The recent discovery of a narrow resonance in $D_s{\pi }^0$ by the BaBar Collaboration is consistent with the interpretation of a heavy $J^P{(0\mathrm{}}^{+}{,1\mathrm{}}^{+})$ spin multiplet. This system is the parity partner of the ground state ${(0\mathrm{}}^{-}{,1\mathrm{}}^{-})$ multiplet, which we argue is required in the implementation of ${\mathrm{SU}\left(3\right)\mathrm{}}_L\times {\mathrm{SU}\left(3\right)\mathrm{}}_R$ chiral symmetry in heavy-light meson systems. The ${(0\mathrm{}}^{+}{,1\mathrm{}}^{+})\to {(0\mathrm{}}^{-}{,1\mathrm{}}^{-})+\pi$ transition couplings satisfy a Goldberger-Treiman relation, $g_{\pi }=\Delta {M/f}_{\pi },$ where $\Delta M$ is the mass gap. The BaBar resonance fits the $0^{+}$ state, with a kinematically blocked principal decay mode to $D+K.\mathrm{}$ The allowed $D_s+\pi ,$ $D_s+2\mathrm{}\pi ,$ and electromagnetic transitions are computed from the full chiral theory and found to be suppressed, consistent with the narrowness of the state. This state establishes the chiral mass difference for all such heavy-quark chiral multiplets, and precise predictions exist for the analogous $B_s$ and strange doubly heavy baryon states.

To one loop the effective neutrino photon interaction takes place through vector-vector-type and axial-vector–vector–type amplitudes. In this work we explicitly write down the form of the axial-vector–vector amplitude to all orders in the external magnetic field in a medium. We then infer its zero external momentum limit which contributes to the effective charge of the neutrinos inside a magnetized medium. We further show its gauge invariance properties.

An unusual Centauro phenomenon in which cosmic rays enter the atmosphere producing tens of charged hadrons, but virtually no neutral pions, has been a mystery for more than 30 years. Since the discovery of Centauro I in 1972 by the Brazil-Japan Collaboration operating x-ray emulsion chambers at 5200 m on Mt. Chacaltaya in the Bolivian Andes, a variety of models have been proposed (including new types of interaction or the creation of new types of matter). Here we show that the solution to a long-standing scientific puzzle lies with the details of the Chacaltaya detector. The new analysis of the original Centauro I event reveals that there is a difference in the angle between the upper block and lower block events, so the two are not products of the same interaction. That leaves only the lower chamber data connected to the Centauro I event. It is shown that, with the revised understanding of the event, new physics is no longer required for the explanation.

The cross section of the process $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}{\pi }^0$ was measured in the Spherical Neutral Detector (SND) experiment at the VEPP-2M collider in the energy region $\sqrt{s}$ below 980 MeV. This measurement was based on about $1.2\times {10}^6$ selected events. The obtained cross section was analyzed together with the SND and DM2 data in the energy region $\sqrt{s}$ up to 2 GeV. The $\omega$-meson parameters $m_{\omega }=782.79\mathrm{}\pm 0.08\pm 0.09\mathrm{MeV},$ ${\Gamma }_{\omega }=8.68\mathrm{}\pm 0.04\pm 0.15\mathrm{MeV},$ and $\sigma \left(\overrightarrow{\omega }3\pi \right)=1615\mathrm{}\pm 9\pm 57\mathrm{nb}$ were obtained. It was found that the experimental data cannot be described by a sum of only $\omega ,$ $\phi ,$ ${\omega }^{\prime },$ and ${\omega }^{″}$ resonance contributions. This can be interpreted as a manifestation of $\overrightarrow{\rho }3\pi$ decay, suppressed by G parity, with a relative probability $B(\overrightarrow{\rho }3\pi {)=(1.01\mathrm{}}_{-0.36}^{+0.54\mathrm{}}\pm 0.034)\times {10}^{-4}.$

We study the evolution of a Born-Infeld (BI) type phantom in the second Randall-Sundrum brane world scenario, and find that an attractor solution exists for the potential with a maximum, which implies a cosmological constant at late time. Especially, we discuss the BI model of the constant potential without and with dust matter. In the weak tension limit of the brane, we obtain an exact solution for the BI phantom and scale factor and show that there is no big rip during the evolution of the brane.

We study the supergravity dual to the confinement or deconfinement phase transition for the $\mathcal{N}=4\mathrm{}$ $\mathrm{SU}\mathrm{}\left(N\right)\mathrm{}$ super Yang-Mills theory on $R\times {\mathrm{S}}^3$ with a chemical potential conjugate to a $\mathrm{U}\mathrm{}\left(1\right)\mathrm{}\subset \mathrm{SO}{\mathrm{}\left(6\right)\mathrm{}}_R$ charge. The appropriate supergravity system is a single-charge black hole in $D=5\mathrm{}$ $\mathcal{N}=8\mathrm{}$ gauged supergravity. The application of the gauge-string theory holographic renormalization approach leads to new expressions for the black hole Arnowitt-Deser-Misner mass and its generalized free energy. We comment on the relation of this phase transition to the Hagedorn transition for strings in the maximally supersymmetric plane wave background with null Ramond-Ramond five-form field strength.

Free scalar field theory in the sector with a large number of particles can be interpreted as bosonic string theory on anti–de Sitter space of a vanishing radius. Different ways of writing the field theory Hamiltonian translate to different ways of reparametrizing the world-sheet $\sigma$ coordinate. Adding a mass term in the field theory corresponds to cutting off the warped AdS direction, with the cutoff inversely proportional to the mass. The string theory has neither a tachyon nor a critical dimension.

Some of the recent important developments in understanding string/gauge dualities are based on the idea of the highly symmetric motion of “string solitons” in the ${\mathrm{AdS}}_5\times {\mathrm{S}}^5$ geometry originally suggested by Gubser, Klebanov, and Polyakov. In this paper we study the symmetric motion of certain string configurations in the so-called Pilch-Warner geometry. The two-form field $A_2$ breaks down the supersymmetry to $\mathcal{N}=1\mathrm{}$ but for the string configurations considered in this paper the classical values of the energy and the spin are the same as for string in $\mathrm{AdS}\times {\mathrm{S}}^5.$ Although trivial at the classical level, the presence of the NS-NS antisymmetric field couples the fluctuation modes that indicates changes in the quantum corrections to the energy spectrum. We compare our results with those obtained in the case of the pp-wave limit.

Following the Boltzmann-BBGKY paradigm we propose a correlation entropy (of the nth order) for an interacting quantum field. The concept of correlation entropy is useful for addressing issues related to thermalization. As a small yet important step in that direction, we state an H theorem for the correlation entropy of a quantum-mechanical $\mathrm{O}\mathrm{}\left(N\right)\mathrm{}$ model with a closed time path two-particle irreducible effective action at the level of a next-to-leading-order large N approximation. This model may be regarded as a field theory in 0 space dimensions. We verify the validity of the proposed H theorem in two limiting cases.

We calculate the vacuum energy of a spinor field in the background of a Nielsen-Olesen vortex. We use the method of representing the vacuum energy in terms of the Jost function on the imaginary momentum axis. We use zeta-functional regularization. Renormalization is then carried out with the help of the heat kernel expansion. This method gives rise to well convergent sums and integrals which allow for an efficient numerical calculation of the vacuum energy even in the case when the background is not known analytically but only numerically. The vacuum energy is calculated for several choices of the parameters and, as it turns out, is small compared to the classical energy.

Modifications of the electromagnetic Maxwell Lagrangian in four dimensions have been considered by some authors. One may include an explicit massive (Proca) term and a topological but not Lorentz-invariant term within certain observational limits. We find the dual-corresponding gauge-invariant version of this theory by using the recently suggested gauge embedding method. We enforce this dualization procedure by showing that, in many cases, this is actually a constructive method to find a sort of parent action, which manifestly establishes duality. We also use the gauge-invariant version of this theory to formulate a Batalin-Vilkovisky quantization and present a detailed discussion of the excitation spectrum.

We develop the derivative expansion of the one-loop $\mathcal{N}=4\mathrm{}$ super Yang-Mills (SYM) effective action depending both on the $\mathcal{N}=2\mathrm{}$ vector multiplet and on hypermultiplet background fields. Beginning with the formulation of $\mathcal{N}=4\mathrm{}$ SYM theory in terms of $\mathcal{N}=1\mathrm{}$ superfields, we construct the one-loop effective action with the help of superfield functional determinants and calculate this effective action in $\mathcal{N}=1\mathrm{}$ superfield form using the approximation of constant Abelian strength $F_{\mathrm{mn}}$ and corresponding constant hypermultiplet fields. Then we show that the terms in the supercovariant derivative expansion of the effective action can be rewritten in terms of $\mathcal{N}=2\mathrm{}$ superfields. As a result, we get a new derivation of the complete $\mathcal{N}=4\mathrm{}$ supersymmetric low-energy effective action obtained by Buchbinder and Ivanov and find subleading corrections to it.

We summarize the consequences of the twin assumptions of (discrete) self-similarity and spherical symmetry for the global structure of a spacetime. All such spacetimes can be constructed from two building blocks: the “fan” and “splash.” Each building block contains one radial null geodesic that is invariant under the self-similarity (self-similarity horizon).

The lightest Kaluza-Klein particle appearing in models with universal extra dimensions has recently been proposed as a viable dark matter candidate when the extra dimensions are compactified on a scale of the order of 1 TeV. Underlying assumptions of this proposal are that the size of the extra dimensions stays constant and that the evolution of the universe is given by standard cosmology. Here we investigate, both analytically and numerically, whether this is possible without introducing an explicit stabilization mechanism. By analyzing Einstein’s field equations for a $\mathrm{}(3+n+1)\mathrm{}$-dimensional homogeneous, but in general anisotropic, universe, we find that approximately static extra dimensions arise naturally during radiation domination. For matter domination, however, there are no solutions to the field equations that allow static extra dimensions or the usual behavior of the scale factor for ordinary three-dimensional space. We conclude that an explicit mechanism is needed in order to stabilize the extra dimensions and reproduce standard cosmology as we know it.

We examine the particle production via preheating at the end of inflation in supersymmetric theories. The inflaton and matter scalars are now necessarily complex fields, and their relevant interactions are restricted by holomorphy. In general this leads to major changes both in inflaton dynamics and in the efficiency of the preheating process. In addition, supersymmetric models generically contain multiple isolated vacua, raising the possibility of non-thermal production of dangerous topological defects. Because of these effects, the success of leptogenesis or wimpzilla production via preheating depends much more sensitively on the detailed parameters in the inflaton sector than previously thought.

We consider a quantum deformation of the wave equation on a cosmological background as a toy model for possible trans-Planckian effects. We compute the power spectrum of scalar and tensor fluctuations for power-law inflation, and find a noticeable deviation from the standard result. We consider de Sitter inflation as a special case, and find that the resulting power spectrum is scale invariant. For both inflationary scenarios the departure from the standard spectrum is sensitive to the size of the deformation parameter. A modulation in the power spectrum appears to be a generic feature of the model.

We calculate the power spectrum of metric fluctuations in inflationary cosmology starting with initial conditions which are imposed mode by mode when the wavelength equals some critical length ${\mathcal{l}}_{\mathrm{C}}$ corresponding to a new energy scale $M_{\mathrm{C}}$ at which trans-Planckian physics becomes important. In this case, the power spectrum can differ from what is calculated in the usual framework (which amounts to choosing the adiabatic vacuum state). The fractional difference in the results depends on the ratio ${\sigma }_0$ between the Hubble expansion rate $H_{\inf }$ during inflation and the new energy scale $M_{\mathrm{C}}.$ We show how and why different choices of the initial vacuum state (stemming from different assumptions about trans-Planckian physics) lead to fractional differences which depend on different powers of ${\sigma }_0.$ As we emphasize, the power in general also depends on whether one is calculating the power spectrum of density fluctuations or of gravitational waves.

We explore the possibility of detecting horizontal electromagnetic showers of tau neutrinos from individual gamma ray bursts (GRBs), in large scale detectors such as HiRes and the Telescope Array. We study the role of the parameters of a gamma ray burst in determining the expected number of tau events from that burst. The horizontal beam of tau leptons produces visible signals in the atmosphere. We find that there is a slim chance of observing tau lepton appearances from GRBs with the Telescope Array. The number of signals is strongly dependent on the Lorentz factor $\Gamma$ and the redshift z of a GRB, on the energy emitted in muon neutrinos and antineutrinos $E_{\nu ,HE},$ and also on some other parameters of a GRB. It is possible to understand neutrino oscillations in astrophysical neutrinos and the mechanism or model of neutrino production inside a GRB by the detection or nondetection of tau lepton signals from it.

The relativity of Global Positioning System (GPS) pseudorange measurements is explored within the geometrical optics approximation in the curved space-time near Earth. A space-time grid for navigation is created by the discontinuities introduced in the electromagnetic field amplitude by the P-code broadcast by the GPS satellites. We compute the world function of space-time near Earth, and we use it to define a scalar phase function that describes the space-time grid. We use this scalar phase function to define the measured pseudorange, which turns out to be a two-point space-time scalar under generalized coordinate transformations. Though the measured pseudorange is an invariant, it depends on the world lines of the receiver and satellite. While two colocated receivers measure two different pseudoranges to the same satellite, they obtain the correct position and time, independent of their velocity. We relate the measured pseudorange to the geometry of space-time and find corrections to the conventional model of the pseudorange that are on the order of the gravitational radius of the Earth.

The cosmic microwave background (CMB) has provided a precise template for features in the linear power spectrum: the matter-radiation turnover, sound horizon drop, and acoustic oscillations. In a two-dimensional power spectrum in redshift and angular space, the features appear as distorted rings, and yield simultaneous, purely geometric, measures of the Hubble parameter $H\left(z\right)\mathrm{}$ and angular diameter distance $D_A\mathrm{}\left(z\right)\mathrm{}$ via an absolute version of the Alcock-Paczynski test. Employing a simple Fisher matrix tool, we explore how future surveys can exploit these rings of power for dark energy studies. High-z CMB determinations of H and $D_A$ are best complemented at moderate to low redshift $(z\lesssim 0.5)$ with a population of objects that are at least as abundant as clusters of galaxies. We find that a sample similar to that of the ongoing SDSS luminous red galaxy survey can achieve statistical errors at the $\sim 5\%$ level for $D_A\mathrm{}\left(z\right)\mathrm{}$ and $H\left(z\right)\mathrm{}$ in several redshift bins. This, in turn, implies errors of $\sigma \mathrm{}\left(w\right)=0.03\mathrm{}–0.05$ for a constant dark energy equation of state in a flat universe. Deep galaxy cluster surveys such as the planned South Pole Telescope survey can extend this test out to $z\sim 1$ or as far as redshift follow-up is available. We find that the expected constraints are at the $\sigma \mathrm{}\left(w\right)=0.04\mathrm{}–0.08$ level, comparable to those of galaxies and complementary in redshift coverage.