BBGKY hierarchy in scalar QFT

This work is dedicated to obtaining of analog of Bogoliubov's chain for the case of complex scalar field in QFT and renormalization problem of obtained equations is discussed

Baryon stopping and quark-gluon plasma production at RHIC and LHC

Strong chromofields developed at early stages of relativistic heavy-ion collisions give rise to the collective deceleration of net baryons from colliding nuclei. We have solved classical equations of motion for baryonic slabs under the action of time-dependent chromofield. We have studied sensitivity of the slab trajectories and their final rapidities to the initial strength and decay pattern of the chromofield as well as to the back reaction of produced plasma. This mechanism can naturally explain significant baryon stopping observed at RHIC, an average rapidity loss hδyi ≈ 2. Using a Bjorken hydrodynamical model with particle producing source we also study the evolution of partonic plasma produced as the result of chromofield decay. Due to the delayed formation and expansion of plasma its maximum energy density is much lower than the initial energy density of the chromofield. It is shown that the net-baryon and produced parton distributions are strongly correlated in the rapidity space. The shape of net-baryon spectra in midrapidity region found in the BRAHMS experiment cannot be reproduced by only one value of chromofield energy density parameter ǫ0, even if one takes into account novel mechanisms as fluctuations of color charges generated on the slab surface, and weak interaction of baryon-rich matter with produced plasma. The further step to improve our results is to take into account rapidity dependence of saturation momentum as explained in thesis. Different values of parameter ǫ0 has been tried for different variants of chromofield decay to fit BRAHMS data for net-baryon rapidity distribution. In accordance with our analysis, data for fragmentation region correspond to the lower chromofield energy densities than mid-rapidity region. χ2 analysis favors power-law of chromofield decay with corresponding initial chromofield energy density of order ǫf = 30GeV/fm3.Starke Farbfelder, die früh in relativistischen Schwerionenkollisionen entstehen, sorgen für das kollektive Abbremsen von Baryonen der kollidierenden Kerne. In dieser Arbeit werden die klassischen Bewegungsgleichungen für diese Baryonen unter der Einwirkung von zeitabhängigen Farbfeldern gelst. Darüber hinaus wird die Abhängigkeit der Trajektorien und ihrer Endrapiditäten von der anfänglichen Stärke und dem Zerfallsmuster des Farbfeldes sowie von der Rückreaktion des produzierten Plasmas untersucht. Dieser Mechanismus kann mit einem mittlerem Rapiditätsverlust von hδyi ≈ 2 auf natürliche Weise das deutliche Baryonenstoppen erklären, welches am RHIC beobachtet wurde. In einem Bjorken-hydrodynamischen Modell mit einer Teilchenerzeugenden Quelle untersuchen wir auch die Evolution des partonischen Plasmas, das durch den Zerfall des Farbfeldes produziert wird. Aufgrund der verzögerten Bildung und der Expansion des Plasmas ist seine maximale kinetische Energiedichte viel kleiner als die anfängliche Energiedichte des Farbfeldes. Es wird gezeigt, dass die Verteilungen der Baryonen und der erzeugten Partonen im Rapiditätsraum stark korreliert sind. Die Form der Netto-Baryonen Spektren im mittleren Rapiditätsbereich des BRAHMS Experimentes kann nur reproduziert werden wenn man neuartige Mechanismen berücksichtigt, welche die Fluktuationen der auf der Scheibchenoberfläche erzeugten Farbladungen und die schwache Wechselwirkung der Baryonenreichen Materie mit dem produzierten Plasma berücksichtigen. Es zeigt sich, dass alle getesteten Varianten des Zerfalls des Farbfeldes die mittlere Rapiditätsregion reproduzieren können, wenn der Paramter ǫ0 variiert wird, welcher in die Abschätzung der anfänglichen Energiedichte eingeht. ..

Baryon deceleration by strong chromofields in ultrarelativistic nuclear collisions

It is assumed that strong chromofields are generated at early stages of ultrarelativistic heavy-ion collisions which give rise to a collective deceleration of net baryons from colliding nuclei. We have solved classical equations of motion for baryonic slabs under the action of a time-dependent longitudinal chromoelectric field. It is demonstrated that the slab final rapidities are rather sensitive to the strength and decay time of the chromofield as well as to the back reaction of the produced partonic plasma. The net-baryon rapidity loss of about 2 units, found for most central Au-Au collisions at RHIC, can be explained by the action of chromofields with the initial energy density of about 50 GeV/fm^3. Predictions for the baryon stopping at the LHC are made.Comment: 10 pages in revtex, 3 eps figure

Some Features of Boron Isotopes Separation by Laser-Assisted Retardation of Condensation Method

Boron isotopes have many applications in industry: medicine, semiconductor, and solar energy. Especially massive demand is for boron-10 isotopes in nuclear industry for nuclear reactors shielding and control. Various aspects of laser-assisted boron isotope separation by retardation of condensation method, such as irradiation conditions and laser and vacuum system design, have been considered. Irradiation conditions include interaction scheme of laser radiation and supersonic beam, dependence of efficiency of excitation on gas flow temperature and pressure. Basic physical constraints on laser intensity and its spectral properties have been discussed. The relation of gas flow properties, nozzle design, and vacuuming rate has been elucidated as well