1,426 research outputs found

    Narrowing the uncertainty on the total charm cross section and its effect on the J/\psi\ cross section

    Full text link
    We explore the available parameter space that gives reasonable fits to the total charm cross section to make a better estimate of its true uncertainty. We study the effect of the parameter choices on the energy dependence of the J/\psi\ cross section.Comment: 19 pages, 13 figure

    Heavy flavor in heavy-ion collisions at RHIC and RHIC II

    Full text link
    In the initial years of operation, experiments at the Relativistic Heavy Ion Collider (RHIC) have identified a new form of matter formed in nuclei-nuclei collisions at energy densities more than 100 times that of a cold atomic nucleus. Measurements and comparison with relativistic hydrodynamic models indicate that the matter thermalizes in an unexpectedly short time, has an energy density at least 15 times larger than needed for color deconfinement, has a temperature about twice the critical temperature predicted by lattice QCD, and appears to exhibit collective motion with ideal hydrodynamic properties - a "perfect liquid" that appears to flow with a near-zero viscosity to entropy ratio - lower than any previously observed fluid and perhaps close to a universal lower bound. However, a fundamental understanding of the medium seen in heavy-ion collisions at RHIC does not yet exist. The most important scientific challenge for the field in the next decade is the quantitative exploration of the new state of nuclear matter. That will require new data that will, in turn, require enhanced capabilities of the RHIC detectors and accelerator. In this report we discuss the scientific opportunities for an upgraded RHIC facility - RHIC II - in conjunction with improved capabilities of the two large RHIC detectors, PHENIX and STAR. We focus solely on heavy flavor probes. Their production rates are calculable using the well-established techniques of perturbative QCD and their sizable interactions with the hot QCD medium provide unique and sensitive measurements of its crucial properties making them one of the key diagnostic tools available to us.Comment: 96 pages, 53 figures. Accepted for publication in Physics Reports. Fixed typo in Fig. 15 captio

    Improving the J/psi Production Baseline at RHIC and the LHC

    Full text link
    We assess the theoretical uncertainties on the inclusive J/psi production cross section in the Color Evaporation Model (CEM) using values for the charm quark mass, renormalization and factorization scales obtained from a fit to the charm production data. We use our new results to provide improved baseline comparison calculations at RHIC and the LHC. We also study cold matter effects on J/psi production at leading relative to next-to-leading order in the CEM within this approach.Comment: Proceedings for Hard Probes 2012, Cagliari, Ital

    Improved definition of crustal magnetic anomalies for MAGSAT data

    Get PDF
    The routine correction of MAGSAT vector magnetometer data for external field effects such as the ring current and the daily variation by filtering long wavelength harmonics from the data is described. Separation of fields due to low altitude sources from those caused by high altitude sources is affected by means of dual harmonic expansions in the solution of Dirichlet's problem. This regression/harmonic filter procedure is applied on an orbit by orbit basis, and initial tests on MAGSAT data from orbit 1176 show reduction in external field residuals by 24.33 nT RMS in the horizontal component, and 10.95 nT RMS in the radial component

    The Association between women’s choice of birth setting and their use of CAM during labor and birth.

    Full text link
    Purpose: Contemporary maternity care often means women are able to choose a number of settings for their birth including hospitals, birth centers, and community settings. There is also evidence that many women utilised complementary and alternative medicine (CAM) during pregnancy and birth. The purpose of this study is to examine the association between women’s choice of birth setting and their use of CAM during labor and birth. Methods: Longitudinal data from a sub-study of women (n = 2445) from the nationally-representative Australian Longitudinal Study of Women’s Health (ALSWH) was analyzed for relationships between women’s birth setting (hospital, birth center, or community) and their demographics, attitudes towards maternity care (including CAM), and use of CAM during pregnancy and birth. Results: The characteristics associated with women’s choice of birth setting include some demographic features such as employment status, health care subsidy, and level of education. Women’s birth setting choice was also linked to a preference for CAM practitioner by women birthing in birth centers and community settings. In contrast, women birthing in hospitals held more positive views towards obstetric care. There was a higher use of CAM during pregnancy by women birthing in birth centers and community but this was not consistent across all CAMs investigated. Naturopaths, herbal medicines, homeopathy and flower essences were more commonly used by women birthing in community compared with those in a birth center. There was also a higher rate of CAM use for intrapartum pain management for women birthing outside of a hospital setting, although women attending a birth center were more likely than those birthing in community to use pharmacological pain management techniques. Conclusion: There are characteristic differences between women birthing in different birth settings which seems to be influenced as much by preference for maternity care and interest in CAM use as it is by demographics

    Characteristics of women who practice yoga in different locations during pregnancy

    Full text link
    Objectives: Yoga practice during pregnancy is gaining increasing popularity. This study examined the characteristics of pregnant women who practiced yoga in regard to the different locations (at home, in yoga classes, or both). Design: The study sample was drawn from the Australian Longitudinal Study on Women's Health (ALSWH), a national longitudinal study of women to investigate multiple factors affecting health and wellbeing of women over a 20-year period. Setting: Postal survey. Participants: Women born between 1973 and 1978, who were randomly selected from the national Medicare database and identified as being pregnant or having recently given birth (n=2316). Outcome measures: Relationships between yoga use (attending yoga classes and/or practising yoga at home) and women's characteristics (demographic measures, pregnancy-related health concerns, health service utilisation, attitudes to complementary and alternative medicine). Results: Practising yoga both at home and in classes was associated with perceiving complementary and alternative medicine (CAM) as preventative (odds ratio (OR)=1.62); perceiving CAM as affording health control (OR=1.50); experiencing sadness (OR=1.72); preparing for labour (OR=2.31); birthing in a birth centre (OR=7.97); and experiencing less vomiting (OR=0.38). Practising at home only was associated with perceiving CAM as affording health control (OR=1.76); perceiving CAM as promoting a holistic health approach (OR=1.65); and birthing in a birth centre (OR=3.54). Practising in classes only was associated with experiencing stress (OR=1.97); and birthing in a birth centre (OR=4.85) (all p<0.05). Conclusions: The findings suggest that the location in which a woman practices yoga is associated with attitudinal, health-related and birth environmental factors

    Electromagnetic Emission and Energy Loss in the QGP

    Full text link
    I discuss why photon production from the Quark Gluon Plasma (QGP) presents an interesting problem, both experimentally and theoretically. I show how the photon emission rate can be computed under the simplifying assumption that the QGP fully thermalizes. The theoretical issues are very similar to those for jet energy loss; so it should be possible to treat them in a common formalism and relate the predictions of one phenomenon to those of the other.Comment: 8 pages, invited talk at Quark Matter 200

    An intelligent assistant for exploratory data analysis

    Get PDF
    In this paper we present an account of the main features of SNOUT, an intelligent assistant for exploratory data analysis (EDA) of social science survey data that incorporates a range of data mining techniques. EDA has much in common with existing data mining techniques: its main objective is to help an investigator reach an understanding of the important relationships ina data set rather than simply develop predictive models for selectd variables. Brief descriptions of a number of novel techniques developed for use in SNOUT are presented. These include heuristic variable level inference and classification, automatic category formation, the use of similarity trees to identify groups of related variables, interactive decision tree construction and model selection using a genetic algorithm

    An assessment of J/Psi formation in the light of initial RHIC data

    Full text link
    Predictions of J/Psi formation at RHIC via "off-diagonal" combinations of charm and anticharm quarks in a region of color deconfinement are confronted with initial data from the PHENIX collaboration. We find that the measured centrality behavior places significant constraints on the various parameters which control model calculations of J/Psi formation. Within present statistical and systematic uncertainties, one can map out a region of parameter space within which the contribution of formation in a deconfined phase is allowed. As these uncertainties decrease and new data from d-Au interactions becomes available, it is expected that definitive tests for the presence of this formation mechanism will be possible. We anticipate that the rapidity and transverse momentum spectra will prove decisive for a final determination.Comment: 6 pages, 5 figures, presented at SQM2003, March 12-17, 2003. To be published in J. Phys.
    corecore