1000{\mathrm{fb}}^{-1}$ can probe the wino up to 150 GeV (the sensitivity can reach $3.4\sigma$ for $\mathrm{\Delta }M=10\mathrm{GeV}$ and $2\sigma$ for $\mathrm{\Delta }M=15\mathrm{GeV}$). We also investigate the dark matter detection sensitivities for this scenario and find that the planned XENON-1T (2017) cannot fully cover the parameter space with a wino below 150 GeV allowed by relic density and the LUX limits.