120198608
Differential cross sections and analyzing powers for pp elastic scattering at 1. 46 GeV/c in the Coulomb-nuclear interference region
Differential cross sections sigma(theta) and analyzing powers A(theta) for pp elastic scattering have been measured in the Coulomb-nuclear interference region at 800 MeV. The measurements, which extend down to 0.5 deg in the laboratory, have been analyzed to deduce the zero-degree pp scattering amplitudes. The ratio rho of the real to imaginary parts of the spin-independent amplitude was found to be -0.04 +- 0.04; the contribution of the double-spin-flip amplitudes to sigma(0) was found to be 0.16 +- 0.03 times that of the spin-independent amplitude; while the ratios of the imaginary and real parts of the single spin-flip amplitude to sintheta were found to be 0.74 +- 0.04 and -0.03 +- 0.08 fm, respectively. Except for the last, these experimental values agree with the predictions of forward dispersion relations and phase shift analyses.
119819008
Large angle elastic and inelastic scattering of protons from Ca 40 at 800 MeV
Measurements are reported for the elastic and inelastic scattering of 800 MeV protons from $^{40}\mathrm{Ca}$. Differential cross sections were measured out to 42\ifmmode^\circ\else\textdegree\fi{} while analyzing powers were obtained out to 30\ifmmode^\circ\else\textdegree\fi{}. The angular distributions are diffractive in character at all angles. Theoretical analysis of the data was carried out in the framework of the diffraction multiple scattering theory. The following results were obtained: (i) Diffraction multiple scattering theory reproduces the data qualitatively out to the large momentum transfers. (ii) For the ground state density distribution ${〈{{r}_{p}}^{2}〉}^{\frac{1}{2}}\ensuremath{-}{〈{{r}_{n}}^{2}〉}^{\frac{1}{2}}=0.142\ifmmode\pm\else\textpm\fi{}0.075$ fm is obtained and the analysis favors the value of the correlation length ${\ensuremath{\xi}}_{c}=\ensuremath{-}0.5$ fm. (iii) The excitation of the lowest-lying collective states (${3}^{\ensuremath{-}}$, ${5}^{\ensuremath{-}}$, ${2}^{+}$) was analyzed using one-phonon excitation macroscopic parameters. The values of the ${\ensuremath{\beta}}_{2}$, ${\ensuremath{\beta}}_{3}$, ${\ensuremath{\beta}}_{5}$ parameters obtained agree quantitatively with lower energy ($p$,${p}^{\ensuremath{'}}$) scattering results.
119810929
Plane walls interacting with gravitational waves and matter fields
Plane walls with reflection symmetry are studied. A method for generating such solutions to the Einstein equations is developed. It is found that plane wall solutions require very strong restrictions on the metric coefficients and on their derivatives. Using the generalized Bianchi identities, the interaction of plane walls with gravitational waves and matter fields is investigated. In particular, it is shown that a plane wall, in general, interacts with both gravitational plane waves and matter fields. But, a plane domain wall interacts only with matter fields. No matter whether the space‐time out of the wall is curved or not, a plane domain wall is always repulsive.
51426707
COLLAPSING SCALAR FIELD WITH KINEMATIC SELF-SIMILARITY OF THE SECOND KIND IN (2+1) GRAVITY
All the (2+1)-dimensional circularly symmetric solutions with kinematic self-similarity of the second kind to the Einstein-massless-scalar field equations are found and their local and global properties are studied. It is found that some of them represent gravitational collapse of a massless scalar field, in which black holes are always formed.
12109603
Critical collapse of a cylindrically symmetric scalar field in four-dimensional Einstein’s theory of gravity
Four-dimensional cylindrically symmetric spacetimes with homothetic self-similarity are studied in the context of Einstein's Theory of Gravity, and a class of exact solutions to the Einstein-massless scalar field equations is found. Their local and global properties are investigated and found that they represent gravitational collapse of a massless scalar field. In some cases the collapse forms black holes with cylindrical symmetry, while in the other cases it does not. The linear perturbations of these solutions are also studied and given in closed form. From the spectra of the unstable eigen-modes, it is found that there exists one solution that has precisely one unstable mode, which may represent a critical solution, sitting on a boundary that separates two different basins of attraction in the phase space.
18614564
Gravitational collapse of perfect fluid
Abstract The spherical gravitational collapse of a compact packet consisting of perfect fluid is studied. The spacetime outside the packet is described by the out-going Vaidya radiation fluid. It is found that when the collapse has continuous self-similarity the formation of black holes always starts with zero mass, and when the collapse has no self-similarity, the formation of black holes always starts with a finite non-zero mass. The packet is usually accompanied by a thin matter shell. The effects of the shell on the collapse are also studied.
53607562
Rotating cylindrical shell source for Lewis spacetime
Rotating thin-shell-like sources for the stationary cylindrically symmetric vacuum solutions (Lewis) are constructed and studied. By imposing the non-existence of timelike curves in the exterior of the shell, and that the source satisfies the weak, dominant and strong energy conditions, it is found that the parameters, commonly denoted by a and σ, are restricted to 0 ≤ σ ≤ 1/4 when a > 0, or 1/4 ≤ σ ≤ 1/2 when a < 0.