We consider a simple supersymmetric grand unified model which naturally solves the strong $CP$ and $\mu$ problems via a Peccei-Quinn symmetry and leads to the standard realization of hybrid inflation. We show that the Peccei-Quinn field of this model can act as a curvaton. In contrast to the standard curvaton hypothesis, both the inflaton and the curvaton contribute to the total curvature perturbation. The model predicts the existence of an isocurvature perturbation, too, which has mixed correlation with the adiabatic one. The cold dark matter of the Universe is mostly constituted by axions, which are produced at the QCD phase transition, plus a small amount of lightest sparticles. The predictions of the model are confronted with the first-year Wilkinson microwave anisotropy probe and other cosmic microwave background radiation data. We analyze in detail two representative choices of parameters for our model and derive bounds on the curvaton contribution to the adiabatic perturbation. We find that, for the choice which provides the best fitting of the data, the curvaton contribution to the amplitude of the adiabatic perturbation must be smaller than about $67\%$ and the amplitude of the partial curvature perturbation from the curvaton smaller than $43.2\times {10}^{-5}$ (both at $95\%$ confidence level). The best-fit power spectra are dominated by the adiabatic part of the inflaton contribution. We use Bayesian model comparison to show that this choice of parameters is disfavored with respect to the pure inflaton scale-invariant case with odds of about 50 to 1. For the second choice of parameters examined, the adiabatic mode is dominated by the curvaton, but this choice is strongly disfavored relative to the pure inflaton scale-invariant case (with odds of about ${10}^7$ to 1). We conclude that in the present framework the perturbations must be dominated by the adiabatic component from the inflaton.

For a large region of parameter space involving the cosmological constant and mass parameters, we discuss fluctuating spacetime solutions that are effectively Minkowskian on large time and distance scales. Rapid, small amplitude oscillations in the scale factor have a frequency determined by the size of a negative cosmological constant. A field with modes of negative energy is required. If it is gravity that induces a coupling between the ghostlike and normal fields, we find that this results in stochastic rather than unstable behavior. The negative energy modes may also permit the existence of Lorentz invariant fluctuating solutions of finite energy density. Finally we consider higher derivative gravity theories and find oscillating metric solutions in these theories without the addition of other fields.

We consider the gravitational effects of a single, fixed-norm, Lorentz-violating timelike vector field. In a cosmological background, such a vector field acts to rescale the effective value of Newton’s constant. The energy density of this vector field precisely tracks the energy density of the rest of the universe, but with the opposite sign, so that the universe experiences a slower rate of expansion for a given matter content. This vector field similarly rescales Newton’s constant in the Newtonian limit, although by a different factor. We put constraints on the parameters of the theory using the predictions of primordial nucleosynthesis, demonstrating that the norm of the vector field should be less than the Planck scale by an order of magnitude or more.

During the workshop “Transversity: New Developments in Nucleon Spin Structure” (${\mathrm{E}\mathrm{C}\mathrm{T}}^{*}$, Trento, Italy, 14–18 June 2004), a series of recommendations was put forward by the participants concerning definitions and notations for describing effects of intrinsic transverse-momentum of partons in semi-inclusive deep inelastic scattering.

We present the prospects of searches for neutral, long-lived particles that decay to photons using their time of arrival measured with a newly installed timing system on the electromagnetic calorimeter (EMTiming) of the Collider Detector at Fermilab (CDF). A Monte Carlo simulation shows that EMTiming can provide separation between decay photons from neutral, long-lived particles and prompt photons from standard model backgrounds. Using gauge mediated supersymmetry breaking (GMSB) ${\tilde{\chi }}_1^0\to \gamma \tilde{G}$ models, we estimate a quasi-model-independent sensitivity using only direct neutralino pair production, and also estimate the expected 95% confidence level exclusion regions for all superpartner production as a function of the neutralino mass and lifetime. We find that a combination of single photon and diphoton analyses should allow the Tevatron in Run II to easily extend the exclusion regions from ALEPH at LEP II at high neutralino masses and lifetimes, and cover parts of the theoretically favored $m_{\tilde{G}}<\mathrm{\text{few}}\mathrm{k}\mathrm{e}\mathrm{V}/c^2$ GMSB parameter space.

We investigate lepton flavor violating decays in a supersymmetric (SUSY) SO(10) model with symmetric textures recently constructed by us. Unlike the models with lopsided textures which give rise to a large decay rate for $\mu \to e\gamma$, the decay rate we get is much suppressed and yet it is large enough to be accessible to the next generation of experiments. We have also investigated the possibility of baryogenesis resulting from soft leptogenesis. We find that with the soft-SUSY masses assuming their natural values, $B^{\prime }\equiv \sqrt{B{M}_1}\sim 1.4\mathrm{T}\mathrm{e}\mathrm{V}$ and $\mathrm{I}\mathrm{m}(A)\sim 1\mathrm{T}\mathrm{e}\mathrm{V}$, the observed baryon asymmetry in the Universe can be accommodated in our model. We have also updated the predictions of our model for the masses, mixing angles, and $CP$ violating measures in both charged fermion and neutrino sectors, using the most up-to-date experimental data as input.

We report the first observation of a number of decay modes of the $B$ meson, namely $B^0\to D^{*-}(5\pi {)}^{+}$, $B^{+}\to D^{*-}(4\pi {)}^{++}$, and $B^{+}\to {\overline{D}}^{*0}(5\pi {)}^{+}$, where $(n\pi )$ implies the combination of $n$ charged pions. The analysis is based on a $140{\mathrm{f}\mathrm{b}}^{-1}$ data sample collected at the ${\rm Y}(4S)$ resonance with the Belle detector at KEKB. We measure $\mathcal{B}[B^0\to D^{*-}(5\pi {)}^{+}]=(4.72\pm 0.59\pm 0.71)\times {10}^{-3}$, $\mathcal{B}[B^{+}\to D^{*-}(4\pi {)}^{++}]=(2.56\pm 0.26\pm 0.33)\times {10}^{-3}$, and $\mathcal{B}[B^{+}\to {\overline{D}}^{*0}(5\pi {)}^{+}]=(5.67\pm 0.91\pm 0.85)\times {10}^{-3}$. We also provide improved measurements of the branching fractions for the decay modes $B^0\to D^{*-}(3\pi {)}^{+}$, $B^{+}\to {\overline{D}}^{*0}(3\pi {)}^{+}$, and $B^0\to {\overline{D}}^{*0}(4\pi {)}^0$.

We investigate the $SL(2,\mathbb{R})/U(1)$ WZW model with level $0<k<2$ as a solvable time-dependent background in string theory. This model is expected to be dual to the one describing a rolling closed string tachyon with a timelike linear dilaton. We examine its exact metric and minisuperspace wave functions. Two point functions and the one-loop vacuum amplitude are computed and their relation to the closed string emission is discussed. Comparing with the results from the minisuperspace approximation, we find a physical interpretation of our choice to continue the Euclidean model into the Lorentzian one. Three point functions are also examined.

The Bogomol’nyi-Prasad-Sommerfield (BPS) multiwall solutions are constructed in supersymmetric $\mathrm{U}(N_{\mathrm{C}})$ gauge theories in five dimensions with $N_{\mathrm{F}}(>N_{\mathrm{C}})$ hypermultiplets in the fundamental representation. Exact solutions are obtained with full generic moduli for infinite gauge coupling and with partial moduli for finite gauge coupling. The generic wall solutions require nontrivial configurations for either gauge fields or off diagonal components of adjoint scalars depending on the gauge. Effective theories of moduli fields are constructed as world volume gauge theories. Nambu-Goldstone and quasi-Nambu-Goldstone scalars are distinguished and worked out. Total moduli space of the BPS non-Abelian walls including all topological sectors is found to be the complex Grassmann manifold $\mathrm{S}\mathrm{U}(N_{\mathrm{F}})/[\mathrm{S}\mathrm{U}(N_{\mathrm{C}})\times \mathrm{S}\mathrm{U}(N_{\mathrm{F}}-N_{\mathrm{C}})\times \mathrm{U}(1)]$ endowed with a deformed metric.

We demonstrate that parastatistics can be quantized using path integrals by calculating the generating functionals for time-ordered products of both free and interacting parabose and parafermi fields in terms of path integrals. We also give a convenient form of the commutation relations for the Green components of the parabose and parafermi operators in both the canonical and path integral formalisms.

We calculate the harmonic-gauge even $l=1$ mode of the linear metric perturbation (MP) produced by a particle in a weak-field circular orbit around a Schwarzschild black hole (BH). We focus on the Newtonian limit, i.e., the limit in which the mass $M$ of the central BH approaches zero (while fixing the orbital radius and the small-object mass), and obtain explicit expressions for the MP in this limit. We find that the MP are anomalous in this limit, namely, they do not approach their standard, Coulomb-like, flat-space values. Instead, the MP grows on approaching the BH, and this growth becomes worse as $M$ decreases. This anomalous behavior leads to some pathologies which we briefly discuss. We also derive here the next-order correction (in the orbital frequency $\Omega$) to the MP.

Binary black hole spacetimes with a helical Killing vector, which are discussed as an approximation for the early stage of a binary system, are studied in a projection formalism. In this setting the four-dimensional Einstein equations are equivalent to a three-dimensional gravitational theory with a $\mathrm{S}\mathrm{L}(2,\mathbb{R})/\mathrm{S}\mathrm{O}(1,1)$ sigma model as the material source. The sigma model is determined by a complex Ernst equation. $2+1$ decompositions of the three-metric are used to establish the field equations on the orbit space of the Killing vector. The two Killing horizons of spherical topology which characterize the black holes, the cylinder of light where the Killing vector changes from timelike to spacelike, and infinity are singular points of the equations. The horizon and the light cylinder are shown to be regular singularities, i.e., the metric functions can be expanded in a formal power series in the vicinity. The behavior of the metric at spatial infinity is studied in terms of formal series solutions to the linearized Einstein equations. It is shown that the spacetime is not asymptotically flat in the strong sense to have a smooth null infinity under the assumption that the metric tends asymptotically to the Minkowski metric. In this case the metric functions have an oscillatory behavior in the radial coordinate in a nonaxisymmetric setting, the asymptotic multipoles are not defined. The asymptotic behavior of the Weyl tensor near infinity shows that there is no smooth null infinity.

We analyze the Randall-Sundrum two $D$-brane model by linear perturbation and then consider the linearized gravity on the $D$ brane. The qualitative contribution from the Kaluza-Klein modes of gauge fields to the coupling to the gravity on the brane will be addressed. As a consequence, the gauge fields localized on the brane are shown not to contribute to the gravity on the brane at large distances. Although the coupling between gauge fields and gravity appears in the next order, the ordinary coupling cannot be realized.

The general problem of computing the false-alarm probability vs the detection-threshold relationship for a bank of correlators is addressed, in the context of maximum-likelihood detection of gravitational waves in additive stationary Gaussian noise. Specific reference is made to chirps from coalescing binary systems. Accurate (lower-bound) approximants for the cumulative distribution of the whole-bank supremum are deduced from a class of Bonferroni-type inequalities. The asymptotic properties of the cumulative distribution are obtained, in the limit where the number of correlators goes to infinity. The validity of numerical simulations made on small-size banks is extended to banks of any size, via a Gaussian-correlation inequality. The result is used to readdress the problem of relating the template density to the fraction of potentially observable sources which could be dismissed as an effect of template space discreteness.

By treating the Hawking radiation as a system in thermal equilibrium, Marolf and Sorkin have argued that hyperentropic objects (those violating the entropy bounds) would be emitted profusely with the radiation, thus opening a loophole in black hole based arguments for such entropy bounds. We demonstrate, on kinetic grounds, that hyperentropic objects could be formed only extremely slowly and so would be rare in the Hawking radiance, thus contributing negligibly to its entropy. The arguments based on the generalized second law of thermodynamics then rule out weakly self-gravitating hyperentropic objects and a class of strongly self-gravitating ones.

We consider possible effects of new physics (NP) on the angular distributions of the decay $B^0\to \varphi K^{*0}$, showing how these effects depend on the nature of nonstandard interactions. In a general framework based on factorization, we show that triple products can be used to probe the chirality of NP currents. In this analysis we take into account the presence of nonvanishing strong phases, which is motivated by recent experimental evidence. It is seen that the observability of right-handed NP is strongly dependent on the relation between the relative magnitude of these phases and the ratio of standard model and NP scales. As an application we estimate the expected values of relevant observables in a particular left-right symmetric model.

We investigate chiral phase transition of the first order in the quark matter. Using the Nambu-Jona-Lasinio model, an equation of state of the quark matter which is similar to the van der Waals's one is obtained. Moreover the specific heat and the compressibility are calculated. It is shown that they are enhanced in the symmetry broken phase, in particular, diverge near the tricritical point.

The cross section of heavy-ion collisions is represented as a double functional integral with the saddle point being the classical solution of the Yang-Mills equations with boundary conditions/sources in the form of two shock waves corresponding to the two colliding ions. I develop the expansion of this classical solution in powers of the commutator of the Wilson lines describing the colliding particles and calculate the first two terms of the expansion.

The branching fractions of the decays $B^0\to K^{*0}\gamma$ and $B^{+}\to K^{*+}\gamma$ are measured using a sample of $88\times {10}^{6}B\overline{B}$ events collected with the BABAR detector at the PEP-II asymmetric-energy $e^{+}{e}^{-}$ collider. We find $\mathcal{B}(B^0\to K^{*0}\gamma )=[3.92\pm 0.20(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t})\pm 0.24(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})]\times {10}^{-5}$, $\mathcal{B}(B^{+}\to K^{*+}\gamma )=[3.87\pm 0.28(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t})\pm 0.26(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})]\times {10}^{-5}$. Our measurements also constrain the direct $CP$ asymmetry to be $-0.074<\mathcal{A}(B\to K^{*}\gamma )<0.049$ and the isospin asymmetry to be $-0.046<{\Delta }_{0-}<0.146$, both at the 90% confidence level.

We present an algorithm for treating mesh refinement interfaces in numerical relativity. We discuss the behavior of the solution near such interfaces located in the strong-field regions of dynamical black hole spacetimes, with particular attention to the convergence properties of the simulations. In our applications of this technique to the evolution of puncture initial data with vanishing shift, we demonstrate that it is possible to simultaneously maintain second order convergence near the puncture and extend the outer boundary beyond $100M$, thereby approaching the asymptotically flat region in which boundary condition problems are less difficult and wave extraction is meaningful.