2,177 research outputs found

    What to learn from dilepton transverse momentum spectra in heavy-ion collisions?

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    Recently the NA60 collaboration has presented high precision measurements of dimuon spectra double differential in invariant mass MM and transverse pair momentum pTp_T in In-In collisions at 158AGeV158 {\rm AGeV}. While the MM-dependence is important for an understanding of in-medium changes of light vector mesons and is pTp_T integrated insensitive to collective expansion, the pTp_T-dependence arises from an interplay between emission temperature and collective transverse flow. This fact can be exploited to derive constraints on the evolution model and in particular on the contributions of different phases of the evolution to dimuon radiation into a given MM window. We present arguments that a thermalized evolution phase with T>170MeVT > 170 {\rm MeV} leaves its imprint on the spectra.Comment: Contributed to 19th International Conference on Ultrarelativistic Nucleus-Nucleus Collisions: Quark Matter 2006 (QM 2006), Shanghai, China, 14- 20 Nov 200

    Proofs of theorems for the JRSS-B paper `Likelihood ratio tests in linear mixed models with one variance component'

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    Proofs of theorems for the JRSS-B paper `Likelihood ratio tests in linear mixed models with one variance component

    Partonic scattering cross sections in the QCD medium

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    A medium modified gluon propagator is used to evaluate the scattering cross section for the process gg - gg in the QCD medium by performing an ex- plicit sum over the polarizations of the gluons. We incorporate a magnetic sreening mass from a non - perturbative study. It is shown that the medium modified cross section is finite, divergence free, and is independent of any ad-hoc momentum transfer cut-off parameters. The medium modified finite cross sections are necessary for a realistic investigation of the production and equilibration of the minijet plasma expected at RHIC and LHC PACS: 12.38.Mh; 14.70.Dj; 12.38.Bx; 11.10.W

    Intrinsically Legal-For-Trade Objects by Digital Signatures

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    The established techniques for legal-for-trade registration of weight values meet the legal requirements, but in praxis they show serious disadvantages. We report on the first implementation of intrinsically legal-for-trade objects, namely weight values signed by the scale, that is accepted by the approval authority. The strict requirements from both the approval- and the verification-authority as well as the limitations due to the hardware of the scale were a special challenge. The presented solution fulfills all legal requirements and eliminates the existing practical disadvantages.Comment: 4 pages, 0 figure
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