The full LEP-1 data set collected with the ALEPH detector at the Z pole during 1991-1995 is analysed in order to measure the ? decay branching fractions. The analysis follows the global method used in the published study based on 1991-1993 data, but several improvements are introduced, especially concerning the treatment of photons and ?0's. Extensive systematic studies are performed, in order to match the large statistics of the data sample corresponding to over 300 000 measured and identified ? decays. Branching fractions are obtained for the two leptonic channels and 11 hadronic channels defined by their respective numbers of charged particles and ?0's. Using previously published ALEPH results on final states with charged and neutral kaons, corrections are applied to the hadronic channels to derive branching ratios for exclusive final states without kaons. Thus the analyses of the full LEP-1 ALEPH data are combined to yield a complete description of ? decays, encompassing 22 non-strange and 11 strange hadronic modes. Some physics implications of the results are given, in particular related to universality in the leptonic charged weak current, isospin invariance in a 1 decays, and the separation of vector and axial-vector components of the total hadronic rate. Finally, spectral functions are determined for the dominant hadronic modes and updates are given for several analyses. These include: tests of isospin invariance between the weak charged and electromagnetic hadronic currents, fits of the ? resonance lineshape, and a QCD analysis of the non-strange hadronic decays using spectral moments, yielding the value ?s(m? 2) 0.340 ± 0.005exp ± 0.014th. The evolution to the Z mass scale yields ?s(MZ 2) = 0.1209 ± 0.0018. This value agrees well with the direct determination from the Z width and provides the most accurate test to date of asymptotic freedom in the QCD gauge theory. © 2005 by Elsevier B.V. All rights reserved

Due to the interaction of physics and astrophysics we are witnessing in these years a splendid synthesis of theoretical, experimental and observational results originating from three fundamental physical processes. They were originally proposed by Dirac, by Breit and Wheeler and by Sauter, Heisenberg, Euler and Schwinger. For almost seventy years they have all three been followed by a continued effort of experimental verification on Earth-based experiments. The Dirac process, e + e − → 2γ, has been by far the most successful. It has obtained extremely accurate experimental verification and has led as well to an enormous number of new physics in possibly one of the most fruitful experimental avenues by introduction of storage rings in Frascati and followed by the largest accelerators worldwide: DESY, SLAC etc. The Breit-Wheeler process, 2γ → e + e − , although conceptually simple, being the inverse process of the Dirac one, has been by far one of the most difficult to be verified experimentally. Only recently, through the technology based on free electron X-ray laser and its numerous applications in Earth-based experiments, some first indications of its possible verification have been reached. The vacuum polarization process in strong electromagnetic field, pioneered by Sauter, Heisenberg, Euler and Schwinger, introduced the concept of critical electric field E c = m 2 e c 3 /(e ). It has been searched without success for more than forty years by heavy-ion collisions in many of the leading particle accelerators worldwide.The novel situation today is that these same processes can be studied on a much more grandiose scale during the gravitational collapse leading to the formation of a black hole being observed in Gamma Ray Bursts (GRBs). This report is dedicated to the scientific race. The theoretical and experimental work developed in Earth-based laboratories is confronted with the theoretical interpretation of space-based observations of phenomena originating on cosmological scales. What has become clear in the last ten years is that all the three above mentioned processes, duly extended in the general relativistic framework, are necessary for the understanding of the physics of the gravitational collapse to a black hole. Vice versa, the natural arena where these processes can be observed in mutual interaction and on an unprecedented scale, is indeed the realm of relativistic astrophysics.We systematically analyze the conceptual developments which have followed the basic work of Dirac and Breit-Wheeler. We also recall how the seminal work of Born and Infeld inspired the work by Sauter, Heisenberg and Euler on effective Lagrangian leading to the estimate of the rate for the process of electron-positron production in 1 a constant electric field. In addition of reviewing the intuitive semi-classical treatment of quantum mechanical tunneling for describing the process of electron-positron production, we recall the calculations in Quantum Electro-Dynamics of the Schwinger rate and effective Lagrangian for cons...

Given the very accurate data from the BATSE and the Rossi X-Ray Timing Explorer and Chandra satellites, we use GRB 991216 as a prototypical case to test the theory that links the origin of the energy of gamma-ray bursts (GRBs) to the extractable energy of electromagnetic black holes (EMBHs). The fit of the afterglow fixes the only two free parameters of the model and leads to a new paradigm for the interpretation of the burst structure (the IBS paradigm). It leads as well to a reconsideration of the relative roles of the afterglow and burst in GRBs by defining two new phases in this complex phenomenon: (1) the injector phase, giving rise to the proper GRB, and (2) the beam-target phase, giving rise to the extended afterglow peak emission and to the afterglow. Such differentiation leads to a natural possible explanation of the bimodal distribution of GRBs observed by BATSE. The agreement with the observational data in regions extending from the horizon of the EMBH all the way out to the distant observer confirms the uniqueness of the model. Subject headings: black hole physics -gamma rays: bursts -supernovae: generalThe most decisive tool in the identification of the energetics of gamma-ray bursts (GRBs) has been the discovery by BeppoSAX of the afterglow phenomenon. In this Letter, we show how the afterglow data can be fitted using the theory that relates the GRB energy to the extraction process of the electromagnetic energy of a black hole endowed with electromagnetic structure (the EMBH model).

Abstract. Using hydrodynamic computer codes, we study the possible patterns of relativistic expansion of an enormous pair-electromagnetic-pulse (P.E.M. pulse); a hot, high density plasma composed of photons, electronpositron pairs and baryons deposited near a charged black hole (EMBH). On the bases of baryon-loading and energy conservation, we study the bulk Lorentz factor of expansion of the P.E.M. pulse by both numerical and analytical methods.Key words: black hole physics -gamma-ray bursts, theory, observationsIn the paper by Preparata et al. (1998), the "dyadosphere" is defined as the region outside the horizon of a EMBH where the electric field exceeds the critical value for e + e − pair production. In Reissner-Nordstrom EMBHs, the horizon radius is expressed asThe outer limit of the dyadosphere is defined as the radius r ds at which the electric field of the EMBH equals this critical fieldThe total energy of pairs, converted from the static electric energy, deposited within a dyadosphere is thenIn Wilson (1975Wilson ( , 1977 a black hole charge of the order 10% was formed. Thus, we henceforth assume a black hole charge Q = 0.1Q max , Q max = √ GM for our detailed numerical calculations. The range of energy is of interest as a possible gamma-ray burst source. In order to model the radially resolved evolution of the energy deposited within the e + e − -pair and photon plasma fluid created in the dyadosphere of EMBH, we need to discuss the relativistic hydrodynamic equations describing such evolution.The metric for a Reissner-Nordstrom black hole iswhereWe assume the plasma fluid of e + e − -pairs, photons and baryons to be a simple perfect fluid in the curved spacetime (Eq. (4)). The stress-energy tensor describing such a fluid is given by (Misner et al. 1975)where ρ and p are respectively the total proper energy density and pressure in the comoving frame. The U µ is the four-velocity of the plasma fluid. The baryon-number and energy-momentum conservation laws arewhere n B is the baryon-number density. The radial component of Eq. (7) reduces to ∂p ∂rThe component of the energy-momentum conservation Eq. (7) Equations (6) and (9) give rise to the relativistic hydrodynamic equations.

The GRB 991216 and its relevant data acquired from the BATSE experiment and RXTE and Chandra satellites are used as a prototypical case to test the theory linking the origin of gamma ray bursts (GRBs) to the process of vacuum polarization occurring during the formation phase of a black hole endowed with electromagnetic structure (EMBH). The relative space-time transformation paradigm (RSTT paradigm) is presented. It relates the observed signals of GRBs to their past light cones, defining the events on the worldline of the source essential for the interpretation of the data. Since GRBs present regimes with unprecedently large Lorentz γ factor, also sharply varying with time, particular attention is given to the constitutive equations relating the four time variables: the comoving time, the laboratory time, the arrival time at the detector, duly corrected by the cosmological effects. This paradigm is at the very foundation of any possible interpretation of the data of GRBs.

Using GRB 991216 as a prototype, it is shown that the intensity substructures observed in what is generally called the "prompt emission" in gamma ray bursts (GRBs) do originate in the collision between the accelerated baryonic matter (ABM) pulse with inhomogeneities in the interstellar medium (ISM). The initial phase of such process occurs at a Lorentz factor γ ∼ 310. The crossing of ISM inhomogeneities of sizes ∆R ∼ 10 15 cm occurs in a detector arrival time interval of ∼ 0.4 s implying an apparent superluminal behavior of ∼ 10 5 c. The long lasting debate between the validity of the external shock model vs. the internal shock model for GRBs is solved in favor of the first.To reproduce the observed light curve of GRB 991216, we have adopted, as initial conditions (Ruffini et al. 2002a) at t = 10 −21 s ∼ 0 s, a spherical shell of electron-positronphoton neutral plasma laying between the radii r 0 = 6.03 × 10 6 cm and r 1 = 2.35 × 10 8 cm: the temperature of such a plasma is 2.2 MeV, the total energy E tot = 4.83 × 10 53 erg and the total number of pairs N e + e − = 1.99 × 10 58 .Such initial conditions follow from the EMBH theory we have recently developed based on energy extraction from a black hole endowed with electromagnetic structure (EMBH)

We formulate the equations of equilibrium of neutron stars taking into account strong, weak, electromagnetic, and gravitational interactions within the framework of general relativity. The nuclear interactions are described by the exchange of the σ, ω, and ρ virtual mesons. The equilibrium conditions are given by our recently developed theoretical framework based on the Einstein-Maxwell-Thomas-Fermi equations along with the constancy of the general relativistic Fermi energies of particles, the "Klein potentials", throughout the configuration. The equations are solved numerically in the case of zero temperatures and for selected parameterizations of the nuclear models. The solutions lead to a new structure of the star: a positively charged core at supranuclear densities surrounded by an electronic distribution of thickness ∼h/(mec) ∼ 10 2h /(mπc) of opposite charge, as well as a neutral crust at lower densities. Inside the core there is a Coulomb potential well of depth ∼ mπc 2 /e. The constancy of the Klein potentials in the transition from the core to the crust, impose the presence of an overcritical electric field ∼ (mπ/me) 2 Ec, the critical field being Ec = m 2 e c 3 /(eh). The electron chemical potential and the density decrease, in the boundary interface, until values µ crust e < µ core e and ρcrust < ρcore. For each central density, an entire family of core-crust interface boundaries and, correspondingly, an entire family of crusts with different mass and thickness, exist. The configuration with ρcrust = ρ drip ∼ 4.3 × 10 11 g/cm 3 separates neutron stars with and without inner crust. We present here the novel neutron star mass-radius for the especial case ρcrust = ρ drip and compare and contrast it with the one obtained from the traditional Tolman-Oppenheimer-Volkoff treatment.

A theoretical attempt to identify the physical process responsible for the afterglow emission of Gamma-Ray Bursts (GRBs) is presented, leading to the occurrence of thermal emission in the comoving frame of the shock wave giving rise to the bursts. The determination of the luminosities and spectra involves integration over an infinite number of Planckian spectra, weighted by appropriate relativistic transformations, each one corresponding to a different viewing angle in the past light cone of the observer. The relativistic transformations have been computed using the equations of motion of GRBs within our theory, giving special attention to the determination of the equitemporal surfaces. The only free parameter of the present theory is the "effective emitting area" in the shock wave front. A self consistent model for the observed hard-to-soft transition in GRBs is also presented. When applied to GRB 991216 a precise fit χ 2 ≃ 1.078 of the observed luminosity in the 2-10 keV band is obtained. Similarly, detailed estimates of the observed luminosity in the 50-300 keV and in the 10-50 keV bands are obtained.