Measurement of tensor analyzing powers in deuteron photodisintegration

A new accurate measurement of the tensor analyzing powers T20, T21, and T22 in deuteron photodisintegration has been performed. Wide-aperture nonmagnetic detectors allowed broad kinematic coverage in a single set up: E(gamma)=25 to 600 MeV, and theta(p)(cm)=24 degrees to 48 degrees and 70 degrees to 102 degrees . The new data provide a significant improvement over the few existing measurements. The angular dependency of the tensor asymmetries in deuteron photodisintegration is extracted for the first time.     

Tagging system for almost-real photons at VEPP-3 storage ring

At BINP the construction of the tagging system for almost-real photons (TS) is in progress. The energy of tagging photons can be up to 1.5 GeV. The projected energy resolution of TS is better then 1%. For at least a half of photons the linear polarization can be determined. The tagging system will extend the possibilities for photoreaction studying at VEPP-3 significantly. TS would allow to perform a complete kinematics reconstruction, thus permitting a reliable rejection of the background processes; to extend the measurements to higher photon energy; to enabling Σ-asymmetry measurements and double polarization experiments.     

Structural and Magnetic Characteristics of Nanogranular Co–Al2O3 Single- and Multilayer Films Formed by the Solid-State Synthesis

The results of structural and magnetic investigations of nanogranular Co–Al₂O₃ films formed from Co₃O₄/Al thin-film layered structures upon vacuum annealing are reported. The Co₃O₄/Al films have been obtained by sequential reactive magnetron sputtering of a metallic cobalt target in a medium consisting of the Ar + O₂ gas mixture and magnetron sputtering of an aluminum target in the pure argon atmosphere. It is shown that such a technique makes it possible to obtain nanogranular Co–Al₂O₃ single- and multilayer thin films with a well-controlled size of magnetic grains and their distribution over the film thickness.

     

Spin-dependent electron-proton scattering in the Delta-excitation region

We report on measurements of the cross section and provide first data on spin correlation parameters A(TT') and A(TL') in inclusive scattering of longitudinally polarized electrons from nuclear-polarized hydrogen. Polarized electrons were injected into an electron storage ring operated at a beam energy of 720 MeV. Polarized hydrogen was produced by an atomic beam source and injected into an open-ended cylindrical cell, located in the electron storage ring. The four-momentum transfer squared ranged from Q2 = 0.2 GeV(2)/c(2) at the elastic scattering peak to Q2 = 0.11 GeV(2)/c(2) at the Delta(1232) resonance. The data provide a stringent test of pion electroproduction models.     

Tensor observables in electro- and photoreactions on the deuteron

The study of polarization effects in reactions with a simplest nucleus, deuteron, plays an important role for the investigation of deuteron structure as well as for the research of the properties of the strong interaction. However, data on the tensor observables in the electro- and photoreactions with deuteron appeared not so long ago. We present here a brief overview of the experiments on three such reactions with a deuteron: elastic scattering, photodisintegration and coherent photoproduction of the neutral pion.