188 research outputs found
The Experiment Road to the Heavier Quarks and Other Heavy Objects
After a brief history of heavy quarks, I will discuss charm, bottom, and top
quarks in turn. For each one, I discuss its first observation, and then what we
have learned about production, hadronization, and decays - and what these have
taught us about the underlying physics. I will also point out remaining open
issues. For this series of lectures, the charm quark will be emphasized. It is
the first of the heavy quarks, and its study is where many of the techniques
and issues first appeared. Only very brief mention is made of CP violation in
the bottom-quark system since that topic is the subject of a separate series of
lectures by Gabriel Lopez. As the three quarks are reviewed, a pattern of
techniques and lessons emerges. These are identified, and then briefly
considered in the context of anticipated physics signals of the future; e.g.,
for Higgs and SUSY particles.Comment: From three lectures at the "IX Escuela de Particulas y Campos" in
Metepec, Mexico - August, 2000. 30 pages, 5 figures Revised version with
spelling/grammar corrections and clearer figur
Future Hadron Physics at Fermilab
Today, hadron physics research occurs at Fermilab as parts of broader
experimental programs. This is very likely to be the case in the future. Thus,
much of this presentation focuses on our vision of that future - a future aimed
at making Fermilab the host laboratory for the International Linear Collider
(ILC). Given the uncertainties associated with the ILC - the level of needed
R&D, the ILC costs, and the timing - Fermilab is also preparing for other
program choices. I will describe these latter efforts, efforts focused on a
Proton Driver to increase the numbers of protons available for experiments. As
examples of the hadron physics which will be coming from Fermilab, I summarize
three experiments: MIPP/E907 which is running currently, and MINER A and
Drell-Yan/E906 which are scheduled for future running periods. Hadron physics
coming from the Tevatron Collider program will be summarized by Arthur Maciel
in another talk at Hadron05.Comment: To be published in the Proceedings of the XI International Conference
on Hadron Spectroscopy (Alberto Reis, editor) in the AIP Conference
Proceedings series, 10 page
Charm Results on CP Violation and Mixing
The most recent results on CP violation and mixing in the charm system are
reviewed as a guide to the future. While no surprising results are reported so
far, charm provides a unique window to physics beyond the Standard Model. The
results reported here come from four sources: ALEPH at LEP, E791 and FOCUS/E831
at Fermilab, and CLEO II.V at CESR. Results beyond these sources may be
expected as a byproduct of B-motivated experiments.Comment: 17 pages,including 4 figures, Workshop on Physics and Detectors for
Daphne, Frascati, Italy, November 16-19, 199
Gender Differences in Symptoms and Care Delivery for Chronic Obstructive Pulmonary Disease
Abstract Background: Morbidity and mortality for women with chronic obstructive pulmonary disease (COPD) are increasing, and little is known about gender differences in perception of COPD care. Methods: Surveys were administered to a convenience sample of COPD patients to evaluate perceptions about symptoms, barriers to care, and sources of information about COPD. Results: Data on 295 female and 273 male participants were analyzed. With similar frequencies, women and men reported dyspnea and rated their health as poor/very poor. Although more women than men reported annual household income <$30,000, no significant gender differences in frequency of health insurance, physician visits, or ever having had spirometry were detected. In adjusted models (1) women were more likely to report COPD diagnostic delay (odds ratio [OR] 1.66, 95% confidence interval [CI] 1.13-2.45, p=0.01), although anxiety (OR 1.83, 95% CI 1.10-3.06, p=0.02) and history of exacerbations (OR 1.60, 95% CI 1.08-2.37, p=0.01) were also significant predictors, (2) female gender was associated with difficulty reaching one's physician (OR 2.54, 95% CI 1.33-4.86, p=0.004), as was prior history of exacerbations (OR 2.25, 95% CI 1.21-4.20, p=0.01), and (3) female gender (OR 2.15, 95% CI 1.10-4.21, p=0.02) was the only significant predictor for finding time spent with their physician as insufficient. Conclusions: Significant gender-related differences in the perception of COPD healthcare delivery exist, revealing an opportunity to better understand what influences these attitudes and to improve care for both men and women.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98466/1/jwh%2E2012%2E3650.pd
CLASS Observations of Atmospheric Cloud Polarization at Millimeter Wavelengths
The dynamic atmosphere imposes challenges to ground-based cosmic microwave
background observation, especially for measurements on large angular scales.
The hydrometeors in the atmosphere, mostly in the form of clouds, scatter the
ambient thermal radiation and are known to be the main linearly polarized
source in the atmosphere. This scattering-induced polarization is significantly
enhanced for ice clouds due to the alignment of ice crystals under gravity,
which are also the most common clouds seen at the millimeter-astronomy sites at
high altitudes. This work presents a multifrequency study of cloud polarization
observed by the Cosmology Large Angular Scale Surveyor (CLASS) experiment on
Cerro Toco in the Atacama Desert of northern Chile, from 2016 to 2022, at the
frequency bands centered around 40, 90, 150, and 220 GHz. Using a
machine-learning-assisted cloud classifier, we made connections between the
transient polarized emission found in all four frequencies with the clouds
imaged by monitoring cameras at the observing site. The polarization angles of
the cloud events are found to be mostly from the local meridian,
which is consistent with the presence of horizontally aligned ice crystals. The
90 and 150 GHz polarization data are consistent with a power law with a
spectral index of , while an excess/deficit of polarization
amplitude is found at 40/220 GHz compared with a Rayleigh scattering spectrum.
These results are consistent with Rayleigh-scattering-dominated cloud
polarization, with possible effects from supercooled water absorption and/or
Mie scattering from a population of large cloud particles that contribute to
the 220 GHz polarization.Comment: 16 pages, 14 figures, submitted to Ap
- âŠ