Unquenched quark model for baryons: magnetic moments, spins and orbital angular momenta

Abstract

We present an unquenched quark model for baryons in which the effects of the quark-antiquark pairs (up, down and strange) are taken into account in an explicit form via a microscopic, QCD-inspired, quark-antiquark creation mechanism. In the present approach, the contribution of the quark-antiquark pairs can be studied for any inital baryon and for any flavor of the pairs. It is shown that, while the inclusion of quark-antiquark pairs does not affect the baryon magnetic moments, it leads to a sizeable contribution of the orbital angular momentum to the spin of the proton and the Lambda hyperon.

10 pages, 3 figures, 4 tables, Physical Review C, in press

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• Spin and orbital angular momentum of the proton
• The Role of 5-quark Components on the Nucleon Form Factors
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• Looking for a gift of Nature: Hadron loops and hybrid mixing
• Spin Content of Lambda in QCD Sum Rules
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