1,314 research outputs found

    L\'evy-stable two-pion Bose-Einstein correlations in sNN=200\sqrt{s_{_{NN}}}=200 GeV Au++Au collisions

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    We present a detailed measurement of charged two-pion correlation functions in 0%-30% centrality sNN=200\sqrt{s_{_{NN}}}=200 GeV Au++Au collisions by the PHENIX experiment at the Relativistic Heavy Ion Collider. The data are well described by Bose-Einstein correlation functions stemming from L\'evy-stable source distributions. Using a fine transverse momentum binning, we extract the correlation strength parameter λ\lambda, the L\'evy index of stability α\alpha and the L\'evy length scale parameter RR as a function of average transverse mass of the pair mTm_T. We find that the positively and the negatively charged pion pairs yield consistent results, and their correlation functions are represented, within uncertainties, by the same L\'evy-stable source functions. The λ(mT)\lambda(m_T) measurements indicate a decrease of the strength of the correlations at low mTm_T. The L\'evy length scale parameter R(mT)R(m_T) decreases with increasing mTm_T, following a hydrodynamically predicted type of scaling behavior. The values of the L\'evy index of stability α\alpha are found to be significantly lower than the Gaussian case of α=2\alpha=2, but also significantly larger than the conjectured value that may characterize the critical point of a second-order quark-hadron phase transition.Comment: 448 authors, 25 pages, 11 figures, 4 tables, 2010 data. v2 is version accepted for publication in Phys. Rev. C. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

    Nuclear dependence of the transverse-single-spin asymmetry for forward neutron production in polarized pp++AA collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV

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    During 2015 the Relativistic Heavy Ion Collider (RHIC) provided collisions of transversely polarized protons with Au and Al nuclei for the first time, enabling the exploration of transverse-single-spin asymmetries with heavy nuclei. Large single-spin asymmetries in very forward neutron production have been previously observed in transversely polarized pp++pp collisions at RHIC, and the existing theoretical framework that was successful in describing the single-spin asymmetry in pp++pp collisions predicts only a moderate atomic-mass-number (AA) dependence. In contrast, the asymmetries observed at RHIC in pp++AA collisions showed a surprisingly strong AA dependence in inclusive forward neutron production. The observed asymmetry in pp++Al collisions is much smaller, while the asymmetry in pp++Au collisions is a factor of three larger in absolute value and of opposite sign. The interplay of different neutron production mechanisms is discussed as a possible explanation of the observed AA dependence.Comment: 315 authors, 8 pages, 4 figures, 1 table. v2 is version accepted for publication in Phys. Rev. Lett. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

    Assessing prediction of diabetes in older adults using different adiposity measures: a 7 year prospective study in 6,923 older men and women

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    The aim of this study was to examine whether waist circumference (WC) or WHR improve diabetes prediction beyond body mass index in older men and women, and to define optimal cut-off points. In this prospective study, non-diabetic men (n = 3,519) and women (n = 3,404) aged 60-79 years were followed up for 7 years. There were 169 and 128 incident cases of type 2 diabetes in men and women, respectively. BMI, WC and WHR all showed strong associations with incident type 2 diabetes independent of potential confounders. In men, the adjusted relative risks (top vs lowest quartile) were 4.71 (95% CI 2.45-9.03) for BMI, 3.53 (95% CI 1.92-6.48) for WC and 2.76 (95% CI 1.58-4.82) for WHR. For women, the corresponding relative risks were 4.10 (95% CI 2.16-7.79), 12.18 (95% CI 4.83-30.74) and 5.61 (95% CI 2.84-11.09) for BMI, WC and WHR, respectively. Receiver-operating characteristic curve analysis revealed similar associations for BMI and WC in predicting diabetes in men (AUC = 0.726 and 0.713, respectively); WHR was the weakest predictor (AUC = 0.656). In women, WC was a significantly stronger predictor (AUC = 0.780) than either BMI (AUC = 0.733) or WHR (AUC = 0.728; p < 0.01 for both). Inclusion of both WC and BMI did not improve prediction beyond BMI alone in men or WC alone in women. Optimal sensitivity and specificity for the prediction of type 2 diabetes was observed at a WC of 100 cm in men and 92 cm in women. In older men, BMI and WC yielded similar prediction of risk of type 2 diabetes, whereas WC was clearly a superior predictor in older wome
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