Deconfinement of Constituent Quarks and the Hagedorn Temperature

The double phase transition of hadronic matter, $H$, first, to the gas of deconfined constituent quarks (for brevity called {\it valons}), $Q$, and then, secondly, the phase transition from $Q$ to quark-gluon plasma, $QGP$, is considered within bag model ideology. In distinction from previous double phase transition investigations, it is not supposed that at zero chemical potential (~$\mu=0$~) transition temperatures $T_d$ (for $H~\leftrightarrow~Q$) and $T_{ch}$ (for $Q~\leftrightarrow~ QGP$, chiral restoration) coincide. Then for plausible range of chosen bag constants, $B_Q$ for $Q$ and $B_q$ for $QGP$ the phase transition $H~ \leftrightarrow~ QGP$ can proceed {\it only via the $Q$ phase} (at least at not too much $\mu$). For small $\mu$ the gap, $T_{ch}~-~T_d$, is quite essential, up to $\approx~50$ MeV. The physical meaning of the $H~ \leftrightarrow~ Q$ transition temperature, $T_d$, coincide with that of the Hagedorn temperature, $T_H$.Comment: 9 pages, 11 Postscript figure

Color deconfinement and subhadronic matter: phase states and the role of constituent quarks

Major aspects of the subhadronic state of nuclear matter populated with deconfined color particles are reviewed. At high and even at rather low nuclear collision energies, this is expected to be a short-term quark-gluon plasma (QGP), but, seemingly, not only this. Emphasis is put on the self-consistency requirement that must be imposed on any phenomenological description of the evolution of a hot and dense nuclear medium as it expands (cools down) to the point where the final scattering of secondary particles starts. The view is argued and analyzed that massive constituent quarks should then play a major role at a certain cooling stage. A hypothesis is discussed regarding the existence of an intermediate stage (a valon plasma), allowing a consistent explanation of data on the mid-rapidity yields of various kinds of hadrons and direct dileptons (e+e- -pairs) in high-energy heavy-ion collisions.Comment: 20 pages, 14 figure

"Free" Constituent Quarks and Dilepton Production in Heavy Ion Collisions

An approach is suggested, invoking vitally the notion of constituent massive quarks (valons) which can survive and propagate rather than hadrons (except of pions) within the hot and dense matter formed below the chiral transition temperature in course of the heavy ion collisions at high energies. This approach is shown to be quite good for description of the experimentally observed excess in dilepton yield at masses 250 MeV < M < 700 MeV over the prompt resonance decay mechanism (CERES cocktail) predictions. In certain aspects, it looks to be even more successful, than the conventional approaches: it seems to match the data somewhat better at dilepton masses before the two-pion threshold and before the rho-meson peak as well as at higher dilepton masses (beyond the phi-meson one). The approach implies no specific assumptions on the equation of state (EOS) or peculiarities of phase transitions in the expanding nuclear matter.Comment: 13 pages, 3 PNG figures. submitted to Sov. Nucl. Phy

Дистанционный лазерный метод контроля нефтяных загрязнений на земной поверхности

Most of all oil and oil products spill on a terrestrial surface when running through the pipelines. Presently existing systems of monitoring spillages in the pipelines record large spillages and have a sensitivity limit, which makes about 1% of the pipeline capacity. However, such systems do not record spillages with intensity of less than 1%.One of the options of a leakage detection system of oil products with intensity less than 1% can be a remote monitoring system of oil pollution of a terrestrial surface from the aircraft flying over the route of the pipeline.The paper studies the possibilities of using a remote laser fluorescent method to detect and classify oil pollution on a terrestrial surface. This method allows to detect oil products pollution of a terrestrial surface and classify them into four groups: terrestrial surface (free of oil product contaminations); spill of the light cleared oil products on a terrestrial surface; spill of crude oil; spill of heavy oil products.To study the fluorescence spectra features of natural formations and oil pollution a laboratory installation was created for the 266 nm wavelength of fluorescence excitation. The laboratory installation allows measurement of fluorescence spectra in range from 295 to 740 nm.Over 850 fluorescence spectra of various oil products of the pure and polluted terrestrial surfaces received during laboratory researches were further used as the basic data to develop a detection and classification method of oil pollution on a terrestrial surface.Results of pilot studies and mathematical modelling show that the laser remote method of oil pollution detection on a terrestrial surface, which uses the excitement wavelength of 266 nm, records the fluorescent radiation in three narrow spectral ranges with central wavelengths of 313,5; 334,5; 400,0 nm and scattered radiation at the wavelength of 266 nm allows reliable detection of oil pollution with a probability of the correct detection more than 98%. Addition of one more narrow spectral ranges with the central wavelengths of 358.5 nm allows to provide classification of oil products into three types: light oil products, heavy oil products, crude oil with probability of the correct classification more than 0,99. This allows us to consider the described laser method as one of their perspective options of remote system for detection and classification of oil pollution on a terrestrial surface.Рассматривается лазерный метод обнаружения и классификации нефтяных загрязнений на земной поверхности. Приводятся экспериментальные спектры флуоресценции нефтепродуктов и различных земных поверхностей. Показано, что метод, использующий длину волны возбуждения 266 нм, регистрацию флуоресцентного излучения в трех спектральных диапазонах с центральными длинами волн 313,5; 334,5; 400,0 нм и рассеянного излучения на длине волны 266 нм, позволяет обнаруживать нефтяные загрязнения с вероятностью правильного обнаружения 0,98. Использование еще одного спектрального диапазона с центральной длиной волны 358,5 нм позволяет проводить классификацию по трем типам - легкие и тяжелые нефтепродукты, сырая нефть с вероятностью правильной классификации больше 0,99. DOI: 10.7463/rdopt.0315.078207