Up and Down Quark Contributions to Spin Content of Λ from Fragmentation

We check the u and d quark contributions to the spin content of the Λ by means of the q → Λ fragmentation and find that the u and d quarks of the Λ are likely positively polarized. The parton distributions in the Λ are given by a successful statistical model which can reproduce and correlate a vast body of polarized and unpolarized structure function and parton distribution data of the nucleon. With the Gribov-Lipatov relation between the quark distributions and fragmentation functions, the longitudinal spin transfer for the Λ production in the polarized charged lepton deep inelastic scattering (DIS) process and the Λ-polarization in the neutrino (antineutrino) DIS process are predicted. The available experimental data suggests that the u and d quark contributions to the spin of the Λ are positive. In addition, our results provide a collateral evidence for the SU(3) symmetry breaking in hyperon semileptonic decays of the octet baryons, which is very important for a deeper understanding of the proton ’spin crisis’. PACS number(s): 14.20.Jn, 13.87.Fh, 13.60.Hb e-mail: [email protected] Mailing address