Model for describing the production of Centauro events and strangelets in heavy-ion collisions

A phenomenological model for describing the production of Centauro events in relativistic heavy-ion collisions is discussed. The model provides quantitative predictions for kinematical variables, for the baryon number, and for the masses of a Centauro fireball and of its decay products. A Centauro fireball decays predominantly into nucleons, strange hyperons, and possibly strangelets. Centauro events in Pb + Pb collisions at the LHC energy are simulated for the CASTOR detector. The signatures of these events are discussed in detail.     

Temperature effects on the aggregation of decylpyridinium chloride in aqueous solution

Surface tension and conductivity measurements were used to study micelle formation in an aqueous solution of decylpyridinium chloride at 20, 25, 30, 35, and 40°C. The critical micelle concentration (CMC) was minimum at about 30–35°C. After CMC₁, aggregation with CMC₂ and CMC₃ occurred as the concentration increased.     

Oxidative transformations of cembrane diterpenoids. II. Cembra-2,7,11-triene-4,5-diols

Summary 1. The oxidation of cembrene with chromium trioxide in aqueous acetone forms, together with other compounds, the products of its hydroxylation at the C₄ double bond — cembra-2,-7,11-triene-4,5-diols epimeric at the C₄ double bond.2. On the basis of chemical and spectral characteristics, it has been established that these diols have the 4S, 5R and 4R, 5R configurations, respectively.Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Academy of Sciences of the USSR, and Novosibirsk State University. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 54–59, January–February, 1977.     

ARYLATING PROPERTIES OF DERIVATIVES 2,4 - BIO(THRIFLUOROME-THANESULPHONYL)BENZENESULPHONYL ACID

Abstract

Compounds 2,4-(CF₃SO₂)₂C₆H₃X while X = C1 (I), SO₂C1 (II), SO₂F (III), SO₂NHC₆H₅(IV), HNSO₂C_c6H₅(V) are synthesized with the aim of finding active arylating means. Kinetics of the interaction of these compounds with the nucleophylic reagents, the character of the leaving group and the properties of medium are investigated by the spectrophotometric method.     

Effect of γ radiation on the polarization properties of polyethylene oxide

The effect of γ radiation on the dielectric properties of polyethylene oxide is investigated by the polarization-current method. It is found that polarization currents in a γ-irradiated sample decrease in magnitude, which indicates a lower probability of forming a crystalline phase.     

Elliptic flow studies using the CMS detector

The azimuthal anisotropy of charged particles in heavy ion collisions is an important probe of quark-gluon plasma evolution at early stages. The nuclear reaction plane can be determined independently by different detector subsystems and using different analysis methods. This paper reports the capability of the CMS detector at the LHC to reconstruct the reaction plane of the collision and to me asure elliptic flow with calorimetry and a tracking system. The analysis is based on a full CMS detector simulation of Pb + Pb events with the HYDJET event generator.     

γ-radiation of excited nuclear discrete levels in peripheral heavy ion collisions

A new process of a nuclear excitation to discrete states in peripheral heavy ion collisions is studied. High-energy photons are emitted by the exited nuclei with energies up to a few tens of GeV at angles of a few hundred microradians with respect to the beam direction. We show that a two-stage process, where an electron-positron pair is produced by virtual photons emitted by nuclei and then the electron or positron excites the nucleus, has a large cross-section. It is equal to about 5 b for CaCa collisions. On the one hand, it produces a significant γ-rays background in the nuclear fragmentation region but, on the other hand, it could be used for monitoring the nuclear beam intensity at the LHC. These secondary nuclear photons could be a good signal for triggering peripheral nuclear collisions. Received: 14 December 2001 / Accepted: 22 January 2002