We point out a mistake in the derivation of the supersymmetric constraint $\mathcal{S}$ for Bianchi class A models in one of the formalisms used within the $\mathcal{N}=1$ supergravity approach to quantum cosmology. The correct form of the supersymmetric constraint $\mathcal{S}$ is derived, and its consequences are analyzed.

Following a solution generating technique introduced recently by one of us, we transform the Einstein static universe into a twofold infinity class of physically acceptable exact perfect fluid solutions of Einstein’s equations. Whereas the entire class of solutions can be considered as generalizations of the familiar Tolman IV solution, no member of the class can be written explicitly in isotropic coordinates. Further, except for a set of measure zero, no member of the class can be written explicitly in curvature coordinates either.

We use Nambu-Goto numerical simulations to compute the cosmic microwave background (CMB) temperature anisotropies induced at arcminute angular scales by a network of cosmic strings in a Friedmann-Lemaître-Robertson-Walker (FLRW) expanding universe. We generate 84 statistically independent maps on a $7.2°$ field of view, which we use to derive basic statistical estimators such as the one-point distribution and two-point correlation functions. At high multipoles, the mean angular power spectrum of string-induced CMB temperature anisotropies can be described by a power law slowly decaying as ${\ell }^{-p}$, with $p=0.889$ $(+0.001,-0.090)$ (including only systematic errors). Such a behavior suggests that a nonvanishing string contribution to the overall CMB anisotropies may become the dominant source of fluctuations at small angular scales. We therefore discuss how well the temperature gradient magnitude operator can trace strings in the context of a typical arcminute diffraction-limited experiment. Including both the thermal and nonlinear kinetic Sunyaev-Zel’dovich effects, the Ostriker-Vishniac effect, and the currently favored adiabatic primary anisotropies, we find that, on such a map, strings should be “eye visible,” with at least of order ten distinctive string features observable on a $7.2°$ gradient map, for tensions $U$ down to $GU\simeq 2\times {10}^{-7}$ (in Planck units). This suggests that, with upcoming experiments such as the Atacama Cosmology Telescope (ACT), optimal non-Gaussian, string-devoted statistical estimators applied to small-angle CMB temperature or gradient maps may put stringent constraints on a possible cosmic string contribution to the CMB anisotropies.

We present a detailed descriptive analysis of the gravitational radiation from black-hole binary mergers of nonspinning black holes, based on numerical simulations of systems varying from equal mass to a $6:1$ mass ratio. Our primary goal is to present relatively complete information about the waveforms, including all the leading multipolar components, to interested researchers. In our analysis, we pursue the simplest physical description of the dominant features in the radiation, providing an interpretation of the waveforms in terms of an implicit rotating source. This interpretation applies uniformly to the full wave train, from inspiral through ringdown. We emphasize strong relationships among the $\ell =m$ modes that persist through the full wave train. Exploring the structure of the waveforms in more detail, we conduct detailed analytic fitting of the late-time frequency evolution, identifying a key quantitative feature shared by the $\ell =m$ modes among all mass ratios. We identify relationships, with a simple interpretation in terms of the implicit rotating source, among the evolution of frequency and amplitude, which hold for the late-time radiation. These detailed relationships provide sufficient information about the late-time radiation to yield a predictive model for the late-time waveforms, an alternative to the common practice of modeling by a sum of quasinormal mode overtones. We demonstrate an application of this in a new effective-one-body-based analytic waveform model.

If the Universe had a large curvature before inflation there is a deviation from the scale invariant perturbations of the inflaton at the beginning of inflation. This may have some effect on the cosmic microwave background anisotropy at large angular scales. We calculate the density perturbations for both open and closed universe cases using the Bunch-Davies vacuum condition on the initial state. We use our power spectrum to calculate the temperature anisotropy spectrum and compare the results with the Wilkinson microwave anisotropy map five year data. We find that our power spectrum gives a lower quadrupole anisotropy when $\Omega -1>0$, but matches the temperature anisotropy calculated from the standard Ratra-Peebles power spectrum at large $l$. The determination of spatial curvature from temperature anisotropy data is not much affected by the different power spectra which arise from the choice of different boundary conditions for the inflaton perturbation.

We analyze the $WW$ scattering in scenarios of dynamical electroweak symmetry breaking of walking technicolor type. We show that in these theories there are large regions of the parameters space allowed by the electroweak precision data, in which unitarity is delayed at tree level up to around 3–4 TeV without the inclusion of any sub-TeV resonances. If any of these scenarios is actually realized then the new physical states are not within reach of the LHC and International Linear Collider.

We present a new analysis of two-jet event shape distributions in soft collinear effective theory. Extending previous results, we observe that a large class of such distributions can be expressed in terms of vacuum matrix elements of operators in the effective theory. We match these matrix elements to the full theory in the two-jet limit without assuming factorization of the complete set of hadronic final states into independent sums over partonic collinear and soft states. We also briefly discuss the relationship of this approach to diagrammatic factorization in the full theory.

We study the excited baryon states for an arbitrary number of colors $N_c$ from the perspective of the permutation group $S_N$ of $N$ objects. Classifying the transformation properties of states and quark-quark interaction operators under $S_N$ allows a general analysis of the spin-flavor structure of the mass operator of these states, in terms of a few unknown constants parametrizing the unknown spatial structure. We explain how to perform the matching calculation of a general two-body quark-quark interaction onto the operators of the $1/N_c$ expansion. The inclusion of core and excited quark operators is shown to be necessary. Considering the case of the negative parity $L=1$ states transforming in the $MS$ of $S_N$, we discuss the matching of the one-gluon and the Goldstone-boson exchange interactions.

We present the results of the first hadron collider search for heavy, long-lived neutralinos that decay via ${\tilde{\chi }}_1^0\to \gamma \tilde{G}$ in gauge-mediated supersymmetry breaking models. Using an integrated luminosity of $570\pm 34{\mathrm{pb}}^{-1}$ of $p\overline{p}$ collisions at $\sqrt{s}=1.96\mathrm{TeV}$, we select $\gamma +\mathrm{\text{jet}}+\mathrm{\text{missing transverse energy}}$ candidate events based on the arrival time of a high-energy photon at the electromagnetic calorimeter as measured with a timing system that was recently installed on the CDF II detector. We find 2 events, consistent with the background estimate of $1.3\pm 0.7$ events. While our search strategy does not rely on model-specific dynamics, we set cross section limits and place the world-best 95% C.L. lower limit on the ${\tilde{\chi }}_1^0$ mass of $101\mathrm{GeV}/c^2$ at ${\tau }_{{\tilde{\chi }}_1^0}=5\mathrm{ns}$.

Non-Abelian plasma instabilities play a crucial role in the nonequilibrium dynamics of a weakly coupled quark-gluon plasma, and they importantly modify the standard perturbative bottom-up thermalization scenario in heavy-ion collisions. Using the auxiliary-field formulation of the hard-loop effective theory, we study numerically the real-time evolution of instabilities in an anisotropic collisionless Yang-Mills plasma undergoing longitudinal free-streaming expansion. In this first real-time lattice simulation we consider the most unstable modes, long-wavelength coherent color fields that are constant in transverse directions and which therefore are effectively $1+1$ dimensional in space-time, except for the auxiliary fields which also depend on discretized momentum rapidity and transverse velocity components. We reproduce the semianalytical results obtained previously for the Abelian regime, and we determine the nonlinear effects which occur when the instabilities have grown such that non-Abelian interactions become important.

It has been suggested that Einstein’s theory of general relativity can be modified to accommodate mismatches between the gravitational field and luminous matter on a wide range of scales. Covariant theories of modified gravity generically predict the existence of extra degrees of freedom which may be interpreted as dark matter. We study a subclass of these theories where the overall energy density in these extra degrees of freedom is subdominant relative to the baryon density. We find that, although all theories we consider favor the presence of massive neutrinos, it is generally not possible to establish a lower limit on the neutrino mass. For a few very specific cases (such as a flat universe with a cosmological constant), we find a conservative lower bound on the neutrinos mass of $m_{\nu }>0.31\mathrm{eV}$.

The dynamics of Dvali-Gabadadze-Porrati (DGP) braneworld with an anisotropic brane is studied. The Friedmann equations and their solutions are obtained for two branches of anisotropic DGP model. The late time behavior in DGP cosmology is examined in the presence of anisotropy which shows that universe enters a self-accelerating phase much later compared to the isotropic case. The acceleration conditions and slow-roll conditions for inflation are obtained.

We study the validity of the large-$N$ equivalence between four-dimensional $SU(N)$ lattice gauge theory and its momentum quenched version—the quenched Eguchi-Kawai (QEK) model. We find that the assumptions needed for the proofs of equivalence do not automatically follow from the quenching prescription. We use weak-coupling arguments to show that large-$N$ equivalence is in fact likely to break down in the QEK model, and that this is due to dynamically generated correlations between different Euclidean components of the gauge fields. We then use Monte Carlo simulations at intermediate couplings with $20\le N\le 200$ to provide strong evidence for the presence of these correlations and for the consequent breakdown of reduction. This evidence includes a large discrepancy between the transition coupling of the bulk transition in lattice gauge theories and the coupling at which the QEK model goes through a strongly first-order transition. To accurately measure this discrepancy we adapt the recently introduced Wang-Landau algorithm to gauge theories.

We calculate the spatial string tension in ($2+1$) flavor QCD with physical strange quark mass and almost physical light quark masses using lattices with temporal extent $N_{\tau }=4$, 6 and 8. We compare our results on the spatial string tension with predictions of dimensionally reduced QCD. This suggests that also in the presence of light dynamical quarks dimensional reduction works well down to temperatures $1.5T_c$.

The leading twist transverse momentum dependent parton distributions (TMDs) are studied in a light-cone description of the nucleon where the Fock expansion is truncated to consider only valence quarks. General analytic expressions are derived in terms of the six amplitudes needed to describe the three-quark sector of the nucleon light-cone wave function. Numerical calculations for the T-even TMDs are presented in a light-cone constituent quark model, and the role of the so-called pretzelosity is investigated to produce a nonspherical shape of the nucleon.

We determine the time evolution of fluctuations of the Polyakov loop after a quench into the deconfined phase of SU(3) gauge theory from a simple classical relativistic Lagrangian. We compare the structure factors, which indicate spinodal decomposition followed by relaxation, to those obtained via Markov Chain Monte Carlo techniques in SU(3) lattice gauge theory. We find that the time when the structure factor peaks diverges in the long-wavelength limit. This is due to formation of competing Z(3) domains for configurations where the Polyakov loop exhibits nonperturbatively large variations in space, which delay thermalization of long-wavelength modes. For realistic temperatures, and away from the extreme weak-coupling limit, we find that even modes with $k$ on the order of $T$ experience delayed thermalization. Relaxation times of very long-wavelength modes are found to be on the order of the size of the system; thus, the dynamics of competing domains should accompany the hydrodynamic description of the deconfined vacuum.

We report on an improved measurement of the Cabibbo-Kobayashi-Maskawa $CP$-violating phase $\gamma$ through a Dalitz plot analysis of neutral $D$ meson decays to $K_S^0{\pi }^{+}{\pi }^{-}$ and $K_S^0{K}^{+}{K}^{-}$ produced in the processes $B^{\mp }\to D{K}^{\mp }$, $B^{\mp }\to D^{*}{K}^{\mp }$ with $D^{*}\to D{\pi }^0$, $D\gamma$, and $B^{\mp }\to D{K}^{*\mp }$ with $K^{*\mp }\to K_S^0{\pi }^{\mp }$. Using a sample of $383\times {10}^6$ $B\overline{B}$ pairs collected by the BABAR detector, we measure $\gamma =(76\pm 22\pm 5\pm 5)°$ (mod 180°), where the first error is statistical, the second is the experimental systematic uncertainty, and the third reflects the uncertainty on the description of the Dalitz plot distributions. The corresponding 2-standard-deviation region is $29°<\gamma <122°$. This result has a significance of direct $CP$ violation ($\gamma \ne 0$) of 3.0 standard deviations.

We study the energy distributions of dipion transitions ${\rm Y}(5S)$ to ${\rm Y}(1S,2S,3S){\pi }^{+}{\pi }^{-}$ in the final-state rescattering model. Since the ${\rm Y}(5S)$ is well above the open bottom thresholds, the dipion transitions are expected to mainly proceed through the real processes ${\rm Y}(5S)\to B^{(*)}{\overline{B}}^{(*)}$ and $B^{(*)}{\overline{B}}^{(*)}\to {\rm Y}(1S,2S,3S){\pi }^{+}{\pi }^{-}$. We find that the energy distributions of ${\rm Y}(1S,2S,3S){\pi }^{+}{\pi }^{-}$ markedly differ from that of ${\rm Y}(5S)\to B^{(*)}{\overline{B}}^{(*)}$. In particular, the resonance peak will be pushed up by about 7–20 MeV for these dipion transitions relative to the main hadronic decay modes. These predictions can be used to test the final-state rescattering mechanism in hadronic transitions for heavy quarkonia above the open flavor thresholds.

In this paper we explore the effect of nonunitary neutrino mixing on neutrino oscillation probabilities both in vacuum and matter. In particular, we consider the ${\nu }_{\mu }\to {\nu }_{\tau }$ channel and, using a neutrino factory as the source for ${\nu }_{\mu }$’s, discuss the constraints that can be obtained on the moduli and phases of the parameters characterizing the violation of unitarity. We point out how the new $CP$ violation phases present in the case where the nonunitary mixings give rise to spurious “degenerate” solutions in the parameter space. We also discuss how the true solutions can be extricated by combining measurements at several baselines.

The KTeV E799 experiment has conducted a search for the rare decay $K_L\to {\pi }^0{\pi }^0\gamma$ via the topology $K_L\to {\pi }^0{\pi }_D^0\gamma$ (where ${\pi }_D^0\to \gamma e^{+}{e}^{-}$). Because of Bose statistics of the ${\pi }^0$ pair and the real nature of the photon, the $K_L\to {\pi }^0{\pi }^0\gamma$ decay is restricted to proceed at lowest order by the $CP$ conserving direct emission (DE) of an E2 electric quadrupole photon. The rate of this decay is interesting theoretically since chiral perturbation theory predicts that this process vanishes at level $O(p^4)$. Therefore, this mode probes chiral perturbation theory at $O(p^6)$. In this paper we report a determination of an upper limit of $2.43\times {10}^{-7}$ (90% CL) for $K_L\to {\pi }^0{\pi }^0\gamma$. This is approximately a factor of 20 lower than previous results.