2,192 research outputs found
The Role of Higher Twist in Determining Polarized Parton Densities from DIS data
Different methods to extract the polarized parton densities from the world
polarized DIS data are considered. The higher twist corrections to
the spin dependent proton and neutron structure functions are found to be
non-negligible and important in the QCD analysis of the present experimental
data. Their role in determining the polarized parton densities in the framework
of the different approaches is discussed.Comment: To appear in the Proceedings of the Spin2004 Symposium, Trieste,
11-16 Oct 200
Target Mass Effects in Polarized Deep Inelastic Scattering
The target mass effects in polarized DIS have been studied. It was
demonstrated that taking into account the first order target mass corrections
to g1 a very good approximation of the exact formula is achieved. It was also
shown that their magnitude in the preasymptotic DIS region is small except for
x > 0.65, where their large effect is partially suppressed by the large values
of due to the cut . The difference between the size of the
target mass and higher twist corrections is illustrated.Comment: 8 pages, LaTeX, 5 figures, typo in Eq. 3 corrected, comment added, to
appear in Mod. Phys. Lett.
Some Remarks on Methods of QCD Analysis of Polarized DIS Data
The results on polarized parton densities (PDFs) obtained using different
methods of QCD analysis of the present polarized DIS data are discussed. Their
dependence on the method used in the analysis, accounting or not for the
kinematic and dynamic 1/Q^2 corrections to spin structure function g_1, is
demonstrated. It is pointed out that the precise data in the preasymptotic
region require a more careful matching of the QCD predictions to the data in
this region in order to determine the polarized PDFs correctly.Comment: 14 pages, 8 figure
Theoretical and experimental study of high-pressure synthesized B20-type compounds Mn(Co,Rh)Ge
The search and exploration of new materials not found in nature is one of
modern trends in pure and applied chemistry. In the present work, we report on
experimental and \textit{ab initio} density-functional study of the
high-pressure-synthesized series of compounds Mn(Co,Rh)Ge. These
high-pressure phases remain metastable at normal conditions, therewith they
preserve their inherent noncentrosymmetric B20-type structure and chiral
magnetism. Of particular interest in these two isovalent systems is the
comparative analysis of the effect of (Co) and (Rh) substitution for
Mn, since the orbitals are characterized by higher localization and
electron interaction than the orbitals. The behavior of
Mn(Co,Rh)Ge systems is traced as the concentration changes in the
range . We applied a sensitive experimental and theoretical
technique which allowed to refine the shape of the temperature dependencies of
magnetic susceptibility and thereby provide a new and detailed
magnetic phase diagram of MnCoGe. It is shown that both systems
exhibit a helical magnetic ordering that very strongly depends on the
composition . However, the phase diagram of MnCoGe differs from
that of MnRhGe in that it is characterized by coexistence of two
helices in particular regions of concentrations and temperatures.Comment: 12 pages, 11 figure
- …