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J. Adam

Publications and source records attributed to J. Adam.

154 records · Page 9Linked to original sources
arXiv2006

Recoil Products from p+$^{118}Sn$ and d+$^{118}Sn$ at 3.65 GeV/A

The recoil properties of the product nuclei from the interaction of 3.65 GeV/nucleon protons and deuterons with $^{118}Sn$ target have been studied by the method of catching foils on the beams of LHE JINR. The mathematical formalism of the standard two step vector model was used for the analysis of experimental results. The obtained results for the protons are compared with the ones obtained for the deuterons. The total energy of the deuterons beam was 3.65GeV/nucleon. It is interesting to note that the forward velocity v and the recoil nuclei kinetic energy increases linearly with the increase of mass loss of target $ΔA$, but seems to change its slope at around $ΔA=60$. It seems that light and medium mass products are produced partly by a fragmentation mechanism.

nucl-ex↗
arXiv2005

Formation of Light Isotopes by Protons and Deuterons of 3.65 GeV/nucleon on Separated Tin Isotopes

We measure cross sections for residual nuclide formation in the mass range 6 < A < 97 caused by bombardment with protons and deuterons of 3.65 GeV/nucleon energy of enriched tin isotopes (112-Sn, 118-Sn, 120-Sn, 124-Sn). The experimental data are compared with calculations by the codes FLUKA, LAHET, CEM03, and LAQGSM03. Scaling behavior is observed for the whole mass region of residual nuclei, showing a possible multifragmentation mechanism for the formation of light products (6 < A < 31). Our analysis of the isoscaling dependence also shows a possible contribution of multifragmentation to the production of heavier nuclides, in the mass region 39 < A < 81.

nucl-ex↗
arXiv2004

Properties of Excited States in the ^{160}Dy Nucleus

Positive-parity levels and 16 rotational bands are theoretically analyzed on the basis of phenomenological models of the atomic nucleus with the use of new experimental data on excited states in the ^{160}Dy nucleus recently gained in the investigation of the decay ^{160}Er → ^{160m,g}Ho → ^{160}Dy.

nucl-th↗
arXiv2004

Description of the Collective States in 160Dy

The 160Dy nucleus is classified as deformed nucleus (β=0.23) and has quite a complicated scheme of excited states. By now it has been quite well studied experimentally in nuclear reactions, Coulomb excitation, and βdecays of 160Tb and 160m,gHo. Our recent investigation of the decay 160Er ->160m,gHo ->160Dy has made it possible to expand considerably the scheme of excited 160Dy states and to correlate the reaction and β-decay data. Over a hundred new levels are added to the previously known excited states in the 160m,gHo ->160Dy decay scheme. In this paper a theoretical analysis of the experimental data of the spectrum of excited states in 160Dy is presented. The Interacting Vector Boson Model (IVBM) [3] has been applied for classification of low lying collective excited states with Jp =0+,2+,4+,6+ and also for description of the ground, beta, gamma and octupole bands energies.

nucl-th↗
arXiv2004

Analysis of the JINR p(660 MeV) + 129I, 237Np, and 241Am Measurements with Eleven Different Models

We have analyzed the recent JINR measurements on nuclide production cross sections from interaction of 660 MeV proton beams with radioactive targets of enriched 129I (85% 129I and 15% 127I), 237Np, and 241Am with eleven different models, realized in eight transport codes and event-generators: LAHET (Bertini, ISABEL, INCL+ABLA, and INCL+RAL options), CASCADE, CEM95, CEM2k, LAQGSM+GEM2, CEM2k+GEM2, LAQGSM+GEMINI, and CEM2k+GEMINI. We found out that all these models have problems in a correct description of many of these cross sections, though some of these models describe very well most of the recent measurements done at GSI using inverse kinematics, as well as many other reactions. None of the tested here models is able to reproduce well all the JINR data and all of them should be further improved. Development of a better universal evaporation/fission model should be of a highest priority. We conclude that it is impossible to make a correct choice between fission and fragmentation reaction mechanisms analyzing only measurements on product cross sections; addressing this question would require analysis of two- or multi-particle correlation measurements.

nucl-th↗
arXiv2004

Study of Proton Induced Reactions in a Radioactive 129-I Target at Ep=660 MeV

Two NaI (85% 129-I and 15% 127-I) targets were exposed to a beam of 660-MeV protons. Cross sections for formation of 76 residual nuclei were obtained by the induced activity method. The results are compared with other experimental data on 127-I and theoretical calculations by eleven models contained in the codes LAHET3 (using the Bertini+Dresner, ISABEL+Dresner, INCL+Dresner, and INCL+ABLA options), CASCADE, CEM95, CEM2K, LAQGSM+GEM2, CEM2k+GEM2, LAQGSM+GEMINI, and CEM2k+GEMINI. Most of the models describe spallation products with masses close to the target reasonably well while the reliability of the codes differs greatly in the deep spallation and fission/fragmentation regions. The difficulties in describing products with A=40-80 by all of the codes tested here except for CEM2k+GEMINI and LAQGSM+GEMINI is related to the neglect of fission (and fragmentation) processes for targets as light as 129-I.

nucl-ex↗
arXiv2003

Isotope effect in yields of nuclear reactions

The analysis results of the isotopic yields for products obtained in reactions of protons at energies 0.66, 1, 8.1GeV with separated tin isotopes are presented. The experimental data are compared in form of reactions of element cross sections for two targets of different isotope compositions. The scaling behaviour have been shown in the dependence of this ratios from neutron and proton composition at the reaction products. The discussion of scaling parameters allows to explain the mechanism of light and medium mass fragment production.

nucl-ex↗
arXiv2001

Solving the Schwinger-Dyson equation for a scalar propagator in Minkowski space

The Schwinger-Dyson equation for a scalar propagator is solved in Minkowski space with the help of an integral spectral representation, both for spacelike and timelike momenta. The equation is re-written into a form suitable for numerical solution by iterations. This procedure is described for a simple unphysical Lagrangian with a cubic interaction, with future extensions to more realistic theories in mind.

hep-ph↗
arXiv1997

Lagrangian with off-shell vertices and field redefinitions

Meson exchange diagrams following from a lagrangian with off-shell meson-nucleon couplings are compared with those generated from conventional dynamics. The off-shell interactions can be transformed away with the help of a nucleon field redefinition. Contributions to to the $NN$- and $3N$-potentials and nonminimal contact e.m. meson-exchange currents are discussed, mostly for an important case of scalar meson exchange. (pacs 11.10.Lm, 13.75.Cs, 21.30.-x, 24.10.Jv)

nucl-th↗