G.L. Vardenga

A study of pion production in 4.5 GeV/c)/nucleon 4He interactions with nuclear targets

Abstract Inelastic interactions of 4 He nuclei at the incident momentum of 4.5 GeV/ c )/nucleon with pure Li, C, Al, Cu and Pb targets were studied in the SKM-200 streamer chamber. Cross sections and their dependence on the target mass number for fragmentation processes were obtained. The multiplicities, transverse momenta and rapidities of negative pions as well as their correlations were analyzed separately for “central” and “peripheral” collisions. A comparison of the results with the predictions of some theoretical models is presented.

Streamer chamber study of the cross sections and multiplicities in nucleus-nucleus interactions at the incident momentum of 4.5 GeV/c per nucleon

Abstract The experimental data obtained with the SKM-200 streamer chamber set-up are presented. The cross-section values and multiplicity distributions of negative secondaries in the inelastic 12 C interactions and in the central 12 C and 16 O collisions with pure nuclear targets (C, Ne, Si, Cu and Zr) are discussed. The results of this experiment and of the earlier ones concerning the 4 He-nucleus interactions at the same incident momentum of 4.5 GeV/ c are analyzed and compared with those of several other experiments and with the predictions of some theoretical models.

A Study of the production and lifetime of the lightest relativistic hypernuclei

Abstract All results on the production cross sections of the lightest hypernuclei and the lifetimes of the hydrogen hypernuclei obtained in Dubna streamer chamber experiments are presented.

The temperatures of protons andπ− mesons in central nucleus-nucleus interactions at a momentum of 4.5 GeV/c per incident nucleon

An estimate of the temperature of protons andπ− mesons in central He−Li, He−C, C−C, C−Ne, C−Cu, C−Pb, O−Pb, Mg−Mg interactions is presented. The results indicate an increase of the proton temperature with increasing mass numbers of projectile and target nuclei (Ap,AT) fromTp=(118±3) MeV for He−Li toTp=(141±2) MeV for C−Pb. The temperature ofπ− mesons does not depend onAP,AT andTπ≃95 MeV. A satisfactory fit forπ− mesons in C−Cu, C−Pb, O−Pb, Mg−Mg collisions can be achieved by using a form involving two temperatures,T1 andT2. The relative yield of the high temperature component (T2) is ≅24% for C−Cu, C−Pb, and Mg−Mg interactions. The observed results forTP in C−Ne, C−Cu and C−Pb collisions are consistent with the prediction of the thermodynamic hagedorn model.

Characteristics of Λ andK0 particles produced in central nucleus nucleus collisions at a 4.5 GeV/c momentum per incident nucleon

AbstractData on Λs andK0s, produced in central nucleus-nucleus collisions (C−C, C−Ne, O−Ne, C−Cu, C−Zr, C−Pb, O−Pb) at a 4.5 GeV/c momentum per incident nucleon obtained in the streamer chamber spectrometer SKM-200, are presented. Multiplicities, transverse momenta, rapidities and other characteristics are considered and compared with those for inelastic He−Li interactions. The polarization of Λs was found to be consistent with zero. The upper limit of

ASSOCIATIVE PRODUCTION OF BACKWARD EMITTED FAST FRAGMENTS IN NUCLEUS NUCLEUS INTERACTIONS. (IN RUSSIAN)

\bar \Lambda /\Lambda

STREAMER CHAMBER OF A MAGNETIC GIBS SPECTROMETER

production ratio was estimated to be ≤10−2 with a 90% confidence level. The results are compared with data of other experiments and some model calculations.

Collective excitation of Delta isobar in the charge-exchange reactions (7Li,7Be) and (3H, 3He) at a momentum of 3 GeV/(c.nucleon)

Multiplicities of π−-mesons from central collisions of12C and16O(4.5 GeV/c/n momentum) with several target nuclei were studied in a streamer chamber experiment. The parameter η=(〈n−2〉−〈n−〉2)/〈n−〉 was determined for several samples of events characterized by different values of Θch — the “vetoangle” for emission of the projectile charged fragments. The value of η is shown to decrease when the projectile mass number increases from 12 to 16 and to decrease significantly when Θch increases from 0° to 4°, whereas it remains nearly constant when Θch increases further to 14°. The results are compared with predictions of some theoretical models.