485 research outputs found
Flavor asymmetry of polarized antiquark distributions and semi-inclusive DIS
The -expansion of QCD suggests large flavor asymmetries of the
polarized antiquark distributions in the nucleon. This is confirmed by model
calculations in the large- limit (chiral quark-soliton model), which give
sizable results for and . We compute the contributions of
these flavor asymmetries to the spin asymmetries in hadron production in
semi-inclusive deep-inelastic scattering. We show that the large flavor
asymmetries predicted by the chiral quark-soliton model are consistent with the
recent HERMES data for spin asymmetries in charged hadron production.Comment: 21 pages, LaTeX2e, 9 eps figures include
Are there approximate relations among transverse momentum dependent distribution functions?
Certain exact relations among transverse momentum dependent parton
distribution functions due to QCD equations of motion turn into approximate
ones upon the neglect of pure twist-3 terms. On the basis of available data
from HERMES we test the practical usefulness of one such
``Wandzura-Wilczek-type approximation'', namely of that connecting
h_{1L}^{\perp(1)a}(x) to h_L^a(x), and discuss how it can be further tested by
future CLAS and COMPASS data.Comment: 9 pages, 3 figure
Relations between generalized and transverse momentum dependent parton distributions
Recent work suggests non-trivial relations between generalized parton
distributions on the one hand and (naive time-reversal odd) transverse momentum
dependent distributions on the other. Here we review the present knowledge on
such type of relations. Moreover, as far as spectator model calculations are
concerned, the existing results are considerably extended. While various
relations between the two types of parton distributions can be found in the
framework of spectator models, so far no non-trivial model-independent
relations have been established.Comment: 25 pages, 9 figures; Eq. (B17) and typos corrected, identical with
journal versio
Analysis of Laser Ablation of CFRP by Ultra-Short Laser Pulses with Short Wavelength
AbstractMaterial processing of carbon fiber-reinforced polymers (CFRP) by means of shape-cutting technologies is state-of-the-art today. These processes still perform in some applications with lack of part quality such as delamination and low processes productivity. Therefore, laser processing by ultra-short laser pulses has a great potential in material ablation of CFRP. Nevertheless laser process parameters have to be adjusted carefully to reduce extension of heat affected zone (HAZ) and its influence on part quality [1]
Transversity Measurements at COMPASS
The measurement of transverse spin effects in semi-inclusive deep-inelastic
scattering is an important part of the COMPASS physics program. From the
analysis of the 2002-2004 data, new results for the transverse target spin
asymmetry of z-ordered identified pion and kaon pairs are presented. In
addition, a first result for the transverse target spin asymmetry of
exclusively produced rho^0 mesons on the deuteron is shown.Comment: Proceedings of Photon07, Paris, 200
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