2 research outputs found
Exact General Relativistic Thick Disks
A method to construct exact general relativistic thick disks that is a simple
generalization of the ``displace, cut and reflect'' method commonly used in
Newtonian, as well as, in Einstein theory of gravitation is presented. This
generalization consists in the addition of a new step in the above mentioned
method. The new method can be pictured as a ``displace, cut, {\it fill} and
reflect'' method. In the Newtonian case, the method is illustrated in some
detail with the Kuzmin-Toomre disk. We obtain a thick disk with acceptable
physical properties. In the relativistic case two solutions of the Weyl
equations, the Weyl gamma metric (also known as Zipoy-Voorhees metric) and the
Chazy-Curzon metric are used to construct thick disks. Also the Schwarzschild
metric in isotropic coordinates is employed to construct another family of
thick disks. In all the considered cases we have non trivial ranges of the
involved parameter that yield thick disks in which all the energy conditions
are satisfied.Comment: 11 pages, RevTex, 9 eps figs. Accepted for publication in PR
Hadronic response and separation with the H1 lead / fiber calorimeter
Hadronic response and electron identification performance of the new H1 lead-scintillating fibre calorimeter are investigated in the 1 to 7 GeV energy range using data taken at the CERN Proton Synchrotron. The energy response to minimum ionizing particles and interacting pions are studied and compared to Monte Carlo simulations. The measured energy of pions interacting either in the electromagnetic or in the hadronic section is found to scale linearly with the incident energy, providing an energy resolution within a depth of one interaction length and for a total depth of two interaction lengths. Several electron identification estimators are studied and combined as a function of energy and impact point. The probability for pions to be misidentified as electrons of any measured energy above 1 GeV ranges from 5% (for 2 GeV incident pions) to 0.4% (at 7 GeV) for an electron detection efficiency of 90%. The probability for pions of a given energy to be misidentified as electrons of the same energy falls to 0.25% at 7 GeV