Search

Deuteron spin structure program is aimed on extraction of two and three nucleon forces information, including their spin dependent parts, from dp elastic and dp breakup processes investigated at intermediate energies. The dp elastic data were obtained at Internal Target Station of Nuclotron (JINR) in the energy range 400-1800 MeV using polarized deuteron beam. Strong sensitivity to the short range spin structure of the isoscalar nucleon-nucleon correlations is observed in deuteron analyzing powers. Preliminary results of the the cross section for the dp breakup reaction have been obtained at 400 MeV of deuteron energy.

The current deuteron beam polarimetry at the Nuclotron is provided by the Internal Target polarimeter based on the use of the asymmetry in dpelastic scattering at large angles in the cms at 270 MeV. The upgraded deuteron beam polarimeter has been used to obtain the vector and tensor polarizations during 2016/2017 runs for the DSS experimental program. The polarimeter has been also used to tune the polarized ion source parameters for 6 different spin modes. The data analysis has been performed using the developed software based on C++ language and ROOT5 library

The current deuteron beam polarimetry at Nuclotron is provided by the Internal Target polarimeter based on the use of the asymmetry in dp-elastic scattering at large angles in the cms at 270 MeV. The upgraded deuteron beam polarimeter has been used to obtain the vector and tensor polarization during 2016 runs for the DSS experimental program. The polarimeter has been used also for tuning of the polarized ion source parameters for 6 different spin modes. The data analysis has been performed using developed software based on C++ language and ROOT5 library.

Preliminary results on the angular distributions of the vector Ay and tensor Ayy, Axx analyzing powers in dp elastic scattering at the energy of 800 MeV are presented. The measurements have been performed on Internal Target Station of the JINR Nuclotron using polarized deuteron beam from new source of polarized ions. The experimental data are compared with the preliminary calculations obtained within framework of relativistic multiple scattering approach.

The results on the angular dependencies of the vectorAyand tensorAyyandAxxanalyzing powers in deuteron-proton elastic scattering at large scattering angles are presented. These data were obtained at internal target at the JINR Nuclotron in the energy range 400-1800 MeV using polarized deuteron beam from new polarized ion source. New data on the deuteron analyzing powers in the wide energy range demonstrate strong sensitivity to the short-range spin structure of the isoscalar nucleon-nucleon correlations observed earlier. The perspectives of further studies of the short-range correlations using carbon, polarized deuteron and proton beams are discussed.

We report on measurements of neutral pion production in the inclusive reactions d + C → π 0 + x and d + Cu → π 0 + x at an incident momentum of 4.5 GeV/c per nucleon. The experiments were performed on the LHE 90-channel lead glass γ -spectrometer. The cross sections were measured over the kinematical region specified by the inequalities θπ ≤ 16° and Eπ ≥ 2 GeV (in the laboratory frame). The cumulative number and transverse momentum dependencies of the exponent n in the invariant cross section parameterization Ed 3 σ / d 3 p ~ A t n are investigated by comparing of the observed cross sections for π 0 production on carbon and copper targets in the intervals 0.6 ≤ X ≤ 1.8 and 0.04 ≤ p T 2 ≤ 0.40 (GeV/c)2 . The double differential cross section for the reaction d + C → π 0 + x is measured using statistics of about 4.5 · 104 π 0 mesons. On the basis of these data we verified the so-called cluster mechanism of π 0 production. We have compared our data for the reaction d + C → π 0 + x , extrapolated to θπ = 0°, with the data from another experiments on π − production: d + C → π − (0°) + x (P = 1.75 and 2.88 GeV/c per nucleon) [1]; p + d → π − (180°) + x and p + d → π + (180°) + x (P = 8.9 GeV/c per nucleon) [2]; d + p → π − (0°) + x (P = 8.9 GeV/c per nucleon) [3]. The invariant cross sections were approximated by an exponential function Ed 3 σ / d 3 p ~ exp (−X / X 0 ). The slope parameter X 0 at different kinetic energies of the projectiles in the range of 1.05÷8.0 GeV per nucleon is determined.

The data on the vector Ay and tensor Ayy, Axx, Axz analyzing powers for the [Formula: see text] and [Formula: see text] reactions at Ed = 200 and 270 MeV are presented. The data demonstrate large values of analyzing powers and their strong variation versus the scattering angle. The observed negative sign of the tensor analyzing powers for these reactions at small angles clearly demonstrate the sensitivity to the D/S ratio of the 3H and 3He wave functions, respectively. The calculations performed within one-nucleon exchange model with the use of the standard three-nucleon bound state wave functions fail to reproduce the data on the tensor analyzing powers.

The data on the vector A y and tensor A yy , A xx , A xz analyzing powers for the $$ \vec d $$ d → 3H p reaction have been obtained at the energy of the initial deuteron of 200MeV in the angular range of 0–95 degrees in the c.m.s. The calculations performed within one-nucleon exchange model with the use of the standard three-nucleon bound state wave functions fail to reproduce the data on the tensor analyzing powers.

Data on the vector analyzing power A y and the tensor analyzing powers A yy , A xx , and A xz in the reaction $\vec d$ d → 3H p at the deuteron energy of 200 MeV are presented over a full angular range in the c.m. frame. The signs of the tensor analyzing powers for forward and backward scattering are found to be sensitive to the D/S wave ratio in 3H and in the deuteron. High-precision experimental data are compared with the results of theoretical calculations performed on the basis of the multiple-scatteringmodel by using standard wave functions for the three-nucleon bound states and for the deuteron.

First results of a soft photon yield in nucleus-nuclear interactions at 3.5 GeV per nucleon are presented. These photons have been registered at Nuclotron (LHEP, JINR) by an electromagnetic calorimeter built in the SVD Collaboration. The obtained spectra confirm the excess yield in the energy region less than 50 MeV in comparison with theoretical predictions and agree with previous experiments at high-energy interactions., 5 pages, 3 figures, presented at the International Conference on New Photo-detectors July 6-9, 2015, Moscow, Troitsk, Russia

RIKEN Accelerator Research Facility data on the tensor analyzing power T{sub 20} of the dd {sup {yields}} {sup 3}Hen and dd {sup {yields}} {sup 3}Hp reactions at zero angle for deuteron kinetic energies of 140, 200, and 270 MeV are reported. The observed positive sign of T{sub 20} clearly demonstrates the sensitivity to the D/S-wave ratio in the {sup 3}He and {sup 3}H wave functions in the energy range of the experiment. Data on T{sub 20} for the {sup 3}Hen channel are in agreement with those for the {sup 3}Hp channel within the experimental errors.

The experiment with polarized deuteron beam was performed at energies 140, 200 and 270 MeV at RIKEN, Japan, in December 2000. The high-momentum structure of the 3 He , 3 H and deuteron was investigated. For this purpose the angular dependence of the tensor and vector analyzing powers were measured for the reactions d + d →3 H + p and d + d →3 He + n . In this report the results on the tensor Axx, Ayy and vector Ay analyzing powers at 270 MeV are presented.

The vector Ay and tensor analyzing powers Ayy and Axx for dp- elastic scattering were measured at Td = 880 MeV over the c.m. angular range from 60 to 140 degrees at the JINR Nuclotron. The data are compared with predictions of different theoretical models based on the use of nucleon-nucleon forces only. The observed discrepancies of the measured analyzing powers from the calculations require the consideration of additional mechanisms., Comment: 5 pages,3 figures

The status and prospects of 2-nucleon and 3-nucleon short range correlations (SRCs) studies at Nuclotron-M (JINR) are presented. This program is focused on the investigations of the spin part of SRCs with polarized deuteron beam from new high intensity polarized deuterons ion source which is under development at JINR. The wide experimental program on the systematic studies of the polarization effects in dp- elastic scattering, dp- nonmesonic breakup, dd → 3Hen(3Hp) and d3He → p4He reactions sensitive to SRCs using both internal and extracted beam at Nuclotron-M is presented.