Measurement of the tensor analyzing power T20 for the reaction γd → pnπ0

This paper presents new results for the [Formula: see text]-component of the tensor analyzing power of the reaction [Formula: see text] in the photon energy range of [Formula: see text]. The experimental statistics accumulated in 2013 at the VEPP-3 accelerator-storage complex is used. The reaction events are identified by the coincidence registration of the proton and two [Formula: see text]-quanta from the decay of the neutral pion. To determine the [Formula: see text]-component, the asymmetry of the yields with respect to the change of sign of the tensor polarization of the deuterium target is measured. The experimental results are compared with the theoretical calculations in which the MAID 2007 model is used as the elementary pion–nucleon photoproduction amplitude and contributions from the pion–nucleon and nucleon–nucleon rescattering are taken into account.

Measuring space-time properties of baryon resonances around 1 GeV using intensity correlations

We measured the Δ(1232) radius using Bose-Einstein correlations (BEC) between two neutral pions from photo-production off a hydrogen/deuterium target at the incident photon energies around 1 GeV. The experiment was carried out at Research Center for Electron Photon Science (ELPH) in Tohoku University with a 4π electromagnetic calorimeter complex, named FOREST. For low-multiplicity BEC measurements, we developed an event mixing technique by introducing additional mixing constraints to delicately reduce the effect of other non-BEC correlations arising from global conservation law and resonance decays. In addition, a new BEC observing model was established to extract radius information from BEC effects in the presence of resonance decays.

Measurements of the tensor analyzing power T20 of the reaction γd → dπ0

The paper presents the results of measurements of the tensor analyzing power component [Formula: see text] for the coherent neutral pion photoproduction on the deuteron. The measurements were performed in the Budker Institute of Nuclear Physics using the internal tensor polarized deuterium target at VEPP-3 storage ring. The measurements covered the region of the photon energy 240 — 420[Formula: see text]MeV and the region of the center-of-mass pion polar angle 100–140[Formula: see text]. The results of measurements were compared with the calculations performed within frameworks of several theoretical models.

Neutron Detection in the A2 Collaboration Experiment on Neutral Pion Photo-production on Neutron

Neutron detection is of crucial importance for the neutral pion photo-production study on a neutron target that now is in progress at MAMI. Two electro-magnetic calorimeters, based on NaI and BaF2 crystals, are used in the A2 experiment. While these calorimeters are optimized for pion decay photon detection, they have a reason able efficiency for neutron detection also. The paper describes the method, which has been used to measure this efficiency using the same data taken for pion photo-production study on deuterium target with tagged photon been of 800 MeV maximal energy. The detection efficiency is a rising function of neutron momentum that reaches 40% near 1 GeV/c.

Initial Research of np Scattering with Polarized Deuterium Target at ANKE/COSY

The quasi-free np charge-exchange reaction [Formula: see text] has to be employed to extend the investigations of np scattering at ANKE to the highest energy available at COSY. As the proof-of-principle experiment, the initial research has been conducted at proton energy [Formula: see text] MeV using a polarized Deuterium target. The vector and tensor analyzing powers [Formula: see text] and [Formula: see text] were measured for momentum transfers [Formula: see text] MeV/c. These data connect smoothly with the previous measurements at [Formula: see text] MeV/c performed using a polarized deuteron beam. The reported data are well reproduced by the impulse approximation using the SAID np amplitudes. The results therefore proves that it is possible to continue the np programme at higher energies at ANKE.