The Wilkinson Microwave Anisotropy Probe (WMAP) experiment has revealed an excess of microwave emission from the region around the center of our Galaxy. It has been suggested that this signal, known as the “WMAP haze,” could be synchrotron emission from relativistic electrons and positrons generated in dark matter annihilations. In this article, we revisit this possibility. We find that the angular distribution of the WMAP haze matches the prediction for dark matter annihilations with a cusped density profile, $\rho (r)\propto r^{-1.2}$ in the inner kiloparsecs. Comparing the intensity in different WMAP frequency bands, we find that a wide range of possible weakly interacting massive particle (WIMP) annihilation modes are consistent with the spectrum of the haze for a WIMP with a mass in the 100 GeV to multi-TeV range. Most interestingly, we find that to generate the observed intensity of the haze, the dark matter annihilation cross section is required to be approximately equal to the value needed for a thermal relic, $\sigma v\sim 3\times {10}^{-26}{\mathrm{cm}}^3/\mathrm{s}$. No boost factors are required. If dark matter annihilations are in fact responsible for the WMAP haze, and the slope of the halo profile continues into the inner Galaxy, GLAST is expected to detect gamma rays from the dark matter annihilations in the galactic center if the WIMP mass is less than several hundred GeV.

We searched for an anisotropic background of gravitational waves using data from the LIGO S4 science run and a method that is optimized for point sources. This is appropriate if, for example, the gravitational wave background is dominated by a small number of distinct astrophysical sources. No signal was seen. Upper limit maps were produced assuming two different power laws for the source strain power spectrum. For an $f^{-3}$ power law and using the 50 Hz to 1.8 kHz band the upper limits on the source strain power spectrum vary between $1.2\times {10}^{-48}{\mathrm{Hz}}^{-1}$ $(100\mathrm{Hz}/f{)}^3$ and $1.2\times {10}^{-47}{\mathrm{Hz}}^{-1}$ $(100\mathrm{Hz}/f{)}^3$, depending on the position in the sky. Similarly, in the case of constant strain power spectrum, the upper limits vary between $8.5\times {10}^{-49}{\mathrm{Hz}}^{-1}$ and $6.1\times {10}^{-48}{\mathrm{Hz}}^{-1}$. As a side product a limit on an isotropic background of gravitational waves was also obtained. All limits are at the 90% confidence level. Finally, as an application, we focused on the direction of Sco-X1, the brightest low-mass x-ray binary. We compare the upper limit on strain amplitude obtained by this method to expectations based on the x-ray flux from Sco-X1.

to turducken (turduckens, turduckening, turduckened, turduckened) [math.]: To stuff a black hole. We analyze and apply an alternative to black hole excision based on smoothing the interior of black holes with arbitrary initial data, and solving the vacuum Einstein evolution equations everywhere. By deriving the constraint propagation system for our hyperbolic formulation of the BSSN evolution system we rigorously prove that the constraints propagate causally and so any constraint violations introduced inside the black holes cannot affect the exterior spacetime. We present evolutions of Cook-Pfeiffer binary black hole initial configurations showing that these techniques appear to work robustly for generic data. We also present evidence from spherically symmetric evolutions that for the gauge conditions used the same stationary end-state is approached irrespective of the choice of initial data and smoothing procedure.

We introduce a simple general method for finding the equilibrium distribution for a class of widely used inexact Markov chain Monte Carlo algorithms. The explicit error due to the noncommutativity of the updating operators when numerically integrating Hamilton’s equations can be derived using the Baker-Campbell-Hausdorff formula. This error is manifest in the conservation of a shadow Hamiltonian that lies close to the desired Hamiltonian. The fixed point distribution of inexact hybrid algorithms may then be derived taking into account that the fixed point of the momentum heat bath and that of the molecular dynamics do not coincide exactly. We perform this derivation for various inexact algorithms used for lattice QCD calculations.

We calculate the volume dependence of the ground-state energy of $n$ identical bosons with short-range repulsive (or weakly attractive) interactions in a periodic spatial volume of side $L$, up to and including terms of order $L^{-6}$. With this result, Lattice-QCD calculations of the ground-state energies of three or more pions will allow for a systematic extraction of the three-pion interaction at this order in the volume expansion.

We present a method to nonperturbatively determine the parameters of the on-shell, $O(a)$-improved relativistic heavy quark action. These three parameters, $m_0$, $\zeta$, and $c_B=c_E$, are obtained by matching finite-volume, heavy-heavy, and heavy-light meson masses to the exact relativistic spectrum through a finite-volume, step-scaling recursion procedure. We demonstrate that accuracy on the level of a few percent can be achieved by carrying out this matching on a pair of lattices with equal physical spatial volumes but quite different lattice spacings. A fine lattice with inverse lattice spacing $1/a=5.4\mathrm{GeV}$ and ${24}^3\times 48$ sites and a coarse, $1/a=3.6\mathrm{GeV}$, ${16}^3\times 32$ lattice are used together with a heavy quark mass $m$ approximately that of the charm quark. This approach is unable to determine the initially expected, four heavy quark parameters: $m_0$, $\zeta$, $c_B$, and $c_E$. This apparent nonuniqueness of these four parameters motivated the analytic result, presented in a companion paper, that this set is redundant and that the restriction $c_E=c_B$ is permitted through order $a|\overrightarrow{p}|$ and to all orders in $ma$ where $\overrightarrow{p}$ is the heavy quark’s spatial momenta.

We study the fermion action needed to accurately describe the low energy physics of systems including heavy quarks in lattice QCD even when the heavy fermion mass $m$ is on the order of, or larger than, the inverse lattice spacing: $m\ge 1/a$. We carry out an expansion through first order in $|\overrightarrow{p}|a$ (where $\overrightarrow{p}$ is the heavy quark momentum) and all orders in $ma$, refining the analysis of the Fermilab and Tsukuba groups. We demonstrate that the spectrum of heavy quark bound states can be determined accurately through $|\overrightarrow{p}|a$ and $(ma{)}^n$ for arbitrary exponent $n$ by using a lattice action containing only three unknown coefficients: $m_0$, $\zeta$, and $c_P$ (a generalization of $c_{SW}$), which are functions of $ma$. In a companion paper, we show how these three coefficients can be precisely determined using nonperturbative techniques.

The cross section for high-$E_T$ dijet production in photoproduction has been measured with the ZEUS detector at HERA using an integrated luminosity of $81.8{\mathrm{pb}}^{-1}$. The events were required to have a virtuality of the incoming photon, $Q^2$, of less than $1{\mathrm{GeV}}^2$ and a photon-proton center-of-mass energy in the range $142<W_{\gamma p}<293\mathrm{GeV}$. Events were selected if at least two jets satisfied the transverse-energy requirements of $E_T^{\mathrm{jet}1}>20\mathrm{GeV}$ and $E_T^{\mathrm{jet}2}>15\mathrm{GeV}$ and pseudorapidity (with respect to the proton beam direction) requirements of $-1<{\eta }^{\mathrm{jet}1,2}<3$, with at least one of the jets satisfying $-1<{\eta }^{\mathrm{jet}}<2.5$. The measurements show sensitivity to the parton distributions in the photon and proton and to effects beyond next-to-leading order in QCD. Hence these data can be used to constrain further the parton densities in the proton and photon.

We investigate whether the hypercharge assignments in the standard model can be interpreted as a hint at grand unification in the context of heterotic string theory. Our analysis is a follow-up to the recent mini-landscape analysis of the ${\mathbb{Z}}_6$-II orbifold of the ${\mathrm{E}}_8\times {\mathrm{E}}_8^{\prime }$ heterotic string. In that analysis, an intermediate grand unified theory (GUT) was a requirement for finding MSSM-like theories. Nevertheless, about 1% of the models in this mini-landscape were MSSM-like. In this paper we remove this GUT restriction. To this end, we introduce a general method to calculate $\mathrm{U}(1{)}_Y$ for any heterotic orbifold and compare our findings to the cases where hypercharge arises from a GUT. Surprisingly, in the overwhelming majority of 3-2 standard models, a nonanomalous hypercharge direction can be defined, for which the spectrum is vectorlike. For these models, we calculate ${sin}^2{\theta }_w$ to see how well it agrees with the standard GUT value. We find that 12% have ${sin}^2{\theta }_w=3/8$, while all others have values which are less. Finally, 89% of the models with ${sin}^2{\theta }_w=3/8$ have $\mathrm{U}(1{)}_Y\subset \mathrm{SU}(5)$.

We numerically construct black hole solutions corresponding to the deconfined, chirally symmetric phase of strongly coupled cascading gauge theories at various temperatures. We compute the free energy as a function of the temperature, and we show that it becomes positive below some critical temperature, indicating the possibility of a first order phase transition at which the theory deconfines and restores the chiral symmetry.

We study representations of the Schrödinger algebra in terms of operators in nonrelativistic conformal field theories. We prove a correspondence between primary operators and eigenstates of few-body systems in a harmonic potential. Using the correspondence we compute analytically the energy of fermions at unitarity in a harmonic potential near two and four spatial dimensions. We also compute the energy of anyons in a harmonic potential near the bosonic and fermionic limits.

Dark matter candidates and proton decay in a class of models based on the AdS/CFT correspondence are discussed. We show that the present bound on the proton decay lifetime is inconsistent with $\mathcal{N}=1$ supersymmetry, and strongly constrains $\mathcal{N}=0$ nonsupersymmetry, low scale trinification-type unification of orbifolded $\mathrm{AdS}\otimes S^5$ models.

There exist many observational evidences implying the expansion of our Universe is undergoing a late-time acceleration; the mechanism of this acceleration is yet unknown. In the so-called thick brane model this phenomena is attributed to the thickness of the brane along the extra dimension. In this study we mainly rely on the consistency of this model with most recent observational data related to the background evolution. The new Supernova Type Ia (SNIa) Gold sample and Supernova Legacy Survey (SNLS) data, the position of the acoustic peak at the last scattering surface from the Wilkinson Microwave Anisotropy Probe (WMAP) observations and the baryon acoustic oscillation peak found in the Sloan Digital Sky Survey (SDSS) are used to constrain the free parameter of the thick codimension 1 brane model. To infer its consistency with the age of our Universe, we compare the age of old cosmological objects with what computed using the best-fit values for the model parameters. When the Universe is matter dominated, $w=0$, at 68% level of confidence, the combination of the Gold sample SNIa, cosmic microwave background (CMB) shift parameter and SDSS databases provide ${\Omega }_m={0.31}_{-0.02}^{+0.02}$, ${\Omega }_{\mathcal{C}}={0.05}_{-0.01}^{+0.01}$, $w_r=-{1.40}_{-0.20}^{+0.20}$, hence a spatially open universe with ${\Omega }_k={0.21}_{-0.08}^{+0.08}$. The same combination with the SNLS supernova observation gives ${\Omega }_m={0.28}_{-0.02}^{+0.03}$, ${\Omega }_{\mathcal{C}}={0.037}_{-0.004}^{+0.003}$, $w_r=-{2.05}_{-0.15}^{+0.15}$ consequently provides a spatially open universe ${\Omega }_k={0.11}_{-0.07}^{+0.10}$. These results obviously seem to be in contradiction with the most recent WMAP results indicating a flat universe.

We present a new formalism, together with efficient numerical methods, to directly calculate the cosmic microwave background (CMB) bispectrum today from a given primordial bispectrum using the full linear radiation transfer functions. Unlike previous analyses which have assumed simple separable Ansätze for the bispectrum, this work applies to a primordial bispectrum of almost arbitrary functional form, for which there may have been both horizon-crossing and superhorizon contributions. We employ adaptive methods on a hierarchical triangular grid and we establish their accuracy by direct comparison with an exact analytic solution, valid on large angular scales. We demonstrate that we can calculate the full CMB bispectrum to greater than 1% precision out to multipoles $l<1800$ on reasonable computational time scales. We plot the bispectrum for both the superhorizon (“local”) and horizon-crossing (“equilateral”) asymptotic limits, illustrating its oscillatory nature which is analogous to the CMB power spectrum.

The study of the anisotropy of the arrival directions is an essential tool to investigate the origin and propagation of cosmic ray primaries. A simple way of recording many cosmic rays is to record coincidences between a number of detectors. We have monitored multi-TeV cosmic rays by a small array of water Cherenkov detectors in Tehran ($35°{43}^{\prime }\mathrm{N}$, $51°{20}^{\prime }\mathrm{E}$, 1200 m above sea level). More than $1.1\times {10}^6$ extensive air shower events were recorded. In addition to the Compton-Getting effect due to the motion of the Earth in the Galaxy, an anisotropy has been observed which is due to a unidirectional anisotropy of cosmic ray flow along the Galactic arms.

We study the two-body decay of a polarized neutralino, ${\tilde{\chi }}_i^0(\widehat{n})\to {\tilde{\chi }}_j^0+Z$. It is shown that the decay mode provides a probe of Majorana nature and spin information of the neutralinos.

In the framework of the instanton vacuum model we make expansion over the current mass $m$ and number of colors $N_c$ and evaluate $\mathcal{O}(1/N_c,m,m/N_c,m\ln m/N_c)$ corrections to the dynamical quark mass $M$, the quark condensate $⟨\overline{q}q⟩$, the pion mass $M_{\pi }$, and decay constant $F_{\pi }$. There are several sources of these corrections: meson loops, finite size of the instanton distribution, and the quark-quark “tensor” interaction terms. In contrast to the expectations, we found that numerically the $1/N_c$ corrections to dynamical mass are large and mostly come from meson loops. As a consequence, we have large $1/N_c$ corrections to all the other quantities. To provide the values of $F_{\pi }(m=0)$, $⟨\overline{q}q(m=0)⟩$ in agreement with $\chi \mathrm{PT}$, we offer a new set of parameters $\rho$, $R$. Finally, we find the low-energy $SU(2{)}_f$ chiral Lagrangian constants ${\overline{l}}_3,{\overline{l}}_4$ in a rather good correspondence with the phenomenology.

In the light of the LHC, we revisit the implications of a fourth generation of chiral matter. We identify a specific ensemble of particle masses and mixings that are in agreement with all current experimental bounds as well as minimize the contributions to electroweak precision observables. Higgs masses between 115–315 (115–750) GeV are allowed by electroweak precision data at the 68% and 95% C.L. Within this parameter space, there are dramatic effects on Higgs phenomenology: production rates are enhanced, weak-boson-fusion channels are suppressed, angular distributions are modified, and Higgs pairs can be observed. We also identify exotic signals, such as Higgs decay to same-sign dileptons. Finally, we estimate the upper bound on the cutoff scale from vacuum stability and triviality.

An analytical relationship between the statistical significance of an observed signal and the signal width in the case of a large background was obtained. It can help to explain why high-energy experiments may have different conclusions on the existence of new particles. We illustrate our approach using the experimental data on searches for the ${\Theta }^{+}(1530)$ pentaquark state. The obtained relationship is also useful for planning of future experiments designed to search for signals of new particles in invariant-mass distributions.

The generation of the fermion mass hierarchy in the standard model of particle physics is a long-standing puzzle. The recent discoveries from neutrino physics suggest that the mixing in the lepton sector is large compared to the quark mixings. To understand this asymmetry between the quark and lepton mixings is an important aim for particle physics. In this regard, two promising approaches from the theoretical side are grand unified theories and family symmetries. In this paper we try to understand certain general features of grand unified theories with Abelian family symmetries by taking the simplest $SU(5)$ grand unified theory as a prototype. We construct an $SU(5)$ toy model with $U(1{)}_F\otimes {\mathbb{Z}}_2^{\prime }\otimes {\mathbb{Z}}_2^{\prime \prime }\otimes {\mathbb{Z}}_2^{\prime \prime \prime }$ family symmetry that, in a natural way, duplicates the observed mass hierarchy and mixing matrices to lowest approximation. The system for generating the mass hierarchy is through a Froggatt-Nielsen type mechanism. One idea that we use in the model is that the quark and charged lepton sectors are hierarchical with small mixing angles while the light neutrino sector is democratic with larger mixing angles. We also discuss some of the difficulties in incorporating finer details into the model without making further assumptions or adding a large scalar sector.