We discuss the reconstruction of neutrino flavor ratios at astrophysical sources through the future neutrino-telescope measurements. Taking the ranges of neutrino mixing parameters ${\theta }_{ij}$ as those given by the current global fit, we demonstrate by a statistical method that the accuracies in the measurements of energy-independent ratios $R\equiv \varphi ({\nu }_{\mu })/(\varphi ({\nu }_e)+\varphi ({\nu }_{\tau }))$ and $S\equiv \varphi ({\nu }_e)/\varphi ({\nu }_{\tau })$ among integrated neutrino flux should both be better than 10% in order to distinguish between the pion source and the muon-damped source at the $3\sigma$ level. The 10% accuracy needed for measuring $R$ and $S$ requires an improved understanding of the background atmospheric neutrino flux to a better than 10% level in the future. We discuss the applicability of our analysis to practical situations that the diffuse astrophysical neutrino flux arises from different types of sources and each point source has a neutrino flavor ratio varying with energies. We also discuss the effect of the leptonic $CP$ phase on the flavor-ratio reconstruction.

We present an all-sky search for gravitational waves in the frequency range 1 to 6 kHz during the first calendar year of LIGO’s fifth science run. This is the first untriggered LIGO burst analysis to be conducted above 3 kHz. We discuss the unique properties of interferometric data in this regime. 161.3 days of triple-coincident data were analyzed. No gravitational events above threshold were observed and a frequentist upper limit of $5.4{\mathrm{year}}^{-1}$ on the rate of strong gravitational-wave bursts was placed at a 90% confidence level. Implications for specific theoretical models of gravitational-wave emission are also discussed.

We present the results obtained from an all-sky search for gravitational-wave (GW) bursts in the 64–2000 Hz frequency range in data collected by the LIGO detectors during the first year (November 2005—November 2006) of their fifth science run. The total analyzed live time was 268.6 days. Multiple hierarchical data analysis methods were invoked in this search. The overall sensitivity expressed in terms of the root-sum-square (rss) strain amplitude $h_{\mathrm{rss}}$ for gravitational-wave bursts with various morphologies was in the range of $6\times {10}^{-22}{\mathrm{Hz}}^{-1/2}$ to a $\mathrm{\text{few}}\times {10}^{-21}{\mathrm{Hz}}^{-1/2}$. No GW signals were observed and a frequentist upper limit of 3.75 events per year on the rate of strong GW bursts was placed at the 90% confidence level. As in our previous searches, we also combined this rate limit with the detection efficiency for selected waveform morphologies to obtain event rate versus strength exclusion curves. In sensitivity, these exclusion curves are the most stringent to date.

We measure the evolution of the coupling constant using the Schrödinger functional method in the lattice formulation of SU(2) gauge theory with two massless Dirac fermions in the adjoint representation. We observe strong evidence for an infrared fixed point, where the theory becomes conformal. We measure the $\beta$ function and the coupling constant as a function of the energy scale.

This paper is devoted to the leading twist exclusive bottomonia decays with double charmonium in the final state. Using models of the twist-2 charmonia distribution amplitudes, the widths of these decays are calculated within light cone formalism. In addition, the processes under consideration are studied within nonrelativistic QCD. In our analysis we have found that the production of some of the $P$-wave charmonia mesons with $L_z\ne 0$ is allowed already at the leading twist approximation. This means that the selection rules which predict the suppression of such decays are violated. The mechanism which lies behind this violation is discussed.

We calculate the coupling constants between the light vector mesons and heavy baryons within the framework of the light-cone QCD sum rule in the leading order of heavy quark effective theory. Most resulting sum rules are stable with the variations of the Borel parameter and the continuum threshold. The extracted couplings will be useful in the study of the possible heavy baryon molecular states.

We consider a holographic model constructed using the $\mathrm{D}4/\mathrm{D}8\mathrm{\text{−}}\overline{\mathrm{D}8}$ brane configuration with a Neveu-Schwarz–Neveu-Schwarz background field. We study some properties of the effective field theory in this intersecting brane construction and calculate the effects of this Neveu-Schwarz–Neveu-Schwarz background field on some underlying dynamics. We also discuss some other general brane configurations.

We argue that the most conservative geometric extension of Einstein gravity describing both positive and negative mass sources and observers is bimetric gravity and contains two copies of standard model matter which interact only gravitationally. Matter fields related to one of the metrics then appear dark from the point of view of an observer defined by the other metric, and so may provide a potential explanation for the dark universe. In this framework we consider the most general form of linearized field equations compatible with physically and mathematically well-motivated assumptions. Using gauge-invariant linear perturbation theory, we prove a no-go theorem ruling out all bimetric gravity theories that, in the Newtonian limit, lead to precisely opposite forces on positive and negative test masses.

We present a $k$-essence model where a single scalar field is responsible for the early expansion of the Universe through the process of $k$ inflation and at appropriate subsequent stages acts both as dark matter and dark energy. The Lagrangian contains a potential for the scalar field as well as a noncanonical kinetic term, and is of the form $F(X)V(\varphi )$ which has been widely used as a $k$-essence Lagrangian. After the period of inflation is over the model can be approximated as purely kinetic $k$ essence, generating dark matter and dark energy at late times. We show how observational results are used to put constraints on the parameters of this model.

$CP$ violation in supersymmetry can give rise to rate asymmetries in the decays of supersymmetric particles. In this work we compute the rate asymmetries for the three-body chargino decays ${\tilde{\chi }}_2^{\pm }\to {\tilde{\chi }}_1^{\pm }HH$, ${\tilde{\chi }}_2^{\pm }\to {\tilde{\chi }}_1^{\pm }ZZ$, ${\tilde{\chi }}_2^{\pm }\to {\tilde{\chi }}_1^{\pm }{W}^{+}{W}^{-}$ and ${\tilde{\chi }}_2^{\pm }\to {\tilde{\chi }}_1^{\pm }ZH$. Each of the decays contains contributions mediated by neutral Higgs bosons that can possibly go on shell. Such contributions receive a resonant enhancement; furthermore, the strong phases required for the $CP$ asymmetries come from the widths of the exchanged Higgs bosons. Our results indicate that the rate asymmetries can be relatively large in some cases, while still respecting a number of important low-energy bounds such as those coming from $B$ meson observables and electric dipole moments. For the parameters that we consider, rate asymmetries of order 10% are possible in some cases.

No-scale supersymmetry or gaugino mediation augmented with large negative Higgs soft masses at the input scale provides a simple solution to the supersymmetric flavor problem while giving rise to a neutralino lightest superpartner particle. However, to obtain a neutralino lightest superpartner particle it is often necessary to have tachyonic input Higgs soft masses that can give rise to charge-and-color-breaking minima and unbounded-from-below directions in the low-energy theory. We investigate the vacuum structure in these theories to determine when such problematic features are present. When the standard electroweak vacuum is only metastable, we compute its lifetime under vacuum tunneling. We find that vacuum metastability leads to severe restrictions on the parameter space for larger $\tan \beta \sim 30$, while for smaller $\tan \beta \sim 10$, only minor restrictions are found. Along the way, we derive an exact bounce solution for tunneling through an inverted parabolic potential.

We present the $N_f=2+1$ clover fermion lattice QCD calculation of the nucleon strangeness form factors. We evaluate disconnected insertions using the Z(4) stochastic method, along with unbiased subtractions from the hopping parameter expansion. We find that increasing the number of nucleon sources for each configuration improves the signal significantly. We obtain $G_M^s(0)=-0.017(25)(07)$, where the first error is statistical, and the second is the uncertainties in $Q^2$ and chiral extrapolations. This is consistent with experimental values, and has an order of magnitude smaller error.

Some deviations from special relativity—especially isotropic effects—are most efficiently constrained using particles with velocities very close to 1. While there are extremely tight bounds on some of the relevant parameters coming from astrophysical observations, many of these rely on our having an accurate understanding of the dynamics of these high-energy sources. It is desirable to have reliable laboratory constraints on these same parameters. The fastest-moving particles in a laboratory were electrons and positrons at LEP. The energetics of the LEP beams were extremely well understood, and measurements of the synchrotron emission rate indicate that the isotropic Lorentz violation coefficient $|{\tilde{\kappa }}_{\mathrm{tr}}-\frac{4}{3}{c}_{00}|$ must be smaller than $5\times {10}^{-15}$.

We investigate the ground states of the Abelian Higgs model in ${\mathrm{AdS}}_4$ with various choices of parameters, and with no deformations in the ultraviolet other than a chemical potential for the electric charge under the Abelian gauge field. For W-shaped potentials with symmetry-breaking minima, an analysis of infrared asymptotics suggests that the ground state has emergent conformal symmetry in the infrared when the charge of the complex scalar is large enough. But when this charge is too small, the likeliest ground state has Lifshitz-like scaling in the infrared. For positive mass quadratic potentials, Lifshitz-like scaling is the only possible infrared behavior for constant nonzero values of the scalar. The approach to Lifshitz-like scaling is shown in many cases to be oscillatory.

We present a systematic study of spherically symmetric self-dual solutions of $SU(2)$ Yang-Mills theory on Euclidean Schwarzschild space. All the previously known solutions are recovered and a new one-parameter family of instantons is obtained. The newly found solutions have continuous actions and interpolate between the classic Charap and Duff instantons. We examine the physical properties of this family and show that it consists of dyons of unit (magnetic and electric) charge.

We develop information field theory (IFT) as a means of Bayesian inference on spatially distributed signals, the information fields. A didactical approach is attempted. Starting from general considerations on the nature of measurements, signals, noise, and their relation to a physical reality, we derive the information Hamiltonian, the source field, propagator, and interaction terms. Free IFT reproduces the well-known Wiener-filter theory. Interacting IFT can be diagrammatically expanded, for which we provide the Feynman rules in position-, Fourier-, and spherical-harmonics space, and the Boltzmann-Shannon information measure. The theory should be applicable in many fields. However, here, two cosmological signal recovery problems are discussed in their IFT formulation. (1) Reconstruction of the cosmic large-scale structure matter distribution from discrete galaxy counts in incomplete galaxy surveys within a simple model of galaxy formation. We show that a Gaussian signal, which should resemble the initial density perturbations of the Universe, observed with a strongly nonlinear, incomplete and Poissonian-noise affected response, as the processes of structure and galaxy formation and observations provide, can be reconstructed thanks to the virtue of a response-renormalization flow equation. (2) We design a filter to detect local nonlinearities in the cosmic microwave background, which are predicted from some early-Universe inflationary scenarios, and expected due to measurement imperfections. This filter is the optimal Bayes’ estimator up to linear order in the nonlinearity parameter and can be used even to construct sky maps of nonlinearities in the data.

We study higher-dimensional soliton and hairy black hole solutions of the Einstein equations nonminimally coupled to a scalar field. The scalar field has no self-interaction potential but a cosmological constant is included. Nontrivial solutions exist only when the cosmological constant is negative and the constant governing the coupling of the scalar field to the Ricci scalar curvature is positive. At least some of these solutions are stable when this coupling constant is not too large.

We show that the Big Bang Observer (BBO), a proposed space-based gravitational-wave (GW) detector, would provide ultraprecise measurements of cosmological parameters. By detecting $\sim 3\times {10}^5$ compact-star binaries, and utilizing them as standard sirens, BBO would determine the Hubble constant to $\sim 0.1\%$, and the dark-energy parameters $w_0$ and $w_a$ to $\sim 0.01$ and $\sim 0.1$, respectively. BBO’s dark-energy figure-of-merit would be approximately an order of magnitude better than all other proposed, dedicated dark-energy missions. To date, BBO has been designed with the primary goal of searching for gravitational waves from inflation, down to the level ${\Omega }_{\mathrm{GW}}\sim {10}^{-17}$; this requirement determines BBO’s frequency band (deci-Hz) and its sensitivity requirement (strain measured to $\sim {10}^{-24}$). To observe an inflationary GW background, BBO would first have to detect and subtract out $\sim 3\times {10}^5$ merging compact-star binaries, out to a redshift $z\sim 5$. It is precisely this carefully measured foreground which would enable high-precision cosmology. BBO would determine the luminosity distance to each binary to $\sim$ percent accuracy. In addition, BBO’s angular resolution would be sufficient to uniquely identify the host galaxy for the majority of binaries; a coordinated optical/infrared observing campaign could obtain the redshifts. Combining the GW-derived distances and the electromagnetically-derived redshifts for such a large sample of objects, out to such high redshift, naturally leads to extraordinarily tight constraints on cosmological parameters. We emphasize that such “standard siren” measurements of cosmology avoid many of the systematic errors associated with other techniques: GWs offer a physics-based, absolute measurement of distance. In addition, we show that BBO would also serve as an exceptionally powerful gravitational-lensing mission, and we briefly discuss other astronomical uses of BBO, including providing an early warning system for all short/hard gamma-ray bursts.

We study the thermodynamical properties of electrically charged black hole solutions of a nonlinear electrodynamics theory defined by a power $p$ of the Maxwell invariant, which is coupled to Einstein gravity in four and higher spacetime dimensions. Depending on the range of the parameter $p$, these solutions present different asymptotic behaviors. We compute the Euclidean action with the appropriate boundary term in the grand canonical ensemble. The thermodynamical quantities are identified and, in particular, the mass and the charge are shown to be finite for all classes of solutions. Interestingly, a generalized Smarr formula is derived and it is shown that this latter encodes perfectly the different asymptotic behaviors of the black hole solutions. The local stability is analyzed by computing the heat capacity and the electrical permittivity and we find that a set of small black holes is locally stable. In contrast to the standard Reissner-Nordström solution, there is a first-order phase transition between a class of these nonlinear charged black holes and the Minkowski spacetime.