3,872 research outputs found

    Accessing transversity via J/Psi production in polarized p-pbar interactions

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    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

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    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

    “New” metastases are associated with a poorer prognosis than growth of pre-existing metastases in patients with metastatic breast cancer treated with chemotherapy

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    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 ≀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)

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    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.

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    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)

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    We present a calculation of the two-loop anomalous dimension for the transversity distribution h_1(x,Q^2), Îłnh(1)\gamma^{h(1)}_n, 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), Îłnh(1)\gamma^{h(1)}_n is significantly larger than Îłnf(1)\gamma^{f(1)}_n (the anomalous dimension for the nonsinglet f_1), but approaches Îłnf(1)\gamma^{f(1)}_n very quickly at large n, keeping the relation Îłnh(1)>Îłnf(1)\gamma^{h(1)}_n > \gamma^{f(1)}_n. 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 WW production and the Gottfried Sum Rule

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    The difference in production rate between W+W^+ and W−W^- 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 ds(x,Q2)−us(x,Q2)d_s(x,Q^2) - u_s(x,Q^2) in the sea distributions and the difference Δu(x,Q2)−Δd(x,Q2)\Delta u(x,Q^2) - \Delta d(x,Q^2) 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

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    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

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    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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