3,872 research outputs found
Accessing transversity via J/Psi production in polarized p-pbar interactions
We discuss the possibility of a direct access to transversity distributions
by measuring the double transverse spin asymmetry A_TT in p pbar --> J/Psi + X
--> l^- l^+ + X processes at future GSI-HESR experiments with polarized protons
and anti-protons. In the J/Psi resonance production region, with 30 < s < 45
GeV^2, both the cross-section and A_TT are expected to be sufficiently large to
allow a measurement of h_1^q(x,M^2); numerical estimates are given.Comment: 10 pages, 2 figures. Version accepted for publication in PLB;
comments and references adde
Soffer's inequality and the transversely polarized Drell-Yan process at next-to-leading order
We check numerically if Soffer's inequality for quark distributions is
preserved by next-to-leading order QCD evolution. Assuming that the inequality
is saturated at a low hadronic scale we estimate the maximal transverse double
spin asymmetry for Drell-Yan muon pair production to next-to-leading order
accuracy.Comment: 20 Pages, LaTeX, 7 figures as eps file
âNewâ metastases are associated with a poorer prognosis than growth of pre-existing metastases in patients with metastatic breast cancer treated with chemotherapy
Introduction: Progression-free survival (PFS) and overall survival (OS) endpoints often only weakly correlate. This analysis investigates how different progression events impact on OS, using data from two phase 3 studies with eribulin in women with advanced/metastatic breast cancer (MBC). Methods: In Study 301, 1102 women with â€2 prior chemotherapies for advanced/MBC were randomized to eribulin mesylate (1.4 mg/m2 on days 1 and 8 every 21 days) or capecitabine (1.25 g/m2 twice daily on days 1-14 every 21 days). Study 305/EMBRACE enrolled 762 patients following two to five prior chemotherapies for advanced/MBC, randomized to eribulin (as above) or treatment of physician's choice. We analyzed OS and PFS post hoc for patients whose disease progressed due to development of "new" metastases, growth of pre-existing lesions, and patients with no reported disease progression. Results: In both clinical studies, development of new metastases was associated with an increased risk of death (p < 0.0001). The time to development of new metastasis or death was significantly longer with eribulin than the comparator in Study 305 (p = 0.0017), but not in Study 301 (p = 0.46). Significantly longer OS was observed in the eribulin compared with the comparator arm for the new metastases subgroup in Study 301 (p = 0.008), but not in Study 305 (p = 0.16), compared with other progression subgroups. Conclusions: Patients with MBC progressing with new metastases have a worse prognosis than those whose disease progresses due to growth of existing lesions or patients with no reported disease progression. These findings have potentially important implications for the interpretation of clinical study data and clinical practice.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Measuring the dark side (with weak lensing)
We introduce a convenient parametrization of dark energy models that is
general enough to include several modified gravity models and generalized forms
of dark energy. In particular we take into account the linear perturbation
growth factor, the anisotropic stress and the modified Poisson equation. We
discuss the sensitivity of large scale weak lensing surveys like the proposed
DUNE satellite to these parameters. We find that a large-scale weak-lensing
tomographic survey is able to easily distinguish the Dvali-Gabadadze-Porrati
model from LCDM and to determine the perturbation growth index to an absolute
error of 0.02-0.03.Comment: 19 pages, 11 figure
Influence of grit on lifestyle factors during the COVID-19 pandemic in a sample of adults in the United States.
The novel coronavirus disease (COVID-19) has profoundly impacted the world, including disruptions in lifestyles to support physical distancing. It is well known that personality plays a role in lifestyle behaviors such that certain traits predict health and well-being. The present study examined the relationship between grit and lifestyle behaviors during the early stages of the COVID-19 pandemic and initial lockdowns in the United States. It was hypothesized that those with more grit would engage in healthier lifestyle behaviors of increased physical activity, less sedentary time, and better eating habits. Using an internet-based survey, data was collected from adults from April 13th to May 4th, 2020. Survey questions focused on demographics, grit, physical activity and sedentary time, and dietary habits. Associations between grit and lifestyle were examined using a combination of hierarchical multiple regression analyses and ANCOVAs. The sample of 888 adults (age: 34.8 ± 14.0) was 74.2% female. Those with higher grit were more physically active, reported less sedentary time, and practiced better dietary habits. Collectively, these findings suggest that grit may help individuals lead a healthier lifestyle during stressful or negative events such as a global pandemic. Future work should examine the role of grit on lifestyle behaviors as the quarantine continues
Next-to-leading order Q^2-evolution of the transversity distribution h_1(x, Q^2)
We present a calculation of the two-loop anomalous dimension for the
transversity distribution h_1(x,Q^2), , in the MS scheme of
the dimensional regularization. Due to the chiral-odd nature, h_1 does not mix
with the gluon distributions, and thus our result is the same for the
flavor-singlet and nonsinglet distributions. At small n (moment of h_1),
is significantly larger than (the anomalous
dimension for the nonsinglet f_1), but approaches very
quickly at large n, keeping the relation .
This feature is in parallel to the relation between the one-loop anomalous
dimension for f_1 and h_1.Comment: 28 pages, Latex. 10 figures. Submitted for publication some time ag
Hadronic production and the Gottfried Sum Rule
The difference in production rate between and at hadron colliders
is very sensitive to the the difference between up- and down-quark
distributions in the proton. This sensitivity allows for a variety of useful
measurements. We consider the difference in the sea
distributions and the difference in the
polarized parton distribution functions. In both cases we construct an
asymmetry to reduce systematic uncertainties. Although we discuss measurements
at the Tevatron and future hadron colliders, we find that the Brookhaven
Relativistic Heavy Ion Collider (RHIC) is the most appropriate hadron collider
for these measurements.Comment: 19 pages (20 figures available from the authors), MAD/PH/74
Next-to-leading order QCD corrections to A_TT for prompt photon production
We present a next-to-leading order QCD calculation of the cross section for
isolated large-p_T prompt photon production in collisions of transversely
polarized protons. We devise a simple method of dealing with the phase space
integrals in dimensional regularization in the presence of the cos(2 phi)
azimuthal-angular dependence occurring for transverse polarization. Our results
allow to calculate the double-spin asymmetry A_TT for this process at
next-to-leading order accuracy, which may be used at BNL-RHIC to measure the
transversity parton distributions of the proton.Comment: 19 pages, LaTeX, 2 figures as eps file
Formation and Evolution of Planetary Systems: Placing Our Solar System in Context with Spitzer
We summarize the progress to date of our Legacy Science Program entitled "The
Formation and Evolution of Planetary Systems" (FEPS) based on observations
obtained with the Spitzer Space Telescope during its first year of operation.
In addition to results obtained from our ground-based preparatory program and
our early validation program, we describe new results from a survey for
near-infrared excess emission from the youngest stars in our sample as well as
a search for cold debris disks around sun-like stars. We discuss the
implications of our findings with respect to current understanding of the
formation and evolution of our own solar system.Comment: 8 postscript pages including 3 figures. To appear in "Spitzer New
Views of the Cosmos" ASP Conference Series, eds. L. Armus et al. FEPS website
at http://feps.as.arizona.ed
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