Electromagnetic Shower Properties in a Lead-Scintillator Sampling Calorimeter

The Collider Detector at Fermilab (CDF) is a general-purpose experimental apparatus with an inner tracking detector for measuring charged particles, surrounded by a calorimeter for measurements of electromagnetic and hadronic showers. We describe a {\sc geant4} simulation and parameterization of the response of the CDF central electromagnetic calorimeter (CEM) to incident electrons and photons. The detector model consists of a detailed description of the CEM geometry and material in the direction of the incident particle's trajectory, and of the passive material between the tracker and the CEM. We use {\sc geant4} to calculate the distributions of: the energy that leaks from the back of the CEM, the energy fraction sampled by the scintillators, and the energy dependence of the response. We parameterize these distributions to accurately model electron and photon response and resolution in a custom simulation for the measurement of the $W$ boson mass

Production and decay of spinning black holes at colliders and tests of black hole dynamics

We analyse the angular momentum distribution of black holes produced in high energy collisions in space-times with extra spatial dimensions. We show that the black hole spin significantly affects the energy and angular spectra of Hawking radiation. Our results show the experimental sensitivity to the angular momentum distribution and provide tests of black hole production dynamics.Comment: 6 figure

Mycoplasma Pneumoniae infections in the Maltese Islands

Mycoplasma pneumoniae is a free living micro-organism which is classified in the family Mycoplasmataceae. It is primarily a human respiratory pathogen and the infection may vary from a mild pharyngitis to a pneumonia. M. pneumoniae infections are usually endemic in the community but periodic epidemics can also occur. These micro-organisms are sensitive to specific antibiotics such as tetracycline and erythromycin and a laboratory diagnosis using rapid methods is therefore important. Studies were carried out at the Virology Laboratory, St. Luke’s Hospital involving 1,022 cases during the period 1995 to 1998. These were examined for specific anti-mycoplasmal IgM antibodies using an enzyme immunoassay (EIA) technique. One hundred and forty samples or 13.7% were found to be reactive. Compared to the traditional cultural methods, EIA techniques are very rapid laboratory diagnostic methods, the result being communicated to the clinician within a few hours. The differential diagnosis of the particular case can thus be resolved quickly and appropriate antibiotic therapy instituted without much delay for the maximum benefit to the patient.peer-reviewe

Drift Chamber Alignment using Cosmic Rays

The Collider Detector at Fermilab (CDF) is a general-purpose experimental apparatus with an inner tracking detector for measuring charged particles, surrounded by a calorimeter for measurements of electromagnetic and hadronic showers, and a muon detector system. We present a technique for, and results of, a precise relative alignment of the drift chamber wires of the CDF tracker. This alignment has been an important component of the track momentum calibration, which is the basis for the charged-lepton calibration for the measurement of the W boson mass at CDF

Conditional reversibility in nonequilibrium stochastic systems

For discrete-state stochastic systems obeying Markovian dynamics, we establish the counterpart of the conditional reversibility theorem obtained by Gallavotti for deterministic systems [Ann. de l'Institut Henri Poincar\'e (A) 70, 429 (1999)]. Our result states that stochastic trajectories conditioned on opposite values of entropy production are related by time reversal, in the long-time limit. In other words, the probability of observing a particular sequence of events, given a long trajectory with a specified entropy production rate $\sigma$, is the same as the probability of observing the time-reversed sequence of events, given a trajectory conditioned on the opposite entropy production, $-\sigma$, where both trajectories are sampled from the same underlying Markov process. To obtain our result, we use an equivalence between conditioned ("microcanonical") and biased ("canonical") ensembles of nonequilibrium trajectories. We provide an example to illustrate our findings.Comment: 13 pages, 1 figur