115322655
Single photon and neutral meson production in nuclear collisions at 200-A/GeV
122152880
Large-angle two-particle correlations in nucleus-nucleus collisions at 3.6 GEV/nucl.
Abstract For nucleus-nucleus collisions at 3.6 GeV/nucl., we have measured correlations between a charged particle emitted in the range from 10° to 18° and identified a charged fragment (proton, deutron or pion) emitted at a certain angle in the range of 45°–130°. The following projectile-target combinations were studied: C+Al (45°, 60°, 80°, 130°); C+Cu (45°, 60°, 80°); C+Pb (45°, 60°, 80°, 130°); He+Al (45°, 80°, 130°); He+Pb (45°, 80°, 130°). In all the studied reactions, correlated particle emission has been observed.
123349552
Data implying formation of a moving source in collisions of carbon-12 nuclei with various target nuclei at 3.6 GeV/nucleon
Abstract Inclusive spectra of protons emitted in the interaction of 12 C-projectiles at an energy of 3.6 GeV/nucleon and C, Cu, Sn and Pb target nuclei were measured. The analysis of the experimental data suggests that in all these interactions the main contribution to proton cross sections in the investigated kinematic region is due to emission from a moving source with a rapidity which differs greatly from the target nucleus rapidity, y t , as well as from that of the effective fireball. The properties of this source such as the excitation energy depend only slightly on the combination of the colliding nuclei.
118798878
Two particle correlations for light nuclear fragments in nucleus-nucleus collisions at 3.6-GeV/nucleon
122800820
Universal proton rapidity distributions in high energy nucleus-nucleus collisions
Abstract Inclusive spectra of protons emitted in the interaction of 3 He ions with an energy of 4.9 GeV/nucleon with nuclei of C, Cu and Pb were measured. The analysis of these data as well as of those available on nucleus-nucleus interactions at other energies (0.8, 2.1 and 3.6 GeV/nucleon) and for other combinations of colliding nuclei (from 3 He + C to Ar + Pb) has shown that in the target nucleus fragmentation domain the invariant cross section is described by a certain universal function if we go over into the appropriate moving frame. It is natural to interpret the latter as a real physical object, i.e. a moving source. This source turns out to be highly heated (the average energy being ⪆ 90 MeV/nucleon), at the same time its inner properties (the excitation energy and distribution form) do not depend either on the collision energy or on the projectile-target combination. On the other hand, the source velocity and the number of nucleons involved in it are systematically dependent on the collision conditions.
7992539
Vacuum Einstein metrics with bidimensional Killing leaves ∗ I-Local aspects.
Abstract The solutions of vacuum Einstein's field equations, for the class of Riemannian metrics admitting a non-Abelian bidimensional Lie algebra of Killing fields, are explicitly described. They are parametrized either by solutions of a transcendental equation (the tortoise equation ), or by solutions of a linear second order differential equation in two independent variables. Metrics, corresponding to solutions of the tortoise equation, are characterized as those that admit a 3-dimensional Lie algebra of Killing fields with bidimensional leaves.
126402897
On multiple generalizations of Lie algebras and Poisson manifolds
13357439
Cherenkov glue in opaque nuclear medium
Abstract The spectrum of Cherenkov gluons is calculated within the framework of in-medium QCD. It is compared with experimental data on the double-humped structure around the away-side jet obtained in the experiments STAR and PHENIX at RHIC. The values of the real and imaginary parts of the permittivity of the medium created in ultrarelativistic nuclear collisions are obtained from these fits. It is shown that accounting for an additional smearing of transverse momenta of Cherenkov gluons in the medium allows to provide a very good description of the experimental data.
173184854
Proposal of a compact repetitive dichromatic x-ray generator with millisecond duty cycle for medical applications
Main practical applications of X-rays lie in the important for the society fields of medical imaging, custom, transport inspection and security. Scientific applications besides of fundamental research include material sciences, biomicroscopy, and protein crystallography. Two types of X-ray sources dominate now: conventional tubes and electron accelerators equipped with insertion devices. The first are relatively cheap, robust, and compact but have low brightness and poorly controlled photon spectrum. The second generate low divergent beams with orders of magnitude higher brightness and well-controlled and tunable spectrum, but are very expensive and large in scale. So accelerator based X-ray sources are mainly still used for scientific applications and X-ray tubes--in commercial equipment. The latter motivated by the importance for the society made an impressive progress during last decades mostly due to the fast developments of radiation detectors, computers and software used for image acquisition and processing. At the same time many important problems cannot be solved without radical improvement of the parameters of the X-ray beam that in commercial devices is still provided by conventional X-ray tubes. Therefore there is a quest now for a compact and relatively cheap source to generate X-ray beam with parameters and controllability approaching synchrotron radiation. Rapid developments of lasers and particle accelerators resulted in implementation of laser plasma X-ray sources and free electron lasers for various experiments requiring high intensity, shrt duration and monochromatic X-ray radiation. Further progress towards practical application is expected from the combination of laser and particle accelerator in a single unit for efficient X-ray generation.