17,458 research outputs found
Review of W and Z Production at the Tevatron
The CDF and \D0 collaborations have used recent data taken at the Tevatron to
perform QCD tests with and bosons decaying leptonically. \D0 measures
the production cross section times branching ratio for and bosons. This
also gives an indirect measurement of the total width of the boson:
\gw=2.126\pm0.092 GeV. CDF reports on a direct measurement of
\gw=2.19\pm0.19 GeV, in good agreement with the indirect determination and
Standard Model predictions. \D0's measurement of the differential
distribution for and bosons decaying to electrons agrees
with the combined QCD perturbative and resummation calculations. In addition,
the distribution for the boson discriminates between
different vector boson production models. Studies of production at CDF
find the NLO QCD prediction for the production rate of events to
be in good agreement with the data.Comment: 8 pages, 6 figures, presented at XXXIIIrd Recontres de Moriond, QCD
AND HIGH ENERGY HADRONIC INTERACTIONS,Les Arcs, Savoie, France, 199
Energy balance and cancers
Energy balance results from the exact equilibrium between caloric intake and caloric expenditure. A caloric intake larger than caloric expenditure results in overweight, even obesity, but other determinants, like hormonal dysfunction and/or genetic traits may play a part in obesity syndrome. Obesity, and even overweight, have been recognized as risk factors for the development of cancers. Human epidemiological studies, which have tended to establish the nature of the relationship between energy balance and cancer, are summarized first, with the influence of the various factors which act both on obesity and on cancer risk. Among these factors are the macronutrients responsible for the caloric intake, and some lifestyle factors (physical activity, drinking habits and tobacco use). Second, the animal studies help to distinguish between different relevant factors, and to understand some of the underlying mechanisms. However, the insulin-resistance syndrome, which appears to underlie the relationship between obesity and hormone-dependent cancers, and possibly colon cancer, is only relevant to human physiology because hormonal alterations are part of it. Prevention of hyperinsulinemia, insulin resistance and the accompanying visceral obesity appears to be a major public health task for the prevention of cancers
Studies of single top production at the Tevatron
I present the newest measurements of the production cross sections of single top quarks in pp collisions at √s = 1.96TeV in a data sample corresponding to an integrated luminosity of 5.4 fb−1 collected by the D0 detector at the Fermilab Tevatron Collider. The data is also used to extract limits on the CKM Matrix element |Vtb|
LHC Highlights and Prospects
These lectures were presented at the 2019 CERN Latin-American School of High
Energy Physics. They were centered on the experimental methods used in hadron
colliders to advance our understanding in the field of high energy particle
physics. From accelerators, to particle detector technologies, object
identification and data analyses techniques, the lectures did not attempt to
provide a comprehensive, in-depth technical background, but rather focused on
an overview of experimental techniques that enabled our advances in supporting
and challenging the predictions of the standard model. This document includes a
selection of the material presented in the lectures, focusing on how advances
in detector technologies and object identification enabled the development of
increasingly sophisticated data analysis techniques. This writeup also includes
an outlook to the future LHC program and beyond.Comment: 38 pages, 31 figures, Lecture notes for the 10th CERN Latin-American
School of High-Energy Physics (CLASHEP2019), 13 to 26 March 2019 in Villa
General Belgrano, Cordoba Province, Argentin
Polysilicon vs. Aluminum Gate PMOS Ring Oscillators
A nine stage PMOS ring oscillator was designed using polysilicon gates for a self-aligning process while another was designed using a standard metal gate process. A comparison of the polysilicon and metal gate PMQS processes was planned to show the reduced gate capacitance of the self-aligning process. This reduced gate capacitance was to be observed by measuring and comparing the propagation delay of each design on the oscilloscope
Building school connections through integrating extracurricular programs
The purpose of this study was to develop an integrated extracurricular program and evaluate its effectiveness on improving middle school students\u27 emotional connectedness to the school. The integrated extracurricular program provided an opportunity for a diverse group of students to work cooperatively as a team toward a common goal.
The program\u27s first extracurricular activity was a Haunted House event which was utilized for this study. Participants in the study included 232 students and 21 staff members. Two separate surveys were administered to the student and staff participants. Each survey resulted in general opinions about the effectiveness of the integrated extracurricular program toward increasing student participation and improving students\u27 emotional connectedness with the school. The data from the surveys and after school club attendance sheets revealed that the Integrated Extracurricular Program\u27s event of the Haunted House had a positive impact on the students\u27 sense of connectedness and involvement with the school. However, the program\u27s impact on school unity was explored as discrepancies surfaced between the student and staff responses
The MUCHFUSS photometric campaign
Hot subdwarfs (sdO/Bs) are the helium-burning cores of red giants, which lost
almost all of their hydrogen envelopes. This mass loss is often triggered by
common envelope interactions with close stellar or even substellar companions.
Cool companions like late-type stars or brown dwarfs are detectable via
characteristic light curve variations like reflection effects and often also
eclipses. To search for such objects we obtained multi-band light curves of 26
close sdO/B binary candidates from the MUCHFUSS project with the BUSCA
instrument. We discovered a new eclipsing reflection effect system
(~d) with a low-mass M dwarf companion ().
Three more reflection effect binaries found in the course of the campaign were
already published, two of them are eclipsing systems, in one system only
showing the reflection effect but no eclipses the sdB primary is found to be
pulsating. Amongst the targets without reflection effect a new long-period sdB
pulsator was discovered and irregular light variations were found in two sdO
stars. The found light variations allowed us to constrain the fraction of
reflection effect binaries and the substellar companion fraction around sdB
stars. The minimum fraction of reflection effect systems amongst the close sdB
binaries might be greater than 15\% and the fraction of close substellar
companions in sdB binaries might be as high as . This would result in a
close substellar companion fraction to sdB stars of about 3\%. This fraction is
much higher than the fraction of brown dwarfs around possible progenitor
systems, which are solar-type stars with substellar companions around 1 AU, as
well as close binary white dwarfs with brown dwarf companions. This might be a
hint that common envelope interactions with substellar objects are
preferentially followed by a hot subdwarf phase.Comment: accepted for A&
Test of prototype liquid-water-content meter for aircraft use
This report describes the effort undertaken to meet the objectives of National Science Foundation Grant ATM-9207345 titled 'Test of Prototype Liquid-Water-Content Meter for Aircraft Use.' Three activities were proposed for testing the new aircraft instrument, PVM-100A: (1) Calibrate the PVM-100A in a facility where the liquid-water-content (LWC) channel, and the integrated surface area channel (PSA) could be compared to standard means for LWC and PSA measurements. Scaling constant for the channels were to be determined in this facility. The fog/wind tunnel at ECN, Petten, The Netherlands was judged the most suitable facility for this effort. (2) Expose the PVM-100A to high wind speeds similar to those expected on research aircraft, and test the anti-icing heaters on the PVM-100A under typical icing conditions expected in atmospheric clouds. The high-speed icing tunnel at NRC, Ottawa, Canada was to be utilized. (3) Operate the PVM-100A on an aircraft during cloud penetrations to determine its stability and practicality for such measurements. The C-131A aircraft of the University of Washington was the aircraft of opportunity for these-tests, which were to be conducted during the 4-week Atlantic Stratocumulus Transition Experiment (ASTEX) in June of 1992
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