During the inspiral and merger of black holes, the interaction of gravitational wave multipoles carries linear momentum away, thereby providing an astrophysically important recoil, or “kick” to the system and to the final black hole remnant. It has been found that linear momentum during the last stage (quasinormal ringing) of the collapse tends to provide an “antikick” that in some cases cancels almost all the kick from the earlier (quasicircular inspiral) emission. We show here that this cancellation is not due to peculiarities of gravitational waves, black holes, or interacting multipoles, but simply to the fact that the rotating flux of momentum changes its intensity slowly. We show furthermore that an understanding of the systematics of the emission allows good estimates of the net kick for numerical simulations started at fairly late times, and is useful for understanding qualitatively what kinds of systems provide large and small net kicks.

We construct static multicenter solutions of phantom Einstein-Maxwell-dilaton theory from null geodesics of the target space, leading to regular black holes without spatial symmetry for certain discrete values of the dilaton coupling constant. We also discuss the three-dimensional gravitating sigma models obtained by reduction of phantom Einstein-Maxwell, phantom Kaluza-Klein and phantom Einstein-Maxwell-dilaton-axion theories. In each case, we generate by group transformations phantom charged black hole solutions from a neutral seed.

We revisit the idea of generating the Higgs $\mu$ parameter through a spontaneously broken Peccei-Quinn (PQ) symmetry in a gauge-mediated supersymmetry breaking scenario. For the messenger scale of gauge mediation higher than the PQ scale, the setup naturally generates $\mu \sim m_{\mathrm{soft}}$ and the Higgs soft parameter $B\lesssim \mathcal{O}(m_{\mathrm{soft}})$ with the $CP$ phase of $B$ aligned to the phase of gaugino masses, while giving the PQ scale $v_{\mathrm{PQ}}\sim \sqrt{m_{\mathrm{soft}}\Lambda }$, where $m_{\mathrm{soft}}$ denotes the gauge-mediated gaugino or sfermion masses and $\Lambda$ is the cutoff scale which can be identified as the Planck scale or the grand unified theory scale. The PQ sector of the model results in distinctive cosmology including a late thermal inflation. We discuss the issue of dark matter and baryogenesis in the resulting thermal inflation scenario, and find that a right amount of gravitino dark matter can be produced together with a successful Affleck-Dine leptogenesis, when the gravitino mass $m_{3/2}=\mathcal{O}(100)\mathrm{keV}$.

Recently, we introduced an ekpyrotic model based on a single, canonical scalar field that generates nearly scale-invariant curvature fluctuations through a purely “adiabatic mechanism” in which the background evolution is a dynamical attractor. Despite the starkly different physical mechanism for generating fluctuations, the two-point function is identical to inflation. In this paper, we further explore this concept, focusing in particular on issues of non-Gaussianity and quantum corrections. We find that the degeneracy with inflation is broken at three-point level: for the simplest case of an exponential potential, the three-point amplitude is strongly scale dependent, resulting in a breakdown of perturbation theory on small scales. However, we show that the perturbative breakdown can be circumvented—and all issues raised in Linde et al. (arXiv:0912.0944) can be addressed—by altering the potential such that power is suppressed on small scales. The resulting range of nearly scale-invariant, Gaussian modes can be as much as 12 e-folds, enough to span the scales probed by microwave background and large-scale structure observations. On smaller scales, the spectrum is not scale invariant but is observationally acceptable.

Arm locking is a proposed laser frequency stabilization technique for the Laser Interferometer Space Antenna (LISA), a gravitational-wave observatory sensitive in the milliHertz frequency band. Arm locking takes advantage of the geometric stability of the triangular constellation of three spacecraft that compose LISA to provide a frequency reference with a stability in the LISA measurement band that exceeds that available from a standard reference such as an optical cavity or molecular absorption line. We have implemented a time-domain simulation of a Kalman-filter–based arm-locking system that includes the expected limiting noise sources as well as the effects of imperfect a priori knowledge of the constellation geometry on which the design is based. We use the simulation to study aspects of the system performance that are difficult to capture in a steady-state frequency-domain analysis such as frequency pulling of the master laser due to errors in estimates of heterodyne frequency. We find that our implementation meets requirements on both the noise and dynamic range of the laser frequency with acceptable tolerances and that the design is sufficiently insensitive to errors in the estimated constellation geometry that the required performance can be maintained for the longest continuous measurement intervals expected for the LISA mission.

Several relatively small-scale experimental setups, aimed on prototyping of future laser gravitational-wave detectors and testing of new methods of quantum measurements with macroscopic mechanical objects, are under development now. In these devices, not devoted directly to the gravitational-wave detection, Mach-Zehnder interferometer with pass-through Fabry-Perot cavities in the arms can be used instead of the standard Michelson/Fabry-Perot one. The advantage of this topology is that it does not contain high-reflectivity end mirrors with multilayer coatings, which Brownian noise could constitute the major part of the noise budget of the Michelson/Fabry-Perot interferometers. We consider here two variants of this topology: the “ordinary” position meter scheme, and a new variant of the quantum speed meter.

It may be widely believed that probing short distance physics is limited by the presence of the Planck energy scale above which scale any information is cloaked behind a horizon. If this hypothesis is correct, we could observe quantum behavior of gravity only through a black hole of Planck mass. We numerically show that in a scattering of two black holes in the 5-dimensional spacetime, a visible domain, whose curvature radius is much shorter than the Planck length, can be formed. Our result indicates that super-Planckian phenomena may be observed without an obstruction by horizon formation in particle accelerators.

We present a comment on the kinematic variable $m_{CT2}$ recently proposed in Won Sang Cho, Jihn E. Kim, and Ji-Hun Kim, Phys. Rev. D 81, 095010 (2010). The variable is designed to be applied to models such as $R$-parity conserving supersymmetry (SUSY) when there is pair production of new heavy particles each of which decays to a single massless visible and a massive invisible component. It was proposed by Cho, Kim, and Kim that a measurement of the peak of the $m_{CT2}$ distribution could be used to precisely constrain the masses of the SUSY particles. We show that, for the an example characterized by direct squark decays, when standard model backgrounds are included in simulations, the sensitivity of the $m_{CT2}$ variable to the SUSY particle masses is more seriously impacted for $m_{CT2}$ than for other previously proposed variables.

We extend our recent unquenched ($N_f=2+1$ flavor) calculation of $B_K$ using improved staggered fermions by including in the fits the finite volume shift predicted by one-loop staggered chiral perturbation theory. The net result is to lower the result in the continuum limit by 0.6%. This shift is slightly smaller than our previous estimate of finite volume effects based on a direct comparison between different volumes.

The fixed center approximation to the Faddeev equations has been used lately with success in the study of bound systems of three hadrons. It is also important to set the limits of the approach in those problems to prevent proliferation of inaccurate predictions. In this paper, we study the case of the $\varphi (2170)$, which has been described by means of Faddeev equations as a resonant state of $\varphi$ and $K\overline{K}$, and show the problems derived from the use of the fixed center approximation in its study. At the same time, we also expose the limitations of an alternative approach recently proposed.

Many new physics models predict the existence of TeV-scale charged gauge boson $W^{\prime }$ together with Higgs-boson(s). We study the $W^{\prime }WH$ interaction and explore the angular distribution of charged leptons to distinguish $W_R^{\prime }WH$ from $W_L^{\prime }WH$ in the $pp\to HW\to b\overline{b}l\nu$ process at the LHC. It is found that a new type forward-backward asymmetry ($A_{\mathrm{FB}}$) relating to the angle between the direction of the charged lepton in the $W$ rest frame and that of the reconstructed $W^{\prime }$ in the laboratory frame is useful to investigate the properties of $W^{\prime }WH$ interaction. We analyze the standard model backgrounds and develop a set of cuts to highlight the signal and suppress the backgrounds at LHC. We find that $A_{\mathrm{FB}}$ can reach $0.03(-0.07)$ for $W_R^{\prime }(W_L^{\prime })$ production at $\sqrt{S}=14\mathrm{TeV}$.

We calculate the transverse and time-time components of the instantaneous gluon propagator in Coulomb gauge QCD by using an SU(3) quenched lattice simulation on isotropic and anisotropic lattices. We find that the gluon propagators suffer from strong discretization effects on the isotropic lattice; on the other hand, those on the anisotropic lattices give a better scaling. Moreover, on these two type of lattices the transverse parts are significantly suppressed in the infrared region and have a turnover at about 500 [MeV]. The high resolution to the temporal direction due to the anisotropy yields small discretization errors for the time-time gluon propagators, which also show an infrared enhancement as expected in the Gribov-Zwanziger confinement scenario.

We study the phases and phase transition lines of the finite temperature $G_2$ Higgs model. Our work is based on an efficient local hybrid Monte-Carlo algorithm which allows for accurate measurements of expectation values, histograms, and susceptibilities. On smaller lattices we calculate the phase diagram in terms of the inverse gauge coupling $\beta$ and the hopping parameter $\kappa$. For $\kappa \to 0$ the model reduces to $G_2$ gluodynamics and for $\kappa \to \infty$ to $SU(3)$ gluodynamics. In both limits the system shows a first order confinement-deconfinement transition. We show that the first order transitions at asymptotic values of the hopping parameter are almost joined by a line of first order transitions. A careful analysis reveals that there exists a small gap in the line where the first order transitions turn into continuous transitions or a crossover region. For $\beta \to \infty$ the gauge degrees of freedom are frozen and one finds a nonlinear $O(7)$ sigma model which exhibits a second order transition from a massive $O(7)$ symmetric to a massless $O(6)$ symmetric phase. The corresponding second order line for large $\beta$ remains second order for intermediate $\beta$ until it comes close to the gap between the two first order lines. Besides this second order line and the first order confinement-deconfinement transitions we find a line of monopole-driven bulk transitions which do not interfere with the confinement-deconfinment transitions.

We study electric and magnetic components of the gluon propagators in quark-gluon plasma in terms of center vortices by using a quenched simulation of $SU(2)$ lattice theory. In the Landau gauge, the magnetic components of the propagators are strongly affected in the infrared region by removal of the center vortices, while the electric components are almost unchanged by this procedure. In the Coulomb gauge, the time-time correlators, including an instantaneous interaction, also have an essential contribution from the center vortices. As a result, one finds that magnetic degrees of freedom in the infrared region couple strongly to the center vortices in the deconfinement phase.

Inspired by the newly observed three resonances $X(1835)$, $X(2120)$, and $X(2370)$, in this work we systematically study the two-body strong decays and double pion decays of $\eta (1295)/\eta (1475)$, $\eta (1760)/X(1835)$, and $X(2120)/X(2370)$ by categorizing $\eta (1295)/\eta (1475)$, $\eta (1760)/X(1835)$, $X(2120)$, and $X(2370)$ as the radial excitations of $\eta (548)/{\eta }^{\prime }(958)$. Our numerical results indicate the followings: (1) The obtained theoretical strong decay widths of three pseudoscalar states $\eta (1295)$, $\eta (1475)$, and $\eta (1760)$ are consistent with the experimental measurements; (2) $X(1835)$ could be the second radial excitation of ${\eta }^{\prime }(958)$; (3) $X(2120)$ and $X(2370)$ can be explained as the third and fourth radial excitations of $\eta (548)/{\eta }^{\prime }(958)$, respectively. The predicted two-body decay patterns of $\eta (1295)/\eta (1475)$, $\eta (1760)/X(1835)$, and $X(2120)/X(2370)$ and their double pion decays should be useful for further testing the conventional meson assignment to $\eta (1295)/\eta (1475)$, $\eta (1760)/X(1835)$, $X(2120)$, and $X(2370)$.

The $D\to X_u{l}^{+}{l}^{-}$ transitions—branching ratios, forward-backward (FB) asymmetry $A_{\mathrm{FB}}^c$, the $CP$ asymmetry $A_{CP}^c$, and the $CP$ asymmetry in the forward-backward asymmetry $A_{\mathrm{FB}}^{CP}$—have two sources: for $D^{\pm }$ they represent a pure $\Delta C=1$ & $\Delta Q=0$ current interaction whereas neutral $D$ mesons can also communicate via their antihadron. Standard model (SM) contributions to $\mathrm{BR}(D\to X_u{l}^{+}{l}^{-})$ come primarily from long distance dynamics, which overshadow short distance contributions by several orders of magnitude; still they fall much below the present upper experimental bounds. Even the SM contributions to $A_{\mathrm{FB}}^c$, $A_{CP}^c$, and $A_{\mathrm{FB}}^{CP}$ are tiny, quite unlike in beauty hadrons. The branching ratios are hardly dented by contributions from the littlest Higgs models with $T$ parity (LHT) even in the short distance regime, let alone in the SM long distances dynamics. Yet the asymmetries $A_{\mathrm{FB}}^c$, $A_{CP}^c$, and $A_{\mathrm{FB}}^{CP}$ in these new physics models can be enhanced over SM predictions, as they arise purely from short distance dynamics; this can occur, in particular, for $A_{\mathrm{FB}}^c$ and $A_{\mathrm{FB}}^{CP}$, which get enhanced by orders of magnitudes. Even such enhancements hardly reach absolute sizes for observable experimental effects for $A_{\mathrm{FB}}^c$ and $A_{CP}^c$. However, LHT contributions to $A_{\mathrm{FB}}^{CP}$ could be measured in experiments like the LHCb and the SuperB Collaboration. These results lead us to draw further conclusions on flavor-changing neutral-current interactions within LHT-like models through some simple scaling arguments that encapsulate the essence of flavor dynamics in and beyond the standard model.

I apply commonly used regularization schemes to a multiloop calculation to examine the properties of the schemes at higher orders. I find complete consistency between the conventional dimensional regularization scheme and dimensional reduction, but I find that the four-dimensional helicity scheme produces incorrect results at next-to-next-to-leading order and singular results at next-to-next-to-next-to-leading order. It is not, therefore, a unitary regularization scheme.

First we calculate cross section for the $\gamma p\to \omega p$ reaction from the threshold to very large energies. At low energies the pion exchange is the dominant mechanism. At large energies the experimental cross section can be well described assuming Pomeron exchange within the $k_t$-factorization approach by adjusting light quark constituent mass. Next we calculate differential distributions for the $pp\to pp\omega$ reaction at RHIC, Tevatron and LHC energies for the first time in the literature. We consider photon-Pomeron (Pomeron-photon), photon-pion (pion-photon) as well as novel diffractive hadronic bremsstrahlung mechanisms. The latter are included in the meson/Reggeon exchange picture with parameters fixed from the known phenomenology. Interesting rapidity distributions are predicted. The hadronic bremsstrahlung contributions dominate at large (forward, backward) rapidities. At small energies the photon-Pomeron contribution is negligible compared to the bremsstrahlung contributions. It could be, however, easily identified at large energies at midrapidities. Absorptions effects are included and discussed. Our predictions are ready for verification at RHIC and LHC.

We investigate the effects of the axial-anomaly term with a chiral-diquark coupling on the phase diagram within a two-plus-one-flavor Nambu-Jona-Lasinio model under the charge-neutrality and $\beta$-equilibrium constraints. We find that when such constraints are imposed, the new anomaly term plays a quite similar role as the vector interaction does on the phase diagram, which the present authors clarified in a previous work. Thus, there appear several types of phase structures with multiple critical points at low temperature $T$, although the phase diagrams with intermediate-$T$ critical point(s) are never realized without these constraints even within the same model Lagrangian. This drastic change is attributed to an enhanced interplay between the chiral and diquark condensates due to the anomaly term at finite temperature; the $u\mathrm{\text{−}}d$ diquark coupling is strengthened by the relatively large chiral condensate of the strange quark through the anomaly term, which in turn definitely leads to the abnormal behavior of the diquark condensate at finite $T$, inherent to the asymmetric quark matter. We note that the critical point from which the crossover region extends to zero temperature appears only when the strength of the vector interaction is larger than a critical value. We also show that the chromomagnetic instability of the neutral asymmetric homogenous two-flavor color-superconducting phase is suppressed and can be even completely cured by the enhanced diquark coupling due to the anomaly term and/or by the vector interaction.

The thermodynamical properties of a pure Yang-Mills theory $SU(N)$ is described by a gas of gluonic quasiparticles with temperature-dependent mass $m(T)$ and a bag function $B(T)$. The analytic behavior of $m(T)$ and the pressure $p$ in the temperature range $2.5–5T_c$ are derived and constraints on the parameters defining $B(T)$ are discussed. The trace anomaly $\theta =\rho -3p$ is evaluated in the high $T$ domain: it is dominated by a quadratic behavior $\theta =nK{T}^2$, where $n=2(N^2-1)$ is the number of degrees of freedom and $K$ is an integration constant which does not depend on the bag function $B(T)$. The quadratic rise of $\theta$ is in good agreement with recent lattice simulations.