4,871 research outputs found

    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

    Hadronization of Dense Partonic Matter

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    The parton recombination model has turned out to be a valuable tool to describe hadronization in high energy heavy ion collisions. I review the model and revisit recent progress in our understanding of hadron correlations. I also discuss higher Fock states in the hadrons, possible violations of the elliptic flow scaling and recombination effects in more dilute systems.Comment: 8 pages, 4 figures; plenary talk delivered at SQM 2006, to appear in J. Phys.

    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

    Finite hadronization time and unitarity in quark recombination model

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    The effect of finite hadronization time is considered in the recombination model, and it is shown that the hadron multiplicity turns out to be proportional to the initial quark density and unitarity is conserved in the model. The baryon to meson ratio increases rapidly with the initial quark density due to competition among different channels.Comment: 4 pages in RevTeX, 3 eps figures, to appear in J. Phys.G as a lette

    Pregnancies complicated by maternal osteogenesis imperfecta type III: a case report and review of literature.

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    The restrictive lung disease can be exacerbated by growing fundus in women with osteogenesis imperfecta type III. Regional anesthesia can be performed in these women. Mode of delivery for women with osteogenesis imperfecta type III is generally cesarean delivery. Neonatal outcomes are complicated due to indicated preterm deliveries

    Gender differences in predictors of self-reported physical aggression: exploring theoretically relevant dimensions among adolescents from Santiago, Chile

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    Research findings remain unclear on whether different factors predict aggression for adolescent men and women. Given that aggression research is rarely conducted with Latin American populations, the current study used multiple imputation and linear regression to assess gender differences in levels and predictors of self-reported physical aggression among a community sample of young (ages 11 through 17) men (n=504) and women (n = 471) from Santiago, Chile. Results revealed that adolescent women reported engaging in higher levels of physical aggression than men. The variables found to be significantly associated with higher levels of reported aggression—younger age, less family involvement, less parental control, less positive relationships with caregivers, having more friends who act out and use substances, having fewer friends committed to learning, presence of dating violence, and more exposure to neighborhood crime—were not moderated by gender, implying that similar factors are related to aggression in adolescent men and women from Chile. Implications for prevention and intervention efforts to address high-risk adolescents and reduce aggression among Chilean youth are discussed.http://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC3876925&blobtype=pdfAccepted manuscrip

    Correlated Emission of Hadrons from Recombination of Correlated Partons

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    We discuss different sources of hadron correlations in relativistic heavy ion collisions. We show that correlations among partons in a quasi-thermal medium can lead to the correlated emission of hadrons by quark recombination and argue that this mechanism offers a plausible explanation for the dihadron correlations in the few GeV/c momentum range observed in Au+Au collisions at RHIC.Comment: 4 pages, 2 figures; v2: typo on p.4 correcte

    Relativistic Langevin Dynamics in Expanding Media

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    We study the consequences of different realizations of diffusion processes in relativistic Langevin simulations. We elaborate on the Ito-Stratonovich dilemma by showing how microscopically calculated transport coefficients as obtained from a Boltzmann/Fokker-Planck equation can be implemented to lead to an unambiguous realization of the Langevin process. Pertinent examples within the pre-point (Ito) and post-point (H\"anggi-Klimontovich) Langevin prescriptions are worked out explicitly. Deviations from this implementation are shown to generate variants of the Boltzmann distribution as the stationary (equilibrium) solutions. Finally, we explicitly verify how the Lorentz invariance of the Langevin process is maintained in the presence of an expanding medium, including the case of an "elliptic flow" transmitted to a Brownian test particle. This is particularly relevant for using heavy-flavor diffusion as a quantitative tool to diagnose transport properties of QCD matter as created in ultrarelativistic heavy-ion collisions.Comment: 8 pages, 4 figures; v2: Reference adde
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