2,093 research outputs found
A Precision Measurement of Electroweak Parameters in Neutrino-Nucleon Scattering
The CCFR collaboration reports a precise measurement of electroweak
parameters derived from the ratio of neutral-current to charged-current
cross-sections in neutrino-nucleon scattering at the Fermilab Tevatron. This
ratio of cross-sections measures the neutral current couplings to quarks, which
implies a determination of sin^2 theta_W (on-shell) = 0.2236 +/- 0.0028(expt.)
+/- 0.0030(model) for m_top=175 GeV, m_Higgs=150 GeV. This is equivalent to
M_W=80.35+/-0.21 GeV. The good agreement of this measurement with Standard
Model expectations implies the exclusion of additional
neutrino-neutrino-quark-quark contact interactions at 95% confidence at a mass
scale of 1-8 TeV, depending on the form of the contact interaction.Comment: formatted in revtex, 5 pages, 3 eps figures included via psfig,
submitted to Physical Review Letter
From Design to Production Control Through the Integration of Engineering Data Management and Workflow Management Systems
At a time when many companies are under pressure to reduce "times-to-market"
the management of product information from the early stages of design through
assembly to manufacture and production has become increasingly important.
Similarly in the construction of high energy physics devices the collection of
(often evolving) engineering data is central to the subsequent physics
analysis. Traditionally in industry design engineers have employed Engineering
Data Management Systems (also called Product Data Management Systems) to
coordinate and control access to documented versions of product designs.
However, these systems provide control only at the collaborative design level
and are seldom used beyond design. Workflow management systems, on the other
hand, are employed in industry to coordinate and support the more complex and
repeatable work processes of the production environment. Commercial workflow
products cannot support the highly dynamic activities found both in the design
stages of product development and in rapidly evolving workflow definitions. The
integration of Product Data Management with Workflow Management can provide
support for product development from initial CAD/CAM collaborative design
through to the support and optimisation of production workflow activities. This
paper investigates this integration and proposes a philosophy for the support
of product data throughout the full development and production lifecycle and
demonstrates its usefulness in the construction of CMS detectors.Comment: 18 pages, 13 figure
Studies of the Response of the Prototype CMS Hadron Calorimeter, Including Magnetic Field Effects, to Pion, Electron, and Muon Beams
We report on the response of a prototype CMS hadron calorimeter module to
charged particle beams of pions, muons, and electrons with momenta up to 375
GeV/c. The data were taken at the H2 and H4 beamlines at CERN in 1995 and 1996.
The prototype sampling calorimeter used copper absorber plates and scintillator
tiles with wavelength shifting fibers for readout. The effects of a magnetic
field of up to 3 Tesla on the response of the calorimeter to muons, electrons,
and pions are presented, and the effects of an upstream lead tungstate crystal
electromagnetic calorimeter on the linearity and energy resolution of the
combined calorimetric system to hadrons are evaluated. The results are compared
with Monte Carlo simulations and are used to optimize the choice of total
absorber depth, sampling frequency, and longitudinal readout segmentation.Comment: 89 pages, 41 figures, to be published in NIM, corresponding author: P
de Barbaro, [email protected]
An apparatus to search for mirror dark matter via the invisible decay of orthopositronium in vacuum
Mirror matter is a possible dark matter candidate. It is predicted to exist
if parity is an unbroken symmetry of the vacuum. The existence of the mirror
matter, which in addition to gravity is coupled to our world through
photon-mirror photon mixing, would result in orthopositronium (o-Ps) to mirror
orthopositronium (o-Ps') oscillations. The experimental signature of this
effect is the invisible decay of o-Ps in vacuum.
This paper describes the design of the new experiment for a search for the
o-Ps -> invisible decay in vacuum with a sensitivity in the branching ratio of
Br(o-Ps -> invisible)\simeq 10^{-7}, which is an order of magnitude better than
the present limit on this decay mode from the Big Bang Nucleosynthesis. The
experiment is based on a high-efficiency pulsed slow positron beam, which is
also applicable for other experiments with o-Ps, and (with some modifications)
for applied studies. Details of the experimental design and of a new pulsing
method, as well as preliminary results on requirements for the pulsed beam
components are presented. The effects of o-Ps collisions with the cavity walls
as well as the influence of external fields on the o-Ps to o-Ps' oscillation
probability are also discussed.Comment: 28 pages, 8 figure
- …