The Quark Orbital Angular Momentum in a Light - Cone Representation
نویسنده
چکیده
We perform an analysis of the quark angular momentum in a light-cone representation by taking into account the effect due to the Melosh-Wigner rotation and find that there is a relativistic correction factor connecting the quark orbital angular momentum with the quark model spin distribution: Lq(x) = < ML(x) >∆qQM(x). The quark orbital angular momentum Lq(x) and the quark helicity distribution ∆q(x) are connected to the quark model spin distribution ∆qQM(x) by a relation: 1 2 ∆q(x) + Lq(x) = 1 2 ∆qQM(x), which means that one can decompose the quark model spin contribution ∆qQM(x) by a quark helicity term ∆q(x) plus an orbital angular momentum term Lq(x). There is also a new relation connecting the quark orbital angular momentum with the measurable quark helicity distribution and transversity distribution (δq(x)): ∆q(x)+Lq(x) = δq(x), from which we may have new sum rules connecting the quark orbital angular momentum with the nucleon axial and tensor charges. PACS numbers: 11.55.Hx, 13.60.Hb, 13.88.+e, 14.20.Dh
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