We describe a class of observational strategies for probing the anisotropies in the cosmic microwave background (CMB) where the instrument scans on rings which can be combined into an n-torus, the ring torus. This class has the remarkable property that it allows an exact maximum likelihood power spectrum estimation in operations of order $N^2$ (if the size of the data set is $N)$ under circumstances which would previously have made this analysis intractable: correlated receiver noise, arbitrary asymmetric beam shapes and far side lobes, nonuniform distribution of integration time on the sky, and partial sky coverage. This ease of computation gives us an important theoretical tool for understanding the impact of instrumental effects on CMB observables and hence for the design and analysis of CMB observations in the future. There are members of this class which closely approximate the MAP and Planck satellite missions. We present a numerical example where we apply our ring torus methods to a simulated data set from a CMB mission covering a $20°$ patch on the sky to compute the maximum likelihood estimate of the power spectrum $C_{\mathcal{l}}$ with unprecedented efficiency.

We study the loop-induced process $e^{+}{e}^{-}\to W^{+}{H}^{-}$ in the minimal supersymmetric standard model (MSSM). This process allows the charged Higgs boson to be produced in $e^{+}{e}^{-}$ collisions when $e^{+}{e}^{-}\to H^{+}{H}^{-}$ is kinematically forbidden due to a large charged Higgs boson mass. We scan over the MSSM parameters subject to experimental constraints to examine the range of values the cross section can take. We find that large enhancements of the cross section over that in a nonsupersymmetric two Higgs doublet model are possible, especially for large $\tan \beta$ and light top and bottom squarks. Choosing a few typical MSSM parameter sets, we show the regions in the $m_{H^{\pm }}–\tan \beta$ plane in which at least $10W^{\pm }{H}^{\mp }$ events would be produced at the $e^{+}{e}^{-}$ collider.

The recent developments in theory and experiment related to the anomalous magnetic moment of the muon are applied to supersymmetry. We follow a very cautious course, demanding that the supersymmetric contributions fit within five standard deviations of the difference between experiment and the standard model prediction. Arbitrarily small supersymmetric contributions are then allowed, so no upper bounds on superpartner masses result. Nevertheless, nontrivial exclusions are found. We characterize the substantial region of parameter space ruled out by this analysis that has not been probed by any previous experiment. We also discuss some implications of the results for forthcoming collider experiments.

There exist both continuum and lattice regularizations of gauge theories with fermions which preserve chiral U(1) invariance (“fermion number”). Such regularizations necessarily break gauge invariance but, in a covariant gauge, one recovers gauge invariance to all orders in perturbation theory by including suitable counterterms. At the nonperturbative level, an apparent conflict then arises between the chiral U(1) symmetry of the regularized theory and the existence of ’t Hooft vertices in the renormalized theory. The only possible resolution of the paradox is that the chiral U(1) symmetry is broken spontaneously in the enlarged Hilbert space of the covariantly gauge-fixed theory. The corresponding Goldstone pole is unphysical. The theory must therefore be defined by introducing a small fermion-mass term that breaks explicitly the chiral U(1) invariance and is sent to zero after the infinite-volume limit has been taken. Using this careful definition (and a lattice regularization) for the calculation of correlation functions in the one-instanton sector, we show that the ’t Hooft vertices are recovered as expected.

Top pair production at the CERN LHC is the ideal place to search for nonstandard $\mathrm{Wtb}$ couplings in $\overrightarrow{t}W\overrightarrow{b}l\nu b$ decays. The $\mathrm{lb}$ forward-backward asymmetry in the W rest frame is very sensitive to ${\sigma }^{\mu \nu }$ couplings, and can spot one-loop QCD corrections to the decay vertex with more than $5\sigma$ statistical significance. We discuss the potential of this asymmetry to signal nonstandard ${\gamma }^{\mu }$ and ${\sigma }^{\mu \nu }$ couplings and compare with $t\overline{t}$ spin correlation asymmetries, which have a lower sensitivity. We also briefly summarize the results for the Fermilab Tevatron.

We compute the axial vector current, form factor, and coupling for quarks in the instanton liquid model with two light flavors. Non-local current corrections are derived, as required by the effective ’t Hooft interaction. We obtain a pion-mediated axial form factor and an axial vector coupling which, when simply applied in the non-relativistic limit for constituent quarks, matches the experimental value to within a few percent, both in and out of the chiral limit.

We study the pure penguin decays $\overrightarrow{B}\phi \pi$ and $B^0\to \phi \phi .$ Using QCD factorization, we find $\mathcal{B}{(B}^{\pm }\to \phi {\pi }^{\pm }{)=2.0\mathrm{}}_{-0.1}^{+0.3\mathrm{}}\times {10}^{-8}.$ For the pure penguin annihilation process $B^0\to \phi \phi ,$ analyzed here for the first time, $\mathcal{B}{(B}^0\to \phi \phi {)=2.1\mathrm{}}_{-0.3}^{+1.6\mathrm{}}\times {10}^{-9}.$ The smallness of these decays in the standard model makes them sensitive probes for new physics. From the upper limit of $\overrightarrow{B}\phi \pi ,$ we find constraints on R-parity violating couplings, $|{\lambda }_{i23\mathrm{}}^{″}{\lambda }_{i21\mathrm{}}^{″}|<6\mathrm{}\times {10}^{-5},$ $|{\lambda }_{i23\mathrm{}}^{\prime }{\lambda }_{i21\mathrm{}}^{\prime }|<4\mathrm{}\times {10}^{-4},$ and $|{\lambda }_{i32\mathrm{}}^{\prime }{\lambda }_{i12\mathrm{}}^{\prime }|<4\mathrm{}\times {10}^{-4}$ for $i=1,2,3.\mathrm{}$ Our new bounds on $|{\lambda }_{i23\mathrm{}}^{″}{\lambda }_{i21\mathrm{}}^{″}|$ are one order of magnitude stronger than before. Within the available upper bounds for $|{\lambda }_{i23\mathrm{}}^{″}{\lambda }_{i21\mathrm{}}^{″}|,$ $|{\lambda }_{i23\mathrm{}}^{\prime }{\lambda }_{i21\mathrm{}}^{\prime }|,$ and $|{\lambda }_{i32\mathrm{}}^{\prime }{\lambda }_{i12\mathrm{}}^{\prime }|,$ we find that $\mathcal{B}\left(\overrightarrow{B}\phi \phi \right)$ could be enhanced to ${10}^{-8}–{10}^{-7}.$ Experimental searches for these decays are strongly urged.

Following recent works on the production and subsequent explosive decay of QCD sphaleronlike clusters, we discuss the mechanism of quark pair production in this process. We first show how the gauge field explosive solution of Luscher and Schechter can be achieved by noncentral conformal mapping from the O(4)-symmetric solution. Our main result is a new solution to the Dirac equation in real time in this configuration, obtained by the same inversion of the fermion O(4) zero mode. It explicitly shows how the quark acceleration occurs, starting from the spherically O(3)-symmetric zero energy chiral quark state to the final spectrum of nonzero energies. The sphaleronlike clusters with any Chern-Simons number always produce $N_F\mathbf{L}¯\mathbf{R}$ quarks, and the antisphaleron-like clusters the opposite chirality. The result are relevant for hadron-hadron and nucleus-nucleus collisions at large $\sqrt{s},$ wherein such clusters can be produced.

Nonperturbative parton-parton scattering is studied using the Landau method. Specific singular O(3)-symmetric solutions to the Euclidean Yang-Mills equations are discussed, with instanton dynamics incorporated in the overlap between incoming and vacuum fields. We derive a high-energy solution at small times, and assess the gluonic state produced at the turning point (escape point to Minkowski space-time). We follow the solution as it escapes to Minkowski space and assess its outgoing gluon spectrum. The solution is found to follow from the Yang-Mills sphaleron problem studied recently through a simple rescaling. We also argue, by evaluating the number of incoming gluons for the same singular solution, that this scaling is in fact more general and presumably describes the energy dependence of the spectra and multiplicities at all energies.

In the paper by J. Khoury et al., Phys. Rev. D 66, 046005 (2002), it is argued that the expected spectrum of primordial perturbations should be scale invariant in this scenario. Here we show that, contrary to what is claimed in that paper, the expected spectrum depends on an arbitrary choice of matching variable. As no underlying (microphysical) principle exists at the present time that could lift the arbitrariness, we conclude that the ekpyrotic scenario is not yet a predictive model.

We introduce the notion of the cosmic numbers of a cosmological model, and discuss how they can be used to naturally classify models according to their ability to solve some of the problems of the standard cosmological model.

We investigate the robustness of some recent results obtained for homogeneous and isotropic cosmological models with conformally coupled scalar fields. For this purpose, we investigate anisotropic homogeneous solutions of the models described by the action $S=\int d^{4}x\sqrt{-g}\{F\left(\phi \right)R-{\partial }_a\phi {\partial }^a\phi -2V\left(\phi \right)\},$ with general $F\left(\phi \right)$ and $V\left(\phi \right).\mathrm{}$ We show that such a class of models leads generically to geometrical singularities if for some value of $\phi ,$ $F\left(\phi \right)=0,$ rendering previous cosmological results obtained for the conformal coupling case highly unstable. We show that stable models can be obtained for suitable choices of $F\left(\phi \right)$ and $V\left(\phi \right).\mathrm{}$ Implications for other recent results are also discussed.

We explore bosonic strings and type II superstrings in the simplest time dependent backgrounds, namely orbifolds of Minkowski space by time reversal and some spatial reflections. We show that there are no negative norm physical excitations. However, the contributions of negative norm virtual states to quantum loops do not cancel, showing that a ghost-free gauge cannot be chosen. The spectrum includes a twisted sector, with strings confined to a “conical” singularity which is localized in time. Since these localized strings are not visible to asymptotic observers, interesting issues arise regarding unitarity of the S matrix for scattering of propagating states. The partition function of our model is modular invariant, and for the superstring, the zero momentum dilaton tadpole vanishes. Many of the issues we study will be generic to time-dependent cosmological backgrounds with singularities localized in time, and we derive some general lessons about quantizing strings on such spaces.

We present a class of general relativistic solitonlike solutions composed of multiple minimally coupled, massive, real scalar fields which interact only through the gravitational field. We describe a two-parameter family of solutions we call “phase-shifted boson stars” (parametrized by central density ${\rho }_0$ and phase $\delta ),$ which are obtained by solving the ordinary differential equations associated with boson stars and then altering the phase between the real and imaginary parts of the field. These solutions are similar to boson stars as well as the oscillating soliton stars found by Seidel and Suen [E. Seidel and W. M. Suen, Phys. Rev. Lett. 66, 1659 (1991)]; in particular, long-time numerical evolutions suggest that phase-shifted boson stars are stable. Our results indicate that scalar solitonlike solutions are perhaps more generic than has been previously thought.

We numerically investigate the formation of D-dimensional black holes in high-energy particle collisions with the impact parameter and evaluate the total cross section of black hole production. We find that the formation of an apparent horizon occurs when the distance between the colliding particles is less than 1.5 times the effective gravitational radius of each particle. Our numerical result indicates that although both the one-dimensional hoop and the $\left(D-3\right)$-dimensional volume corresponding to the typical scale of the system give a fairly good condition for horizon formation in the higher-dimensional gravity, the $\left(D-3\right)$-dimensional volume provides a better condition to judge the existence of the horizon.

A four-dimensional black hole solution of the Einstein equations with a positive cosmological constant coupled to a conformal scalar field is given. There is a curvature singularity at the origin, and the scalar field has a divergence inside the event horizon. The electrically charged solution, which has a fixed charge-to-mass ratio, is also found. The quartic self-interacting coupling constant becomes bounded in terms of Newton’s constant and the cosmological constant. The solution satisfies both dominant and the strong energy conditions.

We have investigated the classical stability of magnetically charged black p-brane solutions for string theories that include the case studied by Gregory and Laflamme. It turns out that the stability behaves very differently depending on the coupling parameter between the dilaton and gauge fields. In the case of Gregory and Laflamme, it is known that the black brane instability decreases monotonically as the charge of the black branes increases and finally disappears at the extremal point. For more general cases we found that, when the coupling parameter is small, black brane solutions become stable even before reaching the extremal point. On the other hand, when the coupling parameter is large, black branes are always unstable, and moreover the instability does not continue to decrease, but starts to increase again as they approach the extremal point. However, all extremal black branes are shown to be stable even in this case. It has also been shown that the main features of the classical stability are in good agreement with the local thermodynamic behavior of the corresponding black hole system through the Gubser-Mitra conjecture. Some implications of our results are also discussed.

We study a black hole domain wall system in dilaton gravity, which is the low-energy limit of superstring theory. We solve numerically equations of motion for a real self-interacting scalar field and justify the existence of a static axisymmetric field configuration representing a thick domain wall in the background of a charged dilaton black hole. It is also confirmed that the extreme dilaton black hole always expels the domain wall.

We develop a method based on the collisionless Boltzmann equation to calculate the gravitational clustering of relic neutrinos in realistic cosmological models dominated by cold dark matter (CDM) and the cosmological constant. This method can be used to estimate the phase-space distribution of any light particles in CDM halos. We find that neutrinos with masses $\gtrsim 0.3\mathrm{eV}$ cluster appreciably in dark matter halos above the galactic size. The resulting neutrino overdensity above the cosmic mean neutrino density increases with both the neutrino mass and the halo mass, ranging from $\sim 10$ for 0.3 eV neutrinos in $\sim {10}^{13}{M}_{\odot }$ halos to $\sim 1500$ for 1.8 eV neutrinos in $\sim {10}^{15}{M}_{\odot }$ halos. We examine the implications of neutrino clustering for the Z-burst model of ultrahigh energy cosmic rays (UHECR), which interprets the observed events at $E>\mathrm{}4\mathrm{}\times {10}^{19}\mathrm{eV}$ as decay products of Z bosons from the resonant scattering between relic and high energy neutrinos and antineutrinos. We estimate the UHECR energy spectrum for various neutrino masses towards five of the most massive clusters in the local universe (within 100 Mpc): Virgo, Perseus-Pisces, Hydra, Centaurus, and Coma. The UHECR flux in the Z-burst model is expected to be significantly higher towards these clusters if $m_{\nu }\gtrsim 0.3\mathrm{eV}$ and nearly isotropic otherwise.

We examine the detectability through indirect means of weakly interacting dark matter candidates that may constitute not all but only a subdominant component of galactic cold dark matter. We show that the possibility of indirect detection of neutralinos from their annihilations in the Earth and Sun is not severely hampered by decreasing the neutralino relic density. Upward-going muon fluxes in underground detectors from neutralino annihilations in the Sun can remain above the threshold of detectability of $10{\mathrm{m}\mathrm{u}\mathrm{o}\mathrm{n}\mathrm{s}/\mathrm{k}\mathrm{m}}^2/\mathrm{yr}$ for neutralinos composing $1\%$ or more of the halo dark matter. Similarly, signals from neutralino annihilations in the Earth can also remain high for neutralino densities of $1\%$ of the halo and actually would only be observable close to this low density for neutralinos lighter than 150 GeV. We also show that there are many models which simultaneously have high direct and indirect detection rates making some model discrimination possible if a signal is seen in any of the current dark matter searches.