Target mass correction on the 3He polarized structure function

The diffusion-effusion model has been used to analyse the release and yields of Fr and Cs isotopes from uranium carbide targets of very different thicknesses (6.3 and 148 g/cm²) bombarded by a 1 GeV proton beam. Release curves of several isotopes of the same element and production efficiency versus decay half-life are well fitted with the same set of parameters. Comparison of efficiencies for neutron-rich and neutron-deficient Cs isotopes enables separation of the contributions from the primary (p + ²³⁸U) and secondary (n + ²³⁸U) reactions to the production of neutron-rich Cs isotopes. A rather simple calculation of the neutron contribution describes these data fairly well. The FLUKA code describes the primary and secondary-reaction contributions to the Cs isotopes production efficiencies for different targets quite well.     

Target thickness correction in polarized neutron-and-target experiments

Factors influencing the effective degree of neutron beam polarization in thick polarized targets are discussed. The calculation of creroction formulae is outlined.     

Target mass effects in polarized electroproduction

We examine the target mass effects in spin-dependent deep inelastic electroproduction within the framework of Wilson's operator product expansion. Simple analytic expressions for the Nachtmann moments of polarized structure functions g₁ and g₂ are obtained and their Q² evolutions are considered in QCD. The Bjorken and Burkhardt-Cottingham sum rules including target mass effects are derived and the QCD $\text{g}{}^2$ corrections are discussed.     

Dynamic structure function of liquid 3He

The dynamic structure function S(Q, ω) of liquid ³He is evaluated in the impulse approximation, based on a theoretically calculated momentum distribution n(k). The gap of n(k) at the Fermi surface gives rise to discontinuities in the slope of S(Q = const., ω) which may be detectable in neutron- or γ-ray scattering experiments.     

T-violation neutron experiment and polarized3He

An experimental scheme of the spin detailed balance in polarized neutron transmission through a polarized nuclear target is discussed for the T-violation test. The value of the spin detailed balance is estimated by using the data of the scattering amplitudes. The nuclear polarizations of proton,³He and¹³⁹La are discussed for the T-violation experiment.     

The impact of target mass correction on polarized parton distribution functions

Considering the nonzero mass effect of the target in extracting polarized parton distribution functions (PPDFs) in preasymptotic region is not negligible. We extract PPDFs from available proton structure function data and study the numerical effects of target mass corrections (TMCs). PPDFs with and without this correction are compared.     

Nearside-farside analysis of elastic scattering of polarized 3He

An exact decomposition of the scattering amplitudes into the nearside and farside components has been performed for the elastic scattering of 33 MeV ³He particles by nuclei. Calculations have been carried out for ⁴⁰Ca, ⁵⁴Fe, ⁸⁹Y, ^90,91Zr, ^207,208Pb and ²⁰⁹Bi and compared with the available cross section and polarization data. In particular the behaviour of the vector analysing powers is examined. Calculations of the interference between the nearside and farside components demonstrate that the interference plays a significant role in certain mass/energy regions. Regions where the scattering is dominated by the nearside component are discussed.     

Microscopic spin-orbit potentials for polarized 3He elastic scattering

The M3Y double folding model is used to calculate real central and spin-orbit potentials for ³He elastic scattering. These potentials are used to fit cross sections and analysing powers at 33 MeV for targets ranging from ¹⁶O to ⁵⁸Ni. The real central potential needs a normalization factor of about 0.85, but no change in the strength of the spin-orbit potential is necessary. Comparison is made with phenomenological and other microscopic studies of ³He elastic scattering.     

Effective mass of two-dimensional 3He

We use structural information from diffusion Monte Carlo calculations for two-dimensional 3He to calculate the effective mass. Static effective interactions are constructed from the density and spin-structure functions using sum rules. We find that both spin and density fluctuations contribute about equally to the effective mass. Our results show, in agreement with recent experiments, a flattening of the single-particle self-energy with increasing density, which eventually leads to a divergent effective mass.     

Development of a polarized 3He ion source for RHIC

A Polarized ³He Ion Source in under development for use at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The gas will be polarized using metastability exchange optical pumping, then transferred into the Electron Beam Ion Source for ionization. Nuclear polarization of order 70% is expected under optimal conditions, and roughly 10¹¹ doubly-ionized ³He⁺⁺ ions will be created in each 20 μs pulse.     

Relaxation of spin polarized 3He by magnetized ferromagnetic contaminants

In the first in a series of three papers on wall relaxation of spin polarized ³He we have reported on a breakdown of relaxation times which is observed after exposing the ³He containing glass cells to a strong magnetizing field. In this third paper we give a quantitative analysis of this phenomenon, based on magnetic signal detection by means of SQUIDs, on the pressure dependence of relaxation times in magnetized cells, as well as on Monte Carlo simulations of ³He-relaxation in a macroscopic dipole field. Our analysis allows to identify the contaminants as being aggregates of dust-like Fe₃O₄ particles (magnetite) with a radius R ? 10 mR \approx 10~\mu m and a remanent magnetic moment of the order of m ≈O(10 ^-10 ^{-10}~ A m²). The particles are located at or close to the inner glass surface.