5,725 research outputs found
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
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 boson mass
Comparison of Horace and Photos Algorithms for Multi-Photon Emission in the Context of the W Boson Mass Measurement
The W boson mass measurement is sensitive to QED radiative corrections due to
virtual photon loops and real photon emission. The largest shift in the
measured mass, which depends on the transverse momentum spectrum of the charged
lepton from the boson decay, is caused by the emission of real photons from the
final-state lepton. There are a number of calculations and codes available to
model the final-state photon emission. We perform a detailed study, comparing
the results from the Horace and Photos implementations of the final-state
multi-photon emission in the context of a direct measurement of the W boson
mass at the Tevatron. Mass fits are performed using a simulation of the CDF II
detector
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
An investigation of temperature distribution in cooled guide vanes
A numerical study to determine the temperature distribution in the guide vane blades of a radial inflow turbine is presented. A computer program was developed which permits the temperature distribution to be calculated when the blade is cooled internally using a combination of impingement and film cooling techniques. The study is based on the use of the finite difference method in a two dimensional heat conduction problem. The results are then compared to determine the best cooling configuration for a certain coolant to primary mass flow ratio
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