We present a new method to measure the top quark pair production cross section and the background rates with data corresponding to an integrated luminosity of $2.7{\mathrm{fb}}^{-1}$ from $p\overline{p}$ collisions at $\sqrt{s}=1.96\mathrm{TeV}$ collected with the CDF II Detector. We select events with a single electron or muon candidate, missing transverse energy, and at least one $b$-tagged jet. We perform a simultaneous fit to a jet flavor discriminant across nine samples defined by the number of jets and $b$ tags. An advantage of this approach is that many systematic uncertainties are measured in situ and inversely scale with integrated luminosity. We measure a top cross section of ${\sigma }_{t\overline{t}}=7.64\pm 0.57(\mathrm{stat}+\mathrm{syst})\pm 0.45(\mathrm{\text{luminosity}})\mathrm{pb}$.

Bipartite entanglement for states of a noninteracting bosonic or fermionic field in the spacetime of a spherically symmetric black hole of Einstein-Gauss-Bonnet gravity is investigated. Although the initial state is chosen to be maximally entangled as the Bell states, the Hawking-Unruh effect causes the state to be mixed and the entanglement degrades, but with different asymptotic behaviors for the fermionic and bosonic fields. The Gauss-Bonnet term with positive $\alpha$ can play an antigravitation role and so this causes a decrease in the Hawking-Unruh effect and consequently reduces the entanglement degradation. On the other hand, the suggested higher dimensions for the spacetime lead to increased entanglement degradation by increasing the dimension. There is a dramatic difference between the behaviors of the entanglement in terms of the radius of the horizon for a five-dimensional black hole and that for higher dimensional black holes. Both bosonic and fermionic fields entanglements are treated beyond the single-mode approximation. Also, the cases where the accelerating observers located at regions near and far from the event horizon of black hole are studied separately.

We investigate the stability of $f(R)$-rotating (Kerr) black hole obtained from a limited form of $f(R)$ gravity. In order to avoid the difficulty of handling fourth order linearized equations, we transform this form of $f(R)$ gravity into the scalar-tensor theory by introducing two auxiliary scalars. In this case, the linearized curvature scalar equation leads to a massive scalaron equation. It turns out that the $f(R)$-rotating black hole is unstable because of the superradiant instability known as the black-hole bomb idea.

We study exact vacuum solutions to quadratic gravity (QG) of the Weyl types $N$ and III. We show that in an arbitrary dimension all Einstein spacetimes of the Weyl type $N$ with an appropriately chosen effective cosmological constant $\Lambda$ are exact solutions to QG and we refer to explicitly known metrics within this class. For type III Einstein spacetimes, an additional constraint follows from the field equations of QG and examples of spacetimes obeying such constraint are given. However, type III $pp$ waves do not satisfy this constraint and thus do not solve QG. For type $N$, we also study a wider class of spacetimes admitting a pure radiation term in the Ricci tensor. In contrast to the Einstein case, the field equations of generic QG determine optical properties of the geometry and restrict such exact solutions to the Kundt class. We provide examples of these metrics.

We present a simple method to track the precession of a black-hole-binary system during the inspiral, using only information from the gravitational-wave (GW) signal. Our method consists of locating the frame from which the magnitudes of the ($\ell =2$, $|m|=2$) modes are maximized, which we denote the “quadrupole-aligned” frame. We demonstrate the efficacy of this method when applied to waveforms from numerical simulations. In the test case of an equal-mass nonspinning binary, our method locates the direction of the orbital angular momentum to within $(\Delta \theta ,\Delta \phi )=(0.05°,0.2°)$. We then apply the method to a $q=M_2/M_1=3$ binary that exhibits significant precession. In general, a spinning binary’s orbital angular momentum $\mathbf{L}$ is not orthogonal to the orbital plane. Evidence that our method locates the direction of $\mathbf{L}$ rather than the normal of the orbital plane is provided by comparison with post-Newtonian results. Also, we observe that it accurately reproduces similar higher-mode amplitudes to a comparable non-precessing binary, and that the frequency of the ($\ell =2$, $|m|=2$) modes is consistent with the “total frequency” of the binary’s motion. The simple form of the quadrupole-aligned waveform may be useful in attempts to analytically model the inspiral-merger-ringdown signal of precessing binaries, and in standardizing the representation of waveforms for studies of accuracy and consistency of source modelling efforts, both numerical and analytical.

Physical constants and cosmological parameters could vary with position. On the largest scales such variations would manifest themselves as gradients across our Hubble volume, leading to dipole modulations of the cosmic microwave background anisotropies. Here we derive the cosmic microwave background covariance matrix for models with such gradients, and show that they generically lead to a correlation between adjacent multipoles in the spherical harmonic expansion of the sky. Our results generalize previous studies of anisotropic primordial spectra: essentially any quantity which can be considered as a parameter of the cosmological model could in principle be modulated in this way, yielding a distinctive signal which should be searched for in future data sets. For the case of the fine structure constant ${\alpha }_e$, we find that the Planck satellite could detect variations as low as $\Delta {\alpha }_e/{\alpha }_e\approx {10}^{-4}$ across our observable volume.

Self-annihilating or decaying dark matter in the Galactic halo might produce high energy neutrinos detectable with neutrino telescopes. We have conducted a search for such a signal using 276 days of data from the IceCube 22-string configuration detector acquired during 2007 and 2008. The effect of halo model choice in the extracted limit is reduced by performing a search that considers the outer halo region and not the Galactic Center. We constrain any large-scale neutrino anisotropy and are able to set a limit on the dark matter self-annihilation cross section of $⟨{\sigma }_{A}v⟩\simeq {10}^{-22}{\mathrm{cm}}^3{\mathrm{s}}^{-1}$ for weakly interacting massive particle masses above 1 TeV, assuming a monochromatic neutrino line spectrum.

Several arguments suggest parity violation may be observable in high energy strong interactions. We introduce new analysis tools to describe the azimuthal dependence of multiparticle distributions, or “azimuthal flow.” Analysis uses the representations of the orthogonal group $O(2)$ and dihedral groups $D_N$ necessary to define parity completely in two dimensions. Classification finds that collective angles used in event-by-event statistics represent inequivalent tensor observables that cannot generally be represented by a single “reaction plane.” Many new parity-violating observables exist that have never been measured, while many parity-conserving observables formerly lumped together are now distinguished. We use the concept of “event-shape sorting” to suggest separating right- and left-handed events, and we discuss the effects of transverse and longitudinal spin. The analysis tools are statistically robust, and can be applied equally to low or high multiplicity events at the Tevatron, RHIC or RHIC Spin, and the LHC.

We consider the collider phenomenology of a singlet Majoron model with softly broken lepton number. Lepton number is spontaneously broken when the real part of a new singlet scalar develops a vacuum expectation value. With the additional soft terms violating lepton numbers, the imaginary part of this singlet scalar becomes a massive pseudo-Majoron which can account for the dark matter. In the presence of the coupling of the pseudo-Majoron with the standard model (SM) Higgs, the SM Higgs mostly decays into a pair of pseudo-Majorons, giving rise to ${\cancel{E}}_T$ signals at a hadron collider. Since the Higgs visible decay branching fractions get reduced in the presence of this invisible decay mode, the bounds on the SM Higgs mass from the CERN LEP and Tevatron experiments get diluted, and the invisible decay channel of the Higgs becomes important for the discovery of low mass Higgs at the Large Hadron Collider.

Using the SU(5) symmetry of the 4D hyperdiamond and results on the study of 4D graphene given in Drissi et al. [Phys. Rev. D 84, 014504 (2011)], we engineer a class of 4D lattice QCD fermions whose Dirac operators have two zero modes. We show that generally the zero modes of the Dirac operator in hyperdiamond fermions are captured by a tensor ${\Omega }_{\mu }^l$ with $4\times 5$ complex components linking the Euclidean SO(4) vector $\mu$; and the 5-dimensional representation of SU(5). The Boriçi-Creutz (BC) and the Karsten-Wilzeck (KW) models as well as their Dirac zero modes are rederived as particular realizations of ${\Omega }_{\mu }^l$. Other features are also given.

Using the large $N_C$ approximation we have constructed the most general chiral resonance Lagrangian in the odd-intrinsic parity sector that can generate low-energy chiral constants up to $\mathcal{O}(p^6)$. Integrating out the resonance fields these $\mathcal{O}(p^6)$ constants are expressed in terms of resonance couplings and masses. The role of ${\eta }^{\prime }$ is discussed and its contribution is explicitly factorized. Using the resonance basis we have also calculated two QCD Green functions of currents, $⟨VVP⟩$ and $⟨VAS⟩$, and found, imposing high-energy constraints, additional relations for resonance couplings. We have studied several phenomenological implications based on these correlators which provided, for example, a prediction for the ${\pi }^0$-pole contribution to the muon $g-2$ factor: $a_{\mu }^{{\pi }^0}=65.8(1.2)\times {10}^{-11}$.

We give a simple recipe for computing dissipation and fluctuations (commutator and anticommutator correlation functions) for nonequilibrium black hole geometries. The recipe formulates Hawking radiation as an initial value problem, and is suitable for numerical work. We show how to package the fluctuation and dissipation near the event horizon into correlators on the stretched horizon. These horizon correlators determine the bulk and boundary field theory correlation functions. In addition, the horizon correlators are the components of a horizon effective action, which provides a quantum generalization of the membrane paradigm. In equilibrium, the analysis reproduces previous results on the Brownian motion of a heavy quark. Out of equilibrium, Wigner transforms of commutator and anticommutator correlation functions obey a fluctuation-dissipation relation at high frequency.

We relate the $U$-duality invariants characterizing two-center extremal black-hole solutions in the $stu$, $s{t}^2$, and $t^3$ models of $N=2$, $d=4$ supergravity to the basic invariants used to characterize entanglement classes of four-qubit systems. For the elementary example of a D0D4-D2D6 composite in the $t^3$ model we illustrate how these entanglement invariants are related to some of the physical properties of the two-center solution. Next we show that it is possible to associate elliptic curves to charge configurations of two-center composites. The hyperdeterminant of the hypercube, a four-qubit polynomial invariant of order 24 with 2 894 276 terms, is featuring the $j$ invariant of the elliptic curve. We present some evidence that this quantity and its straightforward generalization should play an important role in the physics of two-center solutions.

We study the finite temperature Casimir interaction between a cylinder and a plate using the exact formula derived from the Matsubara representation and the functional determinant representation. We consider the scalar field with Dirichlet and Neumann boundary conditions. The asymptotic expansions of the Casimir free energy and the Casimir force when the separation $a$ between the cylinder and the plate is small are derived. As in the zero temperature case, it is found that the leading terms of the Casimir free energy and the Casimir force agree with those derived from the proximity force approximation when $rT\gg 1$, where $r$ is the radius of the cylinder. Specifically, when $aT\ll 1\ll rT$ (the medium temperature region), the leading term of the Casimir free energy is of order $T^{5/2}$ whereas, for the Casimir force, it is of order $T^{7/2}$. In this case, the leading terms are independent of the separation $a$. When $1\ll aT\ll rT$ (the high temperature region), the dominating terms of the Casimir free energy and the Casimir force come from the zeroth Matsubara frequency. In this case, the leading terms are linear in $T$, but for the free energy, it is inversely proportional to $a^{3/2}$, whereas, for the force, it is inversely proportional to $a^{5/2}$. The first order corrections to the proximity force approximations in different temperature regions are computed using the perturbation approach. In the zero temperature case, the results agree with those derived in [M. Bordag, Phys. Rev. D 73, 125018 (2006)].

We study $n$-string scattering amplitudes in three-dimensional anti–de Sitter space (${\mathrm{AdS}}_3$). We focus our attention on the processes in which the winding number conservation is violated maximally, that is, those processes in which it is violated in $n-2$ units. A worldsheet conformal field theory calculation leads us to confirm a previous conjecture about the functional form of these observables.

We study the stability of the BTZ black hole in the new massive gravity. This is a nontrivial task because the linearized equation around the BTZ black hole background is a fourth-order differential equation. Away from the critical point of $m^2{\ell }^2=1/2$, this fourth-order equation is split into two second-order equations: one describes a massless graviton, and the other is designed for a massive graviton, which could be obtained from the Fierz-Pauli action. In this case, calculating quasinormal modes leads to confirming the stability of the BTZ black hole. At the critical point, we derive two left- and right-logarithmic quasinormal modes from the logarithmic conformal field theory. Finally, we identify two $s$ massive modes propagating on the black hole background through the conventional black hole stability analysis.

Our aim in this work is to outline some physical consequences of the interaction between black holes and scalar field halos in terms of gravitational waves. In doing so, the black hole is taken as a static and spherically symmetric gravitational source, i.e. the Schwarzschild black hole, and we work within the test field approximation, considering that the scalar field lives in the curved space-time outside the black hole. We focused on the emission of gravitational waves when the black hole is perturbed by the surrounding scalar field matter. The symmetries of the space-time and the simplicity of the matter source allow, by means of a spherical harmonic decomposition, to study the problem by means of a one-dimensional description. Some properties of such gravitational waves are discussed as a function of the parameters of the infalling scalar field, and allow us to make the conjecture that the gravitational waves carry information on the type of matter that generated them.

The PAMELA and Fermi measurements of the cosmic ray electron and positron spectra have generated much interest over the past two years, because they are consistent with a significant component of the electron and positron fluxes between 20 GeV and 1 TeV being produced through dark matter annihilation or decay. However, since the measurements are also consistent with astrophysical interpretations, the message is unclear. In this paper, we point out that dark matter can have a more distinct signal in cosmic rays, that of a charge asymmetry. Such charge asymmetry can result if the dark matter’s abundance is due to a relic asymmetry, allowing its decay to generate an asymmetry in positrons and electrons. This is analogous to the baryon asymmetry, where decaying neutrons produce electrons and not positrons. We explore benchmark scenarios where the dark matter decays into a leptophilic charged Higgs boson or electroweak gauge bosons. These models have observable signals in gamma rays and neutrinos, which can be tested by Fermi and IceCube. The most powerful test will be at AMS-02, given its ability to distinguish electron and positron charge above 100 GeV. Specifically, an asymmetry favoring positrons typically predicts a larger positron ratio and a harder (softer) high energy spectrum for positrons (electrons) than charge symmetric sources. We end with a brief discussion on how such scenarios differ from the leading astrophysical explanations.

We argue that the decomposition of gamma-ray maps in spherical harmonics is a sensitive tool to study dark matter (DM) annihilation or decay in the main Galactic halo of the Milky Way. Using the spherical harmonic decomposition in a window excluding the Galactic plane, we show for 1 yr of Fermi data that adding a spherical template (such as a line-of-sight DM annihilation profile) to an astrophysical background significantly reduces ${\chi }^2$ of the fit to the data. In some energy bins the significance of this DM fraction is above three sigma. This can be viewed as a hint of a DM annihilation signal, although astrophysical sources cannot be ruled out at this moment. We use the derived DM fraction as a conservative upper limit on the DM annihilation signal. In the case of $b\overline{b}$ annihilation channel the limits are about a factor of 2 less constraining than the limits from dwarf galaxies. The uncertainty of our method is dominated by systematics related to modeling the astrophysical background. We show that with 1 yr of Fermi data the statistical sensitivity would be sufficient to detect DM annihilation with thermal freeze-out cross section for masses below 100 GeV.