4,185 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
Black hole relics in large extra dimensions
Recent calculations applying statistical mechanics indicate that in a setting with compactified large extra dimensions a black hole might evolve into a (quasi-)stable state with mass close to the new fundamental scale M f. Black holes and therefore their relics might be produced at the LHC in the case of extra-dimensional topologies. In this energy regime, Hawking's evaporation scenario is modified due to energy conservation and quantum effects. We reanalyse the evaporation of small black holes including the quantisation of the emitted radiation due to the finite surface of the black hole. It is found that observable stable black hole relics with masses sim 1-3 M f would form which could be identified by a delayed single jet with a corresponding hard momentum kick to the relic and by ionisation, e.g. in a TPC
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