Comment on ''Parton distributions, d/u, and higher twist effects at high x''
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 nucleons 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 deuteron via standard two-body wave function, 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) (US)
- DOE Contract Number:
- AC05-84ER40150
- OSTI ID:
- 753184
- Report Number(s):
- DOE/ER/40150-1310; ADP-99-47/T384; JLAB-THY-99-39; TRN: US0002333
- Resource Relation:
- Other Information: PBD: 1 Nov 1999
- Country of Publication:
- United States
- Language:
- English
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