SU(2){sub {ital f}} violation in the nucleon`s light sea within the framework of the effective chiral quark theory
- Institut fuer Physik, Universitaet Dortmund, D-44221 Dortmund (Germany)
The violation of SU(2){sub {ital f}} symmetry in the nucleon`s light sea ({ital {bar u}}{ne}{ital {bar d}}) is analyzed within the framework of the effective chiral quark field theory ``matched`` to the QCD-improved parton model: At some {ital ad} {ital hoc} ``matching`` scale {ital Q}{sub 0}{sup 2}, effective chiral quark fields are associated with QCD valence quark partons and a prediction on the SU(2){sub {ital f}}-violating nonsinglet structure function {ital x}({ital {bar d}}{minus}{ital {bar u}}) is deduced from chiral field theory. A simpler model is also presented, which essentially reproduces the chiral result. The sensitivity of {ital x}({ital {bar d}}{minus}{ital {bar u}}) to the choice of the ``matching`` scale {ital Q}{sub 0}{sup 2} is investigated. It is shown that the effective chiral quark field theory cannot explain the experimentally observed NA51 Drell-Yan measurement {ital {bar u}}/{ital {bar d}}=0.51{plus_minus}0.06 at {ital x}=0.18, {ital Q}{sup 2}{congruent}27 GeV{sup 2}, since the predicted shape of {ital x}({ital {bar d}}{minus}{ital {bar u}}) is concentrated in the very small {ital x} region, with {ital Q}{sub 0}{sup 2} restricted to perturbatively accessible values.
- OSTI ID:
- 115923
- Journal Information:
- Physical Review, D, Vol. 52, Issue 5; Other Information: PBD: 1 Sep 1995
- Country of Publication:
- United States
- Language:
- English
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