3,776 research outputs found
The Tevatron legacy
The Tevatron p¯p collider was shut down in 2011, after almost 10 years of high-performance operation at a center-of-mass energy of 1.96TeV. The two experiments, CDF and D0, continue to analyze the collected data, aiming to extract all possible information on validation of the standard model and on searches for new physics. A short review of some legacy measurements at the Tevatron, and of the impact of the Tevatron program in high-energy physics, is presented
A monitoring method for the Low Voltage Power Supply modules of the ATLAS Tile Calorimeter
We present a method for testing the operational stability of Low Voltage Power Supply modules of the ATLAS Tile Calorimeter, based on a self-consistent determination of the stability criteria. The recorded voltage, current, and temperature values of each module are retrieved from the Oracle database for a long and smooth running period and their mean and RMS values over that period are determined, as well as their average recording rates, by taking into account the â??smoothingâ?? procedure which is applied during data recording to reduce data storage. The average behavior of the ensemble of all modules is determined from those time-integrated quantities and the modules are then tested one-by-one by comparing with the ensemble averages. The proposed method is tested for all Long Barrel modules operated during April of 2007
A PMT-Block test bench
The front-end electronics of the ATLAS hadronic calorimeter (Tile Cal) is
housed in a unit, called {\it PMT-Block}. The PMT-Block is a compact instrument
comprising a light mixer, a PMT together with its divider and a {\it 3-in-1}
card, which provides shaping, amplification and integration for the signals.
This instrument needs to be qualified before being assembled on the detector. A
PMT-Block test bench has been developed for this purpose. This test bench is a
system which allows fast, albeit accurate enough, measurements of the main
properties of a complete PMT-Block. The system, both hardware and software, and
the protocol used for the PMT-Blocks characterisation are described in detail
in this report. The results obtained in the test of about 10000 PMT-Blocks
needed for the instrumentation of the ATLAS (LHC-CERN) hadronic Tile
Calorimeter are also reported.Comment: 23 pages, 10 figure
Chemical Transport and Transformation in Large Soil Cores
Proceedings of the 1993 Georgia Water Resources Conference, April 20-21, 1993, Athens, Georgia.Sponsored and Organized by: U.S. Geological Survey, Georgia Department of Natural Resources, The University of Georgia, Georgia State University, Georgia Institute of TechnologyThis book was published by the Institute of Natural Resources, The University of Georgia, Athens, Georgia 30602 with partial funding provided by the U.S. Department of Interior, Geological Survey, through the Georgia Water Research Institute as authorized by the Water Resources Research Act of 1984 (P.L. 98-242).
The views and statements advanced in this publication are solely those of the authors and do not represent official views or policies of the University of Georgia or the U.S. Geological Survey or the conference sponsors
Measurement of the Induced Proton Polarization P_n in the 12C(e,e'\vec{p}) Reaction
The first measurements of the induced proton polarization, P_n, for the 12C
(e,e'\vec{p}) reaction are reported. The experiment was performed at quasifree
kinematics for energy and momentum transfer (\omega,q) \approx (294 MeV, 756
MeV/c) and sampled a recoil momentum range of 0-250 MeV/c. The induced
polarization arises from final-state interactions and for these kinematics is
dominated by the real part of the spin-orbit optical potential. The
distorted-wave impulse approximation provides good agreement with data for the
1p_{3/2} shell. The data for the continuum suggest that both the 1s_{1/2} shell
and underlying l > 1 configurations contribute.Comment: 5 pages LaTeX, 2 postscript figures, accepted by Physical Reveiw
Letter
Measurement of the Transverse-Longitudinal Cross Sections in the p (e,e'p)pi0 Reaction in the Delta Region
Accurate measurements of the p(e,e?p)pi0 reaction were performed at
Q^2=0.127(GeV/c)^2 in the Delta resonance energy region. The experiments at the
MIT-Bates Linear Accelerator used an 820 MeV polarized electron beam with the
out of plane magnetic spectrometer system (OOPS). In this paper we report the
first simultaneous determination of both the TL and TL? (``fifth" or polarized)
cross sections at low Q^{2} where the pion cloud contribution dominates the
quadrupole amplitudes (E2 and C2). The real and imaginary parts of the
transverse-longitudinal cross section provide both a sensitive determination of
the Coulomb quadrupole amplitude and a test of reaction calculations.
Comparisons with model calculations are presented. The empirical MAID
calculation gives the best overall agreement with this accurate data. The
parameters of this model for the values of the resonant multipoles are
|M_{1+}(I=3/2)|= (40.9 \pm 0.3)10^{-3}/m_pi, CMR= C2/M1= -6.5 \pm 0.3%,
EMR=E2/M1=-2.2 \pm 0.9%, where the errors are due to the experimental
uncertainties.Comment: 10 pages, 3 figures, minor corrections and addition
Relativistic effects and two-body currents in using out-of-plane detection
Measurements of the reaction were performed
using an 800-MeV polarized electron beam at the MIT-Bates Linear Accelerator
and with the out-of-plane magnetic spectrometers (OOPS). The
longitudinal-transverse, and , and the
transverse-transverse, , interference responses at a missing momentum
of 210 MeV/c were simultaneously extracted in the dip region at Q=0.15
(GeV/c). On comparison to models of deuteron electrodisintegration, the
data clearly reveal strong effects of relativity and final-state interactions,
and the importance of the two-body meson-exchange currents and isobar
configurations. We demonstrate that these effects can be disentangled and
studied by extracting the interference response functions using the novel
out-of-plane technique.Comment: 4 pages, 4 figures, and submitted to PRL for publicatio
Study of CP violation in Dalitz-plot analyses of B0 --> K+K-KS, B+ --> K+K-K+, and B+ --> KSKSK+
We perform amplitude analyses of the decays , , and , and measure CP-violating
parameters and partial branching fractions. The results are based on a data
sample of approximately decays, collected with the
BABAR detector at the PEP-II asymmetric-energy factory at the SLAC National
Accelerator Laboratory. For , we find a direct CP asymmetry
in of , which differs
from zero by . For , we measure the
CP-violating phase .
For , we measure an overall direct CP asymmetry of
. We also perform an angular-moment analysis of
the three channels, and determine that the state can be described
well by the sum of the resonances , , and
.Comment: 35 pages, 68 postscript figures. v3 - minor modifications to agree
with published versio
Search for the Higgs boson in events with missing transverse energy and b quark jets produced in proton-antiproton collisions at s**(1/2)=1.96 TeV
We search for the standard model Higgs boson produced in association with an
electroweak vector boson in events with no identified charged leptons, large
imbalance in transverse momentum, and two jets where at least one contains a
secondary vertex consistent with the decay of b hadrons. We use ~1 fb-1
integrated luminosity of proton-antiproton collisions at s**(1/2)=1.96 TeV
recorded by the CDF II experiment at the Tevatron. We find 268 (16) single
(double) b-tagged candidate events, where 248 +/- 43 (14.4 +/- 2.7) are
expected from standard model background processes. We place 95% confidence
level upper limits on the Higgs boson production cross section for several
Higgs boson masses ranging from 110 GeV/c2 to 140 GeV/c2. For a mass of 115
GeV/c2 the observed (expected) limit is 20.4 (14.2) times the standard model
prediction.Comment: 8 pages, 2 figures, submitted to Phys. Rev. Let
Observation and Mass Measurement of the Baryon
We report the observation and measurement of the mass of the bottom, strange
baryon through the decay chain , where
, , and .
Evidence for observation is based on a signal whose probability of arising from
the estimated background is 6.6 x 10^{-15}, or 7.7 Gaussian standard
deviations. The mass is measured to be (stat.) (syst.) MeV/.Comment: Minor text changes for the second version. Accepted by Phys. Rev.
Let
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