52 research outputs found

    Measurement of the Bottom contribution to non-photonic electron production in p+pp+p collisions at s\sqrt{s} =200 GeV

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    The contribution of BB meson decays to non-photonic electrons, which are mainly produced by the semi-leptonic decays of heavy flavor mesons, in p+pp+p collisions at s=\sqrt{s} = 200 GeV has been measured using azimuthal correlations between non-photonic electrons and hadrons. The extracted BB decay contribution is approximately 50% at a transverse momentum of pT5p_{T} \geq 5 GeV/cc. These measurements constrain the nuclear modification factor for electrons from BB and DD meson decays. The result indicates that BB meson production in heavy ion collisions is also suppressed at high pTp_{T}.Comment: 6 pages, 4 figures, accepted by PR

    Longitudinal double-spin asymmetry and cross section for inclusive neutral pion production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV

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    We report a measurement of the longitudinal double-spin asymmetry A_LL and the differential cross section for inclusive Pi0 production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV. The cross section was measured over a transverse momentum range of 1 < p_T < 17 GeV/c and found to be in good agreement with a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry was measured in the range of 3.7 < p_T < 11 GeV/c and excludes a maximal positive gluon polarization in the proton. The mean transverse momentum fraction of Pi0's in their parent jets was found to be around 0.7 for electromagnetically triggered events.Comment: 6 pages, 3 figures, submitted to Phys. Rev. D (RC

    Event-plane-dependent Dihadron Correlations With Harmonic Vn Subtraction In Au + Au Collisions At S Nn =200 Gev

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    STAR measurements of dihadron azimuthal correlations (Δφ) are reported in midcentral (20-60%) Au+Au collisions at sNN=200 GeV as a function of the trigger particle's azimuthal angle relative to the event plane, φs=|φt-ψEP|. The elliptic (v2), triangular (v3), and quadratic (v4) flow harmonic backgrounds are subtracted using the zero yield at minimum (ZYAM) method. The results are compared to minimum-bias d+Au collisions. It is found that a finite near-side (|Δφ|π/2) correlation shows a modification from d+Au data, varying with φs. The modification may be a consequence of path-length-dependent jet quenching and may lead to a better understanding of high-density QCD. © 2014 American Physical Society.894DOE; U.S. Department of EnergyArsene, I., (2005) Nucl. Phys. A, 757, p. 1. , (BRAHMS Collaboration), () NUPABL 0375-9474 10.1016/j.nuclphysa.2005.02. 130;Back, B.B., (2005) Nucl. Phys. A, 757, p. 28. , (PHOBOS Collaboration), () NUPABL 0375-9474 10.1016/j.nuclphysa.2005.03. 084;Adams, J., (2005) Nucl. Phys. A, 757, p. 102. , (STAR Collaboration), () NUPABL 0375-9474 10.1016/j.nuclphysa.2005.03. 085;Adcox, K., (2005) Nucl. Phys. A, 757, p. 184. , (PHENIX Collaboration),. NUPABL 0375-9474 10.1016/j.nuclphysa.2005.03.086Heinz, U., Kolb, P.F., (2002) Nucl. Phys. A, 702, p. 269. , NUPABL 0375-9474 10.1016/S0375-9474(02)00714-5Wang, X.-N., Gyulassy, M., (1992) Phys. Rev. Lett., 68, p. 1480. , PRLTAO 0031-9007 10.1103/PhysRevLett.68.1480Adler, S., (2003) Phys. Rev. Lett., 91, p. 072301. , (PHENIX Collaboration), () PRLTAO 0031-9007 10.1103/PhysRevLett.91. 072301;Adams, J., (2003) Phys. Rev. Lett., 91, p. 072304. , (STAR Collaboration), () PRLTAO 0031-9007 10.1103/PhysRevLett.91.072304;Adler, C., (2003) Phys. Rev. Lett., 90, p. 082302. , (STAR Collaboration),. PRLTAO 0031-9007 10.1103/PhysRevLett.90.082302Adams, J., (2005) Phys. Rev. Lett., 95, p. 152301. , (STAR Collaboration), () PRLTAO 0031-9007 10.1103/PhysRevLett.95.152301;Aggarwal, M.M., (2010) Phys. Rev. C, 82, p. 024912. , (STAR Collaboration),. PRVCAN 0556-2813 10.1103/PhysRevC.82.024912Adams, J., (2004) Phys. Rev. Lett., 93, p. 252301. , (STAR Collaboration),. PRLTAO 0031-9007 10.1103/PhysRevLett.93.252301Poskanzer, A.M., Voloshin, S.A., (1998) Phys. Rev. C, 58, p. 1671. , PRVCAN 0556-2813 10.1103/PhysRevC.58.1671Alver, B., (2008) Phys. Rev. C, 77, p. 014906. , PRVCAN 0556-2813 10.1103/PhysRevC.77.014906Feng, A., (2008), Ph.D. thesis, Institute of Particle Physics, CCNU, (unpublished);Konzer, J., (2013), Ph.D. thesis, Purdue University, (unpublished)Agakishiev, H., (STAR Collaboration), arXiv:1010.0690Ackermann, K.H., (2003) Nucl. Instrum. Meth., A499, p. 624. , (STAR Collaboration),. NIMAER 0168-9002 10.1016/S0168-9002(02)01960-5Ackermann, K.H., (1999) Nucl. Phys. A, 661, p. 681. , (STAR Collaboration),. NUPABL 0375-9474 10.1016/S0375-9474(99)85117-3Adams, J., (2004) Phys. Rev. Lett., 92, p. 112301. , (STAR Collaboration),. PRLTAO 0031-9007 10.1103/PhysRevLett.92.112301Borghini, N., Dinh, P.M., Ollitrault, J.Y., (2000) Phys. Rev. C, 62, p. 034902. , PRVCAN 0556-2813 10.1103/PhysRevC.62.034902Adams, J., (2005) Phys. Rev. C, 72, p. 014904. , (STAR Collaboration),. PRVCAN 0556-2813 10.1103/PhysRevC.72.014904Abelev, B.I., (2009) Phys. Rev. C, 79, p. 034909. , (STAR Collaboration),. PRVCAN 0556-2813 10.1103/PhysRevC.79.034909Bielcikova, J., (2004) Phys. Rev C, 69, p. 021901. , (R) () PRVCAN 0556-2813 10.1103/PhysRevC.69.021901;Konzer, J., Wang, F., (2009) Nucl. Instrum. Meth., A606, p. 713. , NIMAER 0168-9002 10.1016/j.nima.2009.05.011Mishra, A.P., (2008) Phys. Rev. C, 77, p. 064902. , PRVCAN 0556-2813 10.1103/PhysRevC.77.064902;Alver, B., Roland, G., (2010) Phys. Rev. C, 81, p. 054905. , PRVCAN 0556-2813 10.1103/PhysRevC.81.054905Alver, B., Roland, G., (2010) Phys. Rev. C, 82, p. 039903. , 0556-2813 10.1103/PhysRevC.82.039903Xu, J., Ko, C.M., (2011) Phys. Rev. C, 84, p. 014903. , PRVCAN 0556-2813 10.1103/PhysRevC.84.014903Petersen, H., (2010) Phys. Rev. C, 82, p. 041901. , PRVCAN 0556-2813 10.1103/PhysRevC.82.041901Takahashi, J., (2009) Phys. Rev. Lett., 103, p. 242301. , PRLTAO 0031-9007 10.1103/PhysRevLett.103.242301;Andrade, R.P.G., (2012) Phys. Lett. B, 712, p. 226. , PYLBAJ 0370-2693 10.1016/j.physletb.2012.04.044;Qian, W.L., (2013) Phys. Rev. C, 87, p. 014904. , PRVCAN 0556-2813 10.1103/PhysRevC.87.014904Schenke, B., Jeon, S., Gale, C., (2011) Phys. Rev. Lett., 106, p. 042301. , PRLTAO 0031-9007 10.1103/PhysRevLett.106.042301;Qiu, Z., Heinz, U.W., (2011) Phys. Rev. C, 84, p. 024911. , PRVCAN 0556-2813 10.1103/PhysRevC.84.024911;Song, H., (2011) Phys. Rev. Lett., 106, p. 192301. , PRLTAO 0031-9007 10.1103/PhysRevLett.106.192301;Schenke, B., Jeon, S., Gale, C., (2012) Phys. Rev. C, 85, p. 024901. , PRVCAN 0556-2813 10.1103/PhysRevC.85.024901;Schenke, B., Tribedy, P., Venugopalan, R., (2012) Phys. Rev. Lett., 108, p. 252301. , PRLTAO 0031-9007 10.1103/PhysRevLett.108.252301Adare, A., (2011) Phys. Rev. Lett., 107, p. 252301. , (PHENIX Collaboration),. PRLTAO 0031-9007 10.1103/PhysRevLett.107.252301Adamczyk, L., (2013) Phys. Rev. C, 88, p. 014904. , (STAR Collaboration),. PRVCAN 0556-2813 10.1103/PhysRevC.88.014904Abelev, B.I., (2008) Phys. Rev. Lett., 101, p. 252301. , (STAR Collaboration),. PRLTAO 0031-9007 10.1103/PhysRevLett.101.252301Teaney, D., Yan, L., (2011) Phys. Rev. C, 83, p. 064904. , PRVCAN 0556-2813 10.1103/PhysRevC.83.064904Pandit, Y., (2013) J. Phys. Conf. Ser., 446, p. 012012. , (STAR Collaboration),. 1742-6596 10.1088/1742-6596/446/1/012012Ajitanand, N.N., (2005) Phys. Rev. C, 72, p. 011902. , PRVCAN 0556-2813 10.1103/PhysRevC.72.011902Agakishiev, G., (2012) Phys. Rev. C, 86, p. 064902. , (STAR Collaboration),. PRVCAN 0556-2813 10.1103/PhysRevC.86.064902Adler, C., (2002) Phys. Rev. C, 66, p. 034904. , (STAR Collaboration),. PRVCAN 0556-2813 10.1103/PhysRevC.66.034904Abelev, B.I., (2009) Phys. Rev. C, 80, p. 064912. , (STAR Collaboration), () PRVCAN 0556-2813 10.1103/PhysRevC.80.064912;Abelev, B.I., (2010) Phys. Rev. Lett., 105, p. 022301. , PRLTAO 0031-9007 10.1103/PhysRevLett.105.022301Adler, S.S., (2006) Phys. Rev. Lett., 97, p. 052301. , (PHENIX Collaboration), () PRLTAO 0031-9007 10.1103/PhysRevLett.97. 052301;Adare, A., (2008) Phys. Rev. C, 78, p. 014901. , (PHENIX Collaboration),. PRVCAN 0556-2813 10.1103/PhysRevC.78.014901Stoecker, H., (2005) Nucl. Phys. A, 750, p. 121. , NUPABL 0375-9474 10.1016/j.nuclphysa.2004.12.074;Casalderrey-Solana, J., Shuryak, E.V., Teaney, D., (2005) J. Phys. Conf. Ser., 27, p. 22. , 1742-6588 10.1088/1742-6596/27/1/003;Ruppert, J., Müller, B., (2005) Phys. Lett. B, 618, p. 123. , PYLBAJ 0370-2693 10.1016/j.physletb.2005.04.075Betz, B., (2010) Phys. Rev. Lett., 105, p. 222301. , PRLTAO 0031-9007 10.1103/PhysRevLett.105.222301;Ma, G.L., Wang, X.N., (2011) Phys. Rev. Lett., 106, p. 162301. , PRLTAO 0031-9007 10.1103/PhysRevLett.106.162301Abelev, B.I., (2009) Phys. Rev. Lett., 102, p. 052302. , (STAR Collaboration),. PRLTAO 0031-9007 10.1103/PhysRevLett.102.052302Adamczyk, L., (2014) Phys. Rev. Lett., 112, p. 122301. , (STAR Collaboration),. 10.1103/PhysRevLett.112.12230

    Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950–2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021

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    Background: Estimates of demographic metrics are crucial to assess levels and trends of population health outcomes. The profound impact of the COVID-19 pandemic on populations worldwide has underscored the need for timely estimates to understand this unprecedented event within the context of long-term population health trends. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 provides new demographic estimates for 204 countries and territories and 811 additional subnational locations from 1950 to 2021, with a particular emphasis on changes in mortality and life expectancy that occurred during the 2020–21 COVID-19 pandemic period. Methods: 22 223 data sources from vital registration, sample registration, surveys, censuses, and other sources were used to estimate mortality, with a subset of these sources used exclusively to estimate excess mortality due to the COVID-19 pandemic. 2026 data sources were used for population estimation. Additional sources were used to estimate migration; the effects of the HIV epidemic; and demographic discontinuities due to conflicts, famines, natural disasters, and pandemics, which are used as inputs for estimating mortality and population. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate under-5 mortality rates, which synthesised 30 763 location-years of vital registration and sample registration data, 1365 surveys and censuses, and 80 other sources. ST-GPR was also used to estimate adult mortality (between ages 15 and 59 years) based on information from 31 642 location-years of vital registration and sample registration data, 355 surveys and censuses, and 24 other sources. Estimates of child and adult mortality rates were then used to generate life tables with a relational model life table system. For countries with large HIV epidemics, life tables were adjusted using independent estimates of HIV-specific mortality generated via an epidemiological analysis of HIV prevalence surveys, antenatal clinic serosurveillance, and other data sources. Excess mortality due to the COVID-19 pandemic in 2020 and 2021 was determined by subtracting observed all-cause mortality (adjusted for late registration and mortality anomalies) from the mortality expected in the absence of the pandemic. Expected mortality was calculated based on historical trends using an ensemble of models. In location-years where all-cause mortality data were unavailable, we estimated excess mortality rates using a regression model with covariates pertaining to the pandemic. Population size was computed using a Bayesian hierarchical cohort component model. Life expectancy was calculated using age-specific mortality rates and standard demographic methods. Uncertainty intervals (UIs) were calculated for every metric using the 25th and 975th ordered values from a 1000-draw posterior distribution. Findings: Global all-cause mortality followed two distinct patterns over the study period: age-standardised mortality rates declined between 1950 and 2019 (a 62·8% [95% UI 60·5–65·1] decline), and increased during the COVID-19 pandemic period (2020–21; 5·1% [0·9–9·6] increase). In contrast with the overall reverse in mortality trends during the pandemic period, child mortality continued to decline, with 4·66 million (3·98–5·50) global deaths in children younger than 5 years in 2021 compared with 5·21 million (4·50–6·01) in 2019. An estimated 131 million (126–137) people died globally from all causes in 2020 and 2021 combined, of which 15·9 million (14·7–17·2) were due to the COVID-19 pandemic (measured by excess mortality, which includes deaths directly due to SARS-CoV-2 infection and those indirectly due to other social, economic, or behavioural changes associated with the pandemic). Excess mortality rates exceeded 150 deaths per 100 000 population during at least one year of the pandemic in 80 countries and territories, whereas 20 nations had a negative excess mortality rate in 2020 or 2021, indicating that all-cause mortality in these countries was lower during the pandemic than expected based on historical trends. Between 1950 and 2021, global life expectancy at birth increased by 22·7 years (20·8–24·8), from 49·0 years (46·7–51·3) to 71·7 years (70·9–72·5). Global life expectancy at birth declined by 1·6 years (1·0–2·2) between 2019 and 2021, reversing historical trends. An increase in life expectancy was only observed in 32 (15·7%) of 204 countries and territories between 2019 and 2021. The global population reached 7·89 billion (7·67–8·13) people in 2021, by which time 56 of 204 countries and territories had peaked and subsequently populations have declined. The largest proportion of population growth between 2020 and 2021 was in sub-Saharan Africa (39·5% [28·4–52·7]) and south Asia (26·3% [9·0–44·7]). From 2000 to 2021, the ratio of the population aged 65 years and older to the population aged younger than 15 years increased in 188 (92·2%) of 204 nations. Interpretation: Global adult mortality rates markedly increased during the COVID-19 pandemic in 2020 and 2021, reversing past decreasing trends, while child mortality rates continued to decline, albeit more slowly than in earlier years. Although COVID-19 had a substantial impact on many demographic indicators during the first 2 years of the pandemic, overall global health progress over the 72 years evaluated has been profound, with considerable improvements in mortality and life expectancy. Additionally, we observed a deceleration of global population growth since 2017, despite steady or increasing growth in lower-income countries, combined with a continued global shift of population age structures towards older ages. These demographic changes will likely present future challenges to health systems, economies, and societies. The comprehensive demographic estimates reported here will enable researchers, policy makers, health practitioners, and other key stakeholders to better understand and address the profound changes that have occurred in the global health landscape following the first 2 years of the COVID-19 pandemic, and longer-term trends beyond the pandemic. Funding: Bill & Melinda Gates Foundation

    PHENIX study of the initial state with forward hadron measurements in 200 GeV p(d)+A and 3He+Au collisions

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    International audienceForward hadron measurements in p(d)+A provide a signal to study nuclear shadowing, initial state energy loss and/or gluon saturation effects as a function of rapidity, centrality and energy. High p T identified π0 measurements are an essential first step toward measuring prompt photon production. The π0 measurements are enabled by the PHENIX MPC-EX detector, a Si-W preshower detector located in front of the Muon Piston Calorimeter (MPC), expanding the neutral pion reconstruction capabilities in the rapidity range 3.1 < η < 3.8 out to high energies, E < 80 GeV. Previous PHENIX measurements of punch-through charged hadrons in the muon arms in the rapidity range 1.4 < | η | < 2.2 were significantly improved through the capability of the forward silicon vertex detector (FVTX) to determine the transverse momentum and rapidity with high precision and reject background from secondary hadrons

    The STAR Collaboration

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    Absence of suppression in particle production at large transverse momentum in sNN\sqrt{s_{NN}} = 200 GeV d+Au collisions

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