We study the contribution of the strong interactions between the two pions in $S$ and $P$ waves to the weak $B\to \pi \pi K$ decay amplitudes. The interference between these two waves is analyzed in the $\pi \pi$ effective-mass range of the $\rho (770{)}^0$ and $f_0(980)$ resonances. We use a unitary $\pi \pi$ and $\overline{K}K$ coupled-channel model to describe the $S$-wave interactions and a Breit-Wigner function for the $P$-wave amplitude. The weak $B$-decay amplitudes, obtained from QCD factorization, are supplemented with charming penguin contributions in both waves. The four complex parameters of these long-distance terms are determined by fitting the model to the BABAR and Belle data on $B^{\pm ,0}\to {\pi }^{+}{\pi }^{-}{K}^{\pm ,0}$ branching fractions, $CP$ asymmetries, $\pi \pi$ effective-mass and helicity-angle distributions. This set of data, and, in particular, the large direct $CP$ asymmetry for $B^{\pm }\to \rho (770{)}^0{K}^{\pm }$ decays, is well reproduced. The interplay of charming penguin amplitudes and the interference of $S$ and $P$ waves describes rather successfully the experimental $\mathcal{S}$ and $\mathcal{A}$ values of the $CP$-violating asymmetry for both $B^0\to f_0(980)K_S^0$ and $B^0\to \rho (770{)}^0{K}_S^0$ decays.

We calculate the quark-antiquark contribution to the next-to-leading logarithmic (NLL) corrections to the BFKL kernel, retaining the dependence on the momenta of the produced particles. This allows us to study the details of the NLL corrections. We demonstrate that the standard calculation of the NLL corrections to the scattering of two off-shell gluons includes contributions from energies far above that which is probed at LL. This explicitly violates energy and momentum conservation in the evolution and could be a source of the reported large NLL corrections. The presented calculation is a step towards combining energy and momentum conservation with full NLL accuracy in the evolution.

We present a model for dihadron fragmentation functions, describing the fragmentation of a quark into two unpolarized hadrons. We tune the parameters of our model to the output of the PYTHIA event generator for two-hadron semi-inclusive production in deep-inelastic scattering at HERMES. Once the parameters of the model are fixed, we make predictions for other unknown fragmentation functions and for a single-spin asymmetry in the azimuthal distribution of ${\pi }^{+}{\pi }^{-}$ pairs in semi-inclusive deep-inelastic scattering on a transversely polarized target at HERMES and COMPASS. Such asymmetry could be used to measure the quark transversity distribution function.

A mass-independent texture is a set of linear relations of the fermion mass-matrix elements which imposes no constraint on the fermionic masses nor the Majorana phases. Magic and 2–3 symmetries are examples. We discuss the general construction and the properties of these textures, as well as their relation to the quark and neutrino mixing matrices. Such a texture may be regarded as a symmetry, whose unitary generators of the symmetry group can be explicitly constructed. In particular, the symmetries connected with the tribimaximal neutrino mixing matrix are discussed, together with the physical consequence of breaking one symmetry but preserving another.

We consider a scenario for the quark-lepton complementarity relations between mixing angles in which the bimaximal mixing follows from the neutrino mass matrix. According to this scenario in the lowest order the angle ${\theta }_{12}$ is $\sim 1\sigma$ (1.5°–2°) above the best fit point coinciding practically with the tribimaximal mixing prediction. Realization of this scenario in the context of the seesaw type-I mechanism with leptonic Dirac mass matrices approximately equal to the quark mass matrices is studied. We calculate the renormalization group corrections to ${\theta }_{12}$ as well as to ${\theta }_{13}$ in the standard model (SM) and minimal supersymmetric standard model (MSSM). We find that in a large part of the parameter space corrections $\Delta {\theta }_{12}$ are small or negligible. In the MSSM version of the scenario, the correction $\Delta {\theta }_{12}$ is in general positive. Small negative corrections appear in the case of an inverted mass hierarchy and opposite $CP$ parities of ${\nu }_1$ and ${\nu }_2$ when leading contributions to ${\theta }_{12}$ running are strongly suppressed. The corrections are negative in the SM version in a large part of the parameter space for values of the relative $CP$ phase of ${\nu }_1$ and ${\nu }_2$: $\phi >\pi /2$.

We point out that the Type Ia supernovae in the SNLS dataset are consistent with an early beginning of the cosmic acceleration if dark energy interacts strongly with dark matter. We find that the acceleration could have started at redshift $z\approx 3$ and higher.

We investigate the vacuum expectation value of the surface energy-momentum tensor for a massive scalar field with general curvature coupling parameter obeying the Robin boundary conditions on two codimension one parallel branes in a $(D+1)$-dimensional background spacetime ${\mathrm{AdS}}_{D_1+1}\times \Sigma$ with a warped internal space $\Sigma$. These vacuum densities correspond to a gravitational source of the cosmological constant type for both subspaces of the branes. Using the generalized zeta function technique in combination with contour integral representations, the surface energies on the branes are presented in the form of the sum of single-brane and second-brane-induced parts. For the geometry of a single brane both regions, on the left and on the right of the brane, are considered. At the physical point the corresponding zeta functions contain pole and finite contributions. For an infinitely thin brane taking these regions together, in odd spatial dimensions the pole parts cancel and the total zeta function is finite. The renormalization procedure for the surface energies and the structure of the corresponding counterterms are discussed. The parts in the surface densities generated by the presence of the second brane are finite for all nonzero values of the interbrane separation and are investigated in various asymptotic regions of the parameters. In particular, it is shown that for large distances between the branes the induced surface densities give rise to an exponentially suppressed cosmological constant on the brane. The total energy of the vacuum including the bulk and boundary contributions is evaluated by the zeta function technique and the energy balance between separate parts is discussed.

We examine coherent active-active channel neutrino flavor evolution in environments where neutrino-neutrino forward scattering can engender large-scale collective flavor transformation. We introduce the concept of neutrino flavor isospin which treats neutrinos and antineutrinos on an equal footing, and which facilitates the analysis of neutrino systems in terms of the spin precession analogy. We point out a key quantity, the “total effective energy,” which is conserved in several important regimes. Using this concept, we analyze collective neutrino and antineutrino flavor oscillation in the synchronized mode and what we term the bi-polar mode. We thereby are able to explain why large collective flavor mixing can develop on short time scales even when vacuum mixing angles are small in, e.g., a dense gas of initially pure ${\nu }_e$ and ${\overline{\nu }}_e$ with an inverted neutrino mass hierarchy (an example of bi-polar oscillation). In the context of the spin precession analogy, we find that the corotating frame provides insights into more general systems, where either the synchronized or bi-polar mode could arise. For example, we use the corotating frame to demonstrate how large flavor mixing in the bi-polar mode can occur in the presence of a large and dominant matter background. We use the adiabatic condition to derive a simple criterion for determining whether the synchronized or bi-polar mode will occur. Based on this criterion, we predict that neutrinos and antineutrinos emitted from a protoneutron star in a core-collapse supernova event can experience synchronized and bi-polar flavor transformations in sequence before conventional Mikhyev-Smirnov-Wolfenstein flavor evolution takes over. This certainly will affect the analyses of future supernova neutrino signals, and might affect the treatment of shock reheating rates and nucleosynthesis depending on the depth at which collective transformation arises.

We study the pion electromagnetic form factor and the dilepton production rate in hot matter using the hidden local symmetry theory as an effective field theory for pions and $\rho$ mesons. In this framework, the chiral symmetry restoration is realized as the vector manifestation (VM) in which the massless vector meson becomes the chiral partner of the pion, giving a theoretical support to the dropping $\rho$ à la Brown-Rho scaling. In the VM, the vector dominance (VD) is strongly violated near the phase transition point associated with the dropping $\rho$. We show that the effect of the violation of the VD substantially suppresses the dilepton production rate compared with the one predicted by assuming the VD together with the dropping $\rho$.

We consider the color spin locking (CSL) phase of two-flavor quark matter at zero temperature for nonlocal instantaneous separable interactions. We employ a Lorentzian-type form factor allowing a parametric interpolation between the sharp [Nambu-Jona-Lasinio (NJL) model] and very smooth (e.g. Gaussian) cutoff models for systematic studies of the influence on the CSL condensate the deviation from the NJL model entails. This smoothing of the NJL model form factor shows advantageous features for the phenomenology of compact stars: (i) a lowering of the critical chemical potential for the onset of the chiral phase transition as a prerequisite for stability of hybrid stars with extended quark matter cores and (ii) a reduction of the smallest pairing gap to the order of 100 keV, being in the range of values interesting for phenomenological studies of hybrid star cooling evolution.

The AdS/CFT correspondence and a classical test string approximation are used to calculate the drag force on an external quark moving in a thermal plasma of $\mathcal{N}=4$ super-Yang-Mills theory. This computation is motivated by the phenomenon of jet-quenching in relativistic heavy ion collisions.

We study the phase space of the spherically symmetric solutions of the system obtained from the dimensional reduction of the six-dimensional Einstein-Gauss-Bonnet action. We show that all the physically significant solutions are either asymptotically flat or asymptotically anti–de Sitter.

Thermal inflation can solve serious cosmological problems such as overproduction of gravitinos and moduli. However, it also dilutes the preexisting baryon asymmetry. We investigate a possibility that the Affleck-Dine mechanism works after thermal inflation and generates the baryon number at an acceptable level using lattice calculation. We find that a proper amount of baryon number can be generated for appropriate model parameters.

We measure the large-scale real-space power spectrum $P(k)$ using luminous red galaxies (LRGs) in the Sloan Digital Sky Survey (SDSS) and use this measurement to sharpen constraints on cosmological parameters from the Wilkinson Microwave Anisotropy Probe (WMAP). We employ a matrix-based power spectrum estimation method using Pseudo-Karhunen-Loève eigenmodes, producing uncorrelated minimum-variance measurements in 20 $k$-bands of both the clustering power and its anisotropy due to redshift-space distortions, with narrow and well-behaved window functions in the range $0.01h/\mathrm{Mpc}<k<0.2h/\mathrm{Mpc}$. Results from the LRG and main galaxy samples are consistent, with the former providing higher signal-to-noise. Our results are robust to omitting angular and radial density fluctuations and are consistent between different parts of the sky. They provide a striking confirmation of the predicted large-scale $\Lambda \mathrm{CDM}$ power spectrum. Combining only SDSS LRG and WMAP data places robust constraints on many cosmological parameters that complement prior analyses of multiple data sets. The LRGs provide independent cross-checks on ${\Omega }_m$ and the baryon fraction in good agreement with WMAP. Within the context of flat $\Lambda \mathrm{CDM}$ models, our LRG measurements complement WMAP by sharpening the constraints on the matter density, the neutrino density and the tensor amplitude by about a factor of 2, giving ${\Omega }_m=0.24\pm 0.02$ ($1\sigma$), $\sum _{}^{}{m}_{\nu }\lesssim 0.9\mathrm{eV}$ (95%) and $r<0.3$ (95%). Baryon oscillations are clearly detected and provide a robust measurement of the comoving distance to the median survey redshift $z=0.35$ independent of curvature and dark energy properties. Within the $\Lambda \mathrm{CDM}$ framework, our power spectrum measurement improves the evidence for spatial flatness, sharpening the curvature constraint ${\Omega }_{\mathrm{tot}}=1.05\pm 0.05$ from WMAP alone to ${\Omega }_{\mathrm{tot}}=1.003\pm 0.010$. Assuming ${\Omega }_{\mathrm{tot}}=1$, the equation of state parameter is constrained to $w=-0.94\pm 0.09$, indicating the potential for more ambitious future LRG measurements to provide precision tests of the nature of dark energy. All these constraints are essentially independent of scales $k>0.1h/\mathrm{Mpc}$ and associated nonlinear complications, yet agree well with more aggressive published analyses where nonlinear modeling is crucial.

We compute the Bayesian evidences for one- and two-parameter models of evolving dark energy, and compare them to the evidence for a cosmological constant, using current data from Type Ia supernova, baryon acoustic oscillations, and the cosmic microwave background. We use only distance information, ignoring dark energy perturbations. We find that, under various priors on the dark energy parameters, $\Lambda \mathrm{CDM}$ is currently favored as compared to the dark energy models. We consider the parameter constraints that arise under Bayesian model averaging, and discuss the implication of our results for future dark energy projects seeking to detect dark energy evolution. The model selection approach complements and extends the figure-of-merit approach of the Dark Energy Task Force in assessing future experiments, and suggests a significantly-modified interpretation of that statistic.

We update a previous search for anisotropies in the neutrino background using the new results from the WMAP satellite. We found that the new data confirm the indication for anisotropies in the neutrino background at about $\sim 2\sigma$ c.l.. Parametrizing the neutrino background through the viscosity parameter $c_{\mathrm{vis}}^2$, we demonstrate that current cosmological data provide the constraint $c_{\mathrm{vis}}^2>0.145$ at 95% c.l. We discuss the stability of the result when the assumptions of massless neutrinos and the number of massless neutrino families are relaxed. In particular, we found that an extra background of relativistic particles, still compatible with the data, prefers anisotropic stresses with $c_{\mathrm{vis}}^2>0.09$ at 95% c.l..

We present new M2- and M5-brane solutions in M-theory based on transverse self-dual Bianchi type IX space. All the other recently M2- and M5-branes constructed on transverse self-dual Taub-NUT, Egughi-Hanson and Atiyah-Hitchin spaces are special cases of this solution. The solution provides a smooth transition from Eguchi-Hanson type I based M-branes to corresponding branes based on Eguchi-Hanson type II space. All the solutions can be reduced down to ten-dimensional fully localized intersecting brane configurations.

We develop systematically to all orders the forward scattering description for retarded amplitudes in field theories at zero temperature. Subsequently, through the application of the thermal operator, we establish the forward scattering description at finite temperature. We argue that, beyond providing a graphical relation between the zero temperature and the finite temperature amplitudes, this method is calculationally quite useful. As an example, we derive the important features of the one-loop retarded gluon self-energy in the hard thermal loop approximation from the corresponding properties of the zero temperature amplitude.

We give an argument for deriving analytically the infrared Abelian dominance in a gauge-invariant way for the Wilson loop average in SU(2) Yang-Mills theory. In other words, we propose a possible mechanism for realizing the dynamical Abelian projection in the SU(2) gauge-invariant manner without breaking color symmetry. This supports validity of the dual superconductivity picture for quark confinement. We also discuss the stability of the vacuum with magnetic condensation as a by-product of this result.

The construction of ready to use templates for gravitational waves from spinning binaries is an important challenge in the investigation of detectable gravitational wave signals. Here we present a method to evaluate the gravitational wave polarization states for inspiralling compact binaries in the extreme mass ratio limit. We discuss the effects caused by the rotation of the central massive object for eccentric orbits in the Lense-Thirring approximation and give the formal expressions of the polarization states including higher order corrections. Our results are in agreement with existing calculations for the spinless and circular orbit limits.