Higher twists in polarized DIS and the size of the constituent quark

Details Higher twists in polarized DIS and the size of the constituent quark Higher twists in polarized DIS and the size of the constituent quark

2006-02-15

arxiv.org/abs/hep-ph/0602142v1

Phys.Rev.D73:074016,2006

Physics

High Energy Physics

High Energy Physics - Phenomenology

8 pages, 4 figures

Scientific paper

10.1103/PhysRevD.73.074016

The spontaneous breaking of chiral symmetry implies the presence of a short-distance scale in the QCD vacuum, which phenomenologically may be associated with the "size" of the constituent quark, rho ~ 0.3 fm. We discuss the role of this scale in the matrix elements of the twist-4 and 3 quark-gluon operators determining the leading power (1/Q^2-) corrections to the moments of the nucleon spin structure functions. We argue that the flavor-nonsinglet twist-4 matrix element, f_2^{u - d}, has a sizable negative value of the order rho^{-2}, due to the presence of sea quarks with virtualities ~ rho^{-2} in the proton wave function. The twist-3 matrix element, d_2, is not related to the scale rho^{-2}. Our arguments support the results of previous calculations of the matrix elements in the instanton vacuum model. We show that this qualitative picture is in agreement with the phenomenological higher-twist correction extracted from an NLO QCD fit to the world data on g_1^p and g_1^n, which include recent data from the Jefferson Lab Hall A and COMPASS experiments. We comment on the implications of the short-distance scale rho for quark-hadron duality and the x-dependence of higher-twist contributions.

Affiliated with

Also associated with

No associations

Rating

Higher twists in polarized DIS and the size of the constituent quark does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Higher twists in polarized DIS and the size of the constituent quark, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Higher twists in polarized DIS and the size of the constituent quark will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-255137