We study the dynamics in phases with vector condensates of gluons (gluonic phases) in dense two-flavor quark matter. These phases yield an example of dynamics in which the Higgs mechanism is provided by condensates of gauge (or gauge plus scalar) fields. Because vacuum expectation values of spatial components of vector fields break the rotational symmetry, it is natural to have a spontaneous breakdown both of external and internal symmetries in this case. In particular, by using the Ginzburg-Landau approach, we establish the existence of a gluonic phase with both the rotational symmetry and the electromagnetic $U(1)$ being spontaneously broken. In other words, this phase describes an anisotropic medium in which the color and electric superconductivities coexist. It is shown that this phase corresponds to a minimum of the Ginzburg-Landau potential and, unlike the two-flavor superconducting (2SC) phase, it does not suffer from the chromomagnetic instability. The dual (confinement) description of its dynamics is developed and it is shown that there are light exotic vector hadrons in the spectrum, some of which condense. Because most of the initial symmetries in this system are spontaneously broken, its dynamics is very rich.

The presence of the antisymmetric background field $B_{\mu \nu }$ leads to the noncommutativity of the Dp-brane manifold, while the linear dilaton field in the form $\Phi (x)={\Phi }_0+a_{\mu }{x}^{\mu }$ causes the appearance of the commutative Dp-brane coordinate, $x_c=a_{\mu }{x}^{\mu }$. In the present article we consider the case where the conformal invariance is realized by inclusion of the Liouville term. Then, the theory is conformally invariant even in the presence of the world-sheet conformal factor $F$, and it depends on the new parameter, the central charge $c$. As well as in the absence of the Liouville action, for particular relations between background fields, the local gauge symmetries appear in the theory. They turn some Neumann boundary conditions into the Dirichlet ones, and decrease the number of the Dp-brane dimensions.

The Born-Infeld strategy to smooth theories having divergent solutions is applied to the teleparallel equivalent of general relativity. Differing from other theories of modified gravity, modified teleparallelism leads to second order equations, since the teleparallel Lagrangian only contains first derivatives of the vierbein. We show that the Born-Infeld-modified teleparallelism solves the particle horizon problem in a spatially flat Friedmann-Robertson-Walker (FRW) universe by providing an initial exponential expansion without resorting to an inflaton field.

It is widely believed that the existence of singlet scalars in some standard model extensions can easily make the electroweak phase transition strongly first order, which is needed for the electroweak baryogenesis scenario. In this paper, we will examine the strength of the electroweak phase transition in the simplest extension of the standard model with a real singlet using the sphaleron energy at the critical temperature. We find that the phase transition is stronger by adding a singlet; and also that the criterion for a strong phase transition $\Omega (T_c)/T_c\gtrsim 1$, where $\Omega =({\upsilon }^2+(x-x_0{)}^2{)}^{1/2}$ and $x$ ($x_0$) is the singlet vev in the broken (symmetric) phase, is not valid for models containing singlets, even though often used in the literature. The usual condition ${\upsilon }_c/T_c\gtrsim 1$ is more meaningful, and it is satisfied for a large part of the parameter space for physically allowed Higgs masses.

We use the Cosmic Microwave Background Anisotropies (CMBA) power spectra to constrain the cosmological variation of gravitational constant $G$. It is found that the sensitivity of CMBA to the variation of $G$ is enhanced when $G$ is required to converge to its present value. The variations of $G$ from the CMB decoupling epoch $z\sim 1000$ to the present time are modeled by a step function and a linear function of scale factor $a$ respectively, and the corresponding 95% confidence intervals for $G/G_0$ are [0.95, 1.05] and [0.89, 1.13], $G_0$ being the present value. The CMBA constraint is unique in the sense that it entails the range of redshift from $z\approx 1000$ to 0.

We examine the choice of scale at which constraints on inflationary observables are presented. We describe an implementation of the hierarchy of inflationary consistency equations which ensures that they remain enforced on different scales, and then seek to optimize the scale for presentation of constraints on marginalized inflationary parameters from WMAP3 data. For models with spectral index running, we find a strong variation of the constraints through the range of observational scales available, and optimize by finding the scale which decorrelates constraints on the spectral index $n_{\mathrm{S}}$ and the running. This scale is $k=0.017{\mathrm{Mpc}}^{-1}$, and gives a reduction by a factor of more than four in the allowed parameter area in the $n_{\mathrm{S}}–r$ plane ($r$ being the tensor-to-scalar ratio) relative to $k=0.002{\mathrm{Mpc}}^{-1}$. These optimized constraints are similar to those obtained in the no-running case. We also extend the analysis to a larger compilation of data, finding essentially the same conclusions.

We develop a nonperturbative method that yields analytical expressions for the deflection angle of light in a general static and spherically symmetric metric. The method works by introducing into the problem an artificial parameter, called $\delta$, and by performing an expansion in this parameter to a given order. The results obtained are analytical and nonperturbative because they do not correspond to a polynomial expression in the physical parameters. Already to first order in $\delta$ the analytical formulas obtained using our method provide at the same time accurate approximations both at large distances (weak deflection limit) and at distances close to the photon sphere (strong deflection limit). We have applied our technique to different metrics and verified that the error is at most 0.5% for all regimes. We have also proposed an alternative approach which provides simpler formulas, although with larger errors.

It is shown that instantons can provide an explanation of the strong polarization transfer observed in exclusive hyperon photoproduction at JLab.

We consider Semi-Exclusive Deeply Virtual Compton Scattering, ${\gamma }^{*}p\to \gamma Y$ (SECS), where $Y$ is an inclusive state of intermediate mass, ${\Lambda }_{\mathrm{QCD}}\ll m_Y\ll Q$. When the photon is produced with a large transverse momentum $k_{\perp }\sim m_Y$ the subprocess is hard and the struck quark fragments independently of the target spectators. Using completeness this allows us to express the SECS cross section in terms of ordinary parton distributions. Apart from direct comparisons with data (yet to come) new information on Bloom-Gilman duality may be obtained through comparisons of resonance production via DVCS (${\gamma }^{*}p\to \gamma N^{*}$) with the SECS scaling distribution in $m_Y$.

We reconsider thermal production of gravitinos in the early universe, adding to previously considered $2\to 2$ gauge scatterings: (a) production via $1\to 2$ decays, allowed by thermal masses: this is the main new effect, (b) the effect of the top Yukawa coupling, and (c) a proper treatment of the reheating process. Our final result behaves physically (larger couplings give a larger rate) and is twice larger than previous results, implying e.g. a constraint on the reheating temperature that is twice as strong. Accessory results about (supersymmetric) theories at finite temperature and gravitino couplings might have some pertinence.

General constraints on fluid velocity divergences for particles in quark matter are derived from baryon number conservation and enforced electric charge neutrality. A new oscillation pattern in three-flavor normal quark matter satisfying these conditions is found and its bulk viscosity is calculated. The result may have astrophysical implication for maximum rotation frequencies of compact stars.

In many calculations of the two-photon decay of hadronic molecules, the decay matrix element is estimated using the wave function at the origin prescription, in analogy to the two-photon decay of parapositronium. We question the applicability of this procedure to the two-photon decay of hadronic molecules for it introduces an uncontrolled model dependence into the calculation. As an alternative approach, we propose an explicit evaluation of the hadron loop. For shallow bound states, this can be done as an expansion in powers of the range of the molecule binding force $1/\beta$. In the leading order one gets the well-known pointlike limit answer. We estimate, in a self-consistent and gauge-invariant way, the leading range corrections for the two-photon decay width of weakly bound hadronic molecules emerging from kaon loops. We find them to be small, of order $\mathcal{O}(m\epsilon /{\beta }^2)$, where $m$ and $\epsilon$ denote the mass of the constituents and the binding energy, respectively. The role of possible short-ranged operators and of the width of the scalars remains to be investigated.

We improve on a recent determination of ${\alpha }_{\mathrm{s}}$ from $\Gamma ({\rm Y}(1S)\to \gamma X)/\Gamma ({\rm Y}(1S)\to X)$ with CLEO data by taking into account color octet contributions and avoiding any model dependence in the extraction. We obtain ${\alpha }_{\mathrm{s}}(M_{{\rm Y}(1S)})={0.184}_{-0.014}^{+0.015}$, which corresponds to ${\alpha }_{\mathrm{s}}(M_Z)={0.119}_{-0.005}^{+0.006}$.

We point out that an accurate in situ determination of the earth matter density $\rho$ is possible in neutrino factory by placing a detector at the magic baseline, $L=\sqrt{2}\pi /G_F{N}_e$ where $N_e$ denotes electron number density. The accuracy of matter density determination is excellent in a region of relatively large ${\theta }_{13}$ with fractional uncertainty $\delta \rho /\rho$ of about 0.43%, 1.3%, and $\lesssim 3\%$ at $1\sigma$ CL at ${sin}^{2}2{\theta }_{13}=0.1$, ${10}^{-2}$, and $3\times {10}^{-3}$, respectively. At smaller ${\theta }_{13}$ the uncertainty depends upon the $CP$ phase $\delta$, but it remains small, 3%–7% in more than $3/4$ of the entire region of $\delta$ at ${sin}^{2}2{\theta }_{13}={10}^{-4}$. The results would allow us to solve the problem of obscured $CP$ violation due to the uncertainty of earth matter density in a wide range of ${\theta }_{13}$ and $\delta$. It may provide a test for the geophysical model of the earth, or it may serve as a method for a stringent test of the Mikheyev-Smirnov-Wolfenstein theory of neutrino propagation in matter once an accurate geophysical estimation of the matter density is available.

The extrapolation of nucleon magnetic form factors calculated within lattice QCD is investigated within a framework based upon heavy baryon chiral effective-field theory. All one-loop graphs are considered at arbitrary momentum transfer and all octet and decuplet baryons are included in the intermediate states. Finite range regularization is applied to improve the convergence in the quark-mass expansion. At each value of the momentum transfer ($Q^2$), a separate extrapolation to the physical pion mass is carried out as a function of $m_{\pi }$ alone. Because of the large values of $Q^2$ involved, the role of the pion form factor in the standard pion-loop integrals is also investigated. The resulting values of the form factors at the physical pion mass are compared with experimental data as a function of $Q^2$ and demonstrate the utility and accuracy of the chiral extrapolation methods presented herein.

We report improved measurements of $B$ decays with an $\eta$ meson in the final state using $492{\mathrm{fb}}^{-1}$ of data collected by the Belle detector at the KEKB $e^{+}{e}^{-}$ collider. We observe the decays $B^{\pm }\to \eta {\pi }^{\pm }$ and $B^{\pm }\to \eta K^{\pm }$ and measure the branching fractions $\mathcal{B}(B^{\pm }\to \eta {\pi }^{\pm })=\mathbf{(}4.2\pm 0.4(\mathrm{stat})\pm 0.2(\mathrm{sys})\mathbf{)}\times {10}^{-6}$ and $\mathcal{B}(B^{\pm }\to \eta K^{\pm })=\mathbf{(}1.9\pm 0.3(\mathrm{stat}{)}_{-0.1}^{+0.2}(\mathrm{sys})\mathbf{)}\times {10}^{-6}$. The corresponding $CP$-violating asymmetries are measured to be $-0.23\pm 0.09(\mathrm{stat})\pm 0.02(\mathrm{sys})$ for $\eta {\pi }^{\pm }$ and $-0.39\pm 0.16(\mathrm{stat})\pm 0.03(\mathrm{sys})$ for $\eta K^{\pm }$. We also search for $B^0\to \eta K^0$ decays and set an upper limit of $1.9\times {10}^{-6}$ at the 90% confidence level.

We present an expression for the leading-color (planar) four-loop four-point amplitude of $\mathcal{N}=4$ supersymmetric Yang-Mills theory in $4-2ϵ$ dimensions, in terms of eight separate integrals. The expression is based on consistency of unitarity cuts and infrared divergences. We expand the integrals around $ϵ=0$, and obtain analytic expressions for the poles from $1/{ϵ}^8$ through $1/{ϵ}^4$. We give numerical results for the coefficients of the $1/{ϵ}^3$ and $1/{ϵ}^2$ poles. These results all match the known exponentiated structure of the infrared divergences, at four separate kinematic points. The value of the $1/{ϵ}^2$ coefficient allows us to test a conjecture of Eden and Staudacher for the four-loop cusp (soft) anomalous dimension. We find that the conjecture is incorrect, although our numerical results suggest that a simple modification of the expression, flipping the sign of the term containing ${\zeta }_3^2$, may yield the correct answer. Our numerical value can be used, in a scheme proposed by Kotikov, Lipatov, and Velizhanin, to estimate the two constants in the strong-coupling expansion of the cusp anomalous dimension that are known from string theory. The estimate works to 2.6% and 5% accuracy, providing nontrivial evidence in support of the AdS/CFT correspondence. We also use the known constants in the strong-coupling expansion as additional input to provide approximations to the cusp anomalous dimension which should be accurate to under 1% for all values of the coupling. When the evaluations of the integrals are completed through the finite terms, it will be possible to test the iterative, exponentiated structure of the finite terms in the four-loop four-point amplitude, which was uncovered earlier at two and three loops.

It is argued that dimensional reduction of the Seiberg-Witten map for a gauge field induces Seiberg-Witten maps for the other noncommutative fields of a gauge invariant theory. We demonstrate this observation by dimensionally reducing the noncommutative $N=1$ super Yang-Mills (SYM) theory in 6 dimensions to obtain noncommutative $N=2$ SYM in 4 dimensions. We explicitly derive Seiberg-Witten maps of the component fields in 6 and 4 dimensions. Moreover, we give a general method to define the deformed supersymmetry transformations that leave the actions invariant after performing Seiberg-Witten maps.

We show that four-dimensional Einstein-Maxwell-dilaton-Gauss-Bonnet gravity admits asymptotically flat black hole solutions with a degenerate event horizon of the Reissner-Nordström type ${\mathrm{AdS}}_2\times S^2$. Such black holes exist for the dilaton coupling constant within the interval $0\le a^2<a_{\mathrm{cr}}^2$. Black holes must be endowed with an electric charge and (possibly) with magnetic charge (dyons) but they cannot be purely magnetic. Purely electric solutions are constructed numerically and the critical dilaton coupling is determined $a_{\mathrm{cr}}\simeq 0.488219703$. For each value of the dilaton coupling $a$ within this interval and for a fixed value of the Gauss-Bonnet coupling $\alpha$ we have a family of black holes parametrized by their electric charge. The relation between the mass, the electric charge, and the dilaton charge at both ends of the allowed interval of $a$ is reminiscent of the Bogomol’nyi-Prasad-Sommerfield condition for dilaton black holes in the Einstein-Maxwell-dilaton theory. The entropy of the dilaton-Gauss-Bonnet extremal black holes is twice the Bekenstein-Hawking entropy.