V. I. Ivanov

Measurement of the tensor Ayy and vector Ay analyzing powers of the deuteron inelastic scattering of beryllium at 5.0 GeV/c and 178 mrad

Tensor Ayy and vector Ay analyzing powers in the inelastic scattering of deuterons with a momentum of 5.0 GeV/c on beryllium at an angle of 178 mrad in the vicinity of the excitation of baryonic resonances with masses up to ∼ 1.8 GeV/c2 have been measured. The Ayy data are in good agreement with the previous data obtained at 4.5 and 5.5 GeV/c. The results of the experiment are compared with the predictions of the plane-wave impulse approximation and ω meson-exchange models.Tensor Ayy and vector Ay analyzing powers in the inelastic scattering of deuterons with the momentum of 5.0 GeV/c on beryllium at an angle of 178 mr in the vicinity of the excitation of baryonic resonances with masses up to 1.8 GeV/c^2 have been measured. The Ayy data are in a good agreement with the previous data obtained at 4.5 and 5.5 GeV/c. The results of the experiment are compared with the predictions of the plane wave impulse approximation and \omega-meson exchange models.

Search for η-mesic nuclei in the reaction d + C at JINR

Results of a search for quasi-bound states of the η-meson and a target nucleus obtained during several years using the internal target at the Nuclotron d-beam are presented. Formation of η-mesic nuclei was studied in the reaction d + C in the energy interval 1.5 to 2.2 GeV/nucl. Decay products of S11 resonances excited by η-mesons captured by nucleons in the nuclear target have been analyzed. Measurements were performed with a scintillation spectrometer SCAN. Analysis of obtained data is presented.

Investigation of the deuteron spin structure at short nucleon-nucleon distances in the reaction of polarized-deuteron fragmentation to cumulative pions

Experimental results on the vector (Ay) and tensor (Ayy) analyzing powers in the fragmentation of 5- and 9-GeV/c polarized deuterons to high-momentum pions in the kinematical region corresponding to pion production on a strongly correlated nucleon pair (cumulative meson production) are presented. The angular and momentum dependences of Ayy are not described by calculations performed in the impulse approximation by using standard deuteron wave functions. An explanation for our data should be sought on the basis of models that treat the deuteron at short distances (deuteron-core region) as a multiquark state—for example, a 6q cluster, whose high orbital angular momentum (D wave) leads to the observed strong dependence of the reaction tensor analyzing power A(

A data acquisition system and a trigger of the SCAN setup

\vec d

Tensor Ayy and vector Ay analyzing powers in the 1H(d,d')X and 12C(d,d')x reactions at initial deuteron momenta of 9 GeV/c in the region of baryonic resonance excitation

, π)X on the pion transverse momentum.

Measurement of the tensor A(yy) and vector A(y) analyzing powers in the fragmentation of a 9-GeV/c deuteron on hydrogen and carbon nuclei at high proton transverse momenta

The trigger, data acquisition, and monitoring systems of the double-arm SCAN spectrometer are described. The SCAN spectrometer has been designed for seeking η-mesic nuclei in reaction pA → (A − 1)η + np at the internal target of the nuclotron at the Joint Institute for Nuclear Research. A brief description of the spectrometer is presented. A system of triggers has been developed for selection of events with η-mesic nuclei, which are identified by a two-particle decay of the S11(1535) resonance produced in a target nucleus (S11 → pπ−). A two-level trigger is used. At the first level, fast selection of events with two charged particles from a stream of 104 triggers/s is performed. The second level includes extraction of events with a pair of particles (p, π−) flying apart at angle of ∼180° and subsequent identification of pairs corresponding to the kinematics of the S11 resonance decay, which is effected by a special trigger module.

Measurement of the tensor analyzing power Ayy in the inelastic scattering of 4.5-GeV/c deuterons on beryllium at an angle of 80 mrad

The angular dependence of the tensor Ayy and vector Ay analyzing powers in the inelastic scattering of deuterons with a momentum of 9.0 GeV/c on hydrogen and carbon have been measured. The range of measurements corresponds to the baryonic resonance excitation with masses 2.2--2.6 GeV/c^2. The Ayy data being in good agreement with the previous results demonstrate an approximate

Identification of the Xe beam at the JINR NUCLOTRON-M by the track length measurement method

t

Measurement of the differential cross section and of the tensor and vector analyzing powers for the fragmentation of 4.5-GeV/c deuterons on beryllium in the reaction involving proton emission at an angle of 80 mrad

scaling up to -1.5 (GeV/c)^2. The large values of A_y show a significant role of the spin-dependent part of the elementary amplitude of the NN->NN* reaction. The results of the experiment are compared with model predictions of the plane-wave impulse approximation.The angular dependence of the tensor Ayy and vector Ay analyzing powers in the inelastic scattering of deuterons with a momentum of 9.0 GeV/c on hydrogen and carbon has been measured. The range of measurements corresponds to the baryonic resonance excitation with masses of ∼2.2–2.6 GeV/c2. The Ayy data, being in good agreement with the previous results, demonstrate an approximate t scaling up to −1.5 (GeV/c)2. The large values of Ay show a significant role of the spin-dependent part of the elementary amplitude of the NN → NN* reaction. The results of the experiment are compared with model predictions of the plane-wave impulse approximation.

Measurements of the Vector and Tensor Analyzing Powers of the Inelastic Scattering of Deuterons on Nuclei in the Vicinity of Baryonic Resonances Excitation

Data on the tensor and vector analyzing powers (Ayy and Ay, respectively) in the fragmentation of a 9-GeV/c deuteron on hydrogen and carbon nuclei at high proton transverse momenta are presented. These data are compared with the results of relevant calculations performed within light-front dynamics by using various deuteron wave functions. The best description of the data is attained with the relativistic deuteron wave function derived within field-theory light-front dynamics.