9 research outputs found
Distribution of valence quarks and light-cone QCD sum rules
A method for calculating the pion structure function directly in terms of
light-cone wave functions is suggested. Taking twist-2 and twist-4 pion
light-cone wave functions into account, it is shown that the QCD sum rule
prediction is in agreement with quark distribution obtained from analysis of
the Drell-Yan process. Twist-4 quark-gluon light-cone wave functions give a
large positive contribution to the pion structure function for x_B<0.2. A new
constraint on the twist-2 pion light-cone wave function is obtained. We argue
that the leading twist pion wave function \phi_\pi(u) \simeq 1 for u=0.3 with
an accuracy of about 20-30%.Comment: 18 pages, Latex, epsfig, 2 figure
Analysis of the proton longitudinal structure function from the gluon distribution function
We make a critical, next-to-leading order, study of the relationship between the longitudinal structure function F
L
and the gluon distribution proposed in Cooper-Sarkar et al. (Z. Phys. C 39:281, 1988; Acta Phys. Pol. B 34:2911 2003), which is frequently used to extract the gluon distribution from the proton longitudinal structure function at small x. The gluon density is obtained by expanding at particular choices of the point of expansion and compared with the hard Pomeron behavior for the gluon density. Comparisons with H1 data are made and predictions for the proposed best approach are also provided