123291997
Interactions between 't Hooft-Polyakov monopoles
We use the stress-energy tensor and the associated energy- momentum conservation to study the interactions between two widely separated monopoles (or monopole and antimonopole). By defining a set of minimal conditions to represent the above systems, we show how the problem reduced mathematically to a known electrostatic problem. The force between the monopoles (or monopole and antimonopole) is then, to the leading order, the expected repulsive (attractive) Coulomb force. We also discuss how the Prasad-Sommerfield limit alters the problem, leading to twice the Coulomb force between a monopole and antimonopole and zero force between two monopoles.
119537735
Newman‐Penrose Constants and Their Invariant Transformations
The origin and significance of the Newman‐Penrose (N‐P) constants of the motion are examined from the point of view that constants of the motion generate invariant transformations. Here the calculation makes use of a generalization of Green's theorem to a situation applicable to the coupled Einstein‐Maxwell fields in general relativity. One finds strictly electromagnetic constants generated by an incoming electromagnetic shock wave, with dipole symmetry, at future null infinity. The gravitational constants contain an admixture from the electromagnetic field. They are generated by an incident quadrupole gravitational shock wave at future null infinity (J+). Both the electromagnetic dipole field and the gravitational quadrupole field behave like linearized fields at J+. All higher‐multipole fields do not uncouple from the nonlinear corrections induced by the self‐coupling of the gravitational field and its coupling with the electromagnetic field. It is shown that the gravitational constants are related to t...
119857978
ASYMPTOTIC INVARIANTS IN GRAVITATIONAL RADIATION FIELDS
Asymptotic integral invariants are constructed for the electromagnetic and gravitational fields. The integrals are taken over closed two-dimensional surfaces embedded in a null hypersurface. In the absence of incoming radiation the asymptotic behavior of the electromagnetic field F/sup ab/ and the Riemann tensor R/sub abcd/ is such that the integrals formed with these quantities are independent of the particular space-like surface of integration, as long as it lies in the same null hypersurface. Therefore, the integrals are related to the multipole structure of the charge distribution please delete the above abstract no. 31658=====
35621396
Conserved quantities at spatial and null infinity: The Penrose potential.
We define a superpotential for energy-momentum and rotation momentum which is built out of the conformal tensor and a bivector. This superpotential is identified with that used by Penrose in his definition of quasilocal energy. It is applied to the definition of energy-momentum and rotation momentum at spatial and at null infinities. At spatial infinity the results are in agreement with those of Ashtekar and Hansen. At null infinity the results are unsatisfactory; they are tied to a specific Bondi frame. Thus, they are not in agreement with the results of Tamburino and Winicour, Geroch and Winicour, nor with those of Dray and Streubel. Some reasons for this failure are discussed.
120204158
Developments and predictions
117256701
Limiting behavior of asymptotically flat gravitational fields
AbstractCouch and Torrence suggest that the vacuum Einstein equations admit a larger class of asymptotically flat solutions than those exhibiting the peeling property. Starting with the assumption that
$$\Psi _0  = O(r^{ - 2 - \varepsilon _0 } )$$
, (d/dr)
$$\Psi _0  = O(r^{ - 3 - \varepsilon _0 } )$$
 and (δ/δxA)
$$\Psi _1  = O(r^{ - 2 - \varepsilon _0 } )$$
, wherexA (A = 2, 3) are angular coordinates, they show that
$$\Psi _1  = O(r^{ - 2 - \varepsilon _1 } )$$
, where ε1⩽ 2 and ε1<ε0;
$$< \varepsilon _0 ;\Psi _2  = O(r^{ - 2 - \varepsilon _2 } )$$
, where ε2 ⩽ 1 and ε1< ε1; and Ψ4 and Ψ3 peel as they would under the stronger peeling conditions. The Winicour-Tamburino energy-momentun and angular momentum integrals for these solutions, in general, diverge. In fact, since Couch and Torrence determine only the radial dependence of the solution, it is not clear that the solutions are well defined. We find that the stronger assumption
$$\Psi _0  = O(r^{ - 3 - \varepsilon _0 } )$$
, (d/dr)
$$\Psi _0  = O(r^{ - 4 - \varepsilon _0 } )$$
, and (δ/δxA)
$$\Psi _0  = O(r^{ - 3 - \varepsilon _0 } )$$
 does result in well-defined solutions for which both the energy-momentum and angular momentum intergrals are not only finite but result in the same expressions as are obtained for peeling space-times. This assumption appears to be the minimal assumption that is necessary for investigating outgoing radiation at null infinity.
119498503
Baryonic Dark Matter and Big-Bang Nucleosynthesis
The enclosed paper was submitted for publication in Ap.J Lett. in February 1992. It has been rejected on the grounds that it predicts primordial Deuterium abundance which is contradicted by observations and because it disagreed with published analysis and conclusions of previous authors. However, in a recent article in NATURE (14 April 1994) Vol. 368 pp. 599-603, Songalia, Cowie, Hogan and Rugers describe a recent measurement (November 1993) with the Keck 10-m Telescope, of the Deuterium abundance in a high redshift cloud between us and a distant quasar. They find D/H\approx 1.9-2.5 x10^{-4} in good agreement with our prediction D/H=(2.1+\- 0.35)x10^{-4}, which is larger by an order of magnitude than believed before. Songalia et al. found that the baryon density inferred from Big Bang Nucleosynthesis is "consistent with the amount of presently observed luminous matter comprising all the baryons in the Universe" while we found the same. We post here our unpublished 1991 paper, which was reported in international conferences and was distributed only as a preprint, mainly because of its physics and its sad moral: If you submit for publication a correct paper with important results that contradict the "party line" it has only slim chances to be accepted for publication.
123460442
A new high gain thin gap detector for the opal hadron calorimeter
Abstract A new type of thin gap multiwire gas detector operating in a high gain mode has been developed for use in the OPAL pole tip calorimeter. The detector thickness is only 6.6 mm and its area is 0.61 m 2 . The induced pad readout provides high output pulses which require no amplification. The set-up for the detector mass production and quality control test is described. Results from a test beam set-up that simulates the OPAL pole tip calorimeter are presented and compared with computer simulations.
123161968
A new description of high energy antiproton (proton)-proton elastic scattering
Abstract We develop a generalization of the geometric picture for high-energy antiproton (proton)-proton elastic scattering. The eikonal at each impact parameter is considered to have fluctuations about an average value, and is thus characterized by a distribution. A connection to parton branching is made through the specific form of the distribution function for the eikonal. A unified physical theory with significant fluctuations accurately describes the p(p)-p data at both s =546 GeV and 53 GeV. The fluctuation parameter is remarkably well given by that directly observed in multiparticle production.
16978878
What is the statistical significance of the solar neutrino flux problem
Uniform random numbers, not Gaussian random numbers, should have been used with Standard Solar Models to estimate the effect on the neutrino flux of uncertainties in input data. The observed discrepancy is therefore probably quite smaller than currently accepted.