A. Isupov

Fragmentation of tensor polarized deuterons into cumulative pions

Abstract The tensor analyzing power T20 of the reaction d +A→π − (0°)+X has been measured in the fragmentation of 9 GeV tensor polarized deuterons into pions with momenta from 3.5 to 5.3 GeV/c on hydrogen, beryllium and carbon targets. This kinematic range corresponds to the region of cumulative hadron production with the cumulative variable xc from 1.08 to 1.76. The values of T20 have been found to be small and consistent with positive values. This contradicts the predictions based on a direct mechanism assuming NN collision between a high momentum nucleon in the deuteron and a target nucleon (NN→NNπ).

Tensor analyzing power T20 for cumulative pion production from deuterons in the GeV energy region

Abstract The tensor analyzing power T 20 for the reaction d ↑ + 12 C → π ± (0°) + X has been measured with a polarized deuteron beam from 6.2 to 9.0 GeV/ c at a pion momentum3.0 GeV/ c . This experiment is focused on “cumulatively produced pions”, which are produced beyond the kinematically allowed limit for free nucleon-nucleon collisions. The measured values of T 20 turn out to be close to zero. They are in disagreement with the results of our impulse approximation calculation which is based on a single NN → πNN interaction and takes into account the internal motion of nucleons in the deuteron. Possible explanations of the result are discussed.

Fragmentation of polarized deuteron into high momentum mesons as source of spin information of deuteron core structure

Abstract A study of spin effects at fragmentation of 9 GeV polarized deuterons into high momentum pions d A → π (θ) X was for the first time performed at Dubna polarized deuteron facility. Large D -state effects were observed at fragmentation of tensor polarized deuterons into cumulative pions at non-zero emission angles.

Soft photon registration at Nuclotron

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.

TENSOR ANALYZING POWER AYY IN DEUTERON INCLUSIVE BREAKUP AT LARGE PT AND SPIN STRUCTURE OF THE DEUTERON AT SHORT INTERNUCLEONIC DISTANCES

The Ayy data for deuteron inclusive breakup off hydrogen and carbon at a deuteron momentum of 9.0 GeV/c and large Pt of emitted protons are presented. The large values of Ayy independent of the target mass reflect the sensitivity of the data to the deuteron spin structure. The data obtained at fixed

Spin effects at fragmentation of polarized deuterons into cumulative pions

x

Spin effects at fragmentation of polarized deuterons into pions

and plotted versus Pt clearly demonstrate the dependence of the deuteron spin structure at short internucleonic distances on two variables. The data are compared with the calculations using Paris, CD-Bonn and Karmanovs deuteron wave functions.

Measurement of the Tensor Analyzing Power T20 in the Fragmentation of 9 GeV Tensor Polarized Deuterons into Cumulative Pions

Tensor analyzing power T20 of the reaction dA→π(0°)X was measured in the fragmentation of 9 GeV deuterons into points with the momenta from 3.5 to 5.3 GeV/c at hydrogen, beryllium and carbon targets. This momentum range corresponds to region of cumulative pion production The values of T20 are found to be small and consistent with positive values in contradiction with the Impulse Approximation calculations based on assuming a direct mechanism of pion production (NN→NNπ). New data on tensor Ayy analyzing power for pion production at the non-zero angle (θπ=135,180mr) with pion transverse momenta up to Pt=0.8 GeV/c are presented. Ayy increases with rise of Pt in the cumulative region.

Search for D-state effects in cumulative pion production off polarized deuterons

Tensor analyzing power T20 in dA→π(θ=0°)X has been measured at fragmentation of 9 GeV deuterons into pions with the momenta from 3.5 to 5.3 GeV/c at H-, Be-, and C-targets. This momentum range corresponds to region of cumulative pion production where the deuteron core structure up to r≃0.4 fm is probed. The values of T20 are found to be small and positive in contradiction with the Impulse Approximation calculations assuming a direct mechanism of pion production on high momentum nucleon in the deuteron (NN→NNπ). In this report we present new data on tensor Ayy analyzing powers at non-zero angles (θ=135,180mr) with pion transverse momenta up to Pt=0.8 GeV/c. Ayy increases with rise of Pt in the cumulative region reaching the magnitude of −0.4 at Pt=0.7–0.8 GeV/c.

23p-F-7 GeV領域偏極重陽子による中間子生成II

Tensor analyzing power T 20 of the reaction d ↑ A → π–(0°)X was measured in the fragmentation of 9 GeV deuterons into pions with momenta from 3.5 to 5.3 GeV/c on hydrogen, beryllium and carbon targets. This momentum range corresponds to the region of cumulative production with the cumulative variable x c from 1.08 to 1.76. The values of T 20 were found to be small and consistent with positive values in contradiction with the predictions based on a direct mechanism assuming N N collision between a high momentum nucleon in the deuteron and a target nucleon (N N → N N π).