8,254 research outputs found

    Pedestal and Peak Structure in Jet Correlation

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    We study the characteristics of correlation between particles in jets produced in heavy-ion collisions. In the framework of parton recombination we calculate the η\eta and ϕ\phi distributions of a pion associated with a trigger particle. The origin of the pedestal in Δη\Delta\eta is related to the longitudinal expansion of the thermal partons that are enhanced by the energy loss of hard partons traversing the bulk medium. The peaks in Δη\Delta\eta and Δϕ\Delta\phi are related to the same angular spread of the shower partons in a jet cone. No artificial short- or long-range correlations are put in by hand. A large part of the correlation between hadrons in jets is due to the correlation among the shower partons arising from momentum conservation. Recombination between thermal and shower partons dominates the correlation characterisitics in the intermediate pTp_T region.Comment: 14 pages in LaTex and 2 figures in ep

    A combinatorial smoothness criterion for spherical varieties

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    We suggest a combinatorial criterion for the smoothness of an arbitrary spherical variety using the classification of multiplicity-free spaces, generalizing an earlier result of Camus for spherical varieties of type AA.Comment: 14 pages, 2 table

    Kyoto\u27s Clean Development Mechanism in Action: India, China and Brazil

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    The Kyoto Protocol is the principal international agreement to reduce global climate change. The Clean Development Mechanism (CDM) helps achieve the Protocol’s objectives by allowing developed countries to pay for reductions of greenhouse gases in developing countries. The developing countries that are most actively involved in the CDM – and that have the greatest potential for future involvement – are India, China and Brazil. The purpose of this article is to describe the CDM, the activities in these three countries under the CDM, and the current and future role of the United States under the CDM

    Exploring the properties of the phases of QCD matter - research opportunities and priorities for the next decade

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    This document provides a summary of the discussions during the recent joint QCD Town Meeting at Temple University of the status of and future plans for the research program of the relativistic heavy-ion community. A list of compelling questions is formulated, and a number of recommendations outlining the greatest research opportunities and detailing the research priorities of the heavy-ion community, voted on and unanimously approved at the Town Meeting, are presented. They are supported by a broad discussion of the underlying physics and its relation to other subfields. Areas of overlapping interests with the "QCD and Hadron Structure" ("cold QCD") subcommunity, in particular the recommendation for the future construction of an Electron-Ion Collider, are emphasized. The agenda of activities of the "hot QCD" subcommunity at the Town Meeting is attached.Comment: 34 pages of text, 254 references,16 figure

    Asymptotic normalization coefficient of ^{8}B from breakup reactions and the S_{17} astrophysical factor

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    We show that asymptotic normalization coefficients (ANC) can be extracted from one nucleon breakup reactions of loosely bound nuclei at 30-300 MeV/u. In particular, the breakup of ^{8}B is described in terms of an extended Glauber model. The 8B ANC extracted for the ground state of this nucleus from breakup data at several energies and on different targets, C^2 = 0.450+/-0.039} fm^-1, leads to the astrophysical factor S_{17}(0)= 17.4+/-1.5 eVb for the key reaction for solar neutrino production 7Be(p,gamma)8B. The procedure described here is more general, providing an indirect method to determine reaction rates of astrophysical interest with beams of loosely bound radioactive nuclei.Comment: 4 pages, RevTex, 3 figures revised version to appear in Phys Rev Let
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