We derive the event-by-event likelihood that allows us to extract the complete information contained in the energy, time, and direction of supernova neutrinos, and specify it in the case of SN1987A data. We resolve discrepancies in the previous literature, numerically relevant already in the concrete case of SN1987A data.

The lighter top squark in supersymmetry can live long enough to form hadronic bound states if it has no kinematically allowed two-body decays that conserve flavor. In this case, scalar stoponium may be observable through its diphoton decay mode at the CERN Large Hadron Collider, enabling a uniquely precise measurement of the top-squark mass. The viability of the signal depends crucially on the branching ratio to diphotons. We compute the next-to-leading-order QCD radiative corrections to stoponium annihilation decays to hadrons, photons, and Higgs scalar bosons. We find that the effect of these corrections is to significantly decrease the predicted branching ratio to the important diphoton channel. We also find a greatly improved renormalization-scale dependence of the diphoton branching ratio prediction.

We perform a global fit to the structure function $F_2$ measured in lepton-proton experiments at small values of Bjorken-$x$, $x\le 0.01$, for all experimentally available values of $Q^2$, $0.045{\mathrm{GeV}}^2\le Q^2\le 800{\mathrm{GeV}}^2$. We show that the recent improvements resulting from the inclusion of running coupling corrections allow for a description of data in terms of nonlinear QCD evolution equations. In this approach $F_2$ is calculated within the dipole model with all Bjorken-$x$ dependence described by the running coupling Balitsky-Kovchegov equation. Two different initial conditions for the evolution are used, both yielding good fits to data with ${\chi }^2/\mathrm{d}.\mathrm{o}.\mathrm{f}.<1.1$. The proton longitudinal structure function $F_L$, not included in the fits, is also well described. Our analysis allows to perform a first principle extrapolation of the proton-dipole scattering amplitude once the initial condition has been fitted to presently available data. We provide predictions for $F_2$ and $F_L$ in the kinematical regions of interest for future colliders and ultra-high energy cosmic rays. A numerical implementation of our results down to $x={10}^{-12}$ is released as a computer code for public use.

We discuss techniques and results for the extraction of the nucleon’s spin-dependent parton distributions and their uncertainties from data for polarized deep-inelastic lepton-nucleon and proton-proton scattering by means of a global QCD analysis. Computational methods are described that significantly increase the speed of the required calculations to a level that allows one to perform the full analysis consistently at next-to-leading order accuracy. We examine how the various data sets help to constrain different aspects of the quark, antiquark, and gluon helicity distributions. Uncertainty estimates are performed using both the Lagrange multiplier and the Hessian approaches. We use the extracted parton distribution functions and their estimated uncertainties to predict spin asymmetries for high-transverse momentum pion and jet production in polarized proton-proton collisions at 500 GeV center-of-mass system energy at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, as well as for $W$ boson production.

The $\pi \pi$ $S$-wave phase shifts below 0.6 GeV are extracted out from the published data of the decay $\psi (2S)\to {\pi }^{+}{\pi }^{-}J/\psi$. In fitting to the $m_{\pi \pi }$ distribution, several $\pi \pi$ production mechanisms are modeled in the amplitude. The fit results show that the amplitude including the $\pi \pi$ rescattering process with the minimal coupling $g_1{ϵ}^{\prime }·{ϵ}^{*}$ plus the direct nonresonant three-body decay process yields phase shifts consistent with those measured in scattering experiments and $K_{e4}$ decays. This result agrees with the expectation of the Watson theorem.

We examine the one-loop partition function describing the fluctuations of the superstring in a Schwarzschild-${\mathrm{AdS}}_5\times S^5$ background. On the bosonic side, we demonstrate the one-loop equivalence of the Nambu-Goto action and the Polyakov action for a general world sheet, while on the fermionic side, we consider the reduction of the ten-dimensional Green-Schwarz fermion action to a two-dimensional world sheet action. We derive the partition functions of the world sheets corresponding to both straight and parallel Wilson lines. We discuss the cancellation of the UV divergences of the functional determinants in the thermal AdS background.

We apply the dynamical systems tools to study the linear dynamics of a self-interacting scalar field trapped in the braneworld, for a wide variety of self-interaction potentials. We focus on Randall-Sundrum and on Dvali-Gabadadze-Porrati braneworld models exclusively. These models are complementary to each other: while the Randall-Sundrum brane produces UV) corrections to general relativity, the Dvali-Gabadadze-Porrati braneworld modifies Einstein’s theory at large scales, i e., produces IR modifications of general relativity. This study of the asymptotic properties of both braneworld models, shows—in the phase space—the way the dynamics of a scalar field trapped in the brane departs from standard general relativity behavior.

A systematic study of the different phases of Lorentz-breaking massive gravity in a curved background is performed. For tensor and vector modes, the analysis is very close to that of Minkowski space. The most interesting results are in the scalar sector where, generically, there are two propagating degrees of freedom (DOF). While in maximally symmetric spaces ghostlike instabilities are inevitable, they can be avoided in a FRW background. The phases with less than two DOF in the scalar sector are also studied. Curvature allows an interesting interplay with the mass parameters; in particular, we have extended the Higuchi bound of de Sitter to Friedman-Robertson-Walker and Lorentz-breaking masses. As in dS, when the bound is saturated there is no propagating DOF in the scalar sector. In a number of phases the smallness of the kinetic terms gives rise to strongly coupled scalar modes at low energies. Finally, we have computed the gravitational potentials for pointlike sources. In the general case we recover the general relativity predictions at small distances, whereas the modifications appear at distances of the order of the characteristic mass scale. In contrast with Minkowski space, these corrections may not spoil the linear approximation at large distances.

If dark matter is made up of weakly interacting massive particles, the annihilation of these particles in halos results in energy being released, some of which is absorbed by gas, causing partial ionization and heating. Dark matter annihilation may result in partial ionization and gas heating at high redshifts, even before the formation of the first stars. It is shown that early ionization results in a transfer of power to higher multipoles in the large angle CMB polarization power spectra. Future CMB experiments may be able to place constraints on certain light dark matter models. We also investigate the effect of gas heating on the expected H21 cm power spectrum. Heating by particle annihilation results in a decrease in the amplitude of the H21 cm power spectrum as the gas temperature $T$ becomes comparable to the CMB temperature $T_{\gamma }$, and then an increase as $T>T_{\gamma }$. The result is a minimum in the power spectrum at the redshift for which $T\approx T_{\gamma }$. Only certain models (low particle masses $\sim 10\mathrm{GeV}$, or favorable halo parameters) show this effect. Within these models, observations of the H21 cm power spectrum at multiple redshifts can help us obtain constraints on dark matter particle and halo properties.

We analyze the Tevatron reach for neutral Higgs bosons in the minimal supersymmetric standard model, using current exclusion limits on the standard model Higgs. We study four common benchmark scenarios for the soft supersymmetry-breaking parameters of the minimal supersymmetric standard model, including cases where the Higgs decays differ significantly from the standard model, and provide projections for the improvements in luminosity and efficiency required for the Tevatron to probe sizeable regions of the $(m_A,\tan \beta )$ plane.

We study for what specific values of the theoretical parameters the axion can form the totality of cold dark matter. We examine the allowed axion parameter region in the light of recent data collected by the WMAP5 mission plus baryon acoustic oscillations and supernovae, and assume an inflationary scenario and standard cosmology. We also upgrade the treatment of anharmonicities in the axion potential, which we find important in certain cases. If the Peccei-Quinn symmetry is restored after inflation, we recover the usual relation between axion mass and density, so that an axion mass $m_a=(85\pm 3)\mu \mathrm{eV}$ makes the axion 100% of the cold dark matter. If the Peccei-Quinn symmetry is broken during inflation, the axion can instead be 100% of the cold dark matter for $m_a<15\mathrm{meV}$ provided a specific value of the initial misalignment angle ${\theta }_i$ is chosen in correspondence to a given value of its mass $m_a$. Large values of the Peccei-Quinn symmetry breaking scale correspond to small, perhaps uncomfortably small, values of the initial misalignment angle ${\theta }_i$.

The PAMELA, ATIC, and Fermi collaborations have recently reported an excess in the cosmic ray positron and electron fluxes. These lepton anomalies might be related to cold dark matter particles annihilating within a nearby dark matter clump. We outline regions of the parameter space for both the dark matter subhalo and particle model, where data from the different experiments are reproduced. We then confront this interpretation of the data with the results of the cosmological $N$-body simulation Via Lactea II. Having a sizable clump ($V_{\max }=9\mathrm{km}{\mathrm{s}}^{-1}$) at a distance of only 1.2 kpc could explain the PAMELA excess, but such a configuration has a probability of only 0.37%. Reproducing also the ATIC bump would require a very large, nearby subhalo, which is extremely unlikely ($p\simeq 3\times {10}^{-5}$). It is even less probable for the smaller Fermi bump to be caused by the presence of such an object. In either case, we predict Fermi will detect the gamma-ray emission from the subhalo. We conclude that under canonical assumptions, the cosmic ray lepton anomalies are unlikely to originate from a nearby cold dark matter subhalo.

Gluon field configurations with nonzero topological charge generate chirality, inducing $\mathcal{P}$- and $\mathcal{C}\mathcal{P}$-odd effects. When a magnetic field is applied to a system with nonzero chirality, an electromagnetic current is generated along the direction of the magnetic field. The induced current is equal to the chiral magnetic conductivity times the magnetic field. In this article we will compute the chiral magnetic conductivity of a high-temperature plasma for nonzero frequencies. This allows us to discuss the effects of time-dependent magnetic fields, such as produced in heavy ion collisions, on chirally asymmetric systems.

The first measurements of the coherence factors ($R_{K\pi {\pi }^0}$ and $R_{K3\pi }$) and the average strong-phase differences (${\delta }_D^{K\pi {\pi }^0}$ and ${\delta }_D^{K3\pi }$) for $D^0\to K^{-}{\pi }^{+}{\pi }^0$ and $D^0\to K^{-}{\pi }^{+}{\pi }^{+}{\pi }^{-}$ are presented. These parameters can be used to improve the determination of the unitarity triangle angle $\gamma$ in $B^{-}\to D{K}^{-}$ decays, where $D$ is a $D^0$ or ${\overline{D}}^0$ meson decaying to the same final state. The measurements are made using quantum-correlated, fully reconstructed $D^0{\overline{D}}^0$ pairs produced in $e^{+}{e}^{-}$ collisions at the $\psi (3770)$ resonance. The measured values are: $R_{K\pi {\pi }^0}=0.84\pm 0.07$, ${\delta }_D^{K\pi {\pi }^0}=({227}_{-17}^{+14})°$, $R_{K3\pi }={0.33}_{-0.23}^{+0.20}$, and ${\delta }_D^{K3\pi }=({114}_{-23}^{+26})°$. These results indicate significant coherence in the decay $D^0\to K^{-}{\pi }^{+}{\pi }^0$, whereas lower coherence is observed in the decay $D^0\to K^{-}{\pi }^{+}{\pi }^{+}{\pi }^{-}$. The analysis also results in a small improvement in the knowledge of other $D$-meson parameters, in particular, the strong-phase difference for $D^0\to K^{-}{\pi }^{+}$, ${\delta }_D^{K\pi }$, and the mixing parameter $y$.

We report on a search for gravitational waves from coalescing compact binaries, of total mass between 2 and $35M_{\odot }$, using LIGO observations between November 14, 2006 and May 18, 2007. No gravitational-wave signals were detected. We report upper limits on the rate of compact binary coalescence as a function of total mass. The LIGO cumulative 90%-confidence rate upper limits of the binary coalescence of neutron stars, black holes and black hole-neutron star systems are $1.4\times {10}^{-2}$, $7.3\times {10}^{-4}$ and $3.6\times {10}^{-3}{\mathrm{yr}}^{-1}{\mathrm{L}}_{10}^{-1}$, respectively, where ${\mathrm{L}}_{10}$ is ${10}^{10}$ times the blue solar luminosity.

We derive actions for projective $N=2$ superspace (“hyperspace”) from those for harmonic hyperspace, including that for non-Abelian Yang-Mills theory (a new result). The method uses Wick rotation of the sphere from complex conjugate coordinates to real, null ones, which can be treated as independent. The result can be considered “holographic” in that the dimension of the internal ($R$ symmetry) space is reduced from 2 to 1, by solving equations of motion or gauge conditions for dependence on the other coordinate. The auxiliary nature of the redundant dimension makes the hypergraph rules and evaluation almost identical.

The Einstein static universe has played a central role in a number of emergent scenarios recently put forward to deal with the singular origin of the standard cosmological model. Here we study the existence and stability of the Einstein static solution in the presence of vacuum energy corresponding to conformally invariant fields. We show that the presence of vacuum energy stabilizes this solution by changing it to a center equilibrium point, which is cyclically stable. This allows nonsingular emergent cosmological models to be constructed in which initially the Universe oscillates indefinitely about an initial Einstein static solution and is thus past eternal.

We compute the tree-level connected four-point function of the primordial curvature perturbation for a fairly general minimally coupled single field inflationary model, where the inflaton’s Lagrangian is a general function of the scalar field and its first derivatives. This model includes K inflation and DBI inflation as particular cases. We show that, at the leading order in the slow-roll expansion and in the small sound speed limit, there are two important tree-level diagrams for the trispectrum. One is a diagram where a scalar mode is exchanged and the other is a diagram where the interaction occurs at a point, i.e. a contact interaction diagram. The scalar exchange contribution is comparable to the contact interaction contribution. For the DBI-inflation model, in the so-called equilateral configuration, the scalar exchange trispectrum is maximized when the angles between the four momentum vectors are equal and in this case the amplitude of the trispectrum from the scalar exchange is 1 order of magnitude higher than the contact interaction trispectrum.

The generalized Gauss-Bonnet theory, introduced by Lagrangian $F(R,G)$, has been considered as a general modified gravity for explanation of the dark energy. $G$ is the Gauss-Bonnet invariant. For this model, we seek the situations under which the late-time behavior of the theory is the de Sitter space-time. This is done by studying the two-dimensional phase space of this theory, i.e. the $R\mathrm{\text{−}}H$ plane. By obtaining the conditions under which the de Sitter space-time is the stable attractor of this theory, several aspects of this problem have been investigated. It has been shown that there exist at least two classes of stable attractors: the singularities of the $F(R,G)$, and the cases in which the model has a critical curve, instead of critical points. This curve is $R=12H^2$ in $R\mathrm{\text{−}}H$ plane. Several examples, including their numerical calculations, have been discussed.

We predict the acceleration of the Local Group generated by the 2MASS Redshift Survey within the framework of $\Lambda$ cold dark matter and the halo model of galaxies. We show that as the galaxy fluctuations derived from the halo model have more power on small scales compared with the mass fluctuations, the misalignment angle between the CMB velocity vector and the 2MASS Redshift Survey dipole is in reasonable agreement with the observed 21°. This statistical analysis suggests that it is not necessary to invoke a hypothetical nearby galaxy or a distant cluster to explain this misalignment.