5 research outputs found
Alignment of the CMS silicon strip tracker during stand-alone commissioning
The results of the CMS tracker alignment analysis are presented using the
data from cosmic tracks, optical survey information, and the laser alignment
system at the Tracker Integration Facility at CERN. During several months of
operation in the spring and summer of 2007, about five million cosmic track
events were collected with a partially active CMS Tracker. This allowed us to
perform first alignment of the active silicon modules with the cosmic tracks
using three different statistical approaches; validate the survey and laser
alignment system performance; and test the stability of Tracker structures
under various stresses and temperatures ranging from +15C to -15C. Comparison
with simulation shows that the achieved alignment precision in the barrel part
of the tracker leads to residual distributions similar to those obtained with a
random misalignment of 50 (80) microns in the outer (inner) part of the barrel.Comment: 41 pages, 63 postscript figures, submitted to JINS
Improved measurement of B+->rho(+)rho(0) and determination of the quark-mixing phase angle alpha
We present improved measurements of the branching fraction B, the longitudinal polarization fraction f(L), and the direct CP asymmetry A(CP) in the B meson decay channel B+->rho(+)rho(0). The data sample was collected with the BABAR detector at SLAC. The results are B(B+->rho(+)rho(0))=(23.7 +/- 1.4 +/- 1.4)x10(-6), f(L)=0.950 +/- 0.015 +/- 0.006, and A(CP)=-0.054 +/- 0.055 +/- 0.010, where the uncertainties are statistical and systematic, respectively. Based on these results, we perform an isospin analysis and determine the Cabibbo-Kobayashi-Maskawa phase angle alpha=arg(-VtdVtb*/VudVub*) to be (92.4(-6.5)(+6.0))degrees
Stand-alone cosmic muon reconstruction before installation of the CMS silicon strip tracker
The subsystems of the CMS silicon strip tracker were integrated and
commissioned at the Tracker Integration Facility (TIF) in the period from
November 2006 to July 2007. As part of the commissioning, large samples of
cosmic ray data were recorded under various running conditions in the absence
of a magnetic field. Cosmic rays detected by scintillation counters were used
to trigger the readout of up to 15% of the final silicon strip detector, and
over 4.7 million events were recorded. This document describes the cosmic track
reconstruction and presents results on the performance of track and hit
reconstruction as from dedicated analyses.Comment: Added missing LaTex command / no change in contents w.r.t. v
Track Reconstruction with Cosmic Ray Data at the Tracker Integration Facility
The subsystems of the CMS silicon strip tracker were integrated and commissioned at the Tracker Integration Facility (TIF) in the period from November 2006 to July 2007.
As part of the commissioning, large samples of cosmic ray data were recorded under various running conditions in the absence of a magnetic field.
Cosmic rays detected by scintillation counters were used to trigger the readout of up to 15\,\% of the final silicon strip detector, and over 4.7~million events were recorded.
This document describes the cosmic track reconstruction and presents results on the performance of track and hit reconstruction as from dedicated analyses