Nucleon Structure Functions from ν_µ-Fe Interactions and a Study of the Valence Quark Distribution

Citation

Purohit, Milind Vasant (1984) Nucleon Structure Functions from ν_µ-Fe Interactions and a Study of the Valence Quark Distribution. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/4RBK-RV59. https://resolver.caltech.edu/CaltechTHESIS:04082013-111418042

Abstract

Data were taken in 1979-80 by the CCFRR high energy neutrino experiment at Fermilab. A total of 150,000 neutrino and 23,000 antineutrino charged current events in the approximate energy range 25 < E_v < 250 GeV are measured and analyzed. The structure functions F₂ and xF₃ are extracted for three assumptions about σ_L/σ_T: R = 0., R = 0.1 and R = a QCD based expression. Systematic errors are estimated and their significance is discussed. Comparisons or the X and Q² behaviour or the structure functions with results from other experiments are made.

We find that statistical errors currently dominate our knowledge of the valence quark distribution, which is studied in this thesis. xF₃ from different experiments has, within errors and apart from level differences, the same dependence on x and Q², except for the HPWF results. The CDHS F₂ shows a clear fall-off at low-x from the CCFRR and EMC results, again apart from level differences which are calculable from cross-sections.

The result for the the GLS rule is found to be 2.83 ± .15 ± .09 ± .10 where the first error is statistical, the second is an overall level error and the third covers the rest of the systematic errors. QCD studies of xF₃ to leading and second order have been done. The QCD evolution of xF₃, which is independent of R and the strange sea, does not depend on the gluon distribution and fits yield

ʌ_LO = 88⁺¹⁶³_-78 ⁺¹¹³_-70MeV

The systematic errors are smaller than the statistical errors. Second order fits give somewhat different values of ʌ, although α_s (at Q²₀ = 12.6 GeV²) is not so different.

A fit using the better determined F₂ in place of xF₃ for x > 0.4 i.e., q = 0 in that region, gives

ʌ_LO = 266⁺¹¹⁴_-104 ⁺⁸⁵_-79MeV

Again, the statistical errors are larger than the systematic errors. An attempt to measure R was made and the measurements are described. Utilizing the inequality q(x) ≥ 0 we find that in the region x > .4 R is less than 0.55 at the 90% confidence level.

Thesis Files