853 research outputs found

    Correlations in the Parton Recombination Model

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    We describe how parton recombination can address the recent measurement of dynamical jet-like two particle correlations. In addition we discuss the possible effect realistic light-cone wave-functions including higher Fock-states may have on the well-known elliptic flow valence-quark number scaling law.Comment: 4 pages, two figures, proceedings of the 18th International Conference on Ultrarelativistic Nucleus-Nucleus Collisions: Quark Matter 2005 (QM 2005), Budapest, Hungary, 4-9 Aug 200

    Phenomenology of lepton-nucleus DIS

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    The results of recent phenomenological studies of unpolarized nuclear deep-inelastic scattering are discussed and applied to calculate neutrino charged-current structure functions and cross sections for a number of nuclei.Comment: 6 pages, 5 figures, to appear in Proceedings of 4th International Workshop On Neutrino-Nucleus Interactions In The Few-GeV Region (NuInt05), 26-29 Sep. 2005, Okayama, Japa

    Thermal Recombination: Beyond the Valence Quark Approximation

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    Quark counting rules derived from recombination models agree well with data on hadron production at intermediate transverse momenta in relativistic heavy-ion collisions. They convey a simple picture of hadrons consisting only of valence quarks. We discuss the inclusion of higher Fock states that add sea quarks and gluons to the hadron structure. We show that, when recombination occurs from a thermal medium, hadron spectra remain unaffected by the inclusion of higher Fock states. However, the quark number scaling for elliptic flow is somewhat affected. We discuss the implications for our understanding of data from the Relativistic Heavy Ion Collider.Comment: 5 pages, 5 figure

    The renormalization of the axial anomaly in dimensional regularization

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    The prescription for the Îł5\gamma_5-matrix within dimensional regularization in multiloop calculations is elaborated. The three-loop anomalous dimension of the singlet axial current is calculated.Comment: 11 pages, 1 figure available on request from the author, NIKHEF-H/92-1

    Directed and Elliptic Flow in Pb+Pb collisions at 40 and 158 AGeV

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    Directed and elliptic flow are reported for charged pions and protons as a function of transverse momentum, rapidity, and centrality in 40 and 158 AGeV Pb + Pb collisions. The standard method of correlating particles with an event plane is used. The directed flow of protons is small and shows little variation near to midrapidity, but rises fast towards projectile rapidity in the 40 AGeV data. For most peripheral collisions the flat region becomes negative resulting in v1v_1 changing sign three times. Elliptic flow doesn't seem to change very much from 40 AGeV to 158 AGeV. The difference is smaller than anticipated from the overall energy dependence from AGS to RHIC.Comment: Presented at 16th International Conference on Ultrarelativistic Nucleus-Nucelus Collisions, Quark Matter 2002 (QM 2002), Nantes, France, 18-24 Jul 2002, 4 pages, 3 figure

    On the SO(N) symmetry of the chiral SU(N) Yang--Mills model

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    The posibility of quantizing the anomalous SU(N)SU(N) Yang--Mills model preserving the symmetry under the orthogonal subgroup is indicated. The corresponding Wess--Zumino action (1-cocycle) possesses the additional SO(N)SO(N) symmetry and can be expressed in terms of chiral fields taking values in the homogeneous space SU(N)/SO(N)SU(N)/SO(N). The modified anomaly and the constraints commutator (2-cocycle) are calculated.Comment: 9 pages, preprint PAR-LPTHE 92-48 (DECEMBER 1992), Late

    Time transfer and frequency shift to the order 1/c^4 in the field of an axisymmetric rotating body

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    Within the weak-field, post-Newtonian approximation of the metric theories of gravity, we determine the one-way time transfer up to the order 1/c^4, the unperturbed term being of order 1/c, and the frequency shift up to the order 1/c^4. We adapt the method of the world-function developed by Synge to the Nordtvedt-Will PPN formalism. We get an integral expression for the world-function up to the order 1/c^3 and we apply this result to the field of an isolated, axisymmetric rotating body. We give a new procedure enabling to calculate the influence of the mass and spin multipole moments of the body on the time transfer and the frequency shift up to the order 1/c^4. We obtain explicit formulas for the contributions of the mass, of the quadrupole moment and of the intrinsic angular momentum. In the case where the only PPN parameters different from zero are beta and gamma, we deduce from these results the complete expression of the frequency shift up to the order 1/c^4. We briefly discuss the influence of the quadrupole moment and of the rotation of the Earth on the frequency shifts in the ACES mission.Comment: 17 pages, no figure. Version 2. Abstract and Section II revised. To appear in Physical Review

    Anisotropic flow

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    Recent experimental results on directed and elliptic flow, theoretical developments, and new techniques for anisotropic flow analysis are reviewed.Comment: 10 pages, review talk at Quark Matter 2002 conference, Nantes, France, July 2002 Corrected typographical errors in the reference section. No other change

    Anisotropic flows from initial state of a fast nucleus

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    We analyze azimuthal anisotropy in heavy ion collisions related to the reaction plane in terms of standard reggeon approach and find that it is nonzero even when the final state interaction is switched off. This effect can be interpreted in terms of partonic structure of colliding nuclei. We use Feynman diagram analysis to describe details of this mechanism. Main qualitative features of the appropriate azimuthal correlations are discussed.Comment: 16 pages, 11 figures. This paper is an extended version of a talk given at Session of Nuclear Physics Division of Russian Academy of Sciences in November 200

    Structural Routability of n-Pairs Information Networks

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    Information does not generally behave like a conservative fluid flow in communication networks with multiple sources and sinks. However, it is often conceptually and practically useful to be able to associate separate data streams with each source-sink pair, with only routing and no coding performed at the network nodes. This raises the question of whether there is a nontrivial class of network topologies for which achievability is always equivalent to routability, for any combination of source signals and positive channel capacities. This chapter considers possibly cyclic, directed, errorless networks with n source-sink pairs and mutually independent source signals. The concept of downward dominance is introduced and it is shown that, if the network topology is downward dominated, then the achievability of a given combination of source signals and channel capacities implies the existence of a feasible multicommodity flow.Comment: The final publication is available at link.springer.com http://link.springer.com/chapter/10.1007/978-3-319-02150-8_
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