Engineering topics
Prok, Yelena
Publications and source records attributed to Prok, Yelena.
High precision determination of the Q^2-evolution of the Bjorken Sum
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Q2-Evolution of the Spin Structure Function g1(x,Q2) of the Proton and the Deuteron
Inelastic scattering using polarized nucleon targets and polarized charged lepton beams allows the extraction of spin structure functions that provide information about the helicity structure of the nucleon. A program designed to study such processes at low and intermediate Q2 for the proton and deuteron has been pursued by the CLAS Collaboration at Jefferson Lab since 1998. The latest inclusive data with high statistical precision were measured using polarized 6 GeV electrons incident on a 2.5\% r.l. polarized ammonia target. In the framework of pQCD, these results can be used to better constrain the polarization of quarks and gluons in the nucleon, as well as high-twist contributions. Some preliminary results will be shown, along with the expected impact on the NLO global fits and phenomenological models of valent spin structure.
Overview of Spin Structure Program at Jefferson Lab
An extensive experimental program to study spin physics at low and moderate four - momentum transfer, Q{sup 2}, has been pursued by Jefferson Lab during the last 15 years, with complementary measurements taking place in all 3 experimental halls. Our inclusive data with high statistical precision and extensive kinematic coverage allow us to better constrain the polarized parton distributions, to accurately determine various moments of spin structure functions, to test the spin content of valent quarks, and to investigate the effects of resonance excitations and higher twist, dominant in this kinematic regime. Our recent semi-inclusive and exclusive measurements have given us new avenues of exploration, and inspired a new generation of experiments planned with 12 GeV beam. Highlights from 6 GeV experimental program are discussed, along with the 12 GeV data projections, and expected impact on the NLO global fits and phenomenological models of valent spin structure.
Spin Physics with CLAS
Inelastic scattering using polarized nucleon targets and polarized charged lepton beams allows the extraction of double and single spin asymmetries that provide information about the helicity structure of the nucleon. A program designed to study such processes at low and intermediate Q{sup 2} for the proton and deuteron has been pursued by the CLAS Collaboration at Jefferson Lab since 1998. Our inclusive data with high statistical precision and extensive kinematic coverage allow us to better constrain the polarized parton distributions and to accurately determine various moments of spin structure function g{sub 1} as a function of Q{sup 2}. The latest results are shown, illustrating our contribution to the world data, with comparisons of the data with NLO global fits, phenomenological models, chiral perturbation theory and the GDH and Bjorken sum rules. The semi-inclusive measurements of single and double spin asymmetries for charged and neutral pions are also shown, indicating the importance of the orbital motion of quarks in understanding of the spin structure of the nucleon.