Discriminant Analysis and Secondary-Beam Charge Recognition

The discriminant-analysis method has been applied to optimize the exotic-beam charge recognition in a projectile fragmentation experiment. The experiment was carried out at the GSI using the fragment separator (FRS) to produce and select the relativistic secondary beams, and the ALADIN setup to measure their fragmentation products following collisions with Sn target nuclei. The beams of neutron poor isotopes around 124La and 107Sn were selected to study the isospin dependence of the limiting temperature of heavy nuclei by comparing with results for stable 124Sn projectiles. A dedicated detector to measure the projectile charge upstream of the reaction target was not used, and alternative methods had to be developed. The presented method, based on the multivariate discriminant analysis, allowed to increase the efficacy of charge recognition up to about 90%, which was about 20% more than achieved with the simple scalar methods.Comment: 6 pages, 7 eps figures, elsart, submitted to Nucl. Instr. and Meth.

Weak lensing, dark matter and dark energy

Weak gravitational lensing is rapidly becoming one of the principal probes of dark matter and dark energy in the universe. In this brief review we outline how weak lensing helps determine the structure of dark matter halos, measure the expansion rate of the universe, and distinguish between modified gravity and dark energy explanations for the acceleration of the universe. We also discuss requirements on the control of systematic errors so that the systematics do not appreciably degrade the power of weak lensing as a cosmological probe.Comment: Invited review article for the GRG special issue on gravitational lensing (P. Jetzer, Y. Mellier and V. Perlick Eds.). V3: subsection on three-point function and some references added. Matches the published versio

Weak gravitational lensing

In this brief review I consider the advances made in weak gravitational lensing over the last 8 years, concentrating on the large scales - cosmic shear. I outline the theoretical developments, observational status, and the challenges which cosmic shear must overcome to realise its full potential. Finally I consider the prospects for probing Dark Energy and extra-dimensional gravity theories with future experiments.Comment: 6 pages. Short version of invited review at Moriond Cosmology 200

Measurements of the Ratios B(Ds+→ηℓ+ν)/B(Ds+→ϕℓ+ν){\cal B}(D_s^+\to \eta\ell^+\nu)/{\cal B}(D_s^+\to \phi\ell^+\nu) and B(Ds+→η′ℓ+ν)/B(Ds+→ϕℓ+ν){\cal B}(D_s^+\to \eta'\ell^+\nu)/{\cal B}(D_s^+\to \phi\ell^+\nu)

Using the CLEO~II detector we measure ${\cal B}(D_s^+\to \eta e^+\nu)/{\cal B}(D_s^+\to \phi e^+\nu) =1.24\pm0.12\pm0.15$, ${\cal B}(D_s^+\to \eta' e^+\nu)/{\cal B}(D_s^+\to \phi e^+\nu) =0.43\pm0.11\pm0.07$ and ${\cal B}(D_s^+\to \eta' e^+\nu)/{\cal B}(D_s^+\to \eta e^+\nu) =0.35\pm0.09\pm0.07$. We find the vector to pseudoscalar ratio, ${\cal B}(D_s^+\to \phi e^+\nu)/{\cal B}(D_s^+\to (\eta+\eta') e^+\nu) =0.60\pm0.06\pm0.06$, which is similar to the ratio found in non strange $D$ decays.Comment: 11 page uuencoded postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

Mechanisms linking gender-based violence to worse HIV treatment and care outcomes among women in the United States

Objective:To test whether substance use mediates the associations between gender-based violence (GBV) and suboptimal adherence to antiretroviral therapy (ART), and GBV and poor engagement in care, among women living with HIV (WLHIV) in the United States (US).Design:We analyzed longitudinal data collected among 1717 WLHIV in the Women's Interagency HIV Study (WIHS).Methods:From 2013 to 2017, WLHIV completed semi-annual assessments on GBV, substance use, and HIV treatment and care. Adjusted multilevel logistic regression models were built to estimate the impact of GBV on; suboptimal (<95%) adherence and at least one missed HIV care appointment without rescheduling in the past 6 months. Mediation analyses were performed to test whether heavy drinking and illicit drug use mediated the associations between GBV and the two HIV outcomes.Results:The mean age was 47 (standard deviation = 9), 5% reported experiencing GBV, 17% reported suboptimal adherence and 15% reported at least one missed appointment in the past 6 months. Women who experienced GBV had a significantly higher odds of suboptimal adherence [adjusted odds ratio (aOR) = 1.99; 95% confidence interval (CI) = 1.40-2.83] and missed appointments (aOR = 1.92, 95% CI = 1.32-2.33). Heavy drinking and illicit drug use mediated 36 and 73% of the association between GBV and suboptimal adherence and 29 and 65% of the association between GBV and missed appointments, respectively.Conclusions:Substance use is an underlying mechanism through which GBV affects outcomes along the HIV care continuum among WLHIV in the US. To optimize HIV treatment and care among women, interventions should address the combined epidemics of substance use, violence, and HIV

Mental Health Mediates the Association Between Gender-Based Violence and HIV Treatment Engagement in US Women

Background: Gender-based violence (GBV) is associated with poorer engagement in HIV care and treatment. However, there is a dearth of research on the psychological (eg, mental health) and structural (eg, food insecurity) factors that mediate and moderate this association. GBV could lead to poor mental health, which in turn affects adherence, whereas food insecurity could worsen the effect of GBV on engagement in care. This study uses data from the Women's Interagency HIV Study to address these gaps. Methods: Women completed 6 assessments from 2013 to 2016 on GBV, mental health, food insecurity, adherence to antiretroviral therapy, and missed HIV care appointments in the past 6 months. Multilevel logistic regression models estimated associations between GBV and engagement in care and whether associations were mediated by depression, generalized anxiety disorder (GAD), and posttraumatic stress disorder (PTSD) and moderated by food insecurity. Results: GBV was associated with higher odds of suboptimal adherence (adjusted odds ratio: 1.88; 95% confidence interval: 1.24 to 2.87) and missed appointments (adjusted odds ratio: 1.76; 95% confidence interval: 1.16 to 2.67). The association between GBV and adherence was mediated by depressive symptoms, GAD, and PTSD, accounting for 29.7%, 15.0%, and 16.5%, respectively, of the total association. The association between GBV and missed appointments was mediated by depression and GAD, but not PTSD, with corresponding figures of 25.2% and 19.7%. Associations did not differ by food insecurity. Conclusions: GBV is associated with suboptimal engagement in care, which may be explained by mental health. Interventions should address women's mental health needs, regardless of food insecurity, when improving engagement in HIV care

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio