673 research outputs found

    The STAR Photon Multiplicity Detector

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    Details concerning the design, fabrication and performance of STAR Photon Multiplicity Detector (PMD) are presented. The PMD will cover the forward region, within the pseudorapidity range 2.3--3.5, behind the forward time projection chamber. It will measure the spatial distribution of photons in order to study collective flow, fluctuation and chiral symmetry restoration.Comment: 15 pages, including 11 figures; to appear in a special NIM volume dedicated to the accelerator and detectors at RHI

    A terminal assessment of stages theory : introducing a dynamic states approach to entrepreneurship

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    Stages of Growth models were the most frequent theoretical approach to understanding entrepreneurial business growth from 1962 to 2006; they built on the growth imperative and developmental models of that time. An analysis of the universe of such models (N=104) published in the management literature shows no consensus on basic constructs of the approach, nor is there any empirical confirmations of stages theory. However, by changing two propositions of the stages models, a new dynamic states approach is derived. The dynamic states approach has far greater explanatory power than its precursor, and is compatible with leading edge research in entrepreneurship

    Production of singlet P-wave ccˉc \bar c and bbˉb \bar b states

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    No spin-singlet bbˉb \bar b quarkonium state has yet been observed. In this paper we discuss the production of the singlet P-wave bbˉb\bar{b} and ccˉc\bar{c} 1P1^1P_1 states hbh_b and hch_c. We consider two possibilities. In the first the 1P1^1P_1 states are produced via the electromagnetic cascades \ups(3S) \to \eta_b(2S) + \gamma \to h_b + \gamma \gamma \to \eta_b +\gamma\gamma\gamma and ψηc+γhc+γγηc+γγγ\psi'\to \eta_c' + \gamma \to h_c + \gamma \gamma \to \eta_c + \gamma\gamma\gamma. A more promising process consists of single pion transition to the 1P1^1P_1 state followed by the radiative transition to the 11S01^1S_0 state: \ups(3S)\to h_b + \pi^0 \to \eta_b + \pi^0 +\gamma and ψhc+π0ηc+π0+γ\psi' \to h_c + \pi^0 \to \eta_c + \pi^0 +\gamma. For a million \ups(3S) or ψ\psi''s produced we expect these processes to produce several hundred events.Comment: 13 pages, LaTeX, 1 figure, to be published Phys. Rev. D. Some equation numbers and one table number correcte

    Search for DCC in 158A GeV Pb+Pb Collisions

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    A detailed analysis of the phase space distributions of charged particles and photons have been carried out using two independent methods. The results indicate the presence of nonstatistical fluctuations in localized regions of phase space.Comment: Talk at the PANIC99 Conference, June 9-16, 199

    Integrating adolescent livelihood activities within a reproductive health program for urban slum dwellers in India

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    The Population Council’s Frontiers in Reproductive Health (FRONTIERS) program and Policy Research Division, in collaboration with CARE India, conducted an operations research study in Allahabad, Uttar Pradesh to examine the feasibility and impact of adding livelihood counseling and training, savings formation activities, and follow-up support to an ongoing reproductive health program for adolescents. The short-term objective of the study was to foster development of alternative socialization processes for adolescent girls that encourage positive sexual and reproductive health behaviors. The study also aimed to produce a replicable model for CARE and other agencies to use in adding livelihood activities to adolescent reproductive health programs. Results from the midline survey showed a positive impact of the intervention in terms of increased skill use, changing time use patterns, increased work aspirations, and more progressive gender role attitudes. Girls expressed satisfaction with the courses and trainers; many used their skills after completing the vocational courses; and they expressed a desire for the adolescent meetings to continue, seeing them as a time to relax and mingle with their peers

    Present Status and Future of DCC Analysis

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    Disoriented Chiral Condensates (DCC) have been predicted to form in high energy heavy ion collisions where the approximate chiral symmetry of QCD has been restored. This leads to large imbalances in the production of charged to neutral pions. Sophisticated analysis methods are being developed to disentangle DCC events out of the large background of events with conventionally produced particles. We present a short review of current analysis methods and future prospects.Comment: 12 pages, 5 figures. Invited talk presented at the 13th International Conference on Ultrarelativistic Nucleus-Nucleus Collisions (Quark Matter 97), Tsukuba, Japan, 1-5 Dec 199

    Central Pb+Pb Collisions at 158 A GeV/c Studied by Pion-Pion Interferometry

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    Two-particle correlations have been measured for identified negative pions from central 158 AGeV Pb+Pb collisions and fitted radii of about 7 fm in all dimensions have been obtained. A multi-dimensional study of the radii as a function of kT is presented, including a full correction for the resolution effects of the apparatus. The cross term Rout-long of the standard fit in the Longitudinally CoMoving System (LCMS) and the vl parameter of the generalised Yano-Koonin fit are compatible with 0, suggesting that the source undergoes a boost invariant expansion. The shapes of the correlation functions in Qinv and Qspace have been analyzed in detail. They are not Gaussian but better represented by exponentials. As a consequence, fitting Gaussians to these correlation functions may produce different radii depending on the acceptance of the experimental setup used for the measurement.Comment: 13 pages including 10 figure

    Search for Disoriented Chiral Condensates in 158 AGeV Pb+Pb Collisions

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    The restoration of chiral symmetry and its subsequent breaking through a phase transition has been predicted to create regions of Disoriented Chiral Condensates (DCC). This phenomenon has been predicted to cause anomalous fluctuations in the relative production of charged and neutral pions in high-energy hadronic and nuclear collisions. The WA98 experiment has been used to measure charged and photon multiplicities in the central region of 158 AGeV Pb+Pb collisions at the CERN SPS. In a sample of 212646 events, no clear DCC signal can be distinguished. Using a simple DCC model, we have set a 90% C.L. upper limit on the maximum DCC production allowed by the data.Comment: 20 Pages, LaTeX, uses elsart.cls, 8 eps figures included, submitted to Physics Letters

    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
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