We derive the post-Newtonian next-to-leading order conservative spin-orbit and spin(a)-spin(b) gravitational interaction Hamiltonians for arbitrary many compact objects. The spin-orbit Hamiltonian completes the knowledge of Hamiltonians up to and including 2.5 post Newtonian for the general relativistic three-body problem. The new Hamiltonians include highly nontrivial three-body interactions, in contrast to the leading order consisting of two-body interactions only. This may be important for the study of effects like Kozai resonances in mergers of black holes with binary black holes. The derivation was done via two independent methods giving fully consistent results.

We perform high-resolution $N$-body simulations for $f(R)$ gravity based on a self-adaptive particle-mesh code MLAPM. The chameleon mechanism that recovers general relativity on small scales is fully taken into account by self-consistently solving the nonlinear equation for the scalar field. We independently confirm the previous simulation results, including the matter power spectrum, halo mass function, and density profiles, obtained by Oyaizu et al. [Phys. Rev. D 78, 123524 (2008)] and Schmidt et al. [Phys. Rev. D 79, 083518 (2009)], and extend the resolution up to $k\sim 20h/\mathrm{Mpc}$ for the measurement of the matter power spectrum. Based on our simulation results, we discuss how the chameleon mechanism affects the clustering of dark matter and halos on full nonlinear scales.

The discovery of many novel realizations of the inflationary universe paradigm has led to a degeneracy problem: many different inflationary Lagrangians generate the same perturbation spectra. Resolving this problem requires the future discovery of additional observables beyond the scalar adiabatic and tensor two-point functions on CMB scales. One important source of degeneracy arises in models where the density perturbation is generated by a noninflationary degree of freedom, for example, through curvatons or modulated reheating. We consider the curvaton scenario as representative of this class, and analyze the degeneracy with single field, canonical inflation that results if the curvaton goes undetected by future observations. We perform Monte Carlo potential reconstructions in the absence of distinguishing observables, such as non-Gaussiantities or isocurvature modes. The resulting degeneracy is considerable and the improved measurements of spectral parameters from future probes like CMBPol offer little to better the situation. Given a degeneracy-breaking observation, the observables must still be inverted to obtain the inflationary potential, with different observations resulting in reconstructions of varying quality. We find that a future detection of isocurvature modes or a precision measurement of the tensor spectral index will enable the most successful reconstructions in the presence of curvatons.

We show how higher derivatives of the expansion factor can be developed into a null diagnostic for concordance cosmology ($\Lambda \mathrm{CDM}$). It is well known that the Statefinder—the third derivative of the expansion factor written in dimensionless form, $a^{(3)}/a{H}^3$, equals unity for $\Lambda \mathrm{CDM}$. We generalize this result and demonstrate that the hierarchy, $a^{(n)}/a{H}^n$, can be converted to a form that stays pegged at unity in concordance cosmology. This remarkable property of the Statefinder hierarchy enables it to be used as an extended null diagnostic for the cosmological constant. The Statefinder hierarchy combined with the growth rate of matter perturbations defines a composite null diagnostic which can distinguish evolving dark energy from $\Lambda \mathrm{CDM}$.

We investigate the conditions on the Higgs sector that allow supersymmetric $SO(10)$ grand unified theories to break spontaneously to the standard electroweak model at the renormalizable level. If one considers Higgs representations of dimension up to the adjoint, a supersymmetric standard model vacuum requires, in most cases, the presence of nonrenormalizable operators. The active role of Planck-induced nonrenormalizable operators in the breaking of the gauge symmetry introduces a hierarchy in the mass spectrum at the grand unified theory scale that may be an issue for gauge unification and proton decay. We show that the minimal Higgs scenario that allows for a renormalizable breaking to the standard model is obtained by considering flipped $SO(10)\otimes U(1)$ with one adjoint (${45}_H$) and two pairs of ${16}_H\oplus {\overline{16}}_H$ Higgs representations. We consider a nonanomalous matter content and discuss the embedding of the model in an $E_6$ grand unified scenario just above the flipped $SO(10)$ scale.

With the advent of the LHC, it is important to devise clear tests for physics beyond the standard model. Such physics could manifest itself in the form of new charged bosons, whose presence is most naturally occurring in left-right symmetric models. We analyze the single $W_R$ boson production in an asymmetric left-right model, where the left and right quark mixing matrices are not constrained to be equal. We investigate the cross sections as well as branching ratios of $W_R$ bosons at the LHC, including constraints from low energy phenomenology. We then look for most likely signals in $pp\to W_{R}t\to t(\mathrm{\text{dijet}})$ production. Including the background, we find that the LHC could show significant signals for the new charged bosons. We compare our results throughout with the manifest left-right symmetric model and comment on similarities and differences.

Heavy-light decays such as $B\to \pi \ell \nu$, $B\to K^{*}\gamma$ and $B\to K^{(*)}\ell \ell$ can be used to constrain the parameters of the standard model and in indirect searches for new physics. While the precision of experimental results has improved over the last years this has still to be matched by equally precise theoretical predictions. The calculation of heavy-light form factors is currently carried out in lattice QCD. Because of its small Compton wavelength we discretize the heavy quark in an effective nonrelativistic theory. By formulating the theory in a moving frame of reference discretization errors in the final state are reduced at large recoil. Over the last years the formalism has been improved and tested extensively. Systematic uncertainties are reduced by renormalizing the m(oving) NRQCD action and heavy-light decay operators. The theory differs from QCD only for large loop momenta at the order of the lattice cutoff and the calculation can be carried out in perturbation theory as an expansion in the strong coupling constant. In this paper we calculate the one-loop corrections to the heavy-light vector and tensor operator. Because of the complexity of the action the generation of lattice Feynman rules is automated and loop integrals are solved by the adaptive Monte Carlo integrator VEGAS. We discuss the infrared and ultraviolet divergences in the loop integrals both in the continuum and on the lattice. The light quarks are discretized in the ASQTad and highly improved staggered quark (HISQ) action; the formalism is easily extended to other quark actions.

The Universal Extra Dimension (UED) model is one of the popular extension of the standard model (SM) which offers interesting phenomenology. In the minimal UED (mUED) model, Kaluza-Klein (KK) parity conservation ensures that $n=1$ KK states can only be pair produced at colliders and the lightest KK particle is stable. In most of the parameter space, first KK excitation of SM hypercharge gauge boson is the lightest one and it can be a viable dark matter candidate. Thus, the decay of $n=1$ KK particles will always involve missing transverse energy (${\cancel{E}}_T$) as well as leptons and jets. The production cross sections of $n=1$ KK particles are large and such particles may be observed at the Large Hadron Collider (LHC). We explore the mUED discovery potential of the LHC with $\sqrt{s}=7\mathrm{TeV}$ in the multileptonic final states. Since in the early LHC run, precise determination of ${\cancel{E}}_T$ may not be possible, we examine the LHC reach with and without using ${\cancel{E}}_T$ information. We observe that ${\cancel{E}}_T$ cut will not improve mUED discovery reach significantly. We have found that opposite-sign di-lepton channel is the most promising discovery mode and with first ${\mathrm{fb}}^{-1}$ of collected luminosity, LHC will be able to discover the strongly interacting $n=1$ KK particles with masses up to $800\sim 900\mathrm{GeV}$.

We report on analyses of tau lepton decays ${\tau }^{-}\to \eta K^{-}{\nu }_{\tau }$ and ${\tau }^{-}\to \eta {\pi }^{-}{\nu }_{\tau }$, with $\eta \to {\pi }^{+}{\pi }^{-}{\pi }^0$, using $470{\mathrm{fb}}^{-1}$ of data from the BABAR experiment at PEP-II, collected at center-of-mass energies at and near the $\mathit{{\rm Y}}(4S)$ resonance. We measure the branching fraction for the ${\tau }^{-}\to \eta K^{-}{\nu }_{\tau }$ decay mode, $\mathcal{B}({\tau }^{-}\to \eta K^{-}{\nu }_{\tau })=(1.42\pm 0.11(\mathrm{stat})\pm 0.07(\mathrm{syst}))\times {10}^{-4}$, and report a 95% confidence level upper limit for the second-class current process ${\tau }^{-}\to \eta {\pi }^{-}{\nu }_{\tau }$, $\mathcal{B}({\tau }^{-}\to \eta {\pi }^{-}{\nu }_{\tau })<9.9\times {10}^{-5}$.

We performed a search for the decay $K_L^0\to 3\gamma$ with the E391a detector at KEK. In the data accumulated in 2005, no event was observed in the signal region. Based on the assumption of $K_L^0\to 3\gamma$ proceeding via parity-violation, we obtained the single event sensitivity to be $(3.23\pm 0.14)\times {10}^{-8}$, and set an upper limit on the branching ratio to be $7.4\times {10}^{-8}$ at the 90% confidence level. This is a factor of 3.2 improvement compared to the previous results. The results of $K_L^0\to 3\gamma$ proceeding via parity-conservation were also presented in this paper.

Collective excitations of $\mathcal{N}=1$ supersymmetric electromagnetic plasma are studied. Since the Keldysh-Schwinger approach is used, not only equilibrium but also nonequilibrium plasma, which is assumed to be ultrarelativistic, is under consideration. The dispersion equations of photon, photino, electron, and selectron modes are written down and the self-energies, which enter the equations, are computed in the hard loop approximation. The self-energies are discussed in the context of effective action which is also given. The photon modes and electron ones appear to be the same as in the usual ultrarelativistic plasma of electrons, positrons, and photons. The photino modes coincide with the electron ones and the selectron modes are as of a free relativistic massive particle.

We constrain the chameleonic Sunyaev-Zel’dovich (CSZ) effect in the Coma cluster from measurements of the Coma radial profile presented in the WMAP 7-year results. The CSZ effect arises from the interaction of a scalar (or pseudoscalar) particle with the cosmic microwave background in the magnetic field of galaxy clusters. We combine this radial profile data with SZ measurements towards the center of the Coma cluster in different frequency bands, to find $\Delta T_{\mathrm{SZ},\mathrm{RJ}}(0)=-410\pm 50\mu \mathrm{K}$ and $\Delta T_{\mathrm{CSZ}}^{204\mathrm{GHz}}(0)\gtrsim -50\mu \mathrm{K}$ (at 95% confidence) for the thermal SZ and CSZ effects in the cluster, respectively. This leads to an estimated bound on the photon to scalar (or pseudoscalar) coupling strength of $g_{\mathrm{eff}}\lesssim (8.3–37.6)\times {10}^{-10}{\mathrm{GeV}}^{-1}$.

In Kaluza-Klein models with toroidal compactification of the extra dimensions, we investigate soliton solutions of Einstein equation. The nonrelativistic gravitational potential of these solitons exactly coincides with the Newtonian one. We obtain the formulas for perihelion shift, deflection of light, time delay of radar echoes and post-Newtonian (PPN) parameters. Using the constraint on PPN parameter $\gamma$, we find that the solitonic parameter $k$ should be very big: $|k|\ge 2.3\times {10}^4$. We define a soliton solution which corresponds to a pointlike mass source. In this case the soliton parameter $k=2$, which is clearly contrary to this restriction. A similar problem with the observations takes place for static spherically symmetric perfect fluid with the dustlike equation of state in all dimensions. The common for both of these models is the same (dustlike) equations of state in our three dimensions and in the extra dimensions. All dimensions are treated at equal footing. This is the crucial point. To be in agreement with observations, it is necessary to break the symmetry (in terms of equations of state) between the external/our and internal spaces. It takes place for black strings which are particular examples of solitons with $k\to \infty$. For such $k$, black strings are in concordance with the observations. Moreover, we show that they are the only solitons which are at the same level of agreement with the observations as in general relativity. Black strings can be treated as perfect fluid with dustlike equation of state $p_0=0$ in the external/our space and very specific equation of state $p_1=-(1/2)\epsilon$ in the internal space. The latter equation is due to negative tension in the extra dimension. We also demonstrate that dimension 3 for the external space is a special one. Only in this case we get the latter equation of state. We show that the black string equations of state satisfy the necessary condition of the internal space stabilization. Therefore, black strings are good candidates for a viable model of astrophysical objects (e.g., Sun) if we can provide a satisfactory explanation of negative tension for particles constituting these objects.

A completely metric-free $sl(5,R)$ gauge framework is developed in four dimensions. After spontaneous symmetry breaking of the corresponding topological $BF$ scheme, Einstein spaces with a tiny cosmological constant emerge, similarly as in (anti-)de Sitter gauge theories of gravity. The induced $\Lambda$ is related to the scale of the symmetry breaking. A “background” metric surfaces from a Higgs-like mechanism. The finiteness of such a topological scheme converts into asymptotic safeness after quantization of the spontaneously broken model.

We perform the Hamiltonian analysis for a nonprojectable Hořava model whose potential is composed of $R$ and $R^2$ terms. We show that Dirac’s algorithm for the preservation of the constraints can be done in a closed way, hence the algebra of constraints for this model is consistent. The model has an extra, odd, scalar mode whose decoupling limit can be seen in a linear-order perturbative analysis on weakly varying backgrounds. Although our results for this model point in favor of the consistency of the Hořava theory, the validity of the full nonprojectable theory still remains unanswered.

We solve the dilaton field equation in the background of a spherically symmetric black hole in bosonic or heterotic string theory with curvature-squared corrections in arbitrary $d$ spacetime dimensions. We then apply this result to obtain a spherically symmetric black hole solution with dilatonic charge and curvature-squared corrections in bosonic or heterotic string theory compactified on a torus. For this black hole, we obtain its free energy, entropy, temperature, specific heat, and mass.

We study analytically the highly damped quasinormal modes of Kerr black holes in the small angular momentum limit. To check the previous analytic calculations in the literature, which use a combination of radial and tortoise coordinates, we reproduce all the results using the radial coordinate only. According to the earlier calculations, the real part of the highly damped quasinormal mode frequency of Kerr black holes approaches zero in the limit where the angular momentum goes to zero. This result is not consistent with the Schwarzschild limit where the real part of the highly damped quasinormal mode frequency is equal to $c^3\ln (3)/(8\pi GM)$. In this paper, our calculations suggest that the highly damped quasinormal modes of Kerr black holes in the zero angular momentum limit make a continuous transition from the Kerr value to the Schwarzschild value. We explore the nature of this transition using a combination of analytical and numerical techniques. Finally, we calculate the highly damped quasinormal modes of the extremal case in which the topology of Stokes/anti-Stokes lines takes a different form.

A commonly adopted relational account of time evolution in generally covariant systems, and more specifically in quantum cosmology, is argued to be unsatisfactory, insofar as it describes evolution relative to observed readings of a clock that does not exist as a bona fide observable object. A modified strategy is proposed, in which evolution relative to the proper time that elapses along the worldline of a specific observer can be described through the introduction of a “test clock,” regarded as internal to, and hence unobservable by, that observer. This strategy is worked out in detail in the case of a homogeneous cosmology, in the context of both a conventional Schrödinger quantization scheme, and a “polymer” quantization scheme of the kind inspired by loop quantum gravity. Particular attention is given to limitations placed on the observability of time evolution by the requirement that a test clock should contribute only a negligible energy to the Hamiltonian constraint. It is found that suitable compromises are available, in which the clock energy is reasonably small, while Dirac observables are reasonably sharply defined.

We construct efficient banks of templates suitable for directed searches of almost monochromatic gravitational waves originating from spinning neutron stars in our Galaxy in data being collected by currently operating interferometric detectors. We thus assume that the position of the gravitational-wave source in the sky is known, but we do not assume that the wave’s frequency and its derivatives are a priori known. In the construction we employ a simplified model of the signal with constant amplitude and phase which is a polynomial function of time. All our template banks enable usage of the fast Fourier transform algorithm in the computation of the maximum-likelihood $\mathcal{F}$-statistic for nodes of the grids defining the bank. We study and employ the dependence of the grid’s construction on the choice of the position of the observational interval with respect to the origin of time axis. We also study the usage of the fast Fourier transform algorithms with nonstandard frequency resolutions achieved by zero padding or folding the data. In the case of the gravitational-wave signal with one spin-down parameter included we have found grids with covering thicknesses which are only 0.1–16% larger than the thickness of the optimal 2-dimensional hexagonal covering.

The physical mechanisms responsible for pulsar timing glitches are thought to excite quasinormal mode oscillations in their parent neutron star that couple to gravitational-wave emission. In August 2006, a timing glitch was observed in the radio emission of PSR B0833-45, the Vela pulsar. At the time of the glitch, the two colocated Hanford gravitational-wave detectors of the Laser Interferometer Gravitational-wave observatory (LIGO) were operational and taking data as part of the fifth LIGO science run (S5). We present the first direct search for the gravitational-wave emission associated with oscillations of the fundamental quadrupole mode excited by a pulsar timing glitch. No gravitational-wave detection candidate was found. We place Bayesian 90% confidence upper limits of $6.3\times {10}^{-21}$ to $1.4\times {10}^{-20}$ on the peak intrinsic strain amplitude of gravitational-wave ring-down signals, depending on which spherical harmonic mode is excited. The corresponding range of energy upper limits is $5.0\times {10}^{44}$ to $1.3\times {10}^{45}\mathrm{erg}$.