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A Dumitru

Publications and source records attributed to A Dumitru.

7 recordsLinked to original sources
PubMed2005

High-density QCD and cosmic-ray air showers.

We discuss particle production in the high-energy, small-x limit of QCD where the gluon density of hadrons is expected to become nonperturbatively large. Strong modifications of the phase-space distribution of produced particles as compared to leading-twist models are predicted, which reflect in the properties of cosmic-ray induced air showers in the atmosphere. Assuming hadronic primaries, our results suggest a light composition near Greisen-Zatsepin-Kuzmin cutoff energies. We also show that cosmic-ray data are sensitive to various QCD evolution scenarios for the rate of increase of the gluon density at small x, such as fixed-coupling and running-coupling Balitsky-Fadin-Kuraev-Lipatov evolution. There are clear indications for a slower growth of the gluon density as compared to RHIC and HERA, due, e.g., to running-coupling effects.

Journal Article↗
PubMed2003

Proton breakup in high-energy pA collisions from perturbative QCD.

We argue that the distribution of hadrons near the longitudinal light cone in central high-energy pA collisions is computable in weak coupling QCD. This is because the density of gluons per unit transverse area in the dense target at saturation provides an intrinsic semihard momentum scale, Q(s). We predict that the longitudinal distribution of (anti)baryons and mesons steepens with increasing energy and atomic number of the target and that the transverse momentum distribution broadens. We show that the evolution of high moments of the longitudinal net baryon distribution with Q(s) is determined by the anomalous dimension gamma(qq).

Journal Article↗
PubMed2001

Pion interferometry at RHIC: porobing a thermalized quark-gluon plasma?

We calculate the Gaussian radius parameters of the pion-emitting source in high-energy heavy-ion collisions, assuming a first-order phase transition from a thermalized quark-gluon plasma (QGP) to a gas of hadrons. Such a model leads to a very long-lived dissipative hadronic rescattering phase which dominates the properties of the two-pion correlation functions. The radii are found to depend only weakly on the thermalization time tau(i), the critical temperature Tc (and thus the latent heat), and the specific entropy of the QGP. The model calculations suggest a rapid increase of R(out)/R(side) as a function of KT if a thermalized QGP were formed.

Journal Article↗
PubMedDate not supplied

[Normothermal extracorporeal perfusion of the liver].

In view of providing hepatic assistance, and for conservation aims in attempts at transplantation conditions have been investigated for achieving extracorporeal normothermal perfusion of the liver isolated from pig and dog. A total of 33 experiments have been performed. The preparations and the devices used allow to apply the method in a patient only after stabilisation of the perfusion, and frees the medical team from a series of technical problems. The duration and the quality of the perfusion are especially influenced by the collecting technique. In the dog the liver should be removed 3--5 hours, and in the pig 7--8 hours before perfusion is started. The functional condition of the liver can be assessed at 45 minutes after the start of the perfusion by evaluating the following criteria: the macroscopic aspect of the liver, the blood flow, the biliary flow, the ascitis fluid, TGP and oxygen consumption. Adequate installations and a permanent involvement of the laboratory team are essential conditions for the application of this method to the treatment of acute severe hepatic failure.

Animals↗