Recently, it has been shown that a slow expansion, which is asymptotically a static state in infinite past and may be described as an evolution with $ϵ\ll -1$, of early universe may lead to the generation of primordial perturbation responsible for the structure formation of observable universe. However, its feasibility depends on whether the growing mode of Bardeen potential before phase transition can be inherited by the constant mode of curvature perturbation after phase transition. In this paper, we phenomenally regard this slow expansion as that driven by multi-NEC (null energy condition) violating scalar fields. We calculate the curvature perturbation induced by the entropy perturbation before phase transition and find that the spectrum is naturally scale invariant with a slight red tilt. The result has an interesting similarity to that of slow roll inflation.

We study supersymmetric QCD in the conformal window as a laboratory for unparticle physics, and analyze couplings between the unparticle sector and the Higgs sector. These couplings can lead to the unparticle sector being pushed away from its scale invariant fixed point. We show that this implies that low energy experiments will not be able to see unparticle physics, and the best hope of seeing unparticles is in high energy collider experiments such as the Tevatron and the LHC. We also demonstrate how the breaking of scale invariance could be observed at these experiments.

A Higgs boson produced in association with one or more bottom quarks is of great theoretical and experimental interest to the high-energy community. A precise prediction of its total and differential cross section can have a great impact on the discovery of a Higgs boson with large bottom-quark Yukawa coupling, like the scalar ($h^0$ and $H^0$) and pseudoscalar ($A^0$) Higgs bosons of the minimal supersymmetric standard model in the region of large $\tan \beta$. In this paper we apply the threshold resummation formalism to determine both differential and total cross sections for $bg\to b\Phi$ (where $\Phi =h^0,H^0$), including up to next-to-next-to-next-to-leading order soft plus virtual QCD corrections at next-to-leading logarithmic accuracy. We present results for both the Fermilab Tevatron and the CERN Large Hadron Collider.

The exclusive decay of ${\rm Y}$ to a vector plus pseudoscalar charmonium is studied in perturbative QCD. The corresponding branching ratios are predicted to be of order ${10}^{-6}$ for the first three ${\rm Y}$ resonances, and one expects these decay modes should be discovered in the prospective high-luminosity $e^{+}{e}^{-}$ facilities such as the Super $B$ factory. As a manifestation of the short-distance loop contribution, the relative phases among strong, electromagnetic, and radiative decay amplitudes can be deduced. It is particularly interesting to find that the relative phase between strong and electromagnetic amplitudes is nearly orthogonal. The resonance-continuum interference effect for double charmonium production near various ${\rm Y}$ resonances in $e^{+}{e}^{-}$ annihilation is addressed.

We examine $e^{+}{e}^{-}\to D_s^{-}{D}_s^{*+}$ and $D_s^{*-}{D}_s^{+}$ interactions at 4170 MeV using the CLEO-c detector in order to measure the decay constant $f_{D_s^{+}}$. We use the $D_s^{+}\to {\ell }^{+}\nu$ channel, where the ${\ell }^{+}$ designates either a ${\mu }^{+}$ or a ${\tau }^{+}$, when the ${\tau }^{+}\to {\pi }^{+}\overline{\nu }$. Analyzing both modes independently, we determine $\mathcal{B}(D_s^{+}\to {\mu }^{+}\nu )=(0.594\pm 0.066\pm 0.031)\%$, and $\mathcal{B}(D_s^{+}\to {\tau }^{+}\nu )=(8.0\pm 1.3\pm 0.4)\%$. We also analyze them simultaneously to find an effective value of ${\mathcal{B}}^{\mathrm{eff}}(D_s^{+}\to {\mu }^{+}\nu )=(0.638\pm 0.059\pm 0.033)\%$ and extract $f_{D_s^{+}}=274\pm 13\pm 7\mathrm{MeV}$. Combining with our previous determination of $\mathcal{B}(D^{+}\to {\mu }^{+}\nu )$, we also find the ratio $f_{D_s^{+}}/f_{D^{+}}=1.23\pm 0.11\pm 0.04$. We compare to current theoretical estimates. Finally, we find $\mathcal{B}(D_s^{+}\to e^{+}\nu )<1.3\times {10}^{-4}$ at 90% confidence level.

Canonical quantization of spherically symmetric initial data appropriate to classical interior black hole solutions in four dimensions is solved exactly without gauge fixing the remaining kinematic Gauss law constraint. The resultant mini-superspace manifold is two dimensional, of signature $(+,-)$, nonsingular, and can be identified with the first Rindler wedge. The associated Wheeler-DeWitt equation with evolution in intrinsic superspace time is a free massive Klein-Gordon equation, and the Hamilton-Jacobi semiclassical limit of plane wave solutions can be matched to the interiors of Schwarzschild black holes. Classical black hole horizons and singularities correspond to the boundaries of the Rindler wedge. Exact wave functions of the Dirac equation in superspace are also considered. Precise correspondence between Schwarzschild black holes and free-particle mechanics in superspace is noted. Despite the presence of classical singularities, Hermiticity of the Dirac Hamiltonian operator, and thus unitarity of the quantum theory, is equivalent to an appropriate boundary condition which must be satisfied by the quantum states. This boundary condition holds for quite generic quantum wave packets of energy eigenstates, but fails for the usual Rindler fermion modes which are eigenstates with zero uncertainty in energy.

We explicitly calculate the lowest order systematic inhomogeneity-induced corrections to the cosmological constant that one would infer from an analysis of the luminosities and redshifts of type Ia supernovae, assuming a homogeneous universe. The calculation entails a post-Newtonian expansion within the framework of second-order perturbation theory, wherein we consider the effects of subhorizon density perturbations in a flat, dust-dominated universe. Within this formalism, we calculate luminosity distances and redshifts along the past light cone of an observer. The luminosity distance-redshift relation is then averaged over viewing angles and ensemble averaged, assuming that density fluctuations at a given cosmic time are a homogeneous random process. The resulting relation is fit to that of a homogeneous model containing dust and a cosmological constant, in order to deduce the best-fit cosmological constant density ${\Omega }_{\Lambda }$. We find that the luminosity distance-redshift relation is indeed modified, even for large sample sizes, but only by a very small fraction, of order ${10}^{-5}$ for $z\sim 0.1$. This lowest order deviation depends on the peculiar velocities of the source and the observer. However, when fitting this perturbed relation to that of a homogeneous universe, via maximizing a likelihood function, we find that the inferred cosmological constant can be surprisingly large, depending on the range of redshifts sampled. For a sample of supernovae extending from $z_{\min }=0.02$ out to a limiting redshift $z_{\max }=0.15$, we find that ${\Omega }_{\Lambda }\approx 0.004$. The value of ${\Omega }_{\Lambda }$ has a large variance, and its magnitude tends to get progressively larger as the limiting redshift $z_{\max }$ gets smaller, implying that precision measurements of ${\Omega }_{\Lambda }$ from nearby supernova data will require taking this effect into account. This effect has been referred to in the past as the “fitting problem,” and more recently as subhorizon “backreaction.” We find that it is likely too small to explain the observed value ${\Omega }_{\Lambda }\approx 0.7$. There have been previous claims of much larger backreaction effects. In contrast to those calculations, our work is directly related to how observers deduce cosmological parameters from astronomical data.

Several cosmological measurements have attained significant levels of maturity and accuracy over the past decade. Continuing this trend, future observations promise measurements of the cosmic mass distribution at an accuracy level of 1% out to spatial scales with $k\sim 10h{\mathrm{Mpc}}^{-1}$ and even smaller, entering highly nonlinear regimes of gravitational instability. In order to interpret these observations and extract useful cosmological information from them, such as the equation of state of dark energy, very costly high precision, multiphysics simulations must be performed. We have recently implemented a new statistical framework with the aim of obtaining accurate parameter constraints from combining observations with a limited number of simulations. The key idea is the replacement of the full simulator by a fast emulator with controlled error bounds. In this paper, we provide a detailed description of the methodology and extend the framework to include joint analysis of cosmic microwave background and large-scale structure measurements. Our framework is especially well suited for upcoming large-scale structure probes of dark energy such as baryon acoustic oscillations and, especially, weak lensing, where percent level accuracy on nonlinear scales is needed.

Energy injection into the early universe can induce turbulent motions of the primordial plasma, which in turn act as a source for gravitational radiation. Earlier work computed the amplitude and characteristic frequency of the relic gravitational wave background, as a function of the total energy injected and the stirring scale of the turbulence. This paper computes the frequency spectrum of relic gravitational radiation from a turbulent source of the stationary Kolmogoroff form which acts for a given duration, making no other approximations. We also show that the limit of long source wavelengths, commonly employed in aeroacoustic problems, is an excellent approximation. The gravitational waves from cosmological turbulence around the electroweak energy scale will be detectable by future space-based laser interferometers for a substantial range of turbulence parameters.

In the dense-neutrino region above the neutrino sphere of a supernova ($r\lesssim 400\mathrm{km}$), neutrino-neutrino refraction causes collective flavor transformations. They can lead to “spectral splits” where an energy $E_{\mathrm{split}}$ splits the transformed spectrum sharply into parts of almost pure but different flavors. Unless there is an ordinary MSW resonance in the dense-neutrino region, $E_{\mathrm{split}}$ is determined by flavor-lepton number conservation alone. Spectral splits are created by an adiabatic transition between regions of large and small neutrino density. We solve the equations of motion in the adiabatic limit explicitly and provide analytic expressions for a generic example.

We study the virtual effects of unparticle physics in the lepton flavor violating processes $M^0\to l^{+}{l}^{\prime -}$ and $e^{+}{e}^{-}\to l^{+}{l}^{\prime -}$ scattering, where $M^0$ denotes the pseudoscalar mesons: ${\pi }^0$, $K_L$, $D_0$, $B_0$, $B_s^0$ and $l$, $l^{\prime }$ denote two different lepton flavors. For the decay of $B^0\to l^{+}{l}^{\prime -}$, there is no constraint from the current experimental upper bounds on the vector unparticle coupling with leptons. The constraint on the coupling constant between scalar unparticle field and leptons is sensitive to the scaling dimension of the unparticle $d_{\mathcal{U}}$. For the scattering process $e^{-}{e}^{+}\to l^{-}{l}^{\prime +}$, there is only constraint from experiments on the vector unparticle couplings with leptons but no constraint on the scalar unparticle. We study the $\sqrt{s}$ dependence of the cross section $\frac{1}{\sigma }\frac{d\sigma }{d\sqrt{s}}$ of $e^{+}{e}^{-}\to l^{-}{l}^{\prime +}$ with different values of $d_{\mathcal{U}}$. If $d_{\mathcal{U}}=1.5$, the cross section is independent on the center mass energy. For $d_{\mathcal{U}}>1.5$, the cross section increases with $\sqrt{s}$.

The Higgs boson offers a unique window to hidden sector fields $S_i$, singlets under the standard model gauge group, via the renormalizable interactions $|H{|}^2{S}_i^2$. We prove that such interactions can provide new patterns for electroweak breaking, including radiative breaking by dimensional transmutation consistent with CERN LEP bounds, and trigger the strong enough first-order phase transition required by electroweak baryogenesis.

We calculate the transverse momentum $Q_{\perp }$ dependence of the helicity structure functions for the hadroproduction of a massive pair of leptons with pair invariant mass $Q$. These structure functions determine the angular distribution of the leptons in the pair rest frame. Unphysical behavior in the region $Q_{\perp }\to 0$ is seen in the results of calculations done at fixed order in QCD perturbation theory. We use current conservation to demonstrate that the unphysical inverse-power and $\ln (Q/Q_{\perp })$ logarithmic divergences in three of the four independent helicity structure functions share the same origin as the divergent terms in fixed-order calculations of the angular-integrated cross section. We show that the resummation of these divergences to all orders in the strong coupling strength ${\alpha }_s$ can be reduced to the solved problem of the resummation of the divergences in the angular-integrated cross section, resulting in well-behaved predictions in the small $Q_{\perp }$ region. Among other results, we show the resummed part of the helicity structure functions preserves the Lam-Tung relation between the longitudinal and double spin-flip structure functions as a function of $Q_{\perp }$ to all orders in ${\alpha }_s$.

In scintillator detectors, the forward displacement of the neutron in the reaction ${\overline{\nu }}_e+p\to e^{+}+n$ provides neutrino directional information as demonstrated by the CHOOZ reactor experiment with 2500 events. The near detector of the forthcoming Double Chooz experiment will collect $1.6\times {10}^5$ events per year, enough to determine the average neutrino direction with a $1\sigma$ half-cone aperture of 2.3° in one year. It is more difficult to separate the two Chooz reactors that are viewed at a separation angle $\varphi =30°$. If their strengths are known and approximately equal, the azimuthal location of each reactor is obtained with $\pm 6°$ ($1\sigma$) and the probability of confusing them with a single source is less than 11%. Five-year’s data reduce this “confusion probability” to less than 0.3%, i.e., a $3\sigma$ separation is possible. All of these numbers improve rapidly with increasing angular separation of the sources. For a setup with $\varphi =90°$ and one-year’s data, the azimuthal $1\sigma$ uncertainty for each source decreases to $\pm 3.2°$. Of course, for Double Chooz the two reactor locations are known, allowing one instead to measure their individual one-year integrated power output to $\pm 11\%$ ($1\sigma$), and their five-year integrated output to $\pm 4.8\%$ ($1\sigma$).

We present a measurement of the time-dependent $CP$ asymmetry for the neutral $B$-meson decay into the $CP=+1$ final state $K_S^0{\pi }^0{\pi }^0$, with $K_S^0\to {\pi }^{+}{\pi }^{-}$. We use a sample of approximately 227 million $B$-meson pairs recorded at the $\mathit{{\rm Y}}(4S)$ resonance with the BABAR detector at the PEP-II $B$-Factory at SLAC. From an unbinned maximum likelihood fit, we extract the mixing-induced $CP$-violation parameter $S=0.72\pm 0.71\pm 0.08$ and the direct $CP$-violation parameter $C=0.23\pm 0.52\pm 0.13$, where the first uncertainty is statistical and the second systematic.

The generalized Darmois-Israel formalism for Einstein-Gauss-Bonnet theory is applied to construct thin-shell Lorentzian wormholes with spherical symmetry. We calculate the energy localized on the shell, and we find that for certain values of the parameters wormholes could be supported by matter not violating the energy conditions.

By adopting the 5D version of the Wu-Yang ansatz we present in closed form a black hole solution in the Einstein-Yang-Mills-Gauss-Bonnet theory. In the Einstein-Yang-Mills limit, we recover the 5D black hole solution already known.

This paper concludes our efforts in describing $SU(3)$-Yang-Mills theories at different couplings/temperatures in terms of effective Polyakov-loop models. The associated effective couplings are determined through an inverse Monte Carlo procedure based on novel Schwinger-Dyson equations that employ the symmetries of the Haar measure. Because of the first-order nature of the phase transition we encounter a fine-tuning problem in reproducing the correct behavior of the Polyakov-loop from the effective models. The problem remains under control as long as the number of effective couplings is sufficiently small.