We report an improved measurement of the B⁺→D⁺D̅ ⁰ and B⁰→D⁰D̅ ⁰ decays based on 657×10⁶ BB̅ events collected with the Belle detector at KEKB. We measure the branching fraction and charge asymmetry for the B⁺→D⁺D̅ ⁰ decay: B(B⁺→D⁺D̅ ⁰)=(3.85±0....

The dimensionless parameter ξ=M_π²/(16π²F_π²), where F_π is the pion decay constant and M_π is the pion mass, is expected to control the convergence of chiral perturbation theory applicable to QCD. Here we demonstrate that a strongly coupled lattice gauge theory model with the same symmetries as t...

We present for the first time a measurement of the weak phase 2β+γ obtained from a time-dependent Dalitz plot analysis of B⁰→D^∓K⁰π^± decays. Using a sample of approximately 347×10⁶ BB̅ pairs collected by the BABAR detector at the PEP-II asymmetric-energy storage rings and assuming ...

So far, the infrared behavior of the gluon and ghost propagator based on the Gribov-Zwanziger approach predicted a positivity violating gluon propagator vanishing at zero momentum, and an infrared enhanced ghost propagator. However, recent data based on huge lattices have revealed a positivity viola...

We report improved measurements of time-dependent CP violation parameters for B⁰(B̅ ⁰)→J/ψπ⁰ decay. This analysis is based on 535×10⁶ BB̅ pairs accumulated at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e⁺e^- collider. From the distribution of pr...

We search for evidence of resonant top quark pair production in 955 pb^-1 of pp̅ collisions at sqrt[s] =1.96  TeV recorded with the CDF II detector at the Fermilab Tevatron. For fully reconstructed candidate tt̅ events triggered on leptons with large transverse momentum and co...

We present a measurement of the branching fraction and photon-energy spectrum for the decay B→X_sγ using data from the BABAR experiment. The data sample corresponds to an integrated luminosity of 210  fb^-1, from which approximately 680 000 BB̅ events are tagged by a fully reconstru...

In a perturbative QCD approach, with inclusion of spin and transverse momentum effects, experimental data on azimuthal asymmetries observed in polarized semiinclusive deeply inelastic scattering and e⁺e^- annihilations can be used to determine the Sivers, transversity, and Collins soft functions. By ...

The Polyakov loop extended Nambu–Jona-Lasinio (PNJL) model with imaginary chemical potential is studied. The model possesses the extended Z₃ symmetry that QCD does. Quantities invariant under the extended Z₃ symmetry, such as the partition function, the chiral condensate, and the modified Polyakov...

We search for the doubly charmed baryonic decay BÌ… ⁰→Λ_c⁺Λ̅ _c^-, in a data sample of 520×10⁶ BBÌ… events accumulated at the Î¥(4S) resonance with the Belle detector at the KEKB asymmetric-energy e⁺e^- collider. We find no significant signal and set an upper limit of B(BÌ...

We study the constraint arising from the recently observed D-D̅ mixing in the context of supersymmetric models with left-right symmetry. In these models, the supersymmetric contributions in the mixing amplitudes of D-D̅ , K-K̅ and B-B̅ are all correlated. We co...

The method of analytic continuation from imaginary to real chemical potentials μ is one of the few available techniques to study QCD at finite temperature and baryon density. One of its most appealing applications is the determination of the critical line for small μ: we perform a direct test of t...

We report measurements of B-meson decays into two- and three-body final states containing two charmed baryons using a sample of 230×10⁶ Υ(4S)→BB̅ decays. We find significant signals in two modes, measuring branching fractions B(B^-→Λ_c⁺Λ̅ _c^-K^-)=(1.14±0.15±0.17±0.60)×10^-3...

We present a measurement of the cross section for W-boson production in association with jets in pp̅ collisions at sqrt[s] =1.96  TeV. The analysis uses a data sample corresponding to an integrated luminosity of 320  pb^-1 collected with the CDF II detector. W bosons are identified ...

We present a search for the decay B⁺→τ⁺ν using 383×10⁶ BB̅ pairs collected at the Υ(4S) resonance with the BABAR detector at the SLAC PEP-II B Factory. We select a sample of events with one completely reconstructed tag B in a hadronic decay mode (B^-→D^(*)0X^-), and examine the rest o...

We present a measurement of the muon charge asymmetry from W boson decays using 0.3  fb^-1 of data collected at sqrt[s] =1.96  GeV between 2002 and 2004 with the D0 detector at the Fermilab Tevatron pp̅ Collider. We compare our findings with expectations from next-to-leading-order c...

The process e⁺e^-→K⁺K^-J/ψ is observed for the first time via initial-state radiation. The cross section of e⁺e^-→K⁺K^-J/ψ for center-of-mass energies between threshold and 6.0 GeV is measured using 673  fb^-1 of data collected with the Belle detector on and off the Υ(4S) resonance. No signif...

A primordial gravitational wave background with positive (blue) spectral index is expected in several nonstandard inflationary cosmologies where the stress-energy tensor violates the null energy condition. Here we show that a sizable amount of blue gravitational waves is compatible with current cosm...

We present the first fully relativistic long-term numerical evolutions of three equal-mass black holes in a system consisting of a third black hole in a close orbit about a black-hole binary. These close-three-black-hole systems have very different merger dynamics from black-hole binaries; displayin...

We present results from numerical relativity simulations of equal-mass, nonspinning binary-black-hole inspirals and mergers with initial eccentricities e≤0.8 and coordinate separations D≥12M of up to 9 orbits (18 gravitational wave cycles). We extract the mass M_f and spin a_f of the final black h...

Based on recent developments by the authors a next-to-leading order spin(1)-spin(2) Hamiltonian is derived for the first time. The result is obtained within the canonical formalism of Arnowitt, Deser, and Misner (ADM) utilizing their generalized isotropic coordinates. A comparison with other methods...

We present a new truncation scheme for the Schwinger-Dyson equations of QCD that respects gauge invariance at any level of the dressed loop expansion. When applied to the gluon self-energy, it allows for its nonperturbative treatment without compromising the transversality of the solution, even when...

We formulate a field theory for resonantly interacting anyons, that enables us to perform a perturbative calculation near the fermionic limit. We derive renormalization group equations for three-body and four-body couplings at one-loop order. In addition to two fixed points, we find a limit cycle be...

We discuss non-Hermitian field theories where the spectrum of the Hamiltonian involves only real energies. We make three observations. (i) The theories obtained from supersymmetric theories by nonanticommutative deformations belong in many cases to this class. (ii) When the deformation parameter i...

The standard ΛCDM paradigm is complemented with a magnetized contribution whose effects on the anisotropies of the cosmic microwave background are assessed by means of a dedicated numerical approach. The accuracy on the temperature and polarization correlations stems from the inclusion of the large...

By finding the spinor eigenvalues for a single deficit angle (d-2)-sphere, we derive the radial potential for fermions on a d-dimensional black hole background that is embedded on a codimension-two brane with conical singularity, where the deficit angle is related to the brane tension. From this we ...

Superstring theory predicts the potential formation of string networks with bound states ending in junctions. Kinematic constraints for junction formation have been derived within the Nambu-Goto thin string approximation. Here we test these constraints numerically in the framework of the Abelian-Hig...

By analyzing the apparent horizon (AH) formation in the collision of two pp waves with rectangular sources in four dimensions, we study to what extent the AH can be distorted without violating the energy conditions. It is shown that the highly distorted AH can form in this system although it cannot ...

The contribution of cosmological perturbations to the time drift of the cosmological redshift is derived. It is shown that the dominant correction arises from the local acceleration of both the emitter and the observer. The amplitude of this effect is estimated to be of the order of 1% of the drift ...

Ground-based gravitational wave detectors may be able to constrain the nuclear equation of state using the early, low frequency portion of the signal of detected neutron star–neutron star inspirals. In this early adiabatic regime, the influence of a neutron star’s internal structure on the phase...

The photon polarization in radiative decays B→Yγ is known to be a subtle probe of the effective Lagrangian structure and possible New Physics effects. We discuss exclusive decay mode B^-→φK^-γ where the experimentally distinct final state makes analysis especially promising. The possibility to ...

We study the dynamical generation of masses for fundamental fermions in quenched quantum electrodynamics, in the presence of magnetics fields of arbitrary strength, by solving the Schwinger-Dyson equation for the fermion self-energy in the rainbow approximation. We employ the Ritus eigenfunction for...

We study the exclusive b→uℓ^-ν̅ _ℓ(ℓ=τ,μ,e) decays in the minimal supersymmetric standard model with and without R-parity violation. From the experimental measurements of branching ratios B(B_u^-→τ^-ν̅ _τ), B(B_u^-→M^′0ℓ^′-ν̅ _ℓ^′) and B(B̅ _d⁰→M^...

We show that for a force mediated by a vector particle coupled to a conserved U(1) charge, the apparent range and strength can depend on the size and density of the source, and the proximity to other sources. This chameleon effect is due to screening from a light charged scalar. Such screening can w...

We calculate gravitational form factors of vector mesons using a holographic model of QCD. These provide restrictions on the generalized parton distributions of vector mesons, via the sum rules connecting stress tensor form factors to generalized parton distributions. We concentrate on the traceless...

We examine the unparticle CP-conserving phase effects on the direct CP asymmetry for both polarized and unpolarized leptons in the inclusive b→dℓ⁺ℓ^- transition, where the flavor-changing neutral currents are forbidden at tree level but are induced by one-loop penguin diagrams. The averaged pol...

We present a two-flavor QCD calculation of B_K on a 16³×32 lattice at a∼0.12  fm (or equivalently a^-1=1.67  GeV). Both valence and sea quarks are described by the overlap fermion formulation. The matching factor is calculated nonperturbatively with the so-called RI/MOM scheme. We find that...

We consider 5-dimensional gauge theories where the 5th direction is compactified on an interval. The Chern-Simons (CS) terms (favored by the naive dimensional analysis) are discussed. A simple scenario with an extra U(1)_X gauge field that couples to SU(3)_color through a CS term in the bulk is constr...

Wilkinson Microwave Anisotropy Probe (WMAP) observations have accurately determined the position of the first two peaks and dips in the cosmic microwave background (CMB) temperature power spectrum. These encode information on the ratio of the distance to the last scattering surface to the sound hori...

Two first order strongly hyperbolic formulations of scalar-tensor theories of gravity allowing nonminimal couplings (Jordan frame) are presented along the lines of the 3+1 decomposition of spacetime. One is based on the Bona-Massó formulation, while the other one employs a conformal decomposition s...

We discuss whether some perturbed Friedmann-Robertson-Walker (FRW) universes could be creatable, i.e., could have vanishing energy, linear momentum, and angular momentum, as it could be expectable if the Universe arose as a quantum fluctuation. On account of previous results, the background is assum...

The Newton equation describing particle motion in a constant external field force on canonical, Lie-algebraic, and quadratic space-time is investigated. We show that for canonical deformation of space-time the dynamical effects are absent, while in the case of Lie-algebraic noncommutativity, when sp...

The modified-inertia MOND is an approach that proposes a change in Newton’s second law at small accelerations as an alternative to dark matter. Recently it was suggested that this approach can be tested in terrestrial laboratory experiments. One way of doing the test is based on the static high-la...

The Stokes V parameter characterizes asymmetry of amplitudes between right- and left-handed waves, and the nonvanishing value of the V parameter yields a circularly polarized signal. Cosmologically, the V parameter may be a direct probe for parity violation in the Universe. In this paper, we theoret...

The 21-cm anisotropies from the neutral hydrogen distribution prior to the era of reionization are a sensitive probe of primordial non-Gaussianity. Unlike the case with cosmic microwave background, 21-cm anisotropies provide multi-redshift information with frequency selection and are not damped at a...

We study the thermodynamics of the Schwarzschild-de Sitter black hole in five dimensions by introducing two temperatures based on the standard and Bousso-Hawking normalizations. We use the first-law of thermodynamics to derive thermodynamic quantities. The two temperatures indicate that the Nariai b...

Modifying the Kerr-Schild transformation used to generate black and white hole spacetimes, new dynamic black and white holes are obtained using a time-dependent Kerr-Schild scalar field. Physical solutions are found for black holes that shrink with time and for white holes that expand with time. The...

We analyze the stability of the structure equations of the vacuum in the brane world models, by using both the linear (Lyapunov) stability analysis, and the Jacobi stability analysis, the Kosambi-Cartan-Chern theory. In the brane world models the four-dimensional effective Einstein equations acquire...

In this article we address the problem of getting the temperature dependence of the π-π scattering lengths in the frame of the linear sigma model. Using the real time formalism, we calculate all the relevant one loop diagrams. The temperature corrections are only considered in the pion sector, due...

We introduce a new κ-star product describing the multiplication of quantized κ-deformed free fields. The κ deformation of local free quantum fields originates from two sources: noncommutativity of space-time and the κ deformation of field oscillators algebra; we relate these two deformations. W...

We consider a universe with a compact extra dimension and a cosmological constant emerging from a suitable ultraviolet cutoff on the zero-point energy of the vacuum. We derive the Casimir force between parallel conducting plates as a function of the following scales: plate separation, radius of the ...

We study constraints on f(R) dark energy models from solar system experiments combined with experiments on the violation of the equivalence principle. When the mass of an equivalent scalar field degree of freedom is heavy in a region with high density, a spherically symmetric body has a thin shell s...

We argue that in the paper we comment on the authors failed to prove that all known solutions of the Bogomol’nyi-Prasad-Sommerfield sector of duality-based Calogero model are indeed all solutions.

We report on a relation between the decay constants of r-like JPC=1- vector mesons, which arises solely from the perturbative analysis of the áVVñ, áTTñ and áVTñ correlators at O(as0) in the large-Nc limit. We find fVT/fV=1/Ö2 for highly excited states together with a pattern of alternation in sign. Quite remarkably, recent lattice determinations reported frT(m)/fr=0.72(2) at m = 2 GeV, in excellent agreement with our large-Nc result. This seems to suggest a pattern like fVnT/fVn=(-1)n/Ö2 for the whole (1-) states. In order to test this conjecture in real QCD we construct a set of spectral sum rules, which turn out to comply nicely with this scenario.

We present a simple formalism for parton-shower Markov chains. As a first step towards more complete `uncertainty bands', we incorporate a comprehensive exploration of the ambiguities inherent in such calculations. To reduce this uncertainty, we then introduce a matching formalism which allows a generated event sample to simultaneously reproduce any infrared safe distribution calculated at leading or next-to-leading order in perturbation theory, up to sub-leading corrections. To enable a more universal definition of perturbative calculations, we also propose a more general definition of the hadronization cutoff. Finally, we present an implementation of some of these ideas for final-state gluon showers, in a code dubbed .

At the quark level there are basically two types of contributions of R-parity violating SUSY ( SUSY) to neutrinoless double beta decay: the short-range contribution involving only heavy virtual superpartners and the long-range one with the virtual squark and neutrino. Hadronization of the effective operators, corresponding to these two types of contributions, may in general involve virtual pions in addition to close on-mass-shell nucleons. From the previous studies it is known that the short-range contribution is dominated by the pion exchange. In the present paper we show that this is also true for the long-range SUSY contribution. Therefore, we conclude that the SUSY contributes to the neutrinoless double beta decay dominantly via charged pion exchange between the decaying nucleons.

Realistic calculations of nuclear disappearance lifetimes induced by n[`n] oscillations are reported for oxygen and iron, using [`n] nuclear potentials derived from a recent comprehensive analysis of [`p] atomic X-ray and radiochemical data. A lower limit tn[`n] > 3.3 ×108 s on the n[`n] oscillation time is derived from the Super-Kamiokande I new lower limit Td(O) > 1.77 ×1032 yr on the neutron lifetime in oxygen. Antineutron scattering lengths in carbon and nickel, needed in trap experiments using ultracold neutrons, are calculated from updated [`N] optical potentials at threshold, with results shown to be largely model independent.

The rare $B_c \rightarrow D_{s,d}^{*}~l^+ l^-$ decays are investigated in the framework of the three point QCD sum rules approach. Considering the gluon condensate corrections to the correlation function, the form factors relevant to these transitions are calculated. The total decay width and branching ratio for these decays are also evaluated. The results for the branching ratios are in good agreement with the quark models.

We discuss a possible interpretation of the scalar Bs0*(5725) and axial Bs1(5778) bottom-strange mesons as hadronic molecules - bound states of B K and B* K mesons, respectively. Using a phenomenological Lagrangian approach we analyze the strong Bs0* ® Bs p0, Bs1 ® Bs* p0 and the radiative Bs0* ® Bs* g, Bs1 ® Bsg, Bs1 ® Bs* g, Bs1 ® Bs0*g decays. We give predictions for the decay properties: effective couplings and decay widths.

We analyze the electromagnetic scattering of massive particles with and without spin wherein one particle (or both) is electrically neutral. Using the techniques of effective field theory, we isolate the leading long distance effects, both classical and quantum mechanical. For spinless systems results are identical to those obtained earlier via more elaborate dispersive methods. However, we also find new results if either or both particles carry spin.

Nonbirefringent modified-Maxwell theory, coupled to standard Dirac particles, involves nine dimensionless parameters, which can be bounded by the inferred absence of vacuum Cherenkov radiation for ultrahigh-energy cosmic rays (UHECRs). With selected UHECR events, two-sided bounds on the eight nonisotropic parameters are obtained at the 10-18 level, together with an improved one-sided bound on the single isotropic parameter at the 10-19 level.

The lightest neutralino, as the dark matter candidate, can be gravitationally captured by the Sun. In this paper, we studied the high energy neutrino signals from solar neutralino annihilations in the core of the Sun in the anomaly mediated supersymmetry (SUSY) breaking (AMSB) model. Based on the event-by-event monte carlo simulation code WimpSim, we studied the detailed energy and angular spectrum of the final muons at large neutrino telescope IceCube. More precisely we simulated the processes since the production of neutrino via neutralino annihilation in the core of the Sun, neutrino propagation from the Sun to the Earth, as well as the converting processes from neutrino to muon. Our results showed that in the AMSB model it is possible to observe the energetic muons at IceCube, provided that the lightest neutralio has relatively large higgsino component, as a rule of thumb N132 + N142 > 4% or equivalently sSD > 10 - 5 pb. Especially, for our favorable parameters the signal annual events can reach 102 and the statistical significance can reach more than 20. We pointed out that the energy spectrum of muons may be used to distinguish among the AMSB model and other SUSY breaking scenarios.

We study the phenomenology of supersymmetric models in which gauge-singlet scalars mix with the MSSM sneutrinos through weak-scale A terms. After reviewing the constraints on mixed-sneutrino dark matter from measurements of WCDM and from direct-detection experiments, we explore mixed-sneutrino signatures relevant to the LHC. For a mixed-sneutrino LSP and a right-handed slepton NLSP, decays of the lightest neturalino can produce opposite-sign, same-flavor (OSSF) dileptons with an invariant-mass distribution shifted away from the kinematic endpoint. This signature is possible for parameters that lead to a cosmologically viable mixed-sneutrino LSP. We also consider signatures that require larger mixing angles than preferred for mixed-sneutrino dark matter, but which are possible regardless of whether a mixed-sneutrino is the LSP. In some parameter regions, the charginos and neutralinos produced in cascades all decay dominantly to the lighter sneutrinos, leading to a kinematic edge in the jet-lepton invariant-mass distribution from the decay chain [q\tilde] ®c- q ® \snu* l q, without an OSSF dilepton signature. We explore the possibility of using mass estimation methods to distinguish this mixed-sneutrino jet-lepton signature from an MSSM one. Finally, we consider signatures associated with Higgs-lepton or Z-lepton production in cascades involving the heavier sneutrinos.

An analysis of electroweak corrections to the anomalous dipole moments of lepton from some special two-loop diagrams where a closed neutralino/chargino loop is inserted into relevant one-loop diagrams of the standard model is presented in the split supersymmetry scenarios. Considering the translational invariance of the inner loop momenta and the electromagnetic gauge invariance, we get all dimension 6 operators and their coefficients. After applying equations of motion to the external leptons, we obtain the anomalous dipole moments of lepton. The numerical results imply that there is parameter space where the contribution to the muon anomalous magnetic dipole moment from this sector is perhaps significant, and the contribution to the electron electric dipole moment from this sector is sizable enough to be observed in next generation experiments.

We investigate self-similar solutions which are asymptotic to the Friedmann universe at spatial infinity and contain a scalar field with potential. The potential is required to be exponential by self-similarity. It is found that there are two distinct one-parameter families of asymptotic solutions, one is asymptotic to the proper Friedmann universe, while the other is asymptotic to the quasi-Friedmann universe, i.e., the Friedmann universe with anomalous solid angle. The asymptotically proper Friedmann solution is possible only if the universe is accelerated or the potential is negative. If the potential is positive, the density perturbation in the asymptotically proper Friedmann solution rapidly falls off at spatial infinity, while the mass perturbation is compensated. In the asymptotically quasi-Friedmann solution, the density perturbation falls off only in proportion to the inverse square of the areal radius and the relative mass perturbation approaches a nonzero constant at spatial infinity. The present result shows that a necessary condition holds in order that a self-gravitating body grows self-similarly due to the constant accretion of quintessence in an accelerating universe.

We revisit inflationary cosmology of axion models in the light of recent developments on the inflaton decay in supergravity. We find that all the cosmological difficulties, including gravitino, axino overproduction and axionic isocurvature fluctuation, can be avoided if the saxion field has large initial amplitude during inflation and decays before big-bang nucleosynthesis.

The bending of light due to the curvature of spacetime close to a black hole is so strong that light can even return to the point of emittance yielding an Einstein ring. Using the analytic solution of the geodesic equation in Schwarzschild spacetime and a distant star or a flash of light, we will be able to determine the mass of a black hole as well as the distance of the observer to this black hole, at least in principle.

The relation between two time physics (2T-physics) and the ordinary one time formulation of physics (1T-physics) is similar to the relation between a 3-dimensional object moving in a room and its multiple shadows moving on walls when projected from different perspectives. The multiple shadows as seen by observers stuck on the wall are analogous to the effects of the 2T-universe as experienced in ordinary 1T spacetime. In this paper we develop some of the quantitative aspects of this 2T to 1T relationship in the context of field theory. We discuss 2T field theory in d+2 dimensions and its shadows in the form of 1T field theories when the theory contains Klein-Gordon, Dirac and Yang-Mills fields, such as the Standard Model of particles and forces. We show that the shadow 1T field theories must have hidden relations among themselves. These relations take the form of dualities and hidden spacetime symmetries. A subset of the shadows are 1T field theories in different gravitational backgrounds (different space-times) such as the flat Minkowski spacetime, the Robertson-Walker expanding universe, AdSd-k×Sk, and others, including singular ones. We explicitly construct the duality transformations among this conformally flat subset, and build the generators of their hidden SO(d,2) symmetry. The existence of such hidden relations among 1T field theories, which can be tested by both theory and experiment in 1T-physics, is part of the evidence for the underlying d+2 dimensional spacetime and the unifying 2T-physics structure.

A description of the transition from the inflationary epoch to radiation domination requires the understanding of quantum fields out of thermal equilibrium, particle creation and thermalisation. This can be studied from first principles by solving a set of truncated real-time Schwinger-Dyson equations, written in terms of the mean field (inflaton) and the field propagators, derived from the 2PI effective action. We investigate some aspects of this problem by considering the dynamics of a slow-rolling mean field coupled to a second quantum field, using a j2c2 interaction. We focus on thermal effects. It is found that interactions lead to an earlier end of slow-roll and that the evolution afterwards depends on details of the heatbath.

We discuss "spectral flow" coordinate transformations that take asymptotically four-dimensional solutions into other asymptotically four-dimensional solutions. We find that spectral flow can relate smooth three-charge solutions with a multi-center Taub-NUT base to solutions where one or several Taub-NUT centers are replaced by two-charge supertubes, and vice versa. We further show that multi-parameter spectral flows can map such Taub-NUT centers to more singular centers that are either D2-D0 or pure D0-brane sources. Since supertubes can depend on arbitrary functions, we establish that the moduli space of smooth horizonless black hole microstate solutions is classically of infinite dimension. We also use the physics of supertubes to argue that some multi-center solutions that appear to be bound states from a four-dimensional perspective are in fact not bound states when considered from a five- or six-dimensional perspective.

Two new formulations of general relativity are introduced. The first one is a parabolization of the Arnowitt, Deser, Misner (ADM) formulation and is derived by addition of combinations of the constraints and their derivatives to the right-hand-side of the ADM evolution equations. The desirable property of this modification is that it turns the surface of constraints into a local attractor because the constraint propagation equations become second-order parabolic independently of the gauge conditions employed. This system may be classified as mixed hyperbolic - second-order parabolic. The second formulation is a parabolization of the Kidder, Scheel, Teukolsky formulation and is a manifestly mixed strongly hyperbolic - second-order parabolic set of equations, bearing thus resemblance to the compressible Navier-Stokes equations. As a first test, a stability analysis of flat space is carried out and it is shown that the first modification exponentially damps and smoothes all constraint violating modes. These systems provide a new basis for constructing schemes for long-term and stable numerical integration of the Einstein field equations.

The current accelerated expansion of our universe could be due to an unknown energy component (dark energy) or a modification to general relativity (modified gravity). It is proposed in literature that combining the probes of cosmic expansion history and growth history can distinguish between dark energy and modified gravity. In the present work, without invoking non-trivial dark energy clustering, we show that the possible interaction between dark energy and dark matter could make interacting dark energy model and modified gravity model indistinguishable. An explicit example is also given. Therefore, it is required to seek some complementary probes beyond the ones of cosmic expansion history and growth history.

The annihilations of neutralino dark matter (or other dark matter candidate) generate, among other Standard Model states, electrons and positrons. These particles emit synchrotron photons as a result of their interaction with the Galactic Magnetic Field. In this letter, we use the measurements of the WMAP satellite to constrain the intensity of this synchrotron emission and, in turn, the annihilation cross section of the lightest neutralino. We find this constraint to be more stringent than that provided by any other current indirect detection channel. In particular, the neutralino annihilation cross section must be less than » 3×10-26cm3/s (1×1025cm3/s) for 100 GeV (500 GeV) neutralinos distributed with an NFW halo profile. For the conservative case of an entirely flat dark matter distribution within the inner 8 kiloparsecs of the Milky Way, the constraint is approximately a factor of 30 less stringent. Even in this conservative case, synchrotron measurements strongly constrain, for example, the possibility of wino or higgsino neutralino dark matter produced non-thermally in the early universe.

It has been suggested that after brane-antibrane inflation in a Klebanov-Strassler (KS) warped throat, metastable Kaluza-Klein (KK) excitations can be formed due to nearly-conserved angular momenta along isometric directions in the throat. If sufficiently long-lived, these relics could conflict with big bang nucleosynthesis or baryogenesis by dominating the energy density of the universe. We make a detailed estimate of the decay rate of such relics using the low energy effective action of type IIB string theory compactified on the throat geometry, with attention to powers of the warp factor. We find that it is necessary to turn on SUSY-breaking deformations of the KS background in order to ensure that the most dangerous relics will decay fast enough. The decay rate is found to be much larger than the naive guess based on the dimension of the operators which break the angular isometries of the throat. For an inflationary warp factor of order w ~ 10-4, we obtain the bound M3/2 \gsim109 GeV on the scale of SUSY breaking to avoid cosmological problems from the relics, which is satisfied in the KKLT construction assumed to stabilize the compactification. Given the requirement that the relics decay before nucleosynthesis or baryogenesis, we place bounds on the mass of the relic as a function of the warp factor in the throat for more general warped backgrounds.

We calculate the quantum noise limited displacement sensitivity of a Michelson-Fabry-Perot (MFP) with detuned cavities, followed by phase-sensitive homodyne detection. We show that the standard quantum limit can be surpassed even with resonant cavities and without any signal-recycling mirror nor additional cavities. Indeed, thanks to the homodyne detection, the output field quadrature can be chosen in such a way to cancel the effect of input amplitude fluctuations, i.e., eliminating the force noise. With detuned cavities, the modified opto-mechanical susceptivity allows to reach unlimited sensitivity for large enough (yet finite) optical power. Our expressions include mirror losses and cavity delay effect, for a realistic comparison with experiments. Our study is particularly devoted to gravitational wave detectors and we consider both an interferometer with free-falling mirrors, and a MFP as readout for a massive detector. In the latter case, the sensitivity curve of the recently conceived 'DUAL' detector, based on two acoustic modes, is obtained.

The bispectrum of cosmic microwave background (CMB) anisotropies is a well-known probe of the non-Gaussianity of primordial perturbations. Just as the intervening large-scale structure modifies the CMB angular power spectrum through weak gravitational lensing, the CMB primary bispectrum generated at the last scattering surface is also modified by lensing. We discuss the lensing modification to the CMB bispectrum and show that lensing leads to an overall decrease in the amplitude of the primary bispectrum at multipoles of interest between 100 and 2000 through additional smoothing introduced by lensing. Since weak lensing is not accounted for in current estimators of the primordial non-Gaussianity parameter, the existing measurements of fNL of the local model with WMAP out to lmax ~ 750 is biased low by about 6%. For a high resolution experiment such as Planck, the lensing modification to the bispectrum must be properly included when attempting to estimate the primordial non-Gaussianity or the bias will be at the level of 30%. For Planck, weak lensing increases the minimum detectable value for the non-Gaussianity parameter of the local type fNL to 7 from the previous estimate of about 5 without lensing. The minimum detectable value of fNL for a cosmic variance limited experiment is also increased from less than 3 to ~ 5.

A small mass m in orbit about a much more massive black hole m moves along a world line that deviates from a geodesic of the black hole geometry by O(m/m). This deviation is said to be caused by the gravitational self-force of the metric perturbation hab from m. For circular orbits about a non-rotating black hole we numerically calculate the O(m/m) effects upon the orbital frequency and upon the rate of passage of proper time on the worldline. These two effects are independent of the choice of gauge for hab and are observable in principle. For distant orbits, our numerical results agree with a post-Newtonian analysis including terms of order (v/c)6.

The addition of an adjoint Polyakov loop term to the action of a pure gauge theory at finite temperature leads to new phases of SU(N) gauge theories. For SU(3), a new phase is found which breaks Z(3) symmetry in a novel way; for SU(4), the new phase exhibits spontaneous symmetry breaking of Z(4) to Z(2), representing a partially confined phase in which quarks are confined, but diquarks are not. The overall phase structure and thermodynamics is consistent with a theoretical model of the effective potential for the Polyakov loop based on perturbation theory.