Comment on Parton distributions, d/u, and higher twist effects at high x''

Technical Report · Mon Nov 01 00:00:00 EST 1999

OSTI ID:5713686

Melnitchouki, W; Afnan, I R; Bissey, F; Thomas, A W

In a recent Letter Yang and Bodek presented results of a new analysis of proton and deuteron structure functions in which the free neutron structure function, F[sub 2][sup n], was extracted at large x. Knowledge of F[sub 2][sup n] is crucial for determining the neutron/proton structure function ratio, whose x [r arrow] 1 limit is sensitive to mechanisms of SU(6) spin-flavor symmetry breaking, and provides one of the fundamental tests of the x dependence of parton distributions in perturbative QCD. Relating nuclear structure functions to those of free nucleus is, however, not straightforward because at large x nuclear effects become quite sizeable. In particular, omitting nuclear binding or off-shell corrections can introduce errors of up to 50% in F[sub 2][sup n]/F[sub 2][sup p] already at x [approximately] 0.75. Rather than follow the conventional procedure of subtracting Fermi motion and binding effects in the deut2048 via standard two-body wave functions, Yang and Bodek instead extract F[sub 2][sup n] by extrapolating the density dependence of the nuclear corrections to the case of the deuteron. Here the authors point out why this approach is likely to be misleading for light nuclei, and correctly applied predicts that the nuclear correction in the deuteron should be zero.

• Research Organization: Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Energy Research (ER) (United States)
• DOE Contract Number: AC05-84ER40150
• OSTI ID: 5713686
• Report Number(s): DOE/ER/40150-1310
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
DEUTERONS
STRUCTURE FUNCTIONS
EMC EFFECT
PARTONS
QUANTUM CHROMODYNAMICS
CORRECTIONS
CHARGED PARTICLES
FUNCTIONS
POSTULATED PARTICLES
QUANTUM FIELD THEORY
ELEMENTARY PARTICLES
FIELD THEORIES
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