References - Bogoliubov Laboratory of Theoretical Physics - JINR

MEASUREMENT OF TENSOR POLARIZATION OF DEUTERON BEAM
PASSING THROUGH MATTER
L.S. Azhgirey 1 † , T.A. Vasiliev 1 , Yu.A. Gurchin 1 ,V.N.Zhmyrov 1 , L.S. Zolin 1 ,
A.Yu. Isupov 1 , A.K. Kurilkin 1 , P.K. Kurilkin 1 ,V.P.Ladygin 1 , A.G. Litvinenko 1 ,
V.F. Peresedov 1 , S.M. Piyadin 1 , S.G. Reznikov , A.A. Rouba 2 ,P.A.Rukoyatkin 1 ,
A.V. Tarasov 1 ,A.N.Khrenov 1 , and M.Janek 1
(1) Joint Institute for Nuclear Research, Dubna
(2) Research Institute of Nuclear Problems, Belarusian State University, Minsk
† E-mail: azhgirey@jinr.ru
Abstract
The results of measurements and the procedure for handling the data on the
tensor polarization of the deuteron beam arising as the beam passes through matter
obtained at the Nuclotron during the June 2008 run using an extracted unpolarized
5-GeV/c deuteron beam are described. The observed effect is compared with the
calculations made within the framework of the Glauber multiple scattering theory.
In the last years it has become more and more obvious, that many modern problems of
nuclear physics and physics of elementary particles cannot be solved without the profound
research of polarization effects which are connected with the search for new methodological
approaches. For example, it is offered to use the effect of spin filtering, occurring at spin
transfer from the polarized electrons in an internal hydrogen gas target to the orbiting
antiprotons to produce their polarization in storage rings [1]. This makes it possible to
measure the transversity distribution of the valence quarks in the proton with the purpose
of overcoming the so-called spin crisis.
The phenomenon of spin filtering can also take place in interactions of others hadrons,
in particular, deuterons. In the case of deuterons the cause to this effect is presence of
the quadrupole momentum in the deuteron.
Baryshevsky has shown [2] that passage of high-energy particles of spin ≥ 1 through
matter is accompanied by new effects: spin oscillations and spin dichroism. These effects
can result in polarization of the beam traveling through the target. Tensor polarization of
the originally unpolarized beam after its passage through the unpolarized target was first
observed for deuterons with the energy up to 20 MeV traveling through carbon foils [3].
The first measurement of the tensor polarization of a beam arising after its passing
through a carbon target, was made in Dubna in the unpolarized deuteron beam with
the momentum of 5 GeV/c extracted from the Nuclotron [4]. In the present report the
results of the recent studies carried out at the Nuclotron with the purpose of confirming
the earlier observed effect are described.
The layout of the experimental equipment is shown in Fig. 1. The deuteron beam
with an intensity of 5 × 10 8 − 3 × 10 9 particles/spill extracted from the Nuclotron was
directed by magnetic elements to the 54, 83 and 137 g/cm 2 -thick carbon targets T 1 serially
placed inside the concrete shield near the focus F 3 of the magnetic-optical channel. The
polarization of the deuterons which passed through the targets T 1 was analyzed using the
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