Annihilating dark matter particles produce roughly as much power in electrons and positrons as in gamma ray photons. The charged particles lose essentially all of their energy to inverse Compton and synchrotron processes in the galactic environment. We discuss the diffuse signature of dark matter annihilations in satellites of the Milky Way (which may be optically dark with few or no stars), providing a tail of emission trailing the satellite in its orbit. Inverse Compton processes provide x rays and gamma rays, and synchrotron emission at radio wavelengths might be seen. We discuss the possibility of detecting these signals with current and future observations, in particular EGRET and GLAST for the gamma rays.

The acceleration of the expansion of the universe arises from unknown physical processes involving either new fields in high energy physics or modifications of gravitation theory. It is crucial for our understanding to characterize the properties of the dark energy or gravity through cosmological observations and compare and distinguish between them. In fact, close consistencies exist between a dark energy equation of state function $w\left(z\right)\mathrm{}$ and changes to the framework of the Friedmann cosmological equations as well as direct spacetime geometry quantities involving the acceleration, such as “geometric dark energy” from the Ricci scalar. We investigate these interrelationships, including for the case of superacceleration or phantom energy where the fate of the universe may be more gentle than the Big Rip.

Resonant annihilation of extremely high-energy cosmic neutrinos on big-bang relic anti-neutrinos (and vice versa) into Z bosons leads to sizable absorption dips in the neutrino flux to be observed at Earth. The high-energy edges of these dips are fixed, via the resonance energies, by the neutrino masses alone. Their depths are determined by the cosmic neutrino background density, by the cosmological parameters determining the expansion rate of the Universe, and by the large redshift history of the cosmic neutrino sources. We investigate the possibility of determining the existence of the cosmic neutrino background within the next decade from a measurement of these absorption dips in the neutrino flux. As a by-product, we study the prospects to infer the absolute neutrino mass scale. We find that, with the presently planned neutrino detectors (ANITA, Auger, EUSO, OWL, RICE, and SalSA) operating in the relevant energy regime above ${10}^{21}\mathrm{eV},$ relic neutrino absorption spectroscopy becomes a realistic possibility. It requires, however, the existence of extremely powerful neutrino sources, which should be opaque to nucleons and high-energy photons to evade present constraints. Furthermore, the neutrino mass spectrum must be quasidegenerate to optimize the dip, which implies $m_{\nu }\gtrsim 0.1\mathrm{eV}$ for the lightest neutrino. With a second generation of neutrino detectors, these demanding requirements can be relaxed considerably.

A comprehensive analysis of the Symanzik improved anisotropic three-dimensional $U\left(1\right)\mathrm{}$ lattice gauge theory in the Hamiltonian limit is made. Monte Carlo techniques are used to obtain numerical results for the static potential, ratio of the renormalized and bare anisotropies, the string tension, lowest glueball masses and the mass ratio. Evidence that rotational symmetry is established more accurately for the Symanzik improved anisotropic action is presented. The discretization errors in the static potential and the renormalization of the bare anisotropy are found to be only a few percent compared to errors of about 20–25 % for the unimproved gauge action. Evidence of scaling in the string tension, antisymmetric mass gap and the mass ratio is observed in the weak coupling region and the behavior is tested against analytic and numerical results obtained in various other Hamiltonian studies of the theory. We find that more accurate determination of the scaling coefficients of the string tension and the antisymmetric mass gap has been achieved, and the agreement with various other Hamiltonian studies of the theory is excellent. The improved action is found to give faster convergence to the continuum limit. Very clear evidence is obtained that in the continuum limit the glueball ratio $M_S{/M}_A$ approaches exactly 2, as expected in a theory of free, massive bosons.

Low-energy results from measurements of leptonic dipole moments are used to derive constraints on the CP-violating phases of the dimensionful parameters of the minimal supersymmetric extension of the standard model (MSSM). We use these (known) bounds to investigate the impact of these phases on CP-even cross sections at high-energy $e^{+}{e}^{-}$ and $e^{-}{e}^{-}$ colliders. To that end we define two measures of the significance with which the existence of nonvanishing phases could be deduced from the measurements of these cross sections. We find that highly significant evidence for deviations from the CP-conserving MSSM could be obtained at the next $e^{+}{e}^{-}$ collider even if the electric dipole moment of the electron is very small or zero. We also analyze a CP-odd final-state polarization, which can be large when two different charginos or neutralinos are produced. Finally, we study correlations between the phase-sensitive observables.  

The MNS matrix structure emerging as a result of recent neutrino measurements strongly suggests two large mixing angles (solar and atmospheric) and one small angle $(|U_{e3\mathrm{}}|\ll 1).$ Especially when combined with the neutrino mass hierarchy, these values turn out to impose rather stringent constraints on possible flavor models connecting the three active fermion generations. Specifically, we show that an extremely small value of $|U_{e3\mathrm{}}|$ would require fine-tuning of Majorana mass matrix parameters, particularly in the context of seesaw models.

We calculate the power spectrum, spectral index, and running spectral index for the RS-II brane inflation in the high-energy regime using the slow-roll expansion. There exist several modifications. As an example, we take the power-law inflation by choosing an inverse power-law potential. When comparing these with those arisen in the standard inflation, we find that the power spectrum is enhanced and the spectral index is suppressed, while the running spectral index becomes zero as in the standard inflation. However, since second-order corrections are rather small, these could not play a role of distinguishing between standard and brane inflations.

The exact bosonic Neumann matrices of the cubic vertex in plane-wave light-cone string field theory are derived using the contour integration techniques developed in our earlier paper. This simplifies the original derivation of the vertex. In particular, the Neumann matrices are written in terms of μ-deformed Gamma-functions, thus casting them into a form that elegantly generalizes the well-known flat-space solution. The asymptotics of the μ-deformed Gamma-functions allow one to determine the large-μ behavior of the Neumann matrices including exponential corrections. We provide an explicit expression for the first exponential correction and make a conjecture for the subsequent exponential correction terms.

An analysis is carried out within mSUGRA of the estimated number of events originating from upward moving ultrahigh energy neutralinos passing through Earth’s crust that could be detected by the Extreme Universe Space Observatory (EUSO). The analysis exploits a recently proposed technique that differentiates ultrahigh energy neutralinos from ultrahigh energy neutrinos using their different absorption lengths in the Earth’s crust. It is shown that for the part of the parameter space, where the neutralino is mostly a B-ino and with squark mass $\sim 1\mathrm{TeV},$ EUSO could see ultrahigh energy neutralino events within mSUGRA models with essentially no background. In the energy range ${10}^9\mathrm{GeV}<E_{\tilde{\chi }}<{10}^{11}\mathrm{GeV}$ the unprecedented aperture of EUSO makes the telescope sensitive, after 3 yr of observation, to neutralino fluxes as low as $d\Phi {/dE}_{\tilde{\chi }}>1.1\mathrm{}\times {10}^{-6}{(E}_{\tilde{\chi }}/\mathrm{GeV}{)}^{-1.3}{\mathrm{GeV}}^{-1}{\mathrm{cm}}^{-2}{\mathrm{yr}}^{-1}{\mathrm{sr}}^{-1},$ at the 95% confidence limit (CL). Such a hard spectrum is characteristic of supermassive particles’ N-body hadronic decay. The case in which the flux of ultrahigh energy neutralinos is produced via decay of metastable heavy ${(m}_X=2\mathrm{}\times {10}^{12}\mathrm{GeV})$ particles with uniform distribution throughout the Universe, and primary decay mode into 5 quarks + 5 squarks, is analyzed in detail. The normalization of the ratio of the relics’ density to their lifetime has been fixed so that the baryon flux produced in the supermassive particle decays contributes to about 1/3 of the events reported by the AGASA Collaboration below ${10}^{11}\mathrm{GeV},$ and hence the associated GeV $\gamma$-ray flux is in complete agreement with EGRET data. For this particular case, EUSO will collect between 4 and 5 neutralino events (with 0.3 of background) in $\approx 3\mathrm{yr}$ of running. NASA’s planned mission, the Orbiting Wide-angle Light-collectors (OWL), is also briefly discussed in this context.

Building on our previous results (Ref. [4]), we study D-brane and string prototypes in weakly coupled (3+1)-dimensional supersymmetric field theory engineered to support (2+1)-dimensional domain walls, “non-Abelian” strings and various junctions. Our main but not exclusive task is the study of localization of non-Abelian gauge fields on the walls. The model we work with is $\mathcal{N}=2\mathrm{}$ QCD, with the gauge group $\mathrm{SU}\mathrm{}\left(2\right)\mathrm{}\times \mathrm{U}\mathrm{}\left(1\right)\mathrm{}$ and $N_f=4\mathrm{}$ flavors of fundamental hypermultiplets (referred to as quarks), perturbed by the Fayet-Iliopoulos term of the U(1) factor. In the limit of large but almost equal quark mass terms a set of vacua exists in which this theory is at weak coupling. We focus on these vacua (called the quark vacua). We study elementary BPS domain walls interpolating between selected quark vacua, as well as their bound state, a composite wall. The composite wall is demonstrated to localize a non-Abelian gauge field on its world sheet. Next, we turn to the analysis of recently proposed “non-Abelian” strings (flux tubes) which carry orientational moduli corresponding to rotations of the “color-magnetic” flux direction inside a global O(3). We find a 1/4-BPS solution for the string ending on the composite domain wall. The end point of this string is shown to play the role of a non-Abelian (dual) charge in the effective world volume theory of non-Abelian (2+1)-dimensional vector fields confined to the wall.

We analyze the Carroll-Field-Jackiw (CFJ) modification of electrodynamics reformulated as the ordinary Maxwell theory with an additional special axion field. In this form, the CFJ model appears as a special case of the premetric approach recently developed by Hehl and Obukhov. This embedding turns out to be nontrivial. Particularly, the premetric energy-momentum tensor does not depend on the axion. This is in contrast to the CFJ energy-momentum tensor which involves the axion addition explicitly. We show that the relation between these two quantities is similar to the correspondence between the Noether conserved tensor and the Hilbert symmetric tensor. As a result the CFJ energy-momentum tensor appears as the unique conserved closure of the premetric one. Another problem is in the description of the birefringence effect, which in the premetric framework does not depend on the axion. The comparison with the CFJ model shows that the corresponding wave propagation (Fresnel) equation has to be extended by a derivative term, which is nonzero for the axion field. In this way, the CFJ birefringence effect is derived in the metric-free approach. Consequently the Lorentz and CPT violating models can be embedded without contradictions in the premetric approach to electrodynamics. This correspondence can be useful for both constructions.

We analyze the uncertainties involved in obtaining the injection spectra of UHECR particles in the top-down scenario of their origin. We show that the Dokshizer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) $Q^2$ evolution of fragmentation functions (FF) to ${Q=M}_X$ (mass of the X particle) from their initial values at low Q is subject to considerable uncertainties. We therefore argue that, for $x\lesssim 0.1$ (the x region of interest for most large $M_X$ values of interest, $x\equiv {2E/M}_X$ being the scaled energy variable), the FF obtained from the DGLAP evolution is no more reliable than that provided, for example, by a simple Gaussian form [in the variable $\ln \mathrm{}(1/x)\mathrm{}]$ obtained under the coherent branching approach to a parton shower development process to lowest order in perturbative QCD. Additionally, we find that for $x\gtrsim 0.1,$ the evolution in $Q^2$ of the singlet FF, which determines the injection spectrum, is “minimal”—the singlet FF changes by barely a factor of 2 after evolving it over $\sim 14$ orders of magnitude in $Q\sim M_X.$ We therefore argue that as long as the measurement of the UHECR spectrum above $\sim {10}^{20}\mathrm{eV}$ is going to remain uncertain by a factor of 2 or larger, it is good enough for most practical purposes to directly use any one of the available initial parametrizations of the FFs in the x region $x\gtrsim 0.1$ based on low energy data, without evolving them to the requisite $Q^2$ value.

We devise a method to obtain a phantom version of FRW k-essence cosmologies with homogeneous k fields by applying form-invariance transformations. It can be seen that the transformation performs the maps $\overrightarrow{H}-H$ and $\rho +\overrightarrow{p}-(\rho +p),$ which in turn give $\overrightarrow{\gamma }-\gamma$ and $\overrightarrow{a}{a}^{-1}.$ The discussion is presented in a general setup, valid for FRW k-essence cosmologies, and then we discuss power-law solutions for illustration purposes. First, we deal with models such that the gradient of the k field is not constant, and they include standard and generalized tachyon cosmologies. We concentrate on the usual tachyon and show that the phantom symmetry involves a change in the potential: and that it generates an extended superaccelerated tachyon field. Then, we turn our attention to models for which the time derivative of the k field is not constant, and we show the transformation can be implemented without changing the potential at all.

The free-electron population during the reionized epoch rescatters the cosmic microwave background (CMB) temperature quadrupole and generates a now well-known polarization signal at large angular scales. While this contribution has been detected in the temperature-polarization cross power spectrum measured with Wilkinson Microwave Anisotropy Probe data, due to the large cosmic variance associated with anisotropy measurements at angular scales of tens of degrees only limited information related to reionization, such as the optical depth to electron scattering, can be extracted. The inhomogeneities in the free-electron population lead to an additional secondary polarization anisotropy contribution at arcminute scales. While the fluctuation amplitude, relative to dominant primordial fluctuations, is small, we suggest that a cross correlation between the arcminute scale CMB polarization data and a tracer field of the high redshift universe, such as through fluctuations captured by the 21 cm neutral hydrogen background or those in the infrared background related to the first protogalaxies, may allow one to study additional details related to reionization. For this purpose, we discuss an optimized higher order correlation measurement, in the form of a three-point function, including information from large angular scale CMB temperature anisotropies in addition to the arcminute scale polarization signal related to inhomogeneous reionization. We suggest that the proposed bispectrum can be measured with a substantial signal-to-noise ratio and does not require all-sky maps of CMB polarization or that of the tracer field. A measurement such as the one proposed may allow one to establish the epoch when CMB polarization related to reionization is generated and to address the question whether the universe was reionized once or twice.

In this paper, we study a type of one-field model for open inflationary universe models in the context of brane world models. In the scenario of a one-bubble universe model, we determine and characterize the existence of the Coleman–De Lucia instanton, together with the period of inflation after tunneling has occurred. Our results are compared to those found in the Einstein theory of relativistic models.

A Monte Carlo calculation of the atmospheric neutrino fluxes [Barr et al., Phys. Rev. D 39, 3532 (1989); Agrawal et al., ibid. 53, 1314 (1996)] has been extended to take account of the three-dimensional (3D) nature of the problem, including the bending of secondary particles in the geomagnetic field. Emphasis has been placed on minimizing the approximations when introducing the 3D considerations. In this paper, we describe the techniques used and quantify the effects of the small approximations which remain. We compare 3D and 1D calculations using the same physics input in order to evaluate the conditions under which the 3D calculation is required and when the considerably simpler 1D calculation is adequate. We find that the 1D and 3D results are essentially identical for $E_{\nu }>5\mathrm{}\mathrm{GeV}$ except for small effects in the azimuthal distributions due to bending of the secondary muon by the geomagnetic field during their propagation in the atmosphere.

I present results for the two-loop self-energy functions for scalars in a general renormalizable field theory, using mass-independent renormalization schemes based on dimensional regularization and dimensional reduction. The results are given in terms of a minimal set of loop-integral basis functions, which are readily evaluated numerically by computers. This paper contains the contributions corresponding to the Feynman diagrams with zero or one vector propagator lines. These are the ones needed to obtain the pole masses of the neutral and charged Higgs scalar bosons in supersymmetry, neglecting only the purely electroweak parts at two-loop order. A subsequent paper will present the results for the remaining diagrams, which involve two or more vector lines. I also include an illustrative example, featuring several nontrivial consistency checks.

The coupling of a neutral hybrid $\{1,3,5\dots {\}}^{-+}$ exotic particle (or current) to two neutral (hybrid) meson particles with the same $J^{\mathrm{PC}}$ and $J=0\mathrm{}$ is proved to be sub-leading to the usual large-$N_c$ QCD counting. The coupling of the same exotic particle to certain two (hybrid) meson currents with the same $J^{\mathrm{PC}}$ and $J=0\mathrm{}$ is also sub-leading. The decay of a $\{1,3,5\dots {\}}^{-+}$ hybrid particle to $\eta {\pi }^0,{\eta }^{\prime }{\pi }^0,{\eta }^{\prime }\eta ,\eta \mathrm{}\left(1295\right)\mathrm{}{\pi }^0,$ $\pi {\mathrm{}\left(1300\right)\mathrm{}}^0{\pi }^0,\eta \mathrm{}\left(1440\right)\mathrm{}{\pi }^0,a_0{\mathrm{}\left(980\right)\mathrm{}}^0\sigma$ or $f_0\mathrm{}\left(980\right)\mathrm{}\sigma$ is sub-leading, assuming that these final state particles are (hybrid) mesons in the limit of large $N_c.$

We examine the phenomenology of a warped 5-dimensional model based on the $\mathrm{SU}{\mathrm{}\left(2\right)\mathrm{}}_L\times \mathrm{SU}{\mathrm{}\left(2\right)\mathrm{}}_R\times \mathrm{U}{\mathrm{}\left(1\right)\mathrm{}}_{B-L}$ model which implements electroweak symmetry breaking through boundary conditions, without the presence of a Higgs boson. We use precision electroweak data to constrain the general parameter space of this model. Our analysis includes independent L and R gauge couplings, radiatively induced UV boundary gauge kinetic terms, and all higher order corrections from the curvature of the 5D space. We show that this setup can be brought into good agreement with the precision electroweak data for typical values of the parameters. However, we find that the entire range of model parameters leads to violation of perturbative unitarity in gauge boson scattering and hence this model is not a reliable perturbative framework. Assuming that unitarity can be restored in a modified version of this scenario, we consider the collider signatures. It is found that new spin-1 states will be observed at the CERN Large Hadron Collider and measurement of their properties would identify this model. However, the spin-2 graviton Kaluza-Klein resonances, which are a hallmark of the Randall-Sundrum model, are too weakly coupled to be detected.