A nonlinear generalization of the fluctuation-dissipation theorem (FDT) for the n-point Green functions and the amputated one particle irreducible vertex functions at finite temperature is derived in the framework of the closed time path formalism. We verify that this generalized FDT coincides with known results for $n=2\mathrm{}$ and 3. New explicit relations among the 4-point nonlinear response and correlation (fluctuation) functions are presented.

Chiral cosmic string loops tend to the stationary (vorton) configuration due to energy loss into gravitational and electromagnetic radiation. We describe the asymptotic behavior of near stationary chiral loops and their fading to vortons. General limits on the gravitational and electromagnetic energy losses by near stationary chiral loops are found. For these loops we estimate the oscillation damping time. We present solvable examples of gravitational radiation energy loss by some chiral loop configurations. The analytical dependence of string energy with time is found in the case of the chiral ring with small amplitude radial oscillations.

It is shown that the Stelle-West Grignani-Nardelli formalism allows, both when odd dimensions and when even dimensions are considered, constructing actions for higher dimensional gravity invariant under local Lorentz rotations and under local Poincaré translations. It is also proved that such actions have the same coefficients as those obtained by Troncoso and Zanelli [Class. Quantum Grav. 17, 4451 (2000)].

We numerically integrate the semiclassical equations of motion for spherically symmetric Einstein-Maxwell theory with a dilaton coupled scalar field and look for zero temperature configurations. The solution we find is studied in detail close to the horizon and comparison is made with the corresponding one in the minimally coupled case.

We calculate the proton decay rate due to five dimensional SU(5) gauge bosons in the Randall-Sundrum scenario with two branes (Planck brane and TeV brane). We consider matter in the usual $10$ and $5¯$ SU(5) representations localized on a brane, and consider the case when SU(5) is broken by a Higgs mechanism on the matter brane. We calculate the proton decay rate mediated by X bosons, due to terms in the Lagrangian with $X_{\mu }$ and its derivative along the extra dimension. We confirm that the experimental limit on the proton decay rate allows SU(5) matter to be on the Planck brane, but excludes it from being on the TeV brane in this scenario.

In this paper we study the strong gravitational lensing scenario where the lens is a Reissner-Nordström black hole. We obtain the basic equations and show that, as in the case of a Schwarzschild black hole, in addition to the primary and secondary images, two infinite sets of relativistic images are formed. We find analytical expressions for the positions and amplifications of the relativistic images. The formalism is applied to the case of a low-mass black hole placed at the galactic halo.

Brane cosmology driven by the tachyon rolling down to its ground state is investigated. We adopt an effective field theoretical description for the tachyon and Randall-Sundrum type brane-world scenario. After formulating the basic equations, we show that the standard cosmology with the usual scalar field can mimic the low-energy behavior of the system near the tachyon ground state. We also investigate the qualitative behavior of the system beyond the low-energy regime for a positive, negative, and vanishing four-dimensional effective cosmological constant ${\Lambda }_4={\kappa }_5^4{V(T}_0{)}^2/12\mathrm{}-|{\Lambda }_5|/2,$ where ${\kappa }_5$ and ${\Lambda }_5$ are the five-dimensional gravitational coupling constant and (negative) cosmological constant, respectively, and ${V(T}_0)$ is the (positive) tension of the brane in the tachyon ground state. In particular, for ${\Lambda }_4<0,$ the tachyon never settles down to its potential minimum and the universe eventually hits a big-crunch singularity.

In generic models for grand unified theories (GUT), various types of baryon-number-violating processes are expected when quarks and leptons propagate in the background of GUT strings. On the other hand, in models with large extra dimensions, the baryon number violation in the background of a string is not trivial because it must depend on the mechanism of the proton stabilization. In this paper, we argue that cosmic strings in models with extra dimensions can enhance the baryon number violation to a phenomenologically interesting level, if the proton decay is suppressed by the mechanism of localized wave functions. We also make some comments on baryogenesis mediated by cosmological defects. We show that at least two scenarios will be successful in this direction. One is the scenario of leptogenesis where the required lepton number conversion is mediated by cosmic strings, and the other is the baryogenesis from the decaying cosmological domain wall. Both scenarios are new and have not been discussed in the past.

We investigate cosmological evolution in models where the effective potential $V\left(\phi \right)$ may become negative for some values of the field $\phi .$ Phase portraits of such theories in the space of variables $(\phi ,\dot{\phi },H)$ have several qualitatively new features as compared with phase portraits in the theories with $V\left(\phi \right)>\mathrm{}0.\mathrm{}$ Cosmological evolution in models with potentials with a “stable” minimum at $V\left(\phi \right)<\mathrm{}0\mathrm{}$ is similar in some respects to the evolution in models with potentials unbounded from below. Instead of reaching an AdS regime dominated by the negative vacuum energy, the universe reaches a turning point where its energy density vanishes, and then it contracts to a singularity with properties that are practically independent of $V\left(\phi \right).\mathrm{}$ We apply our methods to investigation of the recently proposed cyclic universe scenario. We show that in addition to the singularity problem there are other problems that need to be resolved in order to realize a cyclic regime in this scenario. We propose several modifications of this scenario and conclude that the best way to improve it is to add a usual stage of inflation after the singularity and use that inflationary stage to generate perturbations in the standard way.

An improved terrestrial experiment to test the equivalence principle for rotating extended bodies is presented, and a new upper limit for the violation of the equivalence principle is obtained at the level of $1.6\times {10}^{-7},$ which is limited by the friction of the rotating gyroscope. This means that the spin-gravity interaction between the extended bodies has not been observed at this level.

The asymmetries between charm and anticharm mesons observed in fixed-target photoproduction experiments are an order of magnitude larger than the asymmetries predicted by conventional perturbative QCD. We show that these charm meson asymmetries can be explained by a heavy-quark recombination mechanism for heavy meson production. In this process, a charm quark combines with a light antiquark from the hard-scattering process and they subsequently hadronize into a state including the charm meson. This recombination mechanism can be calculated within perturbative QCD up to some nonperturbative constants. After using symmetries of QCD to reduce the number of free parameters to two, we obtain a good fit to all the data on the asymmetries for charmed mesons from the E687 and E691 experiments.

We propose an approach to calculate the next-to-leading-order power corrections to the photon-pion transition form factor $F_{\pi \gamma }{(Q}^2).\mathrm{}$ The effects of the next-to-leading-order power corrections are analyzed.

We have measured the W boson mass using the DØ detector and a data sample of $82\hspace{0.5em}{\mathrm{pb}}^{-1}$ from the Fermilab Tevatron collider. This measurement uses $\overrightarrow{W}e\nu$ decays, where the electron is close to a boundary of a central electromagnetic calorimeter module. Such “edge” electrons have not been used in any previous DØ analysis, and represent a 14% increase in the W boson sample size. For these electrons, new response and resolution parameters are determined, and revised backgrounds and underlying event energy flow measurements are made. When the current measurement is combined with previous DØ W boson mass measurements, we obtain $M_W=80.483\mathrm{}\pm 0.084\hspace{0.5em}\mathrm{GeV}.$ The 8% improvement from the previous DØ measurement is primarily due to the improved determination of the response parameters for non-edge electrons using the sample of Z bosons with non-edge and edge electrons.

The effective average action of Yang-Mills theory is analyzed in the framework of exact renormalization group flow equations. Employing the background-field method and using a cutoff that is adjusted to the spectral flow, the running of the gauge coupling is obtained on all scales. In four dimensions and for the gauge groups SU(2) and SU(3), the coupling approaches a fixed point in the infrared.

The AdS/CFT correspondence can be realized in spaces that are globally different but share the same asymptotic behavior. Two known cases are a compact AdS space and the space generated by a large number of coincident branes. We discuss the physical consistency, in the sense of the Cauchy problem, of these two formulations. We show that the role of the boundary in the compact AdS space is equivalent to that of the flat asymptotic region in the brane space. We also show, by introducing a second coordinate chart for the pure AdS space, that a point at its spatial infinity corresponds to a horizon in the brane system.

Regge calculus is a powerful method to approximate a continuous manifold by a simplicial lattice, keeping the connectivities of the underlying lattice fixed and taking the edge lengths as degrees of freedom. The discrete Regge model employed in this work limits the choice of the link lengths to a finite number. To get more precise insight into the behavior of the four-dimensional discrete Regge model, we coupled spins to the fluctuating manifolds. We examined the phase transition of the spin system and the associated critical exponents. The results are obtained from finite-size scaling analyses of Monte Carlo simulations. We find consistency with the mean-field theory of the Ising model on a static four-dimensional lattice.

We investigate the decay of current on a superconducting cosmic string through quantum tunneling. We construct the instanton describing tunneling in a simple bosonic string model, and estimate the decay rate. The tunneling rate vanishes in the limit of a chiral current. This conclusion, which is supported by a symmetry argument, is expected to apply in general. It has important implications for the stability of chiral vortons.

As recently suggested, nearby quasar remnants are plausible sites of black-hole based compact dynamos that could be capable of accelerating ultrahigh-energy cosmic rays (UHECRs). In such a model, UHECRs would originate at the nuclei of nearby dead quasars, those in which the putative underlying supermassive black holes are suitably spun-up. Based on galactic optical luminosity, morphological type, and redshift, we have compiled a small sample of nearby objects selected to be highly luminous, bulge-dominated galaxies, likely quasar remnants. The sky coordinates of these galaxies were then correlated with the arrival directions of cosmic rays detected at energies $>40\mathrm{}\hspace{0.5em}\mathrm{EeV}.$ An apparently significant correlation appears in our data. This correlation appears at closer angular scales than those expected when taking into account the deflection caused by typically assumed IGM or galactic magnetic fields over a charged particle trajectory. Possible scenarios producing this effect are discussed, as is the astrophysics of the quasar remnant candidates. We suggest that quasar remnants be also taken into account in the forthcoming detailed search for correlations using data from the Auger Observatory.

The massive Schwinger model is studied using a density matrix renormalization group approach to the staggered lattice Hamiltonian version of the model. Lattice sizes up to 256 sites are calculated, and the estimates in the continuum limit are almost two orders of magnitude more accurate than previous calculations. Coleman’s picture of “half-asymptotic” particles at a background field $\theta =\pi$ is confirmed. The predicted phase transition at finite fermion mass $\mathrm{}(m/g)\mathrm{}$ is accurately located and demonstrated to belong in the 2D Ising universality class.

This biennial Review summarizes much of Particle Physics. Using data from previous editions, plus 2205 new measurements from 667 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. This edition features expanded coverage of CP violation in B mesons and of neutrino oscillations. For the first time we cover searches for evidence of extra dimensions (both in the particle listings and in a new review). Another new review is on Grand Unified Theories. A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http://pdg.lbl.gov.