74 research outputs found

    Upsilon (1S+2S+3S) production in d+Au and p+p collisions at sqrt(s_NN)=200 GeV and cold-nuclear matter effects

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    The three Upsilon states, Upsilon(1S+2S+3S), are measured in d+Au and p+p collisions at sqrt(s_NN)=200 GeV and rapidities 1.2<|y|<2.2 by the PHENIX experiment at the Relativistic Heavy-Ion Collider. Cross sections for the inclusive Upsilon(1S+2S+3S) production are obtained. The inclusive yields per binary collision for d+Au collisions relative to those in p+p collisions (R_dAu) are found to be 0.62 +/- 0.26 (stat) +/- 0.13 (syst) in the gold-going direction and 0.91 +/- 0.33 (stat) +/- 0.16 (syst) in the deuteron-going direction. The measured results are compared to a nuclear-shadowing model, EPS09 [JHEP 04, 065 (2009)], combined with a final-state breakup cross section, sigma_br, and compared to lower energy p+A results. We also compare the results to the PHENIX J/psi results [Phys. Rev. Lett. 107, 142301 (2011)]. The rapidity dependence of the observed Upsilon suppression is consistent with lower energy p+A measurements.Comment: 495 authors, 11 pages, 9 figures, 5 tables. Submitted to 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

    Measurement of Υ\Upsilon(1S+2S+3S) production in pp++pp and Au++Au collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV

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    Measurements of bottomonium production in heavy ion and pp++pp collisions at the Relativistic Heavy Ion Collider (RHIC) are presented. The inclusive yield of the three Υ\Upsilon states, Υ(1S+2S+3S)\Upsilon(1S+2S+3S), was measured in the PHENIX experiment via electron-positron decay pairs at midrapidity for Au++Au and pp++pp collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV. The Υ(1S+2S+3S)e+e\Upsilon(1S+2S+3S)\rightarrow e^+e^- differential cross section at midrapidity was found to be Beedσ/dy=B_{\rm ee} d\sigma/dy = 108 ±\pm 38 (stat) ±\pm 15(syst) ±\pm 11 (luminosity) pb in pp++pp collisions. The nuclear modification factor in the 30\% most central Au++Au collisions indicates a suppression of the total Υ\Upsilon state yield relative to the extrapolation from pp++pp collision data. The suppression is consistent with measurements made by STAR at RHIC and at higher energies by the CMS experiment at the Large Hadron Collider.Comment: 506 authors, 15 pages, 17 figures, and 7 tables. v3 is as accepted by Phys. Rev. C. v2 has changes to text and figures, plus additional authors. Published version will be at http://www.phenix.bnl.gov/phenix/WWW/info/pp1/1NN/ Plain text data tables are (or will be) at http://www.phenix.bnl.gov/papers.htm

    Medium modification of jet fragmentation in Au+Au collisions at sqrt(s_NN)=200 GeV measured in direct photon-hadron correlations

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    The jet fragmentation function is measured with direct photon-hadron correlations in p+p and Au+Au collisions at sqrt(s_NN)=200 GeV. The p_T of the photon is an excellent approximation to the initial p_T of the jet and the ratio z_T=p_T^h/p_T^\gamma is used as a proxy for the jet fragmentation function. A statistical subtraction is used to extract the direct photon-hadron yields in Au+Au collisions while a photon isolation cut is applied in p+p. I_ AA, the ratio of jet fragment yield in Au+Au to that in p+p, indicates modification of the jet fragmentation function. Suppression, most likely due to energy loss in the medium, is seen at high z_T. The fragment yield at low z_T is enhanced at large angles. Such a trend is expected from redistribution of the lost energy into increased production of low-momentum particles.Comment: 562 authors, 70 insitutions, 8 pages, and 3 figures. Submitted to Phys. Rev. Lett. v2 has minor changes to improve clarity. 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

    Transverse energy production and charged-particle multiplicity at midrapidity in various systems from sNN=7.7\sqrt{s_{NN}}=7.7 to 200 GeV

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    Measurements of midrapidity charged particle multiplicity distributions, dNch/dηdN_{\rm ch}/d\eta, and midrapidity transverse-energy distributions, dET/dηdE_T/d\eta, are presented for a variety of collision systems and energies. Included are distributions for Au++Au collisions at sNN=200\sqrt{s_{_{NN}}}=200, 130, 62.4, 39, 27, 19.6, 14.5, and 7.7 GeV, Cu++Cu collisions at sNN=200\sqrt{s_{_{NN}}}=200 and 62.4 GeV, Cu++Au collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV, U++U collisions at sNN=193\sqrt{s_{_{NN}}}=193 GeV, dd++Au collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV, 3^{3}He++Au collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV, and pp++pp collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV. Centrality-dependent distributions at midrapidity are presented in terms of the number of nucleon participants, NpartN_{\rm part}, and the number of constituent quark participants, NqpN_{q{\rm p}}. For all AA++AA collisions down to sNN=7.7\sqrt{s_{_{NN}}}=7.7 GeV, it is observed that the midrapidity data are better described by scaling with NqpN_{q{\rm p}} than scaling with NpartN_{\rm part}. Also presented are estimates of the Bjorken energy density, εBJ\varepsilon_{\rm BJ}, and the ratio of dET/dηdE_T/d\eta to dNch/dηdN_{\rm ch}/d\eta, the latter of which is seen to be constant as a function of centrality for all systems.Comment: 706 authors, 32 pages, 20 figures, 34 tables, 2004, 2005, 2008, 2010, 2011, and 2012 data. v2 is version accepted for publication in Phys. Rev.

    Measurements of elliptic and triangular flow in high-multiplicity 3^{3}He++Au collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV

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    We present the first measurement of elliptic (v2v_2) and triangular (v3v_3) flow in high-multiplicity 3^{3}He++Au collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV. Two-particle correlations, where the particles have a large separation in pseudorapidity, are compared in 3^{3}He++Au and in pp++pp collisions and indicate that collective effects dominate the second and third Fourier components for the correlations observed in the 3^{3}He++Au system. The collective behavior is quantified in terms of elliptic v2v_2 and triangular v3v_3 anisotropy coefficients measured with respect to their corresponding event planes. The v2v_2 values are comparable to those previously measured in dd++Au collisions at the same nucleon-nucleon center-of-mass energy. Comparison with various theoretical predictions are made, including to models where the hot spots created by the impact of the three 3^{3}He nucleons on the Au nucleus expand hydrodynamically to generate the triangular flow. The agreement of these models with data may indicate the formation of low-viscosity quark-gluon plasma even in these small collision systems.Comment: 630 authors, 9 pages, 4 figures, 2 tables. v2 is the version accepted for publication by Physical Review Letters. 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

    Measurement of KS0K_S^0 and K0K^{*0} in pp++pp, dd++Au, and Cu++Cu collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV

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    The PHENIX experiment at the Relativistic Heavy Ion Collider has performed a systematic study of KS0K_S^0 and K0K^{*0} meson production at midrapidity in pp++pp, dd++Au, and Cu++Cu collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV. The KS0K_S^0 and K0K^{*0} mesons are reconstructed via their KS0π0(γγ)π0(γγ)K_S^0 \rightarrow \pi^0(\rightarrow \gamma\gamma)\pi^0(\rightarrow\gamma\gamma) and K0K±πK^{*0} \rightarrow K^{\pm}\pi^{\mp} decay modes, respectively. The measured transverse-momentum spectra are used to determine the nuclear modification factor of KS0K_S^0 and K0K^{*0} mesons in dd++Au and Cu++Cu collisions at different centralities. In the dd++Au collisions, the nuclear modification factor of KS0K_S^0 and K0K^{*0} mesons is almost constant as a function of transverse momentum and is consistent with unity showing that cold-nuclear-matter effects do not play a significant role in the measured kinematic range. In Cu++Cu collisions, within the uncertainties no nuclear modification is registered in peripheral collisions. In central collisions, both mesons show suppression relative to the expectations from the pp++pp yield scaled by the number of binary nucleon-nucleon collisions in the Cu++Cu system. In the pTp_T range 2--5 GeV/cc, the strange mesons (KS0K_S^0, K0K^{*0}) similarly to the ϕ\phi meson with hidden strangeness, show an intermediate suppression between the more suppressed light quark mesons (π0\pi^0) and the nonsuppressed baryons (pp, pˉ\bar{p}). At higher transverse momentum, pT>5p_T>5 GeV/cc, production of all particles is similarly suppressed by a factor of \approx 2.Comment: 590 authors, 22 pages, 14 figures, 5 tables. Submitted to 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

    Measurements of identified particle anisotropic flow in Cu plus Au and U plus U collisions by PHENIX experiment

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    Global, regional, and national age-sex-specific mortality and life expectancy, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017

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    BACKGROUND: Assessments of age-specific mortality and life expectancy have been done by the UN Population Division, Department of Economics and Social Affairs (UNPOP), the United States Census Bureau, WHO, and as part of previous iterations of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD). Previous iterations of the GBD used population estimates from UNPOP, which were not derived in a way that was internally consistent with the estimates of the numbers of deaths in the GBD. The present iteration of the GBD, GBD 2017, improves on previous assessments and provides timely estimates of the mortality experience of populations globally. METHODS: The GBD uses all available data to produce estimates of mortality rates between 1950 and 2017 for 23 age groups, both sexes, and 918 locations, including 195 countries and territories and subnational locations for 16 countries. Data used include vital registration systems, sample registration systems, household surveys (complete birth histories, summary birth histories, sibling histories), censuses (summary birth histories, household deaths), and Demographic Surveillance Sites. In total, this analysis used 8259 data sources. Estimates of the probability of death between birth and the age of 5 years and between ages 15 and 60 years are generated and then input into a model life table system to produce complete life tables for all locations and years. Fatal discontinuities and mortality due to HIV/AIDS are analysed separately and then incorporated into the estimation. We analyse the relationship between age-specific mortality and development status using the Socio-demographic Index, a composite measure based on fertility under the age of 25 years, education, and income. There are four main methodological improvements in GBD 2017 compared with GBD 2016: 622 additional data sources have been incorporated; new estimates of population, generated by the GBD study, are used; statistical methods used in different components of the analysis have been further standardised and improved; and the analysis has been extended backwards in time by two decades to start in 1950. FINDINGS: Globally, 18·7% (95% uncertainty interval 18·4–19·0) of deaths were registered in 1950 and that proportion has been steadily increasing since, with 58·8% (58·2–59·3) of all deaths being registered in 2015. At the global level, between 1950 and 2017, life expectancy increased from 48·1 years (46·5–49·6) to 70·5 years (70·1–70·8) for men and from 52·9 years (51·7–54·0) to 75·6 years (75·3–75·9) for women. Despite this overall progress, there remains substantial variation in life expectancy at birth in 2017, which ranges from 49·1 years (46·5–51·7) for men in the Central African Republic to 87·6 years (86·9–88·1) among women in Singapore. The greatest progress across age groups was for children younger than 5 years; under-5 mortality dropped from 216·0 deaths (196·3–238·1) per 1000 livebirths in 1950 to 38·9 deaths (35·6–42·83) per 1000 livebirths in 2017, with huge reductions across countries. Nevertheless, there were still 5·4 million (5·2–5·6) deaths among children younger than 5 years in the world in 2017. Progress has been less pronounced and more variable for adults, especially for adult males, who had stagnant or increasing mortality rates in several countries. The gap between male and female life expectancy between 1950 and 2017, while relatively stable at the global level, shows distinctive patterns across super-regions and has consistently been the largest in central Europe, eastern Europe, and central Asia, and smallest in south Asia. Performance was also variable across countries and time in observed mortality rates compared with those expected on the basis of development. INTERPRETATION: This analysis of age-sex-specific mortality shows that there are remarkably complex patterns in population mortality across countries. The findings of this study highlight global successes, such as the large decline in under-5 mortality, which reflects significant local, national, and global commitment and investment over several decades. However, they also bring attention to mortality patterns that are a cause for concern, particularly among adult men and, to a lesser extent, women, whose mortality rates have stagnated in many countries over the time period of this study, and in some cases are increasing
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