Nucleon tensor form factors at large Nc

초록

The tensor form factors of the nucleon provide essential information on understanding the internal spin structure of the nucleon. The monopole tensor form factors at Q2 = 0 is identified as the transversity of the nucleon, which is the first moment of the leading-twist transverse parton distribution function h1(x). While it has been extensively studied theoretically and experimentally, other tensor form factors have been much less investigated. In this talk, we present recent results for the nucleon multipole tensor form factors of the nucleon within the framework of a pion mean-field theory. The current approach is based on the effective dynamics arising from spontaneous chiral symmetry breaking and the mean-field picture of the nucleon in the large Nc limit. We find that the tensor charge(g u?d T = 0.99) and the tensor anomalous magnetic moment(κ u+d T = 7.61) are dominated by valence quark contributions. While the tensor quadrupole moment(Q u?d T = ?7.02) shows significant sea quark effects. We examine how these moments vary with changes in soliton size and pion mass, revealing a smooth transition between non-relativistic and relativistic regimes. The results are in good agreement with available lattice QCD data and provide predictions for unmeasured quantities.