O. Tarasov

The gell-mann-low function of QCD in the three-loop approximation

An analytic calculation of the Gell-Mann-Low function and anomalous dimensions for non-Abelian gauge theory with fermions is presented.

VANISHING OF THE THREE LOOP CHARGE RENORMALIZATION FUNCTION IN A SUPERSYMMETRIC GAUGE THEORY

Abstract The three-loop calculation of the charge renormalization function β ( g 2 ) for the SU(4)-supersymmetric non-abelian gauge theory is presented. As in the one- and two-loop orders, this function is found to vanish.

Search for 28O and study of neutron-rich nuclei near the N = 20 shell closure

Abstract A search for 28 O with a 78 AMeV beam of the neutron-rich isotope 36 S has been performed for the first time. Evidence for the unbound character of 28 O was obtained. In the same experiment the half-lives of the very neutron-rich isotopes 27,29 F and 30 Ne were measured and those for 28,29 Ne and 30,31 Na reexamined. The results are compared to shell-model predictions and conclusions drawn regarding the extent of the region of deformation around N = 20.

The three-loop beta-function in the N = 1, 2, 4 supersymmetric Yang-Mills theories

Abstract Results of the renormalization group beta-function calculations in the N = 1, 2, 4 supersymmetric Yang-Mills theories are presented. In the N = 2 theory the two- and three-loop coefficients are found to be zero. For N = 4 all the three coefficients vanish as was shown earlier.

Identification of the doubly-magic nucleus 100Sn in the reaction 112Sn+natNi at 63 MeV/nucleon

Abstract We report on the production of the doubly-magic nucleus 100 Sn and other proton-rich nuclei in the A ∼ 100 region in the reaction 112 Sn + nat Ni at 63 MeV/nucleon. The experiment was carried out using the high acceptance device SISSI and the Alpha and LISE3 spectrometers at GANIL. The identification of the reaction products ( A , Z and Q ) was made using the measurements of time-of-flight, energy-loss and kinetic energy.

Identification of μs-isomers produced in the fragmentation of a 112Sn beam

Abstract Decays of over forty short-lived ( T 1 2 from ≈ 50 ns to 70 μs) isomeric states including a new isomer 66mAs produced in the fragmentation of a 112Sn beam (58 A·MeV, 63 A·MeV) on a natNi target were observed at the final focus of the LISE3 spectrometer at GANIL. Their detection, based on the slow (≈ 10 μs) time correlation of identified ions with the characteristic γ-radiation, represents a novel method to search for new isomers and can be used for unambiguous isotope identification for projectile fragment separator experiments. Isomeric yields and isomer-to-total production ratios were determined.

DRIPLINE NUCLEI PRODUCED BY QUASI-FRAGMENTATION OF THE 32,34,36S PRIMARY BEAMS

Some regularities in the production of isotopes with are investigated in reactions induced by beams at on targets , and . A search for using a beam of the neutron-rich has been performed. Evidence for particle instability of was obtained. In the same experiment, the half lives of the very neutron-rich isotopes and were measured for the first time.

Identification of 100Sn and others proton drip-line nuclei in the reaction 112Sn(63 MeV/nucl.)+natNrmNi

Abstract Six new neutron-deficient nuclei 103Sb, 104Sb, 98In, 91Pd, 89Rh and 87Ru have been identified among the products of quasi-fragmentation of a 112Sn beam (63 MeV/nucl.), in addition to the previously reported 100Sn and 102Sn. Decays of over forty short-lived ( T 1 2 from ≈50 ns to 70μ s ) isomeric states including new isomer 66mAs were observed in the same reaction.

8B studied as a secondary beam at GANIL

Abstract The LISE spectrometer at GANIL has been used to form a 8 B secondary beam. Using a multiple silicon telescope, data have been obtained for the reaction and break-up cross sections, as well as for the parallel momentum distribution of 7 Be from break-up. For the first time, separate contributions to the break-up of diffraction and/or Coulomb dissociation and absorption mechanisms have been determined. The ensemble of data supports the existence in 8 B of a “pigmy” halo.

Characteristics of neutron-rich nuclei around shell closures N=20 and 28

Abstract The paper presents a review of experimental results obtained at GANIL and FLNR Dubna on the study of the particle stability of neutron-rich nuclei near the neutron drip line. Very recent data on mass measurements of neutron-rich nuclei in the range A =29–47 at GANIL and some characteristics of binding energies in this region are presented. Nuclear binding energies are very sensitive to the existence of shells and provide clear signatures of shell closures. Experiments have been mostly performed in cooperation GANIL–Orsay–Dubna–Řež–Bucharest–Liverpool.